混凝土和砌體結(jié)構(gòu)設(shè)計(jì)課程設(shè)計(jì)報(bào)告

混凝土和砌體結(jié)構(gòu)設(shè)計(jì)課程設(shè)計(jì)――多層框架結(jié)構(gòu)設(shè)計(jì)指導(dǎo)教師： 蕾春 班級： 11土木（2）班學(xué)生： 施迎寧 學(xué)號： Xf11220222設(shè)計(jì)時(shí)間： 2014.5.7-6,5理工大學(xué)科技與藝術(shù)學(xué)院建筑系wordword資料混凝土和砌體結(jié)構(gòu)設(shè)計(jì)課程設(shè)計(jì)一、目的掌握現(xiàn)澆多層框架結(jié)構(gòu)方案布置、荷載分析、框架結(jié)構(gòu)力分析、力組合、框架梁、柱和節(jié)點(diǎn)設(shè)計(jì)。通過該課程設(shè)計(jì)，能綜合運(yùn)用結(jié)構(gòu)力學(xué)和鋼筋混凝土基本構(gòu)件的知識，掌握結(jié)構(gòu)設(shè)計(jì)的基本程序和方法。二、設(shè)計(jì)任務(wù)1.工程概況本工程為鋼筋混凝土框架結(jié)構(gòu)體系，共三層，層高3.6租，室外高差為0.45m，基礎(chǔ)頂面至室外地面距離0.5m?？蚣芷矫嬷W(wǎng)布置見圖1所示，選擇典型一根框架進(jìn)行計(jì)算?？蚣芰骸⒅?、屋面板、樓面板全部現(xiàn)澆。 1■1 !h 1nih 11g1II11111_?二D,CLD .1:-H%A 51111口§36OJ期0涮：J600防於1嗎11J12OTJG.=J:1號i5 <05U2.設(shè)計(jì)資料（1）氣壓條件基本雪壓0.3kN/m2，基本風(fēng)壓0.4kN/m2，地面粗糙度類別為B類。不上人屋面，屋面活荷載0.5kN/m2。（2）抗震設(shè)防：不考慮抗震設(shè)防。（3）主要建筑做法:構(gòu)件尺寸：梁：250X550；柱：600X600屋面做法：20mm厚板底抹灰，鋼筋混凝土板厚90mm，120mm水泥膨脹珍珠巖保溫層找坡，20mm厚水泥砂漿找平層，4mm厚SBS卷材防水層。樓面做法：20mm厚板底抹灰，鋼筋混凝土板厚90mm，30mm厚水磨石面層。梁柱表面采用20mm厚抹灰。（4）荷載取值：鋼筋砼容重25kN/m3，水泥膨脹珍珠巖砂漿15kN/m3，水泥砂漿容重20kN/m3，石灰砂漿容重17kN/m3，SBS卷材防水層0.30kN/m2，水磨石自重0.65kN/m2。恒載分項(xiàng)系數(shù)為1.2，活荷載3.5kN/m3,分項(xiàng)系數(shù)1.4。（5）材料：混凝土強(qiáng)度等級為C30。受力鋼筋采用三級鋼。根據(jù)地質(zhì)資料，確定基礎(chǔ)頂離外地面為500mm，由此求得底層層高為4.55m。各梁柱構(gòu)件的線剛度經(jīng)計(jì)算后列于圖中。其中在求梁截面慣性矩時(shí)考慮到現(xiàn)澆板的作用，取I=2I0（I0為不考慮樓板翼緣作用的梁截面慣性矩）。1AB、CD跨梁： i=2E義一義0.25*0.553/5.4=1.28義10-3E（m3）c12 c1BC星跨梁：i=2Ex_x0.25x0.553/2.4=2.9x10-3E（m3）c12 c

