天桥桥墩计算书

1、一设计概述该天桥桥墩采用变截面薄壁墩，墩顶由2m变为1m，桥墩纵向宽为0.7m，墩高为11m，跨径布置为（30.5+30.5）m，上部结构宽为4.3m，为人行天桥。本计算针对刚箱梁墩身。二设计标准及设计参数2.1设计规范及技术资料计算中主要用到的规范包括：（1）公路桥涵设计通用规范（JTG D602004）（2）公路钢筋混凝土及预应力混凝土桥涵设计规范（JTG D622004）（3）公路桥涵地基与基础设计规范（JTJ D632007）2.2技术标准（1）结构重要性系数：1.1（2）荷载标准车辆荷载：采用城市-A级计算人群荷载：3.5KN/m三. 主要材料及其设计参数设计中墩身采用C40混凝土，

2、基础采用C25混凝土，普通钢筋采用HRB400、HPB300钢筋。各种材料设计参数见表2.2.1表2.2.2。表2.2.1 混凝土设计参数强度等级弹性模量(Mpa)容重(kN/m3)线膨胀系数标准值设计值fck(Mpa)ftk(Mpa)fcd(Mpa)ftd(Mpa)C40C32 ZHU073.25×10425.001.000e-00526.82.4018.41.65C25C32 ZHU072.80×10425.001.000e-00516.71.7811.51.23表2.2.2 普通钢筋设计参数普通钢筋弹性模量(MPa)容重(kN/m3)线膨胀系数fsk(MPa)fsd(

3、MPa)f'sd(MPa)HRB4002.0×10578.001.000e-005400.00360.00360.00HPB3002.1×10578.001.000e-005300.00270.00270.00四 设计荷载取值4.1外部荷载（单位:kN）恒载： 活载：4.2 汽车荷载本桥为人行天桥，故无制动力和离心力。4.3风荷载风荷载参照公路桥涵设计通用规范（JTG D602004）进行计算。桥址处设计基本风速为26.7m/s，当风荷载参与汽车荷载组合时，墩身顺桥向风荷载标准值按横向风压的70乘以桥墩迎风面积计算。墩身风荷载计算结果如下：风荷载计算桥墩高度11地表

4、类别c桥向(横桥向为1,纵桥向为0)0V10=27.5k0=0.9k1=1.67k3=1k5=1.7高度r(空气重力密度)(KN/m3)k2Vd(m/s)W0(kN/m2)Wd(kN/m2)桥墩宽度(m)q(kN/m)50.0120109930.86 40.21 0.46 0.99 1.0 1.04 100.0120049890.86 40.21 0.46 0.99 1.0 1.04 150.0119989880.86 40.21 0.46 0.99 2.0 2.08 五、使用阶段桥墩计算1）、桥墩稳定验算 成桥阶段桥墩为下端固定上端为铰接，故计算长度系数u=0.7，出于安全考虑本部分计算计算

5、长度系数偏安全取为u=0.8。用欧拉公式计算临界力，如下式中：E-3.25×104Mpa，I-0.00427m4，L0-11.0×0.8=8.8m，所以Ncr=17668.7KN。偏于安全考虑墩顶荷载按梁部荷载加一半墩身重，N=811.1KN,则稳定安全系数为0.046，整体稳定符合要求。2）、桥墩承载能力极限状态验算结构单元离散图见下图：取桥墩风荷载作为水平力加载，竖向荷载为恒载892.8KN，活载459KN,带入MIDAS模型就行桥墩验算，结果如下：单元位置组合 名称类型验算x (mm)rNd (kN)e (mm)e' (mm)Nn (kN)1I1cLCB1偏心

6、-MymaxOK0.00001178.49600.00000.000029295.67901I1cLCB1偏心-MyminOK0.00001178.49600.00000.000029295.67901I1cLCB2偏心-Fxmin(My)OK0.00001885.35600.00000.000029295.67901I1cLCB2轴心-FxminOK0.00001885.35600.00000.000029295.67901J2cLCB2偏心-Fxmin(My)OK0.00001934.77680.00000.000029295.67901J2cLCB2轴心-FxminOK0.0000193

7、4.77680.00000.000029295.67901J2cLCB3偏心-MymaxOK800.00001227.9168363.9881-336.011931953.20571J2cLCB4偏心-MyminOK800.00001227.9168363.9881-336.011931953.20572I2cLCB2偏心-Fxmin(My)OK0.00001934.77680.00000.000026149.27902I2cLCB2轴心-FxminOK0.00001934.77680.00000.000026149.27902I2cLCB3偏心-MymaxOK800.00001227.916

