钢结构设计外文翻译参考文献
钢结构的应用前景外文翻译
钢结构的应用前景外文翻译外文资料(英文)Steel system because of their own with the light weight, high strength, the construction of such advantages, and the reinforced concrete structure, the more "high, light," the development of three unique advantages. Along with the country's economic construction, the long concrete and masonry structure dominate the market situation is changing. Steel products in the large-span space structure, lightweight steel gantry structure, multi-storey and high-rise residential areas of increasing construction, Application areas are expanding. From the West-East Gas sent, the West-East power transmission and-north water diversion project, the Qinghai-Tibet Railway, the 2008 Olympic venues and facilities, residential steel, development of the western region construction practice, the development of a steel construction industry and the market momentum is emerging in our country.1: the steel market development trend of the past 20 years of reform and opening up and economic development, Steel has to create a system of highly favorable environment for development.(1) from the development of the main steel material foundation : Steel is the development of steel a key factor in development. To meet the needs of the construction market, steel varieties will toward complete standardization of materials direction. Domestic steel for construction steel, in terms of quantity, variety and quality havedeveloped rapidly and hot-rolled H-beam, a color plate, Cold steel production increased significantly, the development of steel to create important conditions. Other steel-Steel, Coated Steel Plate and there has been a marked growth, product quality has been greatly improved. Refractory, weathering steel, hot-rolled thin number of H-beam steel has started a new project in the application, Steel to create the conditions for development.(2) from design, production, construction, professional level look : steel industry after years of development, Steel professional design quality in the practice of continually improving. A number of characteristics with the strength of professional institutes, research and design institutes continuously developed steel design software and new technologies. Currently, many domestic steel design software have been brought forth, they can adapt to light steel structure, the network structure, high-rise steel structures, Thin arched structure design needs. With computer technology in the engineering design of the universal application of steel structure design of the software is getting more sophisticated, To help designers complete structural analysis and design, construction mapping provides a great convenience. Steel manufacturers in the country blossom everywhere, and creating a number of strong leading enterprises. Annual output reaching 10 -- 20 million tons of size alone, more than 10 enterprises that the large domestic steel project mission, They fully equipped with the industry and international enterprises to compete on equal strength. At present,some foreign investment, joint ventures, private sector steel manufacturing enterprises in the fierce market competition winners. From the computer design, mapping, digital control, automated processing and manufacturing industries are in the lead, its products range from the traditional building structures, machinery and equipment, non-standard components, and turnkey facilitiesto the value of housing, Container products, port facilitiesdirectly to the end-user products. Steel industrialized mass production, the installation of a new steel structure engineering endless, and energy-efficient, waterproof, insulating, , and other advanced product set and integrated suite of applications, design and construction of integrated production will be raised the level of the construction industry.(3) the steel works from the view of the performance : the world's third 421-meter high Shanghai Jinmao Tower, is a leading international standard. height of 279 meters in Shenzhen SEG buildings, the span of 1,490 meters Runyang Yangtze River Bridge, span of 550 meters of the Lupu Bridge, the 345-meter-high transmission tower across the Yangtze River, and the Capital International Airport, nest national sports center, many of steel construction system of the important projects, Steel Buildings positive marks top heavy and large-span steel structure of space development.(4) from the domestic steel industry view : China has steel in housing construction light on the application of the industry as arevolution. With domestic industry to become China's new economic development and growth, lightweight steel residential housing industry will be the development of the country. And the housing industry is the prerequisite for dealing with the industrialization of matching new technologies, new materials and new systems. As the steel structure system easy to realize industrialization and standardization of production, and to go along with the wall material can be used in energy conservation, environmental protection of new materials. Therefore, the study of steel structures for residential package technology willgreatly promote domestic industry's rapid development.(5) from the government sector can guide and support : government departments guidance and support, so that as a green steel products and development workers. Steel with the traditional concrete structure, compared with light weight, high strength, good seismic performance advantages. Suitable for live load accounted for a smaller proportion of the total load of the structure, and is more suitable for large-span space structure, tall structures and is suitable for the construction of the soft ground. Is also in line with environmental protection and conservation, intensive use of resources policy, The overall economic benefits to investors increasingly are recognized objective will be to promote the designers and developers they chose steel.2: the steel market outlook of the development trend of steel, China Steel Development has tremendous market potential and prospects for development.(1) since China began in 1996 steel output of over 100 million tons, ranking first in the world. 1998 commissioning of a series of rolling H-beam steel to create a sound material basis. Steel and other materials industries, the development of the steel industry to provide good quality, complete specifications for the material. According to the market demand, the next batch of 23 will be color plate production line, hot-rolled H-beam will also be an increase in production lines, large cold-formed unit will soon be launched. By that time China will produce more than 100 color plates million tons, Hot H-beam more than 100million tons of cold and the large and medium-sized rectangular pipe and tube, in addition to the existing H-beamwelding, plate, Sheet steel and other construction, the steel industry can meet development needs. With steel production and quality continues to rise, their prices are gradually declining. Steel has been a corresponding cost of a more substantial reduction. And the steel structure supporting the use of thermal insulation, corrosion-resistant materials, fire resistant paint, various welding material and bolts, connectivity products and the technology of new materials will also continue to enhance innovation.(2) efficient and new welding technology of welding and cutting equipment and welding application development and application of materials, for the development of steel works to create a good technical condition. In ordinary steel, thin light steel structures, steel structures in tall buildings, the door frame of light steel structure,network structure, pressure plate structure, welding and the connecting bolt, steel concrete composite floor. CFST steel reinforced concrete structure and the structure of the design, construction, Statutes regulating acceptance of industry standards and has more than 20 of this issue. The steel structure norms, in order to constantly improve the system of steel lay the necessary technical foundation and basis.(3) At present, the portal frame light steel structure and pressure plate arch shell structure of cost per unit area, Similar single-storey steel and concrete structure approximately the same, or even lower; and light steel structure of the higher levels of commercialization, production and installation rate will reach each class 700 -- 1000 square meters, much faster than the reinforced concrete structure. In recent years, expansion of the market quickly. Tall steel structure of the composite price is higher than the reinforced concrete structure similar 4% -- 5%, but the seismic performance and Construction is fast, especially in high-rise buildings to be used. In November 1997 the Ministry of Construction issued the "China Building Technology Policy", made clear that development of steel construction, construction steel and construction steel construction technology specific requirements, China's long-term practice of "reasonable Steel" policy to "encourage Steel" policy. Steel will promote the popularization and application play a positive role.(4)the steel industry will see a number of characteristics with the strength of the professional design institutes, research institutes,output over 200,000 tons of large-scale steel factories, dozens offirst-class technology and advanced equipment to the construction and installation enterprises。
建筑结构设计及材料中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)Structure in Design of ArchitectureAnd Structural MaterialWe have and the architects must deal with the spatial aspect of activity, physical, and symbolic needs in such a way that overall performance integrity is assured. Hence, he or she well wants to think of evolving a building environment as a total system of interacting and space forming subsystems. Is represents a complex challenge, and to meet it the architect will need a hierarchic design process that provides at least three levels of feedback thinking: schematic,preliminary, and final.Such a hierarchy is necessary if he or she is to avoid being confused , at conceptual stages of design thinking ,by the myriad detail issues that can distract attention from more basic considerations .In fact , we can say that an architect’s ability to distinguish the more basic form the more detailed issues is essential to his success as a designer .The object of the schematic feed back level is to generate and evaluate overall site-plan, activity-interaction, and building-configuration options .To do so the architect must be able to focus on the interaction of the basic attributes of the site context, the spatial organization, and the symbolism as determinants of physical form. This means that ,in schematic terms ,the architect may first conceive and model a building design as an organizational abstraction of essential performance-space in teractions.Then he or she may explore the overall space-form implications of the abstraction. As an actual building configuration option begins to emerge, it will be modified to include consideration for basic site conditions.At the schematic stage, it would also be helpful if the designer could visualize his or her options for achieving overall structural integrity and consider the constructive feasibility and economic ofhis or her scheme .But this will require that the architect and/or a consultant be able to conceptualize total-system structural options in terms of elemental detail .Such overall thinking can be easily fed back to improve the space-form scheme.At the preliminary level, the architect’s emphasis will shift to the elaboration of his or her more promising schematic design options .Here the architect’s structural needs will shift to approximate design of specific subsystem options. At this stage the total structural scheme is developed to a middle level of specificity by focusing on identification and design of major subsystems to the extent that their key geometric, component, and interactive properties are established .Basic subsystem interaction and design conflicts can thus be identified and resolved in the context of total-system objectives. Consultants can play a significant part in this effort; these preliminary-level decisions may also result in feedback that calls for refinement or even major change in schematic concepts.When the designer and the client are satisfied with the feasibility of a design proposal at the preliminary level, it means that the basic problems of overall design are solved and details are not likely to produce major change .The focus shifts again ,and the design process moves into the final level .At this stage the emphasiswill be on the detailed development of all subsystem specifics . Here the role of specialists from various fields, including structural engineering, is much larger, since all detail of the preliminary design must be worked out. Decisions made at this level may produce feedback into Level II that will result in changes. However, if Levels I and II are handled with insight, the relationship between the overall decisions, made at the schematic and preliminary levels, and the specifics of the final level should be such that gross redesign is not in question, Rather, the entire process should be one of moving in an evolutionary fashion from creation and refinement (or modification) of the more general properties of a total-system design concept, to the fleshing out of requisite elements and details.To summarize: At Level I, the architect must first establish, in conceptual terms, the overall space-form feasibility of basic schematic options. At this stage, collaboration with specialists can be helpful, but only if in the form of overall thinking. At Level II, the architect must be able to identify the major subsystem requirements implied by the scheme and substantial their interactive feasibility by approximating key component properties .That is, the properties of major subsystems need be worked out only in sufficient depth to very the inherent compatibility of their basic form-related and behavioral interaction . This will mean a somewhat more specificform of collaboration with specialists then that in level I .At level III ,the architect and the specific form of collaboration with specialists then that providing for all of the elemental design specifics required to produce biddable