钢结构U5课后答案

1、一平台的梁格布置如图所示，铺板为预制钢筋混凝土板，焊于次梁上。设平台恒荷载的标准值（不包括梁自重）为kN/m2。试选择次梁截面，钢材为Q345钢。解：1、普通工字形钢选 I45aW = 1433cm3XI = 32241cm4X3、验算：1）强度M410.4 x 106=M410.4 x 106=272.8Mpa p f = 295MprW 1.05 x 143 3 x 103aX X挠度_ 5 q 14 _ 52）66 x 6000 4V = 384 ElX 384* 2.06 x 105 x 32241 x 10 4=16.77 mm f v = 15 mm重选I50aI = 46472

2、cm 45 q -14566 x 60004V = 384 * E - 384 * 2.06 x 105 x 46472 x 1043）整稳：不必计算。4）局稳：因为是型钢，不必验算。解：图（a）所示的简支梁，其截面为不对称工字形图（b），材料为Q235B钢；梁的中点 和梁端均有侧向支承；在集中荷载（未包括梁自重）F=160kN （设计值）的作用下，梁能否 保证其整体稳定性？1、计算梁自重A = 30 x1 + 80 x 0.8+10 x1 = 104cm2q = 104x10-4 x 76.98 = 0.8kN / muql2 Pl 0.8x122 160 x12M =y-+ = 1.2x8

3、14=497.3kN-m2、计算中和轴位置80 x 0.8x 40.5+10 x1x 81 , y =+ 0.5 = 33.2cm30 x1 + 80 x 30 x1 + 80 x 0.8+10 x11IX=x12WI =Xy13、求甲93440=2810cm333.2+ 10 x1x (48.8 - 0.5)2 =93440cm4b -1I = = x (1x 303 + 1x103) = I = = x (1x 303 + 1x103) = 2330cm4 yi =y入y以t)2J1 +r1+n(4.4h Jb235 xf y4320 Ah xxxWX4320104x82 x=1.75xx

4、127.722810(127.7x1 14.4x 82 ；+ 0.74235x235查附 表3.1 n0 = 1.751 一x 12I2330 ,-=4.7cmA104=IJ i = 600/4.7 = 127.7=I /(I +1 )=303)/12 = 0.9611 22330n = 0.8(2a -1)=0.8x(2x0.96-1)=0.74 bb=2.5 f 0.60.2820.2822.5%，=1.07= 1.07 - -= 0.9572.5b4、梁整体稳定计算=184.9Mpa p f=184.9Mpa p f = 215Mpa(满足)PbW0.957x 2810 x103解：设计

5、习题的中间主梁（焊接组合梁），包括选择截面、计算翼缘焊缝、确定 腹板加劲肋的间距。钢材为Q345钢，E50型焊条（手工焊）。解：qk = 66 KN / m q = 91.2 KN / mF = 66 x 6 = 396KNF = 91.2 x 6 = 547.2KNV = - x 547.2 = 1368KN2M =1368 x 9 - 547.2 x (6 + 3) = 7387.2KN - mM =M = 7387.2 x106- 1.05 x 295=23849 x103 mm3(1)试选截面:一(1)试选截面:一f 12295h min =fx=x 400 x 180001.34 x

6、 106 V1.34 x 106=1585 mmhe = 2W 0.4 = 2 x (23849 x103)0.4 = 1786 mm 取梁腹板高h0 = 1700 mmtwtw/3.5取 t = 12 mm翼缘Af=1.2 x1368 x10twtw/3.5取 t = 12 mm翼缘Af=1.2 x1368 x1031700 x170=11.8 mm=5.7 mmW _t h _ 23849 x 103 _ 12 x 1700 h*17006= 10629 mm0bf = K 匕= 170* 170匕=(340 567) mm取 b = 500 mm则 t 争=1062吒0 = 21.2 m