8、8363.9881-336.011928414.62852I2cLCB4偏心-MyminOK800.00001227.9168363.9881-336.011928414.62852J3cLCB2偏心-Fxmin(My)OK0.00001978.02000.00000.000026149.27902J3cLCB2轴心-FxminOK0.00001978.02000.00000.000026149.27902J3cLCB3偏心-MymaxOK800.00001271.1600366.9202-333.079828187.56072J3cLCB4偏心-MyminOK800.00001271.160

9、0366.9202-333.079828187.56073I3cLCB2偏心-Fxmin(My)OK0.00001978.02000.00000.000023002.87903I3cLCB2轴心-FxminOK0.00001978.02000.00000.000023002.87903I3cLCB3偏心-MymaxOK800.00001271.1600366.9202-333.079824677.26113I3cLCB4偏心-MyminOK800.00001271.1600366.9202-333.079824677.26113J4cLCB2偏心-Fxmin(My)OK0.00002015.0

10、8560.00000.000023002.87903J4cLCB2轴心-FxminOK0.00002015.08560.00000.000023002.87903J4cLCB3偏心-MymaxOK800.00001308.2256371.1325-328.867524397.17893J4cLCB4偏心-MyminOK800.00001308.2256371.1325-328.867524397.17894I4cLCB2偏心-Fxmin(My)OK0.00002015.08560.00000.000019856.47904I4cLCB2轴心-FxminOK0.00002015.08560.00

11、000.000019856.47904I4cLCB3偏心-MymaxOK800.00001308.2256371.1325-328.867520926.72054I4cLCB4偏心-MyminOK800.00001308.2256371.1325-328.867520926.72054J5cLCB2偏心-Fxmin(My)OK0.00002045.97360.00000.000019856.47904J5cLCB2轴心-FxminOK0.00002045.97360.00000.000019856.47904J5cLCB3偏心-MymaxOK800.00001339.1136376.1075-

12、323.892520649.90944J5cLCB4偏心-MyminOK800.00001339.1136376.1075-323.892520649.90945I5cLCB2偏心-Fxmin(My)OK0.00002045.97360.00000.000016710.07905I5cLCB2轴心-FxminOK0.00002045.97360.00000.000016710.07905I5cLCB3偏心-MymaxOK800.00001339.1136376.1075-323.892517225.35705I5cLCB4偏心-MyminOK800.00001339.1136376.1075-

13、323.892517225.35705J6cLCB2偏心-Fxmin(My)OK0.00002071.37040.00000.000016710.07905J6cLCB2轴心-FxminOK0.00002071.37040.00000.000016710.07905J6cLCB3偏心-MymaxOK800.00001364.5104382.0311-317.968916958.27175J6cLCB4偏心-MyminOK800.00001364.5104382.0311-317.968916958.27176I6cLCB2偏心-Fxmin(My)OK0.00002071.37040.00000

14、.000016710.07906I6cLCB2轴心-FxminOK0.00002071.37040.00000.000016710.07906I6cLCB3偏心-MymaxOK800.00001364.5104382.0311-317.968916958.27176I6cLCB4偏心-MyminOK800.00001364.5104382.0311-317.968916958.27176J7cLCB2偏心-Fxmin(My)OK0.00002096.76720.00000.000016710.07906J7cLCB2轴心-FxminOK0.00002096.76720.00000.000016

15、710.07906J7cLCB3偏心-MymaxOK800.00001389.9072388.6936-311.306416667.59426J7cLCB4偏心-MyminOK800.00001389.9072388.6936-311.306416667.59427I7cLCB2偏心-Fxmin(My)OK0.00002096.76720.00000.000016710.07907I7cLCB2轴心-FxminOK0.00002096.76720.00000.000016710.07907I7cLCB3偏心-MymaxOK800.00001389.9072388.6936-311.306416

16、667.59427I7cLCB4偏心-MyminOK800.00001389.9072388.6936-311.306416667.59427J8cLCB2偏心-Fxmin(My)OK0.00002122.16400.00000.000016710.07907J8cLCB2轴心-FxminOK0.00002122.16400.00000.000016710.07907J8cLCB3偏心-MymaxOK800.00001415.3040396.0553-303.944716357.78497J8cLCB4偏心-MyminOK800.00001415.3040396.0553-303.944716