construction documents .Of course this success comes from the development of the Structural Material.The principal construction materials of earlier times were wood and masonry brick, stone, or tile, and similar materials. The courses or layers were bound together with mortar or bitumen, a tar like substance, or some other binding agent. The Greeks and Romans sometimes used iron rods or claps to strengthen their building. The columns of the Parthenon in Athens, for example, have holes drilled in them for iron bars that have now rusted away. The Romans also used a natural cement called puzzling, made from volcanic ash, that became as hard as stone under water.Both steel and cement, the two most important construction materials of modern times, were introduced in the nineteenth century. Steel, basically an alloy of iron and a small amount of carbon had been made up to that time by a laborious process that restricted it to such special uses as sword blades. After the invention of the Bessemer process in 1856, steel was available in large quantities at low prices. The enormous advantage of steel is its tensile forcewhich, as we have seen, tends to pull apart many materials. New alloys have further, which is a tendency for it to weaken as a result of continual changes in stress.Modern cement, called Portland cement, was invented in 1824. It is a mixture of limestone and clay, which is heated and then ground into a power. It is mixed at or near the construction site with sand, aggregate small stones, crushed rock, or gravel, and water to make concrete. Different proportions of the ingredients produce concrete with different strength and weight. Concrete is very versatile; it can be poured, pumped, or even sprayed into all kinds of shapes. And whereas steel has great tensile strength, concrete has great strength under compression. Thus, the two substances complement each other.They also complement each other in another way: they have almost the same rate of contraction and expansion. They therefore can work together in situations where both compression and tension are factors. Steel rods are embedded in concrete to make reinforced concrete in concrete beams or structures where tensions will develop. Concrete and steel also form such a strong bond─ the force that unites them─ that the steel cannot slip within the concrete. Still another advantage is that steel does not rust in concrete. Acid corrodes steel, whereas concrete has an alkaline chemical reaction, the opposite of acid.The adoption of structural steel and reinforced concrete caused major changes in traditional construction practices. It was no longer necessary to use thick walls of stone or brick for multistory buildings, and it became much simpler to build fire-resistant floors. Both these changes served to reduce the cost of construction. It also became possible to erect buildings with greater heights and longer spans.Since the weight of modern structures is carried by the steel or concrete frame, the walls do not support the building. They have become curtain walls, which keep out the weather and let in light. In the earlier steel or concrete frame building, the curtain walls were generally made of masonry; they had the solid look of bearing walls. Today, however, curtain walls are often made of lightweight materials such as glass, aluminum, or plastic, in various combinations.Another advance in steel construction is the method of fastening together the beams. For many years the standard method was riveting.A rivet is a bolt with a head that looks like a blunt screw without threads. It is heated, placed in holes through the pieces of steel, and a second head is formed at the other end by hammering it to hold it in place. Riveting has now largely been replaced by welding, the joining together of pieces of steel by melting a steel materialbetween them under high heat.Priestess’s concrete is an improved form of reinforcement. Steel rods are bent into the shapes to give them the necessary degree of tensile strengths. They are then used to priestess concrete, usually by one of two different methods. The first is to leave channels in a concrete beam that correspond to the shapes of the steel rods. When the rods are run through the channels, they are then bonded to the concrete by filling the channels with grout, a thin mortar or binding agent. In the other (and more common) method, the priestesses steel rods are placed in the lower part of a form that corresponds to the shape of the finished structure, and the concrete is poured around them. Priestess’s concrete uses less steel and less concrete. Because it is a highly desirable material.Progressed concrete has made it possible to develop buildings with unusual shapes, like some of the modern, sports arenas, with large spaces unbroken by any obstructing supports. The uses for this relatively new structural method are constantly being developed.建筑中的结构设计及建筑材料建筑师必须从一种全局的角度出发去处理建筑设计中应该考虑到的实用活动，物质及象征性的需求。
与钢结构有关国外书籍
与钢结构有关国外书籍以下是与钢结构有关的一些国外书籍推荐：1. "Design of Steel Structures" by Edwin H. Gaylord, Jr., Charles N. Gaylord, and James E. Stallmeyer2. "Steel Structures: Design and Behavior" by Charles G. Salmon, John E. Johnson, Faris A. Malhas3. "Steel Design" by William T. Segui4. "Structural Steel Design" by Jack C. McCormac and Stephen F. Csernak5. "Steel Structures: Practical Design Studies" by Hassan Ilyas and Sambit Bhattacharya6. "Design of Welded Structures" by Omer W. Blodgett7. "Steel Structures: Analysis and Design for Vibrations and Earthquakes" by Karuna Moy Ghosh8. "Structural Steel Design to Eurocode 3 and AISC Specifications" by Claudio Bernuzzi and Silvio L. Celaschi9. "Designers' Guide to Eurocode 3: Design of Steel Structures" by Leroy Gardner and David A. Nethercot10. "Composite Structures of Steel and Concrete" by Roger P. Johnson and John F. McCarthy这些书籍涵盖了不同方面的钢结构设计和分析，从基础概念到高级应用都有涉及。
钢结构英文文献1
RESEARCH PAPERFatigue strength improvement of steel structures by high-frequency mechanical impact:proposed procedures and quality assurance guidelinesGary Marquis &Zuheir BarsoumReceived:18March 2013/Accepted:29May 2013/Published online:16June 2013#International Institute of Welding 2013Abstract High-frequency mechanical impact (HFMI)has emerged as a reliable,effective,and user-friendly method for post-weld fatigue strength improvement technique for welded structures.During the past decade,46documents on HFMI technology for fatigue improvements have been presented within Commission XIII of the International Institute of Welding (IIW).This paper presents an overview of the lessons learned concerning appropriate HFMI procedures and quality assurance measures.Due to differences in HFMI tools and the wide variety of potential applications,certain details of proper treatment procedures and quantitative quality control measures are presented generally.Specific details should be documented in an HFMI procedure specification for each structure being treated.It is hoped that this guideline will provide a stimulus to researchers working in the field to test and constructively criticize the proposals made with the goal of developing inter-national guidelines relevant to a variety of HFMI technologies and applicable to many industrial sectors.A companion docu-ment presents a fatigue design proposal for HFMI treatment of welded steel structures.The proposal is considered to apply to steel structures of plate thicknesses of 5to 50mm and for yield strengths ranging from 235to 960MPa.Stress assessment may be based on nominal stress,structural hot spot stress,or effec-tive notch stress.Keywords High-frequency mechanical impact (HFMI).Weld toe improvement .Fatigue improvement .Quality control1IntroductionIn 2007,Commission XIII:Fatigue of Welded Components and Structures approved the best practice recommendations concerning post-weld treatment methods for steel and alu-minum structures [1].This recommendation covers four commonly applied post-weld treatment methods:burr grind-ing,tungsten inert gas (TIG)remelting (i.e.,TIG dressing),hammer peening,and needle peening.Burr grinding and TIG remelting are generally classified as geometry improvement techniques for which the primary aim is to eliminate weld toe flaws and to reduce local stress concentration by achieving a smooth transition between the plate and the weld face.Ham-mer peening and needle peening are classified as residual stress modification techniques which eliminate the high ten-sile residual stress in the weld toe region and induce com-pressive residual stresses at the weld toe.These methods also result in a reduced stress concentration at the weld toe.The guidelines also give practical information on how to imple-ment the four improvement technologies,namely good work practices,training,safety,and quality assurance.The improvement techniques described in these recommen-dations are intended to be used both for increasing the fatigue strength of new structures and for the repair or upgrade of existing structures.It has consistently been emphasized that,especially with respect to new structures,weld improvement techniques should never be implemented to compensate for poor design or bad fabrication practices.Instead,improvement measures should be implemented as a means of providing additional strength after other measures have been taken.Doc.IIW-2395,recommended for publication by Commission XIII “Fatigue of Welded Components and Structures.”G.Marquis (*)Department of Applied Mechanics,Aalto University,Espoo,Finlande-mail:gary.marquis@aalto.fiG.Marquis :Z.BarsoumDivision of Lightweight Structures,KTH-Royal Institute of Technology,Stockholm,SwedenWeld World (2014)58:19–28DOI 10.1007/s40194-013-0077-8Simultaneous with the development of the 2007recom-mendations,an increasing number of presentations within Commission XIII focused on high-frequency mechanical impact (HFMI)as a means of improving the fatigue strength of welded structures.From 2002to 2012,46IIW Commis-sion XIII documents reporting HFMI technology or experi-mental studies involving HFMI-based fatigue strength im-provement were presented.HFMI has emerged as a reliable,effective,and user-friendly method for post-weld fatigue strength improvement technique for welded structures.This paper represents an attempt to summarize and synthe-size the knowledge gained both within the IIWand presented in the open international literature concerning quality assurance of HFMI-treated welds.It covers procedure-related and quality assurance-related items such as relevant equipment,proper application procedures,material requirements,safety,training requirements for operators and inspectors,quality controlmeasures,and documentation.All HFMI devices have unique features,and the type of structure being treated (and especially the material grade and welding procedures)will greatly influ-ence the optimal treatment procedures.For this reason,the current document is intended to provide only general guidance especially with respect to operator training,procedures,and inspection.Specific operator training is provided by the tool manufacturers.Specific treatment procedures and requirements can normally be developed in cooperation with the HFMI device manufacturer.It is not the intention of this paper to compare HFMI tools or their efficiency.The goal is only to give an overview of topics which must be considered when preparing an HFMI procedure specification.A companion document [2]presents a fatigue design pro-posal for HFMI treatment of welded steel structures.The design proposal is considered to apply to steel structures of plate thicknesses between 5and 50mm and for yield strengths ranging from 235to 960MPa.Stress assessment may be based on nominal stress,structural hot spot stress,or effective notch stress using stress analysis procedures as defined by the IIW Commission XIII.The design proposal includes a pro-posal for the effect of material strength and a proposal for high R ratio and variable amplitude loading.Several topics for future study with respect to HFMI are given.2High-frequency mechanical impact 2.1BackgroundThe innovation of improving the fatigue strength of welded structures by locally modifying the residual stress state usingas-weldedafter HFMIHFMIAW Fig.1Typical weld toe profile in the as-welded condition and follow-ing HFMI treatment [13,14]Photo courtesy of Applied Ultrasonics.Photo courtesy of Integrity Testing Laboratory (ITL) and Structural Integrity Technologies Inc. (SINTEC)Photo courtesy of Pfeifer Seil-undHebetechnik GmbHPhoto courtesy of PITEC GmbHbc dFig.2Examples of HFMI devices available worldwide.a ultrasonic impact treatment,b ultrasonic peening,c high-frequency impact treatment,and d pneumatic impact treatment (PIT)ultrasonic technology is attributed to scientists and engineers working in the former Soviet Union [3,4].In the past decade,there has been a steady increase in the number of HFMI peening equipment manufacturers and service providers.In 2010,Commission XIII of the IIW introduced the term HFMI as a generic term to describe several related technologies.Alternate power sources are employed,for example,ultrasonic piezoelectric elements,ultrasonic magnetostrictive elements,or compressed air.In all cases,however,the working principal is identical:cylindrical indenters are accelerated against a component or structure with high frequency (>90Hz).The impacted material is highly plastically deformed causing changes in the material microstructure and the local geometry as well as the residual stress state in the region of impact.Various names have been used in literature to describe the devices:ultrasonic impact treatment [5],ultrasonic peeningPhoto courtesy of Integrity Testing Laboratory (ITL) and Structural Integrity Technologies Inc. (SINTEC)a bFig.3a Examples of indenter sizes and configurations and b a double radius indenter developed by the Northern Scientific and Technical Company,Russia for Esonix UIT [18]weld metalHAZweld metalbase metaldefectbase metaldefectdefectshiny defect-free HFMI grooveabcFig.4a Potential introduction of a crack-like defect due to HFMI treatment of a weld with a steep angle or with too large of an indenter and b resulting grooves for a properly treated weld toe (left )and animproperly treated one (right );c micrographs of the induced crack-like defects due toimproper HFMI treatment [18][6],ultrasonic peening treatment[7][8],high-frequency impact treatment[9],pneumatic