中南大学钢结构设计原理作业参考答案
取盖板截面为260?6mm2,则端缝承载力为w
t f e f B h b N ???=21
查表1-4得
f
wt=160 N/mm2 则
kN N 8.42631616022.167.026021
=?????= 接缝一侧一条焊缝需要长度:
()mm
f h N N L w
t f W 57516067.0410975.40955057.043
1=+????-=+???-= 取LW=60mm.则盖板全长为:
mm
L L W 130********=+?=+?=
3-3.图3-73所示焊接工形截面梁,在腹板上设置一条工厂对接焊缝,梁拼接处承受内力为
m kN M ?=2500,钢材为Q235钢,焊条为E43型,手工焊,二级质量标准,试验算拼接焊缝强度。
(提示:剪力V 可假定全部由腹板承担,弯矩按刚度比分配,即M I
I M w
w =
)
解:查得
2
/215mm N f w t =,
2
/215mm N f w c =,
2
/125mm N f w v =
计算焊缝截面特征值:
()
4237393605953601440006124021200.112
1
cm I =+=???+??=
4
31440001200.1121
cm I w =??=
2
1201120cm A w =?= 验算正应力:
m kN M I I M w w ?=?==
9.486739360144000
2500
2
246/215/9.202600/10144000109.486mm
N mm N W M w w w <=??==σ满足
验算剪应力:
2
22
3/125/7.411012010500mm
N mm N A V w w <=??==τ满足
验算折算应力
2
22222/2362151.1/4.2157.4139.2023mm N mm N w w =?<=?+=+τσ
满足要求
3-4.图3-74所示一柱间支撑与柱的连接节点,支撑杆承受轴拉力设计值kN N 300=,用2L80×6角钢
做成,钢材均为Q235钢,焊条为E43型,手工焊。
(1)支撑与节点板采用角焊缝相连,焊脚尺寸见图,试确定焊缝长度。 (2)节点板与端板用两条角焊缝相连,试演算该连接焊缝强度。
解:查附表1-4得
2
/160mm N f w f =
(1)采用两边围焊,肢背、肢尖的受力为:kN N K N 2103007.011=?=?=
kN N K N 903003.022=?=?=
据题设焊脚高度为:mm h f 81=,mm h f 62= 计算肢背、肢尖所需焊缝长度为:
mm f h N L w f f w 122516087.021021057.023
111
=+????=+?=
mm f h N L w
f f w 72516067.021021057.023
212
=+????=+?=
构件端部按要求做成2f h 绕角焊,故不再加5mm
(2)N 分解为水平拉力kN N 1801=、竖向剪力kN V 2401=
计算焊缝强度:
23
1/8.32490
87.02101807.02mm N L h N w f N
=????=?=σ
23
1/7.43490
87.02102407.02mm N L h V w f V
=????=?=τ
mm X c 77.597
19327300=??+?=
mm r x 23.14777.59207=-=
mm r y 1572
14
300=+=
()
432334.81735733195712
1
25.153719323147121mm I X =??+???+??=
22
33
4
119517271937195147.237314314759.77122122 22038007.07Y I mm ????=???+??-+??+?- ? ?
????=
验算角焊缝强度V =F =
kN 1002002
1
=? ()mm kN L F T ?=+?=?=3472323.147200100
A 处应力为:23227
1932730010100mm N A V W V AY
=??+??==τ
2326.4907
.2203800734.8173573323
.1471034723mm N I I r T Y X y
T
AY
=+??=+?=τ
2353.5207.2203800734.81735733157
1034723mm N I I r T Y X y
T
AX
=+??=+?=τ
b c
84
420
10
20=
?
?
=
?
?
=∑取较小者kN
N b84
.
40
m in
=
kN
f
t
d
N b
c