17、357.78498I8cLCB2偏心-Fxmin(My)OK0.00002122.16400.00000.000016710.07908I8cLCB2轴心-FxminOK0.00002122.16400.00000.000016710.07908I8cLCB3偏心-MymaxOK800.00001415.3040396.0553-303.944716357.78498I8cLCB4偏心-MyminOK800.00001415.3040396.0553-303.944716357.78498J9cLCB2偏心-Fxmin(My)OK0.00002147.56080.00000.000016710

18、.07908J9cLCB2轴心-FxminOK0.00002147.56080.00000.000016710.07908J9cLCB3偏心-MymaxOK800.00001440.7008404.0792-295.920816032.96428J9cLCB4偏心-MyminOK800.00001440.7008404.0792-295.920816032.96429I9cLCB2偏心-Fxmin(My)OK0.00002147.56080.00000.000016710.07909I9cLCB2轴心-FxminOK0.00002147.56080.00000.000016710.07909I

19、9cLCB3偏心-MymaxOK800.00001440.7008404.0792-295.920816032.96429I9cLCB4偏心-MyminOK800.00001440.7008404.0792-295.920816032.96429J10cLCB2偏心-Fxmin(My)OK0.00002172.95760.00000.000016710.07909J10cLCB2轴心-FxminOK0.00002172.95760.00000.000016710.07909J10cLCB3偏心-MymaxOK800.00001466.0976412.7309-287.269115696.879

20、79J10cLCB4偏心-MyminOK800.00001466.0976412.7309-287.269115696.879710I10cLCB2偏心-Fxmin(My)OK0.00002172.95760.00000.000016710.079010I10cLCB2轴心-FxminOK0.00002172.95760.00000.000016710.079010I10cLCB3偏心-MymaxOK800.00001466.0976412.7309-287.269115696.879710I10cLCB4偏心-MyminOK800.00001466.0976412.7309-287.2691

21、15696.879710J11cLCB2偏心-Fxmin(My)OK0.00002198.35440.00000.000016710.079010J11cLCB2轴心-FxminOK0.00002198.35440.00000.000016710.079010J11cLCB3偏心-MymaxOK800.00001491.4944421.9783-278.021715352.890910J11cLCB4偏心-MyminOK800.00001491.4944421.9783-278.021715352.890911I11cLCB2偏心-Fxmin(My)OK0.00002198.35440.000

22、00.000016710.079011I11cLCB2轴心-FxminOK0.00002198.35440.00000.000016710.079011I11cLCB3偏心-MymaxOK800.00001491.4944421.9783-278.021715352.890911I11cLCB4偏心-MyminOK800.00001491.4944421.9783-278.021715352.890911J12cLCB2偏心-Fxmin(My)OK0.00002223.75120.00000.000016710.079011J12cLCB2轴心-FxminOK0.00002223.75120.

23、00000.000016710.079011J12cLCB3偏心-MymaxOK800.00001516.8912431.7915-268.208515003.968911J12cLCB4偏心-MyminOK800.00001516.8912431.7915-268.208515003.968912I12cLCB2偏心-Fxmin(My)OK0.00002223.75120.00000.000016710.079012I12cLCB2轴心-FxminOK0.00002223.75120.00000.000016710.079012I12cLCB3偏心-MymaxOK800.00001516.8

24、912431.7915-268.208515003.968912I12cLCB4偏心-MyminOK800.00001516.8912431.7915-268.208515003.968912J13cLCB2偏心-Fxmin(My)OK0.00002249.14800.00000.000016710.079012J13cLCB2轴心-FxminOK0.00002249.14800.00000.000016710.079012J13cLCB3偏心-MymaxOK552.79251542.2880442.1426-257.857411685.026012J13cLCB4偏心-MyminOK552.

25、79251542.2880442.1426-257.857411685.0260裂缝验算单元位置顶/底组合 名称类型验算Sig_SS (kN/mm2)W_tk (mm)W_AC (mm)1I1底cLCB18MY-MINOK0.03240.02760.21J2底cLCB18MY-MINOK0.03240.02670.22I2底cLCB18MY-MINOK0.02690.02220.22J3底cLCB18MY-MINOK0.02690.02110.23I3底cLCB18MY-MINOK0.0230.0180.23J4底cLCB17MY-MAXOK0.0230.0180.24I4底cLCB17MY-MAXOK0.0230.0180.24J5底cLCB18MY-MINOK0.0230.0180