impact treatment[10],and ultrasonic needle peening[11,12].Figure1shows typical weld profiles in the as-welded condition and following HFMI treatment.In comparison to hammer peening,the operation is considered to be more user-friendly and the spacing between alternate impacts on the work piece is very small resulting in a finer surface finish.2.2EquipmentAs previously mentioned,numerous new HFMI devices have been developed during the past10years,and the number continues to increase.Figure2shows some of the HFMI devices that are in use worldwide.A recent round robin exercise[15]and literature survey[16,17]have iden-tified several HFMI tools which,when properly used,pro-vide the degree of improvement noted in the proposed fa-tigue design guideline for HFMI-treated welded joints[2]. Similar devices can be assigned to this group if they have the same operating principal and are objectively tested and are shown to have the same reliable and beneficial effect on the fatigue strength of welds as in the proposed guideline.Ultrasonic devices consist of a power unit and tool.These normally require compressed air or circulating water to con-trol the temperature of the tool.Other devices known to the authors are pneumatic.The indenters are high-strength steel cylinders,and manufacturers have customized the effective-ness of their own tools by using indenters with different diameters,tip geometries,or multiple indenter configura-tions.Indenters are consumable items which from time to time require replacement or refurbishment.Figure3shows several examples of indenter sizes and configurations which are available.3Procedures3.1Operator trainingWhen delivering new equipment,tool manufacturers normal-ly provide1–2days of operator training.As new applications arise,tool manufactures can provide specialized training or customized procedure specifications.In some cases,HFMI treatment of structures with curvilinear weld toes,e.g.,weld toes in trusses fabricated from circular hollow sections,has proven to be very demanding and will require more expertise than for treating long straight welds or short weld corners.Because HFMI is normally specified as a fatigue strength improvement technology for new structures or during repair and retrofitting operations,it is always essential to consult fatigue experts to ensure that all critical regions in a structure are identified and properly treated.Most fatigue-loaded struc-tures will normally have only a limited number of locations that are critical from a fatigue point of view.Proper identifica-tion of these regions is also important to avoid extra costs and treatment of regions which are not fatigue critical.Additional-ly,the possibility of a failure starting at some other location must always be considered.For instance,if the failure origin is merely shifted from the weld toe to the root,there may be no significant improvement in fatigue life.Some additionalTable1Sample treatment procedure parameters for two HFMI toolsParameter HFMI toolHigh-frequency Impact treatment(HiFIT)[21]Ultrasonic Impact Treatment(UIT)[22,23]Power source Pneumatic Ultrasonic magnetostrictiveNumber of indenters11–4Angle of the axis of the indenters with respect to the plate surface,ϕ(see Fig.5)60°to80°30°to60°[22]40°to80°[23]Angle of the axis of the indenterswith respect to the direction oftravel,ψ(see Fig.5)70°to90°90°(all pins should contact the weld toe)Working speed3to5mm/s5to10mm/s[22]5to25mm/s[23]Other The self-weight of the tool is sufficient[22,23]Minimum of5passes[23]travel speedFig.5Orientation of the HFMI tool with respect to the weld beingtreatedcomments on this topic may be found in the companion fatigue design proposal for HFMI-treated welded joints [2].In the case of multipass welds,it is also needed to treat also the interpass weld toes [19].3.2Weld preparationThe weld cap and adjacent parent material shall be fully de-slagged and wire-brushed or ground to remove all traces of oxide,scale,spatter,and other foreign material.HFMI treat-ment of a convex weld profile or of a weld with a large weld angle can cause the plastically deformed metal to fold over the original weld toe and leave a crack-like lap feature that resembles a cold lap.The weld bead profile should meet the acceptance limits for the weld profile quality level B in ISO 5817[20].This requirement does not imply that the weld must fulfill all quality level B criteria in ISO 5817.However,weld profile-related quality criteria in ISO 5817need to be evaluated.These include undercuts (imperfection 1.7),ex-cessive overfill (imperfection 1.19),excessive concavity (imperfection 1.10)and overlaps (imperfection 1.13).If the weld profile does not comply with these acceptance limits,light grinding before treatment may be desired.It should be noted,however,that HFMI treatment is most effective when the weld toe region itself is treated.Thus,grinding operations which make it difficult for the HFMI operator to distinguish the exact location of the weld toe should be avoided.De-cisions on the need for weld grinding and the proper grinding procedure should be agreed on with an experienced HFMI operator.The need for a proper weld profile before HFMI is illus-trated in Fig.4a which illustrates the formation of a crack-like defect due to improper contact between the indenter and theweld toe.Surface inspection of such a defect reveals a dark crack-like line in the middle of the otherwise smooth and shiny HFMI groove as seen in Fig.4b .Figure 4c shows section micrographs of these defects.The resulting fatigue performance of a welded joint with such defects may actually be less than that of the original as-welded joint.The same type of flaw has been observed in welds with adequate profiles but with improper indenter selection or too severe treatment,i.e.,too many passes over the same region.For specific applica-tions,it may be needed to consult with the HFMI tool manu-facturer in order to select the proper treatment procedures and optimal indenter configuration to avoid crack-like defects.3.3Safety aspectsNoise and vibration from HFMI is significantly less than for more traditional peening equipment.HFMI treatment can be a noisy operation,and it is essential that the operator and others working in the vicinity should use ear protection.Normal protective clothing for working in a fabrication shop is ade-quate but it should include approved eye protection.Vibration from HFMI equipment is usually low enough so that contin-uous operation is permitted without restriction during a nor-mal 8-h work shift.If the vibration of the specific HFMI tool has not been determined,it may be needed to limit the amount of time per day for performing HFMI treatment.Equipment-specific safety issues are provided by the tool manufacturers.3.4Weld toe treatmentSpecific weld toe treatment procedures will vary greatly from application to application and depending on the tool being used.Thus,only general topics can be covered.Table 1weld metalbase metalFig.6The HFMI groove in a shows a thin crack-like defect which reduces or eliminates the effectiveness of the HFMI treatment [21].b shows a defect-free groove but with an individual indenter strike still visible,indicating the need for additional passes [27]Fig.7a Proper profile of an HFMI groove which has no sharp or crack-like features and b an improper HFMI groove profile which shows thepresence of a crack-like feature due to plastic deformation of the materialprovides example procedure parameters for two HFMI tools with alternate power sources and indenter configurations (see also Fig.5).Excessive treatment of a weld toe should be avoided.The American Association of State Highway and Transportation Officials (AASHTO)have developed sample procedures [23]based on research performed at Lehigh University,USA [24,25].3.5Other treatment conditionsHeat treatment and hot-dip galvanizing should not be performed after HFMI.HFMI introduces beneficial compressive residual stresses which may be reduced or eliminated by these opera-tions.The fatigue strength of an HFMI-treated component which is then treated by hot-dip galvanizing may have improved strength with respect to a hot-dip galvanized component without HFMI.In such a case,the fatigue design proposal for HFMI treatment of welded steel structures [2]cannot be used and fatigue strength should be determined by fatigue testing.Static local stresses near a weld toe are the result of both welding residual stresses and dead loads on a structure.If the tensile residual stresses following welding are close to theyield strength of the material (as is normally assumed),the addition of a dead load will cause local yielding but will not result in increased maximum local stresses.HFMI treatment following the application of the dead load will produce compressive residual stresses in the critical weld toe region.On the other hand,if HFMI treatment is performed before the dead loads are applied,the compressive residual stresses following treatment may be partially counteracted by the local tensile stresses due to the dead load.Thus,if significant dead loads are present on the structure during normal usage,it is recommended that the dead loads are applied prior to treatment,i.e.,erect the structure with the welds untreated and then perform the treatment on-site [26].4Quality controlVisual inspection of the HFMI groove following treatment consists of both qualitative and quantitative measures of the treated area.4.1Qualitative measuresVisual inspection following treatment includes an evaluation of the quality of the groove and the groove depth.The resulting groove must be smooth along all defined welds.A smooth and shiny groove without lines is one characteris-tic of a properly treated weld toe (see Fig.4b ).No thin line representing an original fusion line should be visible in the groove.A thin crack-like line such as that shown in Fig.6a is an indication that the weld fusion line has not been treated as previously described in section 3.2.Dye penetrant or simple magnification with a ×3to×10magnifying glass with proper surface illumination (minimum 350lx)will be helpful in assessing the quality of the HFMI groove.Figure 6b shows an HFMI groove which is not smooth and showsindicationsFig.8The HFMI indentation depth following treatment should be 0.2–0.6mm while the resulting width is typically 2–5mmgapFig.9Depth inspection using simple gauges [21].The gap between the base plate and the gauge in the right-hand picture indicates that 0.2mm has not been achievedof individual indenter strikes.Additional passes of the tool would be required to obtain a smooth finish.The HFMI groove must be continuous with no breaks.If the treatment cannot be performed without interruption,e.g.,long welds or around corners,it is recommended that the operation be restarted at least 10mm behind the stop posi-tion.No indications of undercut or porosity in the HFMI area can be visible.Similar qualitative measures have been spec-ified by AASHTO [23,26].HFMI produces significant local cold-forming of the ma-terial near the weld fusion line.If the indenters are directed excessively in one specific location,the resulting plastic displacement of the metal can result in a crack-like featureat the side of the HFMI groove as shown in Fig.7.Failures of this type have been occasionally observed but not studied systematically [28].The crack-like feature should be re-moved by light grinding and the weld toe should be retreated.4.2Quantitative measuresThe depth of the groove is an excellent indicator of the extent of HFMI treatment [29].Depending on the yield strength of the steel and the size of the indenters,typically the optimum HFMI groove will be 0.2–0.6mm in depth and the width will be 3–6mm,see Fig.8[23,26,30,31].However,it should be noted that no single groove dimension is optimal in all situations.AFig.10An example of a HFMI-PS (LETSGlobal —Ultrasonic Peening Procedure Specification)developed for each weld in a structures as a quality assurance measure [19]welded structure with relatively deep undercuts at the weld toe of which requires light grinding of the weld toe before HFMI will necessarily have deeper grooves following HFMI.Also, HFMI grooves in high-strength steel structures will typically be shallower and narrower than grooves in low-strength steel. Groove depth can be checked relatively easily by using simple depth gauges such as is shown in Fig.9.Calipers can be used to measure the width of the groove.The center of the HFMI groove should correspond to the fusion line of the weld.The portion of the HFMI groove in the weld metal must be between 25and75%of the total HFMI groove width[30].In large,complex welded structures,welding heat input will not always be constant along a long weld.For this reason, material hardness at the weld toe may vary and the HFMI treatment may need to be systematically adapted.HFMI groove dimension checks will be needed at regular intervals.4.3DocumentationAn HFMI procedure specification(HFMI-PS)similar to a welding procedure specification should be prepared for the HFMI treatment.The HFMI-PS includes information concerning the component being treated;base and filler material;HFMI equipment type and power settings;number,size and shape of the indenters to be used;special inspection requirements includ-ing HFMI groove dimension,etc.Lopez Martinez and Haagensen have developed an HFMI-PS template which is prepared for each weld in a structure[19],see Fig.10.4.4CalibrationAll of the available HFMI devices have variable power settings which can be adjusted depending on the material being treated and the indenter configuration.As a quality assurance measure,the intensity should be recorded in the HFMI-PS.In some cases,HFMI tool calibration is accom-plished during treatment of a welded joint by ensuring that the resulting HFMI groove dimensions for a specified power setting and treatment time are consistent with predetermined limits.For its own tools,PITEC and other companies have developed a simple test for measuring the intensity of HFMI treatment[32].The concept is similar to that used in the well-known Almen strip test which is common for measuring the intensity of shot peening and blasting operations.The simple equipment used for this test is shown in Fig.11.Residual stress-free flat strips(200mm×20mm×4mm)of S355J2 steel are held in a special fixture.HFMI is applied to the strip via the