1上部結(jié)構(gòu)各層柱：?=Ex x0,6x0.63/3.6=3x10-3E(m3)C12 C1底層柱：?=Exx0.6x0.63/4.55=2.37x10-3E(m3)/?… c12 c' ，. fTLJLJ J>-4門門. fTLJLJ J>-4門門> 金門口結(jié)構(gòu)計(jì)算簡圖圖中數(shù)字為線剛度，單位：X10-圖中數(shù)字為線剛度，單位：X10-3Em3C三、荷載計(jì)算1、恒荷載計(jì)算（1）屋面框架梁線荷載標(biāo)準(zhǔn)值：20mm厚板底抹灰：0.02x17=0.34kN/m290mm厚的鋼筋混凝土板90mm厚的鋼筋混凝土板：0.09x25=2.25kN/m2120mm水泥膨脹珍珠巖保溫層找坡：120mm水泥膨脹珍珠巖保溫層找坡：0.12x15=1.8kN/m220mm厚水泥砂漿找平層20mm厚水泥砂漿找平層：0.02x20=0.4kN/m24mm厚SBS4mm厚SBS卷材防水層：0.3kN/m2屋面恒荷載：5.09kN/屋面恒荷載：5.09kN/m2框架梁自重：0.25x()025=2.875kN/m梁側(cè)粉刷： 2x(0.55-0.09)x0.02x17=0.313kN/m3.19kN/m因此，作用在屋頂框架梁上的線荷載為：gg=g=g=3.19kN/m3AB1 3CD1 3BC1g=g=5.09x3.6=18.324kN/m3AB2 3CD2g=5.09x2.4=12.216kN/m3BC20.02x170.02x17=0.34kN/m20.09x25=2.25kN/m20.65kN/m220mm厚板底抹灰：90mm厚的鋼筋混凝土板：30mm厚水磨石面層：樓面恒荷載： 3.24kN/m2框架梁自重及梁側(cè)粉刷： 3.19kN/m因此，作用在中間層框架梁上的線荷載為：g=g=g=3.19kN/mAB1 BC1CD1g=g=3.24x3.6=11.664kN/mAB2 CD2g=3.24x2.4=7.776kN/mBC2（3）屋面框架節(jié)點(diǎn)集中荷載標(biāo)準(zhǔn)值

邊柱連系梁自重： 0.25x( )x7.2x25=20.7kN粉刷： 0.02x(0.55-0.09)x7.2x2x17=2.252kN邊柱連系梁傳來屋面自重： 1.8x1.8x5.09/2=16.491kN12x0.25x(0.55—0.09)x5.4x25x=7.594kN邊柱次梁自重： 4粉刷： 0.02x(0.55-0.09)x5.4x2x17=1.652kN頂層邊節(jié)點(diǎn)集中荷載：中柱連系梁自重：頂層邊節(jié)點(diǎn)集中荷載：中柱連系梁自重：G=G=48.962kN3A3D20.7kN粉刷：2.525kN柱連系梁傳來屋面自重：1粉刷：2.525kN柱連系梁傳來屋面自重：1—x[(3.6-1.2)+1.2]x1.2x5.09:10.99kN20.5x3.6x3.6/2x5.09=16.491kN頂層中節(jié)點(diǎn)集中荷載：G頂層中節(jié)點(diǎn)集中荷載：G=G=50.433kN3B 3C(4)樓面框架節(jié)點(diǎn)集中荷載標(biāo)準(zhǔn)值邊柱連系梁自重： 0.3x(0.6-0.1)x7.2x25=27kN粉刷： 0.02x(0.6-0.1)x7.2x2x17=2.448kN邊柱連系梁傳來樓面自重： 2.7x1.8x3.24=15.746kN框架柱自重： 0.6x0.6x25x3.6=32.4kN粉刷： 0.02x0.6x4x3.6x17=2.94kN頂層邊節(jié)點(diǎn)集中荷載：

G=G=74.311kN3A3D柱連系梁自重：20.7kN粉刷：2.525kN柱連系梁傳來屋面自重：-x[3.6+3.6-2.4]x1.2x3.24=9.331kN21x3.6x1.8x3.24=10.498kN2框架柱自重：32.4kN粉刷：2.94kN頂層中節(jié)點(diǎn)集中荷載：

G=G=78.394kNBC(5)恒荷載作用下的結(jié)構(gòu)計(jì)算簡圖恒荷載作用下的結(jié)構(gòu)計(jì)算簡圖2、活荷載計(jì)算（1）屋面活荷載計(jì)算活荷載作用在頂層屋面上的線荷載為：TOC\o"1-5"\h\zp=p=0.5x3.6=1.8kN/m3AB 3CDp =0.5x2.4=1.2kN/m3BCP=P=-x（2.7+2.7—1.8）x1.8+-x3.6x1.8x0.5x2=6.48kN3A 3D\_2 2P=P=6.48+-x（3.6—1.2+3.6）x1.2x0.5x2=10.08kN3B 3C 2（2）樓面活荷載計(jì)算活荷載作用在樓面上的線荷載為：p=p=3.5x3.6=12.6kN/mABCDp=3.5x2,4=8.4kN/mBCP=P=6.48x3.5x2=45.36kNADP=P=10.08x3.5x2=75.56kNBC5）活荷載作用下的結(jié)構(gòu)計(jì)算簡圖

