某混合结构办公楼结构设计一、基本资料某五层混合结构办公楼,采用装配式钢筋混凝土梁板楼屋盖,墙体布置及门窗洞口等要求如下图示。大梁截面尺寸为200mm×500mm,梁端伸入墙内240mm,大梁间距(开间)3.6m。底层墙厚为370mm,2~5层墙厚为240mm,墙体均双面批档。砖的强度等级为MU10。二、材料、结构构造方案及计算单元确定(1)墙体材料1~2层采用烧结普通砖强度等级MU10,M7.5混合砂浆;3~5层采用烧结普通砖强度等级MU10,M5混合砂浆。(2)结构构造方案根据建筑功能分区,本设计选用纵横墙混合承重方案,即在房间内无横墙处设置横向的钢筋混凝土进深梁,上面铺设横向120mm厚预应力空心板,大梁支承于窗间墙中部,走廊处用80mm厚现浇实心板支承于内纵墙上。上述结构布置方案的刚性横墙的最大间距Smax=10.832m(刚性方案要求的最大间距),所以该法案属于刚性方案。(3)计算单元纵墙:根据墙体负载面积(②④⑥⑦轴线处大梁负载面积较大,具体看施工图)与墙体刚性(在条件相同的情况下,有开洞口的墙体的刚性较没开洞口的小,故选外纵墙)判断:A、D轴楼屋面梁支承处一个开间范围内窗间墙墙段为最不利位置,取窗间墙墙段3.6m宽的墙体作为计算单元。横墙:根据墙体负载面积(③⑤轴线处内横墙负载面积较大,具体看施工图)判断:②④⑥轴楼屋面支承两侧预制板处1米长墙段为最不利位置,取取1m宽墙作为计算单元。三、墙体的稳定性验算(1)纵墙的高厚比验算底层:层高:H=3.2+0.8=4.0m;墙后h=0.37m;M7.5混合砂浆,则墙的允许高厚比值[]=26;ms8.106.33;msmH8.108422;则计算高度mHH0.40;83.08.10/5.44.012;纵墙的高厚比58.212683.081.1037.0/4/20hH2层:层高:H=3.2m;墙后h=0.24m;M7.5混合砂浆,则墙的允许高厚比值[]=26;ms8.106.33;msmH8.104.62.322;则计算高度mHH2.30;83.08.10/5.44.012;纵墙的高厚比58.212683.03.1324.0/2.3/20hH3-5层:层高:H=3.2m;墙后h=0.24m;M5混合砂浆,则墙的允许高厚比值[]=24;ms8.106.33;msmH8.104.62.322;则计算高度mHH2.30;83.08.10/5.44.012;纵墙的高厚比92.192483.03.1324.0/2.3/20hH符合要求。(2)横墙的高厚比验算底层:层高:H=3.2+0.8=4.0m;墙后h=0.37m;M10混合砂浆,则墙的允许高厚比值[]=26;ms7.5;mHmsmH0.47.58422;则计算高度mHsH08.30.42.07.54.02.04.00;因为横墙没有窗洞口,故12;横墙的高厚比2626132.837.0/08.3/20hH2层:层高:H=3.2m;墙后h=0.24m;M7.5混合砂浆,则墙的允许高厚比值[]=26;ms7.5;mHmsmH2.37.54.62.322;则计算高度mHsH92.22.32.07.54.02.04.00;因为横墙没有窗洞口,故12;横墙的高厚比2626117.1237.0/92.2/20hH3-5层:层高:H=3.2m;墙后h=0.24m;M7.5混合砂浆,则墙的允许高厚比值[]=24;ms7.5;mHmsmH2.37.54.62.322;则计算高度mHsH92.22.32.07.54.02.04.00;因为横墙没有窗洞口,故12;横墙的高厚比2424117.1237.0/92.2/20hH符合要求。四、承重墙体承载力计算(1)外纵墙(窗间墙)的受压承载力计算a、荷载计算①屋面荷载APP改性沥青防水层0.30kN/m220厚水泥砂浆找平层0.40kN/m250厚泡沫混凝土0.25kN/m2120厚空心板1.87kN/m220厚抹灰层0.34kN/m2钢筋混凝土进深梁mmmm500200,折算厚度33mm(含两侧抹灰40mm)0.83kN/m2屋盖永久荷载准值kN/m299.3屋盖活荷载标准值0.7kN/m2由屋盖大梁传给计算墙垛的荷载标准值KNNk12.485.06.37.5)7.099.3(1设计值由可变荷载控制的组合KNQGNkk18.595.06.37.5)7.04.199.32.1(4.12.11由永久荷载控制的组合KNQGNkk45.625.06.37.5)7.00.199.335.1(1035.11②楼面荷载20厚水泥砂浆0.40kN/m2120厚空心板1.87kN/m220厚抹灰层0.34kN/m2钢筋混凝土进深梁mmmm500200,折算厚度33mm(含两侧抹灰40mm)0.83kN/m2楼面永久荷载准值kN/m244.3楼面活荷载标准值2.2kN/m2由楼面大梁传给计算墙垛的荷载标准值KNNk87.575.06.37.5)2.244.3(2设计值由可变荷载控制的组合KNQGNkk95.735.06.37.5)2.24.144.32.1(4.12.12由永久荷载控制的组合KNQGNkk22.705.06.37.5)2.20.144.335.1(1035.12③墙体自重天沟重(厚80mm,高700mm)计入两面抹灰40mm,其标准值为:KNmKNNk57.57.012.06.3/1933设计值由可变荷载控制的组合KN90.62.157.5由永久荷载控制的组合KN76.735.157.5天沟根部至进深梁地面高度范围内的墙体240mm,其自重标准值为:KNmKN6.95.0)4.024.0(5.06.3/193设计值由可变荷载控制的组合KN5.112.16.9由永久荷载控制的组合KN0.1335.16.9计算每层墙体自重时,应扣除窗口面积,加上窗自重,墙体厚度考虑两面抹灰增加40mm一并计算。