longitudinal slots.Four to five passes with an HFMI tool with a predefined power setting are applied.Curvature of the strip,which is related to the resulting residual stress,is measured by means of a dial gauge.5DiscussionA great deal of experimental evidence has demonstrated that HFMI can significantly improve the fatigue strength of welded structures.Rarely,but on occasion,test results have been presented which indicate that the HFMI treatment pro-cedure has not been fully understood and/or implemented incorrectly.While HFMI can be considered as environmen-tally friendly,safe,and relatively easy to apply,operators must still exercise safe work practices and understand the equipment and the nature of the post-weld operation which is being imparted to a welded structure.Longitudinal stotsFixtureSteel strip Dial gaugeFig.11Equipment needed to perform the Almen test-type calibration procedure developed by PITEC[32]This paper presents an overview of the lessons learned concerning appropriate HFMI procedures and quality assur-ance measures as discussed primarily with the IIW.Due to differences in the HFMI tools and the wide variety of poten-tial applications,certain details of proper treatment proce-dures and quantitative quality control measures are presented generally.For example,the HFMI groove depth,which is considered to be an important quantitative quality assurance measure,can optimally vary from0.2mm to as much as 0.6mm depending on the steel being treated and the geom-etry of the indenter(s).Travel speed,the number of passes needed to obtain optimal treatment,and the angle of the axis of the indenters with respect to the plate surface(see Fig.5) will also vary significantly depending on the tool being used. Specific details of the treatment process and inspection re-quirements for a structure or component should be docu-mented in an HFMI procedure specification.Qualitative inspection requirements including the shiny appearance of the HFMI groove,the lack of any crack-like lines in the groove,the position of the groove with respect to the original weld fusion line,and the continuity of the HFMI groove are applicable to all tool types and for all welds.Weld preparation prior to HFMI treatment and safety items can also be considered to be universally applicable.It is hoped that this guideline will provide a stimulus to researchers working in the field to test and constructively criticize the proposals made with the goal of developing an international guideline relevant to a variety of HFMI tech-nologies and applicable for many industrial sectors.There are a number of questions which cannot yet be reliably answered nor included into guidelines.These remain as areas for further research studies.For example,what type of repair procedures can be recommended if a crack-like defect(see Fig.6a)still exists after five HFMI passes?When do crack-like defects such as those shown in Fig.7become significant and how should these be removed?Is it possible to develop a catalog of suitable treatment processes for common HFMI devices and typical construction situations? The influence of fabrication processes following HFMI treat-ment also need to be better quantified.For example,if weld repair is required,at what distance from the weld repair does HFMI treatment remain unaffected.What is the quantitative influence of galvanizing on HFMI-treated structures?In refurbishment situations,what is the precise role of the service load history prior to HFMI treatment?6ConclusionsA proposal for procedures and quality assurance for HFMI-treated welded joints in steel has been presented.It was developed based on discussions,presentations,and experi-mental evidence published within Commission XIII of the IIW.The proposal has been reviewed by several HFMI tool manufacturers and has been compared to other available technical documents.The proposal includes brief descrip-tions of HFMI equipment,operator training,weld prepara-tion,safety aspects,treatment procedures,qualitative and quantitative quality control measures,procedure documen-tation,and equipment.Certain details of the precise treat-ment procedures and quantitative quality control measures can vary greatly depending on the specific welded structure being treated.A companion document presents a fatigue design proposal for HFMI treatment of welded steel struc-tures.The proposal is considered to apply to steel structures of plate thicknesses from5to50mm and for yield strengths ranging from235to960MPa.Stress assessment may be based on nominal stress,structural hot spot stress,or effec-tive notch stress.Acknowledgments Support for this work has been partially provided by the LIGHT research program of the Finnish Metals and Engineering Competence Cluster,the Finnish Funding Agency for Technology and Innovation,and the European Union’s Research Fund for Coal and Steel Research Programme under grant agreement no RFSR-CT-2010-00032:“Improving the fatigue life of high strength steel welded struc-tures by post weld treatments and specific filler material.”Cooperation with HFMI companies Pfeifer Seil-und Hebetechnik GmbH,Germany; Structural Integrity Technologies Inc.,Canada;LETS Global AB,Swe-den,Applied Ultrasonics,the Netherlands;and PITEC GmbH,Germa-ny are acknowledged.References1.Haagensen PJ,Maddox SJ(2012)IIW recommendations on postweld fatigue life improvement of steel and aluminium structures.Woodhead Publishing Ltd.,Cambridge2.Marquis GB,Mikkola E,Yildirim HC,Barsoum Z(2013)Fatiguestrength improvement of steel structures by HFMI:proposed fa-tigue assessment guidelines.International Institute of Welding, Paris,IIW Document XIII-2452r1-133.Statnikov ES,Shevtsov UM,Kulikov VF(1977)Ultrasonic impacttool for welds strengthening and reduction of residual stresses.Publ Sci Works:Metall SEVMASH,USSR92:27–28(in Russian)4.Kudryavtsev YF,Trufyakov VI,Mikheev PP,Statnikov EF,Burenko AG,Dobykina EK(1994)Increasing the fatigue strength of welded joints in cyclic compression.International Institute of Welding,Paris,Document XIII-1596-945.Applied Ultrasonics.In:/.6.Integrity Testing Laboratory Inc.In:/.7.Lets Global.In:/.8.Huo L,Wang D,Zhang Y(2005)Investigation of the fatiguebehaviour of the welded joints treated by TIG dressing and ultra-sonic peening under variable-amplitude load.Int J Fatigue27:95–1019.Pfeifer.In:http://www.pfeifer.de/.10.Pitec.In:/.11.Sonats.In:/.12.Bousseau M,Millot T(2006)Fatigue life improvement of weldedstructures by UNP compared to TIG dressing.International Insti-tute of Welding,Paris,Document XIII-2125-06。
钢结构毕业设计论文(中英)
浅谈钢结构现在，钢以一种或者形式逐渐成为全球应用最广泛的建筑材料。
对于建筑构架，除了很特殊的工程之外，钢材几乎已经完全取代了木材，总的来说，对于桥梁和结构骨架，钢也逐渐代替了铸铁和炼铁。
最为现代最重要的建筑材料，钢是在19世纪被引入到建筑中的，钢实质上是铁和少量碳的合金，一直要通过费力的过程被制造，所以那时的钢仅仅被用在一些特殊用途，例如制造剑刃。
1856年贝塞麦炼钢发发明以来，刚才能以低价大量获得。
刚最显著的特点就是它的抗拉强度，也就是说，当作用在刚上的荷载小于其抗拉强度荷载时，刚不会失去它的强度，正如我们所看到的，而该荷载足以将其他材料都拉断。
新的合金又进一步加强了钢的强度，与此同时，也消除了一些它的缺陷，比如疲劳破坏。
钢作为建筑材料有很多优点。
在结构中使用的钢材成为低碳钢。
与铸铁相比，它更有弹性。
除非达到弹性极限，一旦巴赫在曲调，它就会恢复原状。
即使荷载超出弹性和在很多，低碳钢也只是屈服，而不会直接断裂。
然而铸铁虽然强度较高，却非常脆，如果超负荷，就会没有征兆的突然断裂。
钢在拉力（拉伸）和压力作用下同样具有高强度这是钢优于以前其他结构金属以及砌砖工程、砖石结构、混凝土或木材等建筑材料的优点，这些材料虽然抗压，但却不抗拉。
因此，钢筋被用于制造钢筋混凝土——混凝土抵抗压力，钢筋抵抗拉力。
在钢筋框架建筑中，用来支撑楼板和墙的水平梁也是靠竖向钢柱支撑，通常叫做支柱，除了最底层的楼板是靠地基支撑以外，整个结构的负荷都是通过支柱传送到地基上。
平屋面的构造方式和楼板相同，而坡屋顶是靠中空的钢制个构架，又成为三角形桁架，或者钢制斜掾支撑。
一座建筑物的钢构架设计是从屋顶向下进行的。
所有的荷载，不管是恒荷载还是活荷载（包括风荷载），都要按照连续水平面进行计算，直到每一根柱的荷载确定下来，并相应的对基础进行设计。
利用这些信息，结构设计师算出整个结构需要的钢构件的规格、形状，以及连接细节。
对于屋顶桁架和格构梁，设计师利用“三角剖分”的方法，因为三角形是唯一的固有刚度的结构。
钢结构桥梁中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)Recent Research and Design Developments in Steel and Composite Steel-concrete Structures in USAThe paper will conclude with a look toward the future of structural steel research.1. Research on steel bridgesThe American Association of State Transportation and Highway Officials (AASTHO) is the authority that promulgates design standards for bridges in the US. In 1994 it has issued a new design specification which is a Limit States Design standard that is based on the principles of reliability theory. A great deal of work went into the development of this code in the past decade, especially on calibration and on the probabilistic evaluation of the previous specification. The code is now being implemented in the design office, together with the introduction of the SystemeInternationale units. Many questions remain open about the new method of design, and there are many new projects that deal with the reliability studies of the bridge as a system. One such current project is a study to develop probabilistic models, load factors, and rational load-combination rules for the combined effects of live-load and wind; live-load and earthquake; live-load, wind and ship collision; and ship collision, wind, and scour. There are also many field measurements of bridge behavior, using modern tools of inspection and monitoring such as acoustic emission techniques and other means of non-destructive evaluation. Such fieldwork necessitates parallel studies in the laboratory, and the evolution of ever more sophisticated high-technology data transmission methods.America has an aging steel bridge population and many problems arise from fatigue and corrosion. Fatigue studies on full-scale components of the Williamsburg Bridge in New York have recently been completed at Lehigh University. A probabilistic AASTHO bridge evaluation regulation has been in effect since 1989, and it is employed to assess the future useful life of structures using rational methods that include field observation and measurement together with probabilistic analysis. Such an activity also fosters additional research because many issues are still unresolved. One such area is the study of the shakedown of shear connectors in composite bridges. This work has been recently completed at the University of Missouri.In addition to fatigue and corrosion, the major danger to bridges is the possibility of earthquake induced damage. This also has spawned many research projects on the repair and retrofit of steel superstructures and the supporting concrete piers. Many bridges in the country are being strengthened for earthquake resistance. One area that is receiving much research attention is the strengthening of concrete piers by "jacketing" them by sheets of high-performance reinforced plastic.The previously described research deals mainly with the behavior of existing structures and the design of new bridges. However, there is also a vigorous activity on novel bridge systems. This research is centered on the application of high-performance steels for the design of innovative plate and box-girder bridges, such as corrugated webs, combinations of open and closed shapes, and longer spansfor truss bridges. It should be mentioned here that, in addition to work on steel bridges, there is also very active research going on in the study of the behavior of prestressed concrete girders made from very high strength concrete. The performance and design of smaller bridges using pultruded high-performance plastic composite members is also being studied extensively at present. New continuous bridge systems with steel concrete composite segments in both the positive moment and the negative moment regions are being considered. Several researchers have developed strong capabilities to model the three-dimensional non-linear behavior of individual plate girders, and many studies are being performed on the buckling and post-buckling characteristics of such panion experimental studies are also made,especially on members built from high-performance steels. A full-scale bridge of such steel has been designed, and will soon be constructed and then tested under traffic loading. Research efforts are also underway on the study of the fatigue of large expansion joint elements and on the fatigue of highway sign structures.The final subject to be mentioned is the resurgence of studies of composite steel concrete horizontally curved steel girder bridges. A just completed project at the University of Minnesota monitored the stresses and the deflections in a skewed and curved bridge during all phases of construction, starting from the fabrication yard to the completed bridge.~ Excellent correlation was found to exist between the measured stresses and deformations and the calculated values. The stresses and deflections during construction were found to be relatively small, that is, the construction process did not cause severe trauma to the system. The bridge has now been tested under service loading, using fully loaded gravel trucks, for two years, and it will continue to be studied for further years to measure changes in performance under service over time. A major testing project is being conducted at the Federal Highway Administration laboratory in Washington, DC, where a half-scale curved composite girder bridge is currently being tested to determine its limit states. The test-bridge was designed to act as its own test-frame, where various portions can be replaced after testing. Multiple flexure tests, shear tests, and tests under combined bending and shear, are thus performed with realistic end-conditions and restraints. The experiments arealso modeled by finite element analysis to check conformance between reality and prediction. Finally design standards will be evolved from the knowledge gained. This last project is the largest bridge research project in the USA at the present time.From the discussion above it can be seen that even though there is no large expansion of the nation's highway and railroad system, there is extensive work going on in bridge research. The major challenge facing both the researcher and the transportation engineer is the maintenance of a healthy but aging system, seeing to its gradual replacement while keeping it safe and serviceable.2. Research on steel members and framesThere are many research studies on the strength and behavior of steel building structures. The most important of these have to do with the behavior and design of steel structures under severe seismic events. This topic will be discussed later in this paper. The most significant trends of the non-seismic research are the following: "Advanced" methods of structural analysis and design are actively studied at many Universities, notably at Cornell, Purdue, Stanford, and Georgia Tech Universities. Such analysis methods are meant to determine the load-deformation behavior of frames up to and beyond failure, including inelastic behavior, force