活荷載作用下的結(jié)構(gòu)計(jì)算簡圖3、風(fēng)荷載計(jì)算風(fēng)壓標(biāo)準(zhǔn)值計(jì)算公式： 3=0?山口?3zsz0因結(jié)構(gòu)高度H=11.9m<30m，可取0=1.0；對于矩形平面目=1.3；口可按z sz線性插入法求得。將風(fēng)荷載換算成作用于框架每層節(jié)點(diǎn)上的集中荷載，計(jì)過程如表1所示。表中z為框架節(jié)點(diǎn)至室外地面的高度，A為一根框架各層節(jié)點(diǎn)的受風(fēng)面積，計(jì)算結(jié)果如圖所示。層次0zNsz(m)Nz3(kN/m2)0A(m2)P(kN)w31.01.311.41.03920.4512.967.58221.01.37.810.4525.9215.16311.01.34.210.4528.0816.427風(fēng)荷載計(jì)算表11、恒荷載作用下的力計(jì)算恒載（豎向荷載）作用下的力計(jì)算采用分層法。計(jì)算中柱的線剛度取框架柱實(shí)際線剛度的0.9倍。梁上分布荷載由矩形和梯形兩部分組成，在求固端彎矩時(shí)可直接根據(jù)圖示荷載計(jì)算，也根據(jù)固端彎矩相等的原則，先將梯形分布荷載及三角形分布荷載，化為等效均布荷載。把梯形荷載轉(zhuǎn)化作等效均布荷載a=0.5x36=1i5.43（1）頂層g‘3邊二g3AB1+(1-2a；yg3AB?=4.09+(1-2x0.3332+0.3333)x19.224=19.76kN/mg'=g+5g=4.09+5x12.816=12.1kN/m3中 3BC183BC2 8結(jié)構(gòu)力可用彎矩分配法計(jì)算并可利用結(jié)構(gòu)對稱性去二分之一結(jié)構(gòu)計(jì)算。各桿的固端彎矩為：11M=—g12=x19.76x5.42=48.02kN?m3AB123邊邊1211M=_g' 12=_x12.1x1.22=5.81kN?m3BC 30中中 3M=1g'12=1x12.1x1.22=2.9kN?m3cb 6 中中6頂層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：（單位：k2m）0.4880.5110.1550.1480.697A-1A-BB-AB-2B-CC-B-48.0248.02-5.81-2.9023.4324.54一12.27-4.22一-8.44-8.06-37.97一34.4352.062.16一1.08-0.16-0.16-0.75一0.7525.48-25.5452.77-8.22-44.5335.82（2）中間層g'=g+(1—2a2+a3)g邊AB1 1 1AB2=4.09+(1—2x0.3332+0.3333)x12.564=14.33kN/m=g+5g=4.09+5x8.376=9.325kN/mBC1 8BC2 8結(jié)構(gòu)力可用彎矩分配法計(jì)算并可利用結(jié)構(gòu)對稱性去二分之一結(jié)構(gòu)計(jì)算。各桿的固端彎矩為：11M=一g12= x14.33x5.42=34.82kN?mAB12邊邊1211M=_g'12=_x9.325x1.22=4.476kN?mbc3中中3M=1g'12=1x9.325x1.22=2.238kN?mcB6中中6中間層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：（單位：kWm）0.3280.3280.3440.1350.1290.1290.607A-1A-5A-BB-AB-2B-6B-CC-B-34.8234.82-4.476-2.23811.4211.4211.98一5.99-2.46一-4.91-4.69-4.69-22.05一22.050.810.810.85一0.43-0.06-0.06-0.060.26一0.2612.2312.23-25.4536.27-4.75-4.75-26.78620.072