7、m取 t = 24 mmf(2)强度验算:,1700 s 1700 仁s (2 x12x 耳 + 500 x 24x 862)= 1.468x107 mm1I =正(500 x1740 - 488x1700) = 2.27x10w mmW =顼=2.27x1M = 2.597x107 mm3 h8742A = 500 x 24x 2+1700 x12=44400mm2M7387.2x106a =W = 1 05 2 597 1Ch = 270.9Mp p f = 295mMpX Xt= VmJ = 1368x103x1.468x107 = 73.7Mp p f = 170MpI -12 27x

8、1010 x12a。 七2.27x101。x12(3)整稳验算:4 = 3000/500 = 6 p 16不需验算.刚度验算：翼缘和腹板的连接焊缝计算:主梁加劲肋设计h /1 = 1700 /12 = 142,80 p142 p 170,宜设置横向加劲肋(JL )2+ _5 + (_L)2 0.5 h = 0.5 x 1700 = 850 mm p 2h = 2 x 1700 = 3400 取a = 3000 mm,设在集中荷载作用处.mm/区格:=1368趴M = 1368x1.5 = 2052KN - m=mM h = 2052x106700 =Gi= h = 2.597 x107 X17

9、48 = . PaxV1368x103_ =入 / = 1700 12 = 67.1Mpa 0 /区格: = 820.8KNM =1368x 4.5 - 547.2x1.5 = 5335.2_ =也_ 、= 76.8x 5335.2 = 199.68MPaiiW h2052x820 820 8 x1031700 x12=40.24MFaIII区格:Viii= 273.6KNM iii = 1368 x 7.5 547.2 x (4.5 + 1.5) = 6976.8 kN m_= 76.8 x6976.8一 = 261.12 MPaiii2052计算_cr_cr人=h0tw f1700 =12

10、 x竺=0.97b177 【235177 1234_iii273.61700 x 10 3x 12=13.41MPa0.85 p 孔 p 1.25b = 1 0.75( -0.85)f = 1 0.75(0.97-0.85)x 295 = 268.45MPa=300阳00 = 1.77 =300阳00 = 1.77 f 1.0、tw 0X =s 41J5.34 + &/ )217001241 ：5.34 + 4()23000= 1.627 f 1.2t = 1.1 t = 1.1 f* = 1.1x 17/= 70.6MPas1.627I区格:76.8 )2 + (67.1 )2 = 0.08

11、2 + 0.903 = 0.985 p 1268.4570.6II区格:(1996L)2 + (旦)II区格:(1996L)2 + (旦)2 = 0.553268.4570.6+ 0.325=0.878 p 1III区格:(26HL)2 + (灯)2 = 0.946268.4570.6+ 0.036=0.985横向加劲助尺寸:,、hbs 砰 + 40,、hbs 砰 + 4030170010+ 40 = 97 mm ,取 140 mms 1514075=9.3 mm 取 10 mm114012I = 5x 10 x 140 3 + 140 x 10 x (- + )2=10.4 x 10 6 m

12、m 4中部支承加劲助：f 3 h01 3 = 3 x 1700 x 12 3 = =10.4 x 10 6 mm 4中部支承加劲助：N=1368+547.2-70.6 x 1700 N=1368+547.2-70.6 x 1700 x 121000=475.2 kNA = 2 x 140 x 10 + 360 x 12 = 7120 mm 21I = 12 x 10 x (140 x 2 + 12) 3 = 2.07 x 10 7 mm 4i2入2i2入2N170虬9 = 32 甲=0.929 475 2 x 10 3甲 A 0.929 x 7120支座支承加劲助验算 ：=甲 A 0.929 x 7120支座支承加劲助验算 ：547.2N = 1368 += 1641 .6 kN2采用180 x 16板A = 2 x 180 x 16 + (180 + 100) x 12 = 9120 mm 21x 16 x (180 x 2 + 12) 3 = 6.86 x 10 7 mm 412II26.II26.86 x 107 = 86.79120A1700/6 7