redistribution, plastic hinge formation, second-order effects and frame instability. When these methods are fully operational, the structure will not have to undergo a member check, because the finite element analysis of the frame automatically performs this job. In addition to the research on the best approaches to do this advanced analysis, there are also many studies on simplifications that can be easily utilized in the design office while still maintaining the advantages of a more complex analysis. The advanced analysis method is well developed for in-plane behavior, but much work is yet to be done on the cases where bi-axial bending or lateraltorsional buckling must be considered. Some successes have been achieved, but the research is far from complete.Another aspect of the frame behavior work is the study of the frames with semirigid joints. The American Institute of Steel Construction (AISC) has published design methods for office use. Current research is concentrating on the behavior ofsuch structures under seismic loading. It appears that it is possible to use such frames in some seismic situations, that is, frames under about 8 to 10 stories in height under moderate earthquake loads. The future of structures with semi-rigid frames looks very promising, mainly because of the efforts of researchers such as Leon at Georgia Tech University, and many others.Research on member behavior is concerned with studying the buckling and post buckling behavior of compact angle and wide-flange beam members by advanced commercial finite element programs. Such research is going back to examine the assumptions made in the 1950s and 1960s when the plastic design compactness and bracing requirements were first formulated on a semi-empirical basis. The non-linear finite element computations permit the "re-testing" of the old experiments and the performing of new computer experiments to study new types of members and new types of steels. White of Georgia Tech is one of the pioneers in this work. Some current research at the US military Academy and at the University of Minnesota by Earls is discussed later in this report. The significance of this type of research is that the phenomena of extreme yielding and distortion can be efficiently examined in parameter studies performed on the computer. The computer results can be verified with old experiments, or a small number of new experiments. These studies show a good prospect fornew insights into old problems that heretofore were never fully solved.3. Research on cold-formed steel structuresNext to seismic work, the most active part of research in the US is on cold-formed steel structures. The reason for this is that the supporting industry is expanding, especially in the area of individual family dwellings. As the cost of wood goes up, steel framed houses become more and more economical. The intellectual problems of thin-walled structures buckling in multiple modes under very large deformations have attracted some of the best minds in stability research. As a consequence, many new problems have been solved: complex member stiffening systems, stability and bracing of C and Z beams, composite slabs, perforated columns, standing-seam roof systems, bracing and stability of beams with very complicatedshapes, cold-formed members with steels of high yield stress-to-tensile strength ratio, and many other interesting applications. The American Iron and Steel Institute (AISI) has issued a new expanded standard in 1996 that brought many of these research results into the hands of the designer.4. Research on steel-concrete composite structuresAlmost all structural steel bridges and buildings in the US are built with composite beams or girders. In contrast, very few columns are built as composite members. The area of composite Column research is very active presently to fill up the gap of technical information on the behavior of such members. The subject of steel tubes filled with high-strength concrete is especially active. One of the aims of research performed by Hajjar at the University of Minnesota is to develop a fundamental understanding of the various interacting phenomena that occur in concrete-filled columns and beam-columns under monotonic and cyclic load. The other aim is to obtain a basic understanding of the behavior of connections of wide-flange beams to concrete filled tubes.Other major research work concerns the behavior and design of built-up composite wide-flange bridge girders under both positive and negative bending. This work is performed by Frank at the University of Texas at Austin and by White of Georgia Tech, and it involves extensive studies of the buckling and post-buckling of thin stiffened webs. Already mentioned is the examination of the shakedown of composite bridges. The question to be answered is whether a composite bridge girder loses composite action under repeated cycles of loads which are greater than the elastic limit load and less than the plastic mechanism load. A new study has been initiated at the University of Minnesota on the interaction between a semi-rigid steel frame system and a concrete shear wall connected by stud shear connectors.5. Research on connectionsConnection research continues to interest researchers because of the great variety of joint types. The majority of the connection work is currently related to the seismic problems that will be discussed in the next section of this paper. The most interest in non-seismic connections is the characterization of the monotonic moment-rotationbehavior of various types of semi-rigid joints.6. Research on structures and connections subject to seismic forcesThe most compelling driving force for the present structural steel research effort in the US was the January 17, 1994 earthquake in Northridge, California, North of Los Angeles. The major problem for steel structures was the extensive failure of prequalified welded rigid joints by brittle fracture. In over 150 buildings of one to 26 stories high there were over a thousand fractured joints. The buildings did not collapse, nor did they show any external signs of distress, and there were no human injuries or deaths. A typical joint is shown in Fig. 2.2.1.In this connection the flanges of the beams are welded to the flanges of the column by full-penetration butt welds. The webs are bolted to the beams and welded to the columns. The characteristic features of this type of connection are the backing bars at the bottom of the beam flange, and the cope-holes left open to facilitate the field welding of the beam flanges. Fractures occurred in the welds, in the beam flanges, and/or in the column flanges, sometimes penetrating into the webs.Once the problem was discovered several large research projects were initiated at various university laboratories, such as The University of California at San Diego, the University of Washington in Seattle, the University of Texas at Austin, Lehigh University at Bethlehem, Pennsylvania, and at other places. The US Government under the leadership of the Federal Emergency Management Agency (FEMA) instituted a major national research effort. The needed work was deemed so extensivethat no single research agency could hope to cope with it. Consequently three California groups formed a consortium which manages the work:(1) Structural Engineering Association of California.(2) Applied Technology Council.(3) California Universities for Research in Earthquake Engineering.The first letters in the name of each agency were combined to form the acronym SAC, which is the name of the joint venture that manages the research. We shall read much from this agency as the results of the massive amounts of research performed under its aegis are being published in the next few years.The goals of the program are to develop reliable, practical and cost-effective guidelines for the identification and inspection of at-risk steel moment frame buildings, the repair or upgrading of damaged buildings, the design of new construction, and the rehabilitation of undamaged buildings.~ As can be seen, the scope far exceeds the narrow look at the connections only. The first phase of the research was completed at the end of 1996, and its main aim was to arrive at interim guidelines so that design work could proceed. It consisted of the following components:~ A state-of-the-art assessment of knowledge on steel connections.~ A survey of building damage.~ The evaluation of ground motion.~ Detailed building analyses and case studies.~ A preliminary experimental program.~ Professional training and quality assurance programs.~ Publishing of the Interim Design Guidelines.A number of reports were issued in this first phase of the work. A partial list of these is appended at the end of this paper.During the first phase of the SAC project a series of full-scale connection tests under static and, occasionally, dynamic cyclic tests were performed. Tests were of pre-Northridge-type connections (that is, connections as they existed at the time of the earthquake), of repaired and upgraded details, and of new recommendedconnection details. A schematic view of the testing program is illustrated in Fig.2.2.2 Some recommended strategies for new design are schematically shown in Fig. 2.2.3.Fig. 2.2.3 some recommended improvements in the interim guidelinesThe following possible causes, and their combinations, were found to have contributed to tile connection failures:~ Inadequate workmanship in the field welds.~ Insufficient notch-toughness of the weld metal.~ Stress raisers caused by the backing bars.~ Lack of complete fusion near the backing bar.~ Weld bead sizes were too big.~ Slag inclusion in the welds.While many of the failures can be directly attributed to the welding and thematerial of the joints, there are more serious questions relative to the structural system that had evolved over the years mainly based on economic considerations.' The structural system used relatively few rigid-frames of heavy members that were designed to absorb the seismic forces for large parts of the structure. These few lateral-force resistant frames provide insufficient redundancy. More rigid-frames with smaller members could have provided a tougher and more ductile structural system. There is a question of size effect: Test results from joints of smaller members were extrapolated to joints with larger members without adequate test verification. The effect of a large initial pulse may have triggered dynamic forces that could have caused brittle fracture in joints with fracture critical details and materials. Furthermore, the yield stress of the beams was about 30% to 40% larger than the minimum specified values assumed in design, and so the connection failed before the beams, which were supposed to form plastic hinges.As can be seen, there are many possible reasons for this massive failure rate, and there is blame to go around for everyone. No doubt, the discussion about why and how the joints failed will go on for many more years. The structural system just did not measure up to demands that were more severe than expected. What should be kept in mind, however, is that no structure collapsed or caused even superficial nonstructural damage, and no person was injured or killed. In the strictest sense the structure sacrificed itself so that no physical harm was done to its users. The economic harm, of course, was enormous.7. Future directions of structural steel research and conclusionThe future holds many challenges for structural steel research. The ongoing work necessitated by the two recent earthquakes that most affected conventional design methods, namely, the Northridge earthquake in the US and the Kobe earthquake in Japan, will continue well into the first decade of the next Century. It is very likely that future disasters of this type will bring yet other problems to the steel research community. There is a profound change in the philosophy of design for disasters: We can no longer be content with saving lives only, but we must also design structures which will not be so damaged as to require extensive repairs.Another major challenge will be the emergence of many new materials such as high-performance concrete and plastic composite structures. Steel structures will continually have to face the problem of having to demonstrate viability in the marketplace. This can only be accomplished by more innovative research. Furthermore, the new comprehensive limit-states design codes which are being implemented worldwide, need research to back up the assumptions used in the theories.Specifically, the following list highlights some of the needed research in steel structures:Systems reliability tools have been developed to a high degree of sophistication. These tools should be applied to the studies of bridge and building structures to define the optimal locations of monitoring instruments, to assess the condition and the remaining life of structures, and to intelligently design economic repair and retrofit operations.New developments in instrumentation, data transfer and large-scale computation will enable researchers to know more about the response of structures under severe actions, so that a better understanding of "real-life" behavior can be achieved.The state of knowledge about the strength of structures is well above the knowledge about serviceability and durability. Research is needed on detecting and preventing damage in service and from deterioration.The areas of fatigue and fracture mechanics on the one hand, and the fields of structural stability on the other hand, should converge into a more Unified conceptual entity.The problems resulting from the combination of inelastic stability and low-cycle fatigue in connections subject to severe cyclic loads due to seismic action will need to be solved.The performance of members, connections and connectors (e.g., shear connectors) under severe cyclic and dynamic loading requires extensive new research, including shakedown behavior.The list could go on, but one should never be too dogmatic about the future ofsuch a highly creative activity as research. Nature, society and economics will provide sufficient challenges for the future generation of structural engineers.近期美国在钢结构和钢筋混凝土结构研究和设计方面的发展这篇文章将总结对钢结构的研究展望.1.钢结构桥梁的研究美国国家运输和公路官员协会(AASTH0)是为美国桥梁发布设计标准的权威。
Design of Steel Structures 钢结构的设计-精品文档26页
Design of Steel Structures 《钢结构设计》
By Wang X. P.