中間層分層法彎矩計(jì)算結(jié)果（3）底層底層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：（單位：k2m）0.2930.3450.3620.1380.1120.1310.619A-1A-5A-BB-AB-2B-3B-CC-B-34.8234.82-4.476-2.23810.212.0112.60一6.30-2.53一-5.06-4.10-4.80-22.68一22.680.740.870.92一0.46-0.06-0.05-0.060.28一0.2810.9412.88-23.8336.46-4.15-4.86-27.43620.722

底層層分層法彎矩計(jì)算結(jié)果二次分配不平衡彎矩：標(biāo)準(zhǔn)層傳給頂層的彎矩分配：0.4880.5110.1550.1480.697A-1A-BB-AB-2B-CC-B4.08-1.58-1.99-2.08一-1.04-0.21一0.410.391.83一-1.830.100.11一-0.060.0090.0080.04一-0.04

2.19-1.991-0.681-1.1821.87-1.87底層、頂層傳給標(biāo)準(zhǔn)層的彎矩分配：0.3280.3280.3440.1350.1290.1290.607ATA-2A-BB-AB-2B-3B-CC-B4.298.49-1.62-2.74-4.19-4.19-4.40T-2.20.445一0.890.850.853.98T-3.98-0.146-0.146-0.153T-0.770.010.010.010.05T-0.05-0.0464.154-4.108-1.287-0.76-1.884.03-4.標(biāo)準(zhǔn)層傳給底層的彎矩分配：0.2930.3450.3620.1380.1120.1310.619A-1A-2A-BB-AB-2B-3B-CC-B4.08-1.58-1.195-1.408-1.477T-0.7390.16一0.320.260.3041.44T-1.44-0.05-0.06-0.06-1.2453.612-1.377-0.4190.26-1.2761.44-1.44跨中彎矩計(jì)算：一1 22.67+52.089M =—x19.76x5.42 =32.146kN?m3AB8 21M =—x12.1x2.42-42.66=—33.948kN?m3BC81 1 29.558+34.983M =~x14.33x5.42- 二19.962kN?m2AB8 2

M =1x9.325x2.42-22.756=—16.042kN-m2BC8i1 25.207+36.041M=_x14.33x5.42 二21.609kN?m1A38 21M=-x9.325x2.42-25.996=—19.282kN?m13C8剪力計(jì)算：V33A27.67—52.089+1x19.76x5.42 2 =V33A5.4V=19.76x5.4—48.83=57.874kN3A31x12.1x2.42V=V=2 =14.52kN3BC 3CB 2.429.558-34.983+1x14.33x5.42V= 2 =37.69kN2BA 5.4V=14.33x5.4-37.69=39.692kN2ABx9.325x2.42V=V=2 =11.19kN2BC 2CB 2.425.207-36.04+1x14.33x5.42= 2 =36.68kN1BA 5.4=14.33x5.4-36.68=40.702kNABx9.325x2.42V=V=2 =11.19kN1BC 1CB 2.4軸力計(jì)算：N=109.674+57.874=167.548kNA3N=153.053+48.83+14.52=216.403kNB3N=167.548+115.639+39.692=322.879kNA2N=216.403+126.829+37.69+11.19=392.112kNB2N=322.879+115.639+40.702=479.22kNA1N=399.112+126.829+36.68+11.19=567.521kNB1框架在恒荷載下的梁剪力，柱軸力圖彎矩調(diào)幅：D2、活荷載作用下的力計(jì)算把梯形荷載轉(zhuǎn)化作等效均布荷載。（1）頂層p'=(1-2a2+a3)p3邊 1 1 3AB=(1-2x0.3332+0.3333)x1.8=1.467kN/mp'=5p=5x1.2=0.75kN/m3中83BC 8各桿的固端彎矩11M=一p12= x1.467x5.42=3.564kN?m3AB123邊邊1211M=-p'12=x0.75x1.22=0.36kN?m3BC33中中311M=-p' 12=-x0.75x1.22=0.18kN?m3CB63中中6頂層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：(單位：女山m)0.4880.5110.1550.1480.697A-1A-BB-AB-2B-CC-B-3.5643.564-0.36-0.181.741.82一0.91-0.32一-0.64-0.61-2.87一2.870.1560.1631.896-1.9013.834-0.61-3.232.69(2)中間層p'=(1-2a2+a3)p邊 1 1AB二(1-2x0.3332+0.3333)x12.6=10.27kN/mp=5p二5頂層分雪彎矩N/m果中8BC8各桿的固端彎矩11M=一p12= x10.27x5.42=24.96kN?mAB12邊邊1211M=_p'12=_x5.25X1.22=2.52kN?mbc3中中3M=1p'12=1x5.25X1.22=1.26kN?mCB6中中6中間層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：(單位：kMm)20.3280.3280.3440.1350.1290.1290.607A-1A-2A-BB-AB-2B-3B-CC-B-24.9624.96-2.52-1.268.198.198.59一4.295-1.805一-3.61-3.45-3.45-16.23一16.23