塑钢玻璃自重标准值按0.4kN/m2计算。对2~5层,墙体厚度240mm,计算高度3.2m,其自重标准值为:KNmKN00.484.08.15.1/19)8.15.16.32.3()04.024.0(3设计值由可变荷载控制的组合KN60.572.100.48由永久荷载控制的组合KN80.6435.100.48对低层,墙体厚度370mm,计算高度3.2+0.8-0.5=3.5m,其自重标准值为:KNmKN20.784.08.15.1/19)8.15.16.35.3()04.037.0(3设计值由可变荷载控制的组合KN84.932.120.78由永久荷载控制的组合KN57.10535.120.78b、内力计算楼盖、屋盖大梁截面为b*h=200mm*500mm,梁端在外墙的支承长度为240mm,下设240500180bbbabt的刚性垫块,则梁端垫块上表面有效支承长度用下式计算01chaf对由可变荷载控制及永久荷载控制的组合,计算结果分别列于相应的表中,进深梁传来荷载对外墙的偏心距0eh/20.4a,h为支承墙厚度。墙体在竖向荷载作用的计算模型与计算简图下图所示。由可变荷载控制下的梁端有效支承长度计算01haf0uNA楼层54321h/mm5005005005005002/(/)fNmm)1.501.501.501.691.69/uNKN6.90123.68255.23386.78518.3320/(/)Nmm0.0110.2450.5060.7670.6670/f0.0070.1600.3400.4500.39515.425.645.916.235.990/amm98.96102.98107.91113.75109.37由永久荷载控制下的梁端有效支承长度计算楼层54321h/mm5005005005005002/(/)fNmm)1.501.501.501.501.50/uNKN7.76135.01270.03405.05540.0720/(/)Nmm0.0150.2680.5360.8040.6950/f0.010.1790.3570.4760.41115.425.675.946.366.050/amm98.96103.52108.45116.12110.46各层I-I,IV-IV截面的内力按可变荷载控制和由永久荷载控制的组合分别列于下表中由可变荷载控制的纵向墙体内力计算表楼层上层传荷本层楼盖荷载截面I-I截面IV-IV/UNKN2/emm/lNKN1/emmMKNm/INKN/IVNKN518.4059.1880.424.7677.5884.484135.18073.9578.815.83209.13216.033266.73073.9576.845.68340.68347.582398.28073.9574.55.51472.23479.131529.83-6573.95141.25-23.92603.78610.6810/20.4eha21ulMNeNeIulNNNIVIWNNN由可变荷载控制的纵向墙体内力计算表楼层上层传荷本层楼盖荷载截面I-I截面IV-IV/UNKN2/emm/lNKN1/emmMKNm/INKN/IVNKN520.76062.4580.425.02283.2190.974148.01070.2278.595.52218.23225.993283.03070.2276.625.38353.25361.012418.05070.2273.555.16488.27496.031553.07-6570.22140.82-26.06623.29631.05C.墙体承载力计算本建筑墙体的最大高厚比58.212683.03.1324.0/2.3/20hH满足要求。承载力计算一般可对I-I截面进行,但多层砖房的底部可能IV-IV截面更不利,计算结果列于下表中。纵向墙体由可变荷载控制时的承载力计算表纵向墙体由永久荷载控制时的承载力计算表计算项目第5层第4层第3层第2层第1层I-I截面IV-IV截面I-I截面IV-IV截面/MKNm4.765.835.185.510-23.920/NKN77.58209.13340.68472.23479.13603.78610.68e/h61.3627.8815.2011.70039.620h/mm240240240240240370370e/h0.2560.1160.060.04900.10700/BHh13.313.313.313.313.310.8110.810.3350.5550.6600.6850.7950.6000.8452/Amm504000504000504000504000504000777000777000砖MU10101010101010砂浆M5557.57.57.57.52/(/)fNmm1.501.501.501.691.691.691.69/AfKN253.26419.58498.96583.46677.15787.881109.59/AfN>1>1>1>1>1>1>1计算项目第5层第4层第3层第2层第1层I-I截面IV-IV截面I-I截面IV-IV截面/MKNm5.025.525.385.160-26.060/NKN83.21218.23353.25488.27496.03623.29631.0