王小平
Single-storey industrial steel structures
（单层钢结构厂房）
Content
(学习内容)
Composition of single-storey industrial steel structures (单层钢结构厂房的组成)
1、Loads (荷载）
恒载（Dead load）
Max.wheel Loading （最大轮压 ）P
Transverse horizontal force (横向水平力) T
Longitudinal horizontal force (纵向水平力) TL
1）恒载（Dead load）
2） Max.wheel load（最大轮压 ） 查表
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V = (Mkx • L 2) / (10 E I x)
[v]
2）刚度 (Stiffness)
重级工作制吊车 (Heavy duty crane)
验算横向刚度(Transverse stiffness)
V = (Mky • L 2) / (10 E I y1)
L/2200
3）整体稳定ቤተ መጻሕፍቲ ባይዱ(Total stability)
Design of column and corresponding
members (柱及相关构件设计)
Roof design (屋盖设计)
结构稳定论文之钢结构设计(英文版)
Graduate Course Work Steel Structure Stability DesignAbstractSteel structure has advantages of light weight, high strength and high degree of industryali zation, which has been widely used in the construction engineering. We often hear this the accident case caused by its instability and failure of structure of casualties and property losses, and the cause of the failure is usually caused by structure design flaws. This paper says the experiences in the design of stability of steel structure through the summary of the stability of steel structure design of the concept, principle, analysis method and combination with engineering practice.Key words:steel structure; stability design; detail structureSteel Structure Stability DesignStructurally stable systems were introduced by Aleksandr Andronov and Lev Pontryagin in 1937 under the name "systèmes grossières", or rough systems. They announced a characterization of rough systems in the plane, the Andronov–Pontryagin criterion. In this case, structurally stable systems are typical, they form an open dense set in the space of all systems endowed with appropriate topology. In higher dimensions, this is no longer true, indicating that typical dynamics can be very complex (cf strange attractor). An important class of structurally stable systems in arbitrary dimensions is given by Anosov diffeomorphisms and flows.In mathematics, structural stability is a fundamental property of a dynamical system which means that the qualitative behavior of the trajectories is unaffected by C1-small perturbations. Examples of such qualitative properties are numbers of fixed points and periodic orbits (but not their periods). Unlike Lyapunov stability, which considers perturbations of initial conditions for a fixed system, structural stability deals with perturbations of the system itself. Variants of this notion apply to systems of ordinary differential equations, vector fields on smooth manifolds and flows generated by them, and diffeomorphisms.The stability is one of the content which needs to be addressed in the design of steel structure engineering. Three are more engineering accident case due to the steel structure instability in the real life. For example,the stadium, in the city of Hartford 92 m by 110 m to the plane of space truss structure, suddenly fell on the ground in 1978. The reason is the compressive bar buckling instability;13.2 m by 18.0 m steel truss, in 1988,lack of stability of the web member collapsed in construction process in China;On January 3, 2010 in the afternoon, 38 m steel structure bridge in Kunming New across suddenly collapsed, killing seven people, 8 people seriously injured, 26 people slightly injured.The reason is that the bridge steel structure supporting system is out of stability, suddenly a bridge collapsing down to 8 m tall. We can see from the above case, the usual cause of instability and failure of steel structure is the unreasonable structural design, structural design defects.To fundamentally prevent such accidents, stability of steel structure design is the key.Structural stability of the system provides a justification for applying the qualitative theory of dynamical systems to analysis of concrete physical systems. The idea of such qualitative analysisgoes back to the work of Henri Poincaré on the three-body problem in celestial mechanics. Around the same time, Aleksandr Lyapunov rigorously investigated stability of small perturbations of an individual system. In practice, the evolution law of the system (i.e. the differential equations) is never known exactly, due to the presence of various small interactions. It is, therefore, crucial to know that basic features of the dynamics are the same for any small perturbation of the "model" system, whose evolution is governed by a certain known physical law. Qualitative analysis was further developed by George Birkhoff in the 1920s, but was first formalized with introduction of the concept of rough system by Andronov and Pontryagin in 1937. This was immediately applied to analysis of physical systems with oscillations by Andronov, Witt, and Khaikin. The term "structural stability" is due to Solomon Lefschetz, who oversaw translation of their monograph into English. Ideas of structural stability were taken up by Stephen Smale and his school in the 1960s in the context of hyperbolic dynamics. Earlier, Marston Morse and Hassler Whitney initiated and René Thom developed a parallel theory of stability for differentiable maps, which forms a key part of singularity theory. Thom envisaged applications of this theory to biological systems. Both Smale and Thom worked in direct contact with Maurício Peixoto, who developed Peixoto's theorem in the late 1950's.When Smale started to develop the theory of hyperbolic dynamical systems, he hoped that structurally stable systems would be "typical". This would have been consistent with the situation in low dimensions: dimension two for flows and dimension one for diffeomorphisms. However, he soon found examples of vector fields on higher-dimensional manifolds that cannot be made structurally stable by an arbitrarily small perturbation (such examples have been later constructed on manifolds of dimension three). This means that in higher dimensions, structurally stable systems are not dense. In addition, a structurally stable system may have transversal homoclinic trajectories of hyperbolic saddle closed orbits and infinitely many periodic orbits, even though the phase space is compact. The closest higher-dimensional analogue of structurally stable systems considered by Andronov and Pontryagin is given by the Morse–Smale systems.Structure theory of stability study was conducted on the mathematical model of the ideal, and the actual structure is not as ideal as mathematical model, in fact ,we need to consider the influence of various factors. For example ,for the compressive rods, load could not have absolute alignment section center; There will always be some initial bending bar itself, the so-called"geometric defects"; Material itself inevitably has some kind of "defect", such as the discreteness of yield stress and bar manufacturing methods caused by the residual stress, etc. So, in addition to the modulus of elasticity and geometry size of bar, all the above-mentioned factors affecting the bearing capacity of the push rod in different degrees, in the structure design of this influence often should be considered. Usually will be based on the ideal mathematical model to study the stability of the theory is called buckling theory, based on the actual bar study consider the various factors related to the stability of the stability of the ultimate bearing capacity theory called the theory ofcrushing.Practical bar, component or structure damage occurred during use or as the loading test of the buckling load is called crushing load and ultimate bearing capacity. For simplicity, commonly used buckling load. About geometric defects, according to a large number of experimental results, it is generally believed to assume a meniscus curve and its vector degrees for the rod length of 1/1000. About tissue defects, in the national standard formula is not the same, allow the buckling stress curve given by the very different also, some problems remain to be further research.1.Steel structure stability design concept1.1.The difference between intensity and stabilityThe intensity refers to that the structure or a single component maximum stress (or internal force)caused by load in stable equilibrium state is more than the ultimate strength of building materials, so it is a question of the stress. The ultimate strength value is different according to the characteristics of the material varies. for steel ,it is the yield point. The research of stability is mainly is to find the external load and structure unstable equilibrium between internal resistance. That is to say, deformation began to rapid growth and we should try to avoid the structure entering the state, so it is a question of deformation. For example, for an axial compression columns, in the condition column instability, the lateral deflection of the column add a lot of additional bending moment, thus the fracture load of pillars can be far less than its axial compression strength. At this point, the instability is the main reason of the pillar fracture .1.2.The classification of the steel structure instability1)The stability problem with the equilibrium bifurcation(Branch point instability).2)The axial compression buckling of the perfect straight rod and tablet compression bucklingall belong to this category.3)The stability of the equilibrium bifurcation problem(Extreme value point instability).4)The ability of the loss of stability of eccentric compression member made of constructionsteel in plastic development to a certain degree , fall into this category.5)Jumping instability6)Jumping instability is a kind of different from the above two types of stability problem. Itis a jump to another stable equilibrium state after loss of stability balance.2.The principle of steel structure stability design2.1.For the steel structure arrangement, the whole system and the stability of the part requirements must be considered ,and most of the current steel structure is designed according to plane system, such as truss and frame. The overall layout of structure can guarantee that the flat structure does not appear out-of-plane instability,such as increasing the necessary supporting artifacts, etc. A planar structures of plane stability calculation is consistent with the structure arrangement.2.2.Structure calculation diagram should be consistent with a diagram of a practical calculation method is based on. When designing a single layer or multilayer frame structure, we usually do not make analysis of the framework stability but the frame column stability calculation. When we use this method to calculate the column frame column stability , the length factor should be concluded through the framework of the overall stability analysis which results in the equivalent between frame column stability calculation and stability calculation. For a single layer or multilayer framework, the column length coefficient of computation presented by Specification for design of steel structures (GB50017-2003) base on five basic assumptions. Including:all the pillars in the framework is the loss of stability at the same time, that is ,the critical load of the column reach at the same time. According to this assumes, each column stability parameters of the frame and bar stability calculation method, is based on some simplified assumptions or typical.Designers need to make sure that the design of structure must be in accordance with these assumptions.2.3.The detail structure design of steel structure and the stable calculation of component should be consistent. The guarantee that the steel structure detail structure design and component conforms to the stability of the calculation is a problem that needs high attention in the design of steel structure.Bending moment tonon-transmission bending moment node connection should be assigned to their enough rigidity and the flexibility.Truss node should minimize the rods' bias.But, when it comes to stability, a structure often have different in strength or special consideration. But requirement above in solving the beam overall stability is not enough.Bearing need to stop beam around the longitudinal axis to reverse,meanwhile allowing the beam in the in-plane rotation and free warp beam end section to conform to the stability analysis of boundary conditions. 