0.590.590.62一0.31-0.04-0.04-0.04-0.19一0.198.788.78-17.55525.915-3.49-3.49-18.9415.16（3）底層底層彎矩計(jì)算。彎矩分配法計(jì)算力過程如表：（單位：k2m）0.2930.3450.3620.1380.1120.1310.619ATA-2A-BB-AB-2B-3B-CC-B-24.9624.96-2.52-1.267.318.619.04一4.52-1.86一-3.72-3.02-3.53-16.69一16.690.540.640.67一0.335-0.05-0.04-0.04-0.21一0.217.859.25-17.1126.045-3.06-3.57-19.4215.64

二次分配不平衡彎矩：標(biāo)準(zhǔn)層傳給頂層的彎矩分配：A-1A-BB-AB-3B-CC-B2.93-1.16-1.43-1.5底層分層法彎矩計(jì)算結(jié)7果0.15一0.30.281.33一-1.33-0.07-0.081.43-1.43-0.45-0.881.33-1.330.4880.5110.1550.1480.697底層、頂層傳給標(biāo)準(zhǔn)層的彎矩分配：0.3280.328 0.344 0.135 0.1290.129 0.607A-1A-2 A-B B-A B-2B-3 B-C C-B3.080.632 -1.19-0.203-1.22-1.22 -1.28 - -0.640.135 - 0.27 0.260.26 1.23 - -1.23-0.04-0.04 -0.05 —1.82-0.628-1.195 -0.37 -0.930.057 1.23 -1.13標(biāo)準(zhǔn)層傳給底層的彎矩分配：0.2930.3450.3620.1380.1120.1310.619ATA-2A-BB-AB-2B-3B-CC-B2.93-1.16-0.86-1.01-1.06一-0.5030.115一0.230.190.221.03一-1.03-0.03-0.04-0.04-0.891.88-0.985-0.7330.19-0.941.03-1.03跨中彎矩計(jì)算：一1 3.326+3.384M =—x1.467x5.42 =1.99kN-m3AB8 21M =—x0.75x2.42-1.9=-1.36kN?m3BC81 18.75+25.545M=—x10.27x5.42- 二15.29kN?mTOC\o"1-5"\h\z\o"CurrentDocument"2AB8 2\o"CurrentDocument"M=-x5.25x2.42-17.71=-13.93kN-m2BC 81 1 18.095+25.312M=_x10.27x5.42 二15.73kN?m\o"CurrentDocument"1A3 8 21M=-x5.25x2.42-18.39=-14.61kN?m13C8

3.326框架在活荷載下的彎矩圖剪力計(jì)算：3.326-3.384+1x1.467x5.42= 2 =3.95kN3BA 5.4=1.467x5.4—3.95=3.97kN3ABx0.75x2.42V=V=2 =0.9kN3BC 3CB 2.418.75-25.545+1x10.27x5.42V= 2 =26.47kN2BA 5.4V=10.27X5.4—26.47=28.988kN2AB-X5.25X2.42V=V=2 =6.3kN2BC 2CB 2.418.095—25.312+-x10.27x5.42V= 2 =26.39kN1BA 5.4V=10.27x5.4-26.39=29.068kNABx5.25x2.42V=V=2 =6.3kN2BC 2CB 2.4軸力計(jì)算：N=6.48+3.97=10.45kNA3N=10.08+3.95+0.9=14.93kNB3N=45.36+28.988+10.45=84.798kNA2N=70.56+26.47+6.3+14.93=118.26kNB2N=45.36+29.068+87.798=159.226kNA1N=70.56+26.39+6.3+118.26=221.51kNB1框架在活荷載下的梁剪力，柱軸力圖彎矩調(diào)幅：3、風(fēng)荷載作用下的力計(jì)算 P3=7.582VP3=7.582 K=0.94ac=0.32V=1.30K=3.07ac=0.61V=2.49P2=15.163K=0.94K=3.07ac=0.32ac=0.61VP2=22.745V=3.91V=7.46P1=16.472K=1.23K=4.01ac=0.54ac=0.75VP1=39.172V=8.2V=11.39A B風(fēng)荷載作用下剪力在各柱間分配y0=0.35y0=0.45M上=3.042M上=4.93M下=1.638M下=4.03y0=0.45y0=0.5M上=7.74M上=13.428M下=6.33M下=13.428y0=0.59y0=0.55M上=15.8M上=24.09M下=22.73M下=29.44AB風(fēng)荷載作用下各柱反彎點(diǎn)及柱墻彎矩三1,1T 4尸二—二■T77B三一，CD13.428--I■一門9.378,□.3/_三 -/工心 _?,086^P._3二二S7風(fēng)荷載作用下的框架彎矩圖風(fēng)荷載作用下框架剪力軸力圖五、力組合根據(jù)上述力計(jì)算結(jié)果，即可進(jìn)行框架各梁柱各控制截面上的力組合，其中梁的控制截面為梁端柱邊及跨中，由于對稱性，每層梁有5個(gè)控制截面。柱分為邊柱和中柱，每根柱有2個(gè)控制截面。力組合使用的控制截面標(biāo)于下圖。TOC\o"1-5"\h\z\o"CurrentDocument"6T TT 一5 W3 21 □口WW M梯糖面