3.The analysis method of the steel structure stabilitySteel structure stability analysis is directed at the outer loads under conditions of the deformation of structure.The deformation should be relative to unstability deformation of the structure or buckling. Deformation between load and structure is nonlinear relationship , which belongs to nonlinear geometric stability calculation and uses a second order analysis method. Stability calculated, both buckling load and ultimate load, can be regarded as the calculation of the stability bearing capacity of the structure or component.In the elastic stability theory, the calculation method of critical force can be mainly divided into two kinds of static method and energy method.3.1.Static methodStatic method, both buckling load and ultimate load, can be regarded as the calculation of the stability bearing capacity of the structure or component. Follow the basic assumptions in establishing balance differential equation:1)Components such as cross section is a straight rod.2)Pressure function is always along the original axis component3)Material is in accordance with hooke's law, namely the linear relationship between thestress and strain.4)Component accords with flat section assumption, namely the component deformation infront of the flat cross-section is still flat section after deformation.5)Component of the bending deformation is small ant the curvature can be approximatelyrepresented by the second derivative of the deflection function.Based on the above assumptions, we can balance differential equation,substitude into the corresponding boundary conditions and solve both ends hinged the critical load of axial compression component .3.2.Energy methodEnergy method is an approximate method for solving stability bearing capacity, through the principle of conservation of energy and potential energy in principle to solve the critical load values.1)The principle of conservation of energy to solve the critical loadWhen conservative system is in equilibrium state, the strain energy storaged in the structure is equal to the work that the external force do, namely, the principle of conservation of energy. As the critical state of energy relations:ΔU =ΔWΔU—The increment of strain energyΔW—The increment of work forceBalance differential equation can be established by the principle of conservation of energy.2)The principle of potential energy in value to solve the critical load valueThe principle of potential energy in value refers to: For the structure by external force, when there are small displacement but the total potential energy remains unchanged,that is, the total potential energy with in value, the structure is in a state of balance. The expression is:dΠ=dU-dW =0dU—The change of the structure strain energy caused by virtual displacement , it is always positive;dW—The work the external force do on the virtual displacement;3.3.Power dynamics methodMany parts of the qualitative theory of differential equations and dynamical systems deal with asymptotic properties of solutions and the trajectories—what happens with the system after a long period of time. The simplest kind of behavior is exhibited by equilibrium points, or fixed points, and by periodic orbits. If a particular orbit is well understood, it is natural to ask next whether asmall change in the initial condition will lead to similar behavior. Stability theory addresses the following questions: will a nearby orbit indefinitely stay close to a given orbit? will it converge to the given orbit (this is a stronger property)? In the former case, the orbit is called stable and in the latter case, asymptotically stable, or attracting. Stability means that the trajectories do not change too much under small perturbations. The opposite situation, where a nearby orbit is getting repelled from the given orbit, is also of interest. In general, perturbing the initial state in some directions results in the trajectory asymptotically approaching the given one and in other directions to the trajectory getting away from it. There may also be directions for which the behavior of the perturbed orbit is more complicated (neither converging nor escaping completely), and then stability theory does not give sufficient information about the dynamics.One of the key ideas in stability theory is that the qualitative behavior of an orbit under perturbations can be analyzed using the linearization of the system near the orbit. In particular, at each equilibrium of a smooth dynamical system with an n-dimensional phase space, there is a certain n×n matrix A whose eigenvalues characterize the behavior of the nearby points (Hartman-Grobman theorem). More precisely, if all eigenvalues are negative real numbers or complex numbers with negative real parts then the point is a stable attracting fixed point, and the nearby points converge to it at an exponential rate, cf Lyapunov stability and exponential stability. If none of the eigenvalues is purely imaginary (or zero) then the attracting and repelling directions are related to the eigenspaces of the matrix A with eigenvalues whose real part is negative and, respectively, positive. Analogous statements are known for perturbations of more complicated orbits.For the structure system in balance,if making it vibrate by applying small interference vibration,the structure of the deformation and vibration acceleration is relation to the structure load. When the load is less than the limit load of a stable value, the acceleration and deformation is in the opposite direction, so the interference is removed, the sports tend to be static and the structure of the equilibrium state is stable; When the load is greater than the ultimate load of stability, the acceleration and deformation is in the same direction, even to remove interference, movement are still divergent, therefore the structure of the equilibrium state is unstable. The critical state load is the buckling load of the structure,which can be made of the conditions that the structure vibrationfrequency is zero solution.At present, a lot of steel structure design with the aid of computer software for structural steel structure stress calculation, structure and component within the plane of strength and the overall stability calculation program automatically, can be counted on the structure and component of the out-of-plane strength and stability calculation, designers need to do another analysis, calculation and design. At this time the entire structure can be in the form of elevation is decomposed into a number of different layout structure, under different levels of load, the structure strength and stability calculation.local stability after buckling strength of the beam, it can be set up to the beam transverse or longitudinal stiffener, in order to solve the problem, the local stability of the beam stiffening rib according to Specification for Design of Steel Structures (GB50017-2003) ; Finite element analysis for a web after buckling strength calculation according to specification for design of steel structures (GB50017-2003) 4, 4 provisions. Axial compression member and a local bending component has two ways: one is the control board free overhanging flange width and thickness ratio of; The second is to control web computing the ratio of the height and thickness. For circular tube section compression member, should control the ratio of outer diameter and wall thickness and stiffener according to specification for design of steel structures (GB50017-2003), 5 4 rule.4.ConclusionSteel structure has advantages of light weight, high strength and high degree of industrialization and has been widely used in the construction engineering.I believe that through to strengthen the overall stability and local stability of the structure and the design of out-of-plane stability, we could overcome structure design flaws and its application field will be more and more widely.referencesGB50017-2003,Design Code for Steel Structures[S]Chen Shaofan, Steel structure design principle [M]. Beijing: China building industry press, 2004 Kalman R.E. & Bertram J.F: Control System Analysis and Design via the Second Method of Lyapunov, J. Basic Engrg vol.88 1960 pp.371; 394LaSalle J.P. & Lefschetz S: Stability by Lyapunov's Second Method with Applications, New York 1961 (Academic)Smith M.J. and Wisten M.B., A continuous day-to-day traffic assignment model and the existence of a continuous dynamic user equilibrium , Annals of Operations Research, V olume 60, 1995 Arnold, V. I. (1988). Geometric methods in the theory of differential equations. Grundlehren der Mathematischen Wissenschaften, 250. Springer-Verlag, New York. ISBN 0-387-96649-8 Structural stability at Scholarpedia, curated by Charles Pugh and Maurício Matos Peixoto.9。
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钢结构设计外文翻译参考文献(文档含中英文对照即英文原文和中文翻译)使用高级分析法的钢框架创新设计1．导言在美国，钢结构设计方法包括允许应力设计法(ASD)，塑性设计法(PD)和荷载阻力系数设计法(LRFD)。
在允许应力设计中，应力计算基于一阶弹性分析，而几何非线性影响则隐含在细部设计方程中。
在塑性设计中，结构分析中使用的是一阶塑性铰分析。
塑性设计使整个结构体系的弹性力重新分配。
尽管几何非线性和逐步高产效应并不在塑性设计之中，但它们近似细部设计方程。
在荷载和阻力系数设计中，含放大系数的一阶弹性分析或单纯的二阶弹性分析被用于几何非线性分析，而梁柱的极限强度隐藏在互动设计方程。
所有三个设计方法需要独立进行检查，包括系数K计算。
在下面，对荷载抗力系数设计法的特点进行了简要介绍。
结构系统内的内力及稳定性和它的构件是相关的，但目前美国钢结构协会（AISC）的荷载抗力系数规范把这种分开来处理的。
在目前的实际应用中，结构体系和它构件的相互影响反映在有效长度这一因素上。
这一点在社会科学研究技术备忘录第五录摘录中有描述。
尽管结构最大内力和构件最大内力是相互依存的（但不一定共存），应当承认，严格考虑这种相互依存关系，很多结构是不实际的。
与此同时，众所周知当遇到复杂框架设计中试图在柱设计时自动弥补整个结构的不稳定（例如通过调整柱的有效长度）是很困难的。
因此，社会科学研究委员会建议在实际设计中，这两方面应单独考虑单独构件的稳定性和结构的基础及结构整体稳定性。
图28.1就是这种方法的间接分析和设计方法。
在目前的美国钢结构协会荷载抗力系数规范中，分析结构体系的方法是一阶弹性分析或二阶弹性分析。
在使用一阶弹性分析时，考虑到二阶效果，一阶力矩都是由B1,B2系数放大。
在规范中，所有细部都是从结构体系中独立出来，他们通过细部内力曲线和规范给出的那些隐含二阶效应，非弹性，残余应力和挠度的相互作用设计的。
理论解答和实验性数据的拟合曲线得到了柱曲线和梁曲线，同时Kanchanalai发现的所谓“精确”塑性区解决方案的拟合曲线确定了梁柱相互作用方程。
为了证明单个细部内力对整个结构体系的影响，使用了有效长度系数，如图28.2所示。
有效长度方法为框架结构提供了一个良好的设计。
然而，有效长度方法的使用存在着一些困难，如下所述：1、有效长度的方法不能准确核算的结构系统及其细部之间的互相影响。
这是因为在一个大的结构体系中的相互作用太复杂不能简单地用有效长度系数K代表。
因此，这种方法不能准确地测算框架单元实际需要的强度。
2、有效长度的方法无法获取结构体系中内力非弹性再分配，因为带有B1、B2系数的一阶弹性分析只证明二阶影响，但不是非弹性内力再分配。
有效长度的方法只是保守的估计了最终承载大型结构体系的能力。
3、有效长度方法无法测算的结构体系受负荷载下的失效模式。
这是因为荷载抗力系数相互作用方程不提供在任何负载下结构体系的失效模式的信息。
4、有效长度的方法与计算机程序不兼容。
5、有效长度的方法在涉及系数K的单独构件能力检测时需要耗费比较长的时间。
随着电脑技术的发展，细部结构的稳定性和整体结构的稳定性这两个方面，可以通过结构的最大强度测定来被严格对待。
图28.1就是这种方法的间接分析和设计方法。
直接设计方法的发展被称为高级分析，或者更具体地说，二阶弹性分析框架设计。
用这种直接的方式，无须计算有效长度系数，因为不需要规范方程包含的单独构件能力检测。
凭借目前现有的计算技术，直接使用高级分析法技术框架设计是可行的。
这种方法过去在办公室设计使用时一直被认为是不切实际的。
本章的目的是提出一个切实可行的，直接的钢框架设计方法，使用高级分析法产生跟荷载抗力系数法的相同的结果。
利用高级设计分析的优点概述如下：1、高级分析法是结构工程师进行钢结构设计的另一个工具，它的通过不是强制性的，而是为设计人员提供灵活的选择。
2、高级分析法直接获取了整个结构体系和细部结构极限状态的强度和稳定性，这样就不需要规范方程包含的单独构件能力检测。
3、相比荷载阻力系数设计法和允许应力设计法，高级分析法通过直接弹性二阶分析提供了更多结构性能的信息。
4、高级分析法解决了常规荷载阻力系数设计法中由于不兼容弹性全球分析和单元极限状态设计的困难。
5、高级分析法与计算机程序兼容性良好，但荷载阻力系数设计法和允许应力设计法则无法与计算机程序兼容，因为它们在过程中都需要有对系数K的单独构件能力检测的计算。
6、高级分析法可以得到整个结构体系弹性内力再分配的结果，并且节约高度不确定的钢框架的材料。
7、过去在设计室使用高级分析法被认为不切实际，而现在则是可行的，因为个人电脑和工程工作站的能力正在迅速提高。
8、通过高级分析法测定的各项数据都接近了荷载抗力系数法测定的那些数据，因为高级分析法对荷载抗力系数法的柱曲线和梁柱的相互作用方程进行了校准。
因此，高级分析法替代了荷载抗力系数法。
9、高级分析法比较高效，因为它完全消除了经常引起混淆的冗长的单独构件能力检测，包括荷载阻力系数设计法和允许应力设计法中的系数K的计算。
在各种高级分析法中，包括塑性区准塑性铰法，弹性区塑性铰法，名义负荷塑性铰法和改进塑性铰法，推荐使用改进塑性铰法，因为它保留了计算的效率和简便性及实际应用的准确度。
这个方法是对简单的传统的弹塑性铰法的改进。
其中包括一个简单的修改，证明在塑性铰位置截面刚度的逐步退化和包括细部两个塑性铰之间的逐步刚度退化。
表28.1中对常规荷载抗力系数法和高级实用性分析方法的关键因素做了比较。
荷载抗力系数方法用来证明主要影响隐含在其柱强度和梁柱相互作用方程之中，而高级分析法通过稳定性的功能，刚度退化的功能和几何缺陷方面来证明那些影响，在28.2中有详细讨论。
高级分析法持有许多钢结构实际问题的答案，同样地，我们推荐寻找有效地合理地完成框架设计方法提供给工程师，但这要符合荷载抗力系数规范。
在下面的章节里，我们将提出符合荷载抗力系数钢框架结构设计的高级先进实用分析方法。
该方法的有效性将通过比较基于精确塑性区解决方案和荷载抗力系数设计分析及设计结果的细部和框架的实际案例研究。
大范围的案例研究和比较可以这种高级方法的有效性。
2．高级实用性分析本节介绍了一种消除规范单独构件能力检测的直接设计钢框架的高级实用性分析方法。
改进后的塑性铰法是由简单的传统的弹塑性铰法发展调整而来，实现了简单和真实的反映了实际情况。
下一节将提供了最终确认该方法的有效性的核查方法。
高级分析能够验证连接的灵活性。
常规分析和钢结构的设计通常在假设梁柱连接不是完全刚性或理想的固定下进行。
然而，在大部分实际的连接是半刚性的并且它们的状态介于这两个极端的例子之间。
在允许应力设计-荷载抗力系数规范，有两类特定的建筑：FR（完全受限）结构和PR（部分受限）结构。
荷载抗力系数规范允许通过“合理途径”连接灵活性评估。
瞬间旋转的关系代表了连接的状态，已经完成多方面的试点连接工作和收集大批的瞬时旋转数据。
有了这个数据库，研究人员已经开发了数个连接模型，包括线性，多项式，B曲线，动力和指数。
鉴于此，Kishi和Chen提出的三参数幂函数模型被采用了。
在使用高级分析时，几何缺陷必须由框架单元加以塑造。
几何缺陷在构造或架设过程中导致不可避免的错误。
对于建筑结构的结构构件，几何缺陷的种类属于非线性和非垂直的。
明确建模和等效名义载荷被研究人员用来证明几何缺陷。
在这一章节中，发展了基于进一步减小构件切线刚度的新方法。
这种方法提供了一种简易的途径用来证明没有输入名义载荷或明确几何缺陷的不完善的影响。
本节中描述的高级实用性分析方法仅限于受静载的两维支撑，无支撑，和半刚架。
不考虑结构的空间状态，并且假定有足够的侧向支撑防止侧扭屈曲。
假设W节就是这样的节可以在无局部屈曲情况下发挥全塑性时刻能力。
强轴和弱轴弯曲宽凸缘部分的研究都采用高级实用性分析方法。
该方法可被视为介于现在广泛使用的常规荷载抗力系数方法和像在未来实际应用中塑性区的制定方法等的更严谨的高级分析/设计方法之间的一个临时的分析设计方法。
An Innovative Design for Steel FrameUsing Advanced AnalysisIntroductionThe steel design methods used in the U.S. are allowable stress design (ASD), plastic design (PD), and load and resistance factor design (LRFD). In ASD, the stress computation is based on a first-order elastic analysis, and the geometric nonlinear effects are implicitly accounted for in the member design equations. In PD, a first-order plastic-hinge analysis is used in the structural analysis. PD allows inelastic force redistribution throughout the structural system. Since geometric nonlinearity and gradual yielding effects are not accounted for in the analysis of plastic design, they are approximated in member design equations. In LRFD, a first-order elastic analysis with amplification factors or a direct second-order elastic analysis is used to account for geometric nonlinearity, and the ultimate strength of beam-column members is implicitly reflected in the design interaction equations. All three design methods require separate member capacity checks including the calculation of the K factor. In the following, the characteristics of the LRFD method are briefly described. The strength and stability of a structural system and its members are related, but the interaction is treated separately in the current American Institute of Steel Construction (AISC)-LRFD specification [2]. In current practice, the interaction between the structural system and its members is represented by the effective length factor. This aspect is described in the following excerpt from SSRC Technical Memorandum No. 5 [28]: Although the maximum strength of frames and the maximum strength of component members are interdependent (but not necessarily coexistent), itis recognized that in many structures it is not practical to take this interdependence into account rigorously. At the same time, it is known that difficulties are encountered in complex frameworks when attempting to compensate automatically in column design for the instability of the entire frame (for example, by adjustment of column effective length). Therefore, SSRC recommends that, in design practice, the two aspects, stability of separate members and elements of the structure and stability of the structure as a whole, be considered separately.This design approach is marked in Figure 28.1 as the indirect analysis and design method.In the current AISC-LRFD specification [2], first-order elastic analysis or second-order elastic analysis is used to analyze a structural system. In using first-order elastic analysis, the first-order moment is amplified by B1 and B2 factors to account for second-order effects. In the specification, the members are isolated from a structural system, and they are then designed by the member strength curves and interaction equations as given by the specifications, which implicitly account for second-order effects, inelasticity, residual stresses, and geometric imperfections [8]. The column curve and beam curve were developed by a curve-fit to boththeoretical solutions and experimental data, while the beam-column interaction equations were determined by a curve-fit to the so-called “exact” plastic-zone solutions generated by Kanchanalai [14].In order to account for the influence of a structural system on the strength of individual members, the effective length factor is used, as illustrated in Figure 28.2. The effective length method generally provides a good design of framed structures. However, several difficulties are associated with the use of the effective length method, as follows:1. The effective length approach cannot accurately account for the interaction between the structural system and its members. This is because the interaction in a large structural system is too complex to be represented by the simple effective length factor K. As a result, this method cannot accurately predict the actual required strengths of its framed members.2. The effective length method cannot capture the inelastic redistributions of internal forces in a structural system, since the first-order elastic analysis with B1 and B2 factors accounts only for second-order effects but not the inelastic redistribution of internal forces. The effective length method provides a conservative estimation of the ultimate load-carryingcapacity of a large structural system.3. The effective length method cannot predict the failure modes of a structural system subject to a given load. This is because the LRFD interaction equation does not provide any information about failure modes of a structural system at the factored loads.4. The effective length method is not user friendly for a computer-based design.5. The effective length method requires a time-consuming process of separate member capacity checks involving the calculation of K factors. With the development of computer technology, two aspects, the stability of separate members and the stability of the structure as a whole, can be treated rigorously for the determination of the maximum strength of the structures. This design approach is marked in Figure 28.1 as the direct analysis and design method. The development of the direct approach to design is called advanced analysis, or more specifically, second-order inelastic analysis for frame design. In this direct approach, there is no need to compute the effective length factor, since separate member capacity checks encompassed by the specification equations are not required. With the current available computing technology, it is feasible to employ advanced analysis techniques for direct frame design. This method has been considered impractical for design office use in the past. The purpose of this chapter is to present a practical, direct method of steel frame design, using advanced analysis that will produce almost identical member sizes as those of the LRFD method.The advantages of advanced analysis in design use are outlined as follows: 1. Advanced analysis is another tool for structural engineers to use in steel design, and its adoption is not mandatory but will provide a flexibility of options to the designer.2. Advanced analysis captures the limit state strength and stability ofa structural system and its individual members directly, so separate member capacity checks encompassed by the specification equations are not required.3. Compared to the LRFD and ASD, advanced analysis provides more information of structural behavior by direct inelastic second-order analysis.4. Advanced analysis overcomes the difficulties due to incompatibility between the elastic global analysis and the limit state member design in the conventional LRFD method.5. Advanced analysis is user friendly for a computer-based design, but the LRFD and ASD are not, since they require the calculation of K factor on the way from their analysis to separate member capacity checks.6. Advanced analysis captures the inelastic redistribution of internal forces throughout a structural system, and allows an economic use of material for highly indeterminate steel frames.7. It is now feasible to employ advanced analysis techniques that have been considered impractical for design office use in the past, since the power of personal computers and engineering workstations is rapidly increasing.8. Member sizes determined by advanced analysis are close to those determined by the LRFD method, since the advanced analysis method is calibrated against the LRFD column curve and beam-column interaction equations. As a result, advanced analysis provides an alternative to the LRFD.9. Advanced analysis is time effective since it completely eliminates tedious and often confused member capacity checks, including the calculation of K factors in the LRFD and ASD.Among various advanced analyses, including plastic-zone, quasi-plastic hinge, elastic-plastic hinge, notional-load plastic-hinge, and refined plastic hinge methods, the refined plastic hinge method is recommended, since it retains the efficiency and simplicity of computation and accuracyfor practical use. The method is developed by imposing simple modifications on the conventional elastic-plastic hinge method. These include a simple modification to account for the gradual sectional stiffness degradation at the plastic hinge locations and to include the gradual member stiffness degradation between two plastic hinges.The key considerations of the conventional LRFD method and the practical advanced analysis method are compared in Table 28.1. While the LRFD method does account for key behavioral effects implicitly in its column strength and beam-column interaction equations, the advanced analysis method accounts for these effects explicitly through stability functions, stiffness degradation functions, and geometric imperfections, to be discussed in detail in Section 28.2.Advanced analysis holds many answers to real behavior of steel structures and, as such, we recommend the proposed design method to engineers seeking to perform frame design in efficiency and rationality, yet consistent with the present LRFD specification. In the following sections, we will present a practical advanced analysis method for the design of steel frame structures with LRFD. The validity of the approach will be demonstrated by comparing case studies of actual members and frames with the results of analysis/design based on exact plastic-zone solutions and LRFD designs. The wide range of case studies and comparisons should confirm the validityof this advanced method.2．Practical Advanced AnalysisThis section presents a practical advanced analysis method for the direct design of steel frames by eliminating separate member capacity checks by the specification. The refined plastic hinge method was developed and refined by simply modifying the conventional elastic-plastic hinge method to achieve both simplicity and a realistic representation of actual behavior [15, 25]. Verification of the method will be given in the next section to provide final confirmation of the validity of the method. Connection flexibility can be accounted for in advanced analysis. Conventional analysis and design of steel structures are usually carried out under the assumption that beam-to-column connections are either fully rigid or ideally pinned. However, most connections in practice are semi-rigid and their behavior lies between these two extreme cases. In the AISC-LRFD specification [2], two types of construction are designated: Type FR (fully restrained) construction and Type PR (partially restrained) construction. The LRFD specification permits the evaluation of the flexibility of connections by “rational means”.Connection behavior is represented by its moment-rotation relationship. Extensive experimental work on connections has been performed, and a large body of moment-rotation data collected. With this data base, researchers have developed several connection models, including linear, polynomial, B-spline, power, and exponential. Herein, the three-parameter power model proposed by Kishi and Chen [21] is adopted.Geometric imperfections should be modeled in frame members when using advanced analysis. Geometric imperfections result from unavoidable error during fabrication or erection. For structural members in building frames, the types of geometric imperfections are out-of-straightness andout-of-plumbness. Explicit modeling and equivalent notional loads have been used to account for geometric imperfections by previous researchers. In this section, a new method based on further reduction of the tangent stiffness of members is developed [15, 16]. This method provides a simple means to account for the effect of imperfection without inputting notional loads or explicit geometric imperfections.The practical advanced analysis method described in this section is limited to two-dimensional braced, unbraced, and semi-rigid frames subject to static loads. The spatial behavior of frames is not considered, and lateral torsional buckling is assumed to be prevented by adequate lateral bracing.A compact W section is assumed so sections can develop full plastic moment capacity without local buckling. Both strong- and weak-axis bending of wide flange sections have been studied using the practical advanced analysis method [15]. The method may be considered an interim analysis/design procedure between the conventional LRFD method widely used now and a more rigorous advanced analysis/design method such as the plastic-zone method to be developed in the future for practical use.。