梁和柱力組合表：柱力組合表樓層柱截面①恒荷載②活荷載③風(fēng)荷載④恒載x1.2+活載x1.4^恒載x1.2+0.9x⑤（活載x1.4+風(fēng)載x1.4）Nmax,，MNmin，MSmaxN,V頂層AM626.673.326±3.02436.3278M516.3848.152±1.63830.258436.81340.00840.008N167.58410.45m0.84214.6858245.303243.088243.088V ±1.3 1.479BM6-9.402-1.49±4.93-13.2194-28.403-13.764-28.403M5-6.63-3.433±4.03-12.4189-23.745-14.640-23.745N216.40314.93m1.69279.0926330.131319.469330.131V ±2.49 -3.297中間層AM412.81410.6±7.7429.156826.35143.92543.926M315.49211.3±6.3333.280435.92349.90249.902N322.87984.798m3.55497.6922587.715578.874570.062V ±3.91 4.438BM4-5.51-4.42±13.428-12.358-38.5210.653-38.521M3-6.136-4.51±25.974-13.2262-36.806-4.754-36.806N392.12118.26m7.34624.282782.054736.941782.054V ±7.46 -9.892底層AM29.6956.96±15.820.68210.79942.35942.359M15.473.925±22.7311.6665-15.98146.66646.666N479.22159.26m9.805782.102917.195890.518890.518V ±8.2 -10.022BM2-3.89-2.87±22.73-8.399-44.07517.922-44.075M1-2.075-1.53±29.44-4.479-44.99830.776-44.998N567.521221.51m15.4968.98821249.5271136.2881136.288V±11.39-14.656六、側(cè)移驗(yàn)算7.5820.567x2+1.264x2=2.070mmAu2.07 10=——3= =0.575x10-3<一3h3.6x103 5503，可以。Au222.7450.567x2+1.264x2=6.211mmAu~h26.2113.6x103=1.725x10-3<1550，可以。AuAu1=14.542mm39.1750.547x2+0.8x2制。Au 39.175=—1二 1h 4.7x1031=3.094x10-3>1550，底層框架層間位移角01過大，超過限七、梁的截面設(shè)計(jì)由混凝土強(qiáng)度等級為C30，受力鋼筋采用HRB335查表，f=14.3N/mm;f=1.43N/mm;f=300N/mmcty，截面尺寸為300mmx550mm，f 1.43p=0.45x。=0.45x一=0.2145%<0.2%。b'=7200/3=2400mm，保護(hù)層min f 300 fyv厚度取25mm。頂層：1截面：Mafbh21c033.28x1061x14.3x300x5252=0.0285=1-1-2a=1-<1-2x0.028=0.028Sswordword資料aabhf0.028義0.028義300*525*14.3「℃A=J-占= =5.88mm2f 300y402 h .一取2B16，A=402mm2。p= =0.253%>p?—=0.231%滿足s 300義525 minh02截面：Mafbh21c053.16x1061x14.3x300x5252=0.0455=1-1