【荆山南路大桥施工图设计】13000字【论文】

PAGE1-荆山南路大桥施工图设计目录TOC\o"1-3"\h\u120831引言 1169452设计资料 22762.1设计指标 2263722.2设计过程 2283763方案比选 415713.1自锚式悬索桥 4247973.2地锚式独立斜拉桥 5102503.3上承式拱桥 5248053.4方案比选 635523.5推荐方案调整 7143934桥梁模型的建立 9157485主梁内力计算 1361595.1恒载作用下主梁内力计算 1389255.1.1自重下主梁内力 13261325.1.2二期恒载下主梁内力 1463335.2可变作用下主梁内力计算 15220835.2.1正温度梯度下主梁内力 15322235.2.2负温度梯度下主梁内力 1611365.2.3移动荷载下主梁内力 17242575.2.4支座沉降下主梁内力 1849126内力组合 19172627预应力钢筋面积估算与配置 21171597.1预应力钢筋估算 21267367.1.1按正常使用极限状态的正截面抗裂验算要求估束 21194617.1.2按正常使用极限状态截面压应力要求估算 2393507.1.3按承载能力极限状态的应力要求计算 25218107.1.4估算结果 2622587.2预应力钢筋布置位置 261248预应力损失的计算 29306099持久状况承载能力极限状态验算 37304739.1正截面抗弯承载能力验算 3734989.2斜截面抗剪验算 372799.3斜截面抗弯承载能力验算 382395410持久状况正常使用极限状态验算 391991610.1使用阶段正截面压应力验算 391185410.2使用阶段斜截面主压应力验算 392935310.3预应力钢束拉应力的验算 401833911挠度计算和预拱度设置 411011411.1挠度验算 412373311.2预拱度设置 4111033结论 4228833参考文献 431引言当今世界随着经济快速发展，人们生活水平逐渐提高，出行方式逐渐发生变化，桥梁成为了当今世界必不可少的一部分，也是较为美观的建筑物之一，它的形状多种多样，不同形状对应的建造方式也各不相同。连续梁构造简单、外形美观、施工方式简单，本设计采用连续梁设计，简单方便。2设计资料2.1设计指标荆山南路大桥位于某市建设旅游路南段，该段桥宽20.2m，双向4车道，设计荷载为公路II级，设计车速60km/h。结构设计基准期100年，环境相对湿度75%，基本烈度6度，按7度设防。温度范围为-10℃～+34℃，计算温度+15℃～+20℃，温度梯度按《通用规范》计算，取10cm沥青砼铺装时的温度基数。主要设计指标有：1）设计荷载：公路II级2）桥面宽：0.75米（护栏）+8.85米（车行道）+1米（中央分割带）+8.85米（车行道）+0.75米（护栏）=20.2m3）设计车道：4车道4）设计车速：60km/h5）地震烈度：基本烈度6度，按7度设防6）桥面横坡：双向1.5%横坡7）桥面纵坡：2.5%以内2.2设计过程1）分析和整理基本设计资料，如：桥涵水文、地质、气象、施工条件等资料；2）设计方案的确定：包括桥型、桥长、桥梁分孔、总体布局及上下部结构立面图、平面图和横断面图等。3）完成结构设计计算应综合运用基础课、专业基础课、专业课及专业实习所积累的理论与实践知识，遵循桥梁设计规程等相关要求，在教师指导下，将确定的设计方案进行施工图的设计计算。计算内容包括：（1）行车道板的设计计算；（2）主梁的内力计算；（3）预应力钢束的设计计算；（4）预应力混凝土结构的强度与变形计算（5）墩台及基础设计计算（根据情况选做）4）完成主要施工图的绘制结构设计计算完成后，要求用CAD软件绘制桥梁结构施工图10张以上，主要包括：（1）桥梁总体布置图（立面、平面、横断面）（2）主梁一般构造图（3）主梁预应力钢筋布置图（4）主梁普通钢筋布置图（5）横隔梁构造、配筋图（6）桥墩（或桥台）一般构造图图纸要求布局合理，正确、清晰，符合制图标准和有关规定。5）最终成果：需提交毕业设计毕业设计说明书和结构主要施工图。3方案比选3.1自锚式悬索桥图3.1.1自锚式悬索桥初步拟定为对称双塔三跨布置，主跨径为60m。主桥为钢筋混凝土加劲梁的自锚式悬索桥，主梁顶板宽为20.2m，梁高为1m，塔高25m,塔柱的直径定为1.5m，主梁上吊杆间距为3m，基础采用钻孔灌注桩基础，桩直径为1.6m。该桥主缆矢跨比为1/8，双塔双索面结构，主缆锚固于加劲梁的两端，主缆产生的水平分力通过加劲梁来抵抗。自锚式悬索桥通常由主梁、桥塔、主缆、吊索、主索鞍、副索鞍等组成。它不需要有强大的锚碇，是直接把主缆锚于主梁端部，节省了昂贵的锚碇费用，同时主缆又对主梁施加了强大的预应力，使主梁结构受力大为改善，但是由于主缆直接锚固在加劲梁上，梁承受了很大的轴向力，为此需加大梁的截面，对于钢结构的加劲梁则造价明显增加，对于混凝土材料的加劲梁则增加了主梁自重，从而使主缆钢材用量增加，因此自锚式悬索桥若跨径增大，其额外的施工费用就会增多并且锚固区受力复杂难以判断。3.2地锚式独立斜拉桥图3.2.1地锚式独立斜拉桥独塔混凝土斜拉桥主跨77m，锚固跨23m。索塔选用倒Y形，高度30m。主跨拉索索面在空间布置成双索面，数量为10对，间距为6m；锚固跨拉索索面布置成单索面，数量10根，间距为0.8m。主跨拉索塔上索距取1.7米，锚固跨拉索塔上索距取1.5米。箱梁顶板宽度为15.5m，索塔根部梁高4m,桥台处梁高2.5m。斜拉桥又称斜张桥，是将主梁用许多拉索直接拉在桥塔上的一种桥梁。它的特点是桥梁跨度较大，有利于跨越很宽的障碍物，造型美观。桥体可调整主梁内力，使内力分布均匀合理，且能将主梁做成等截面梁，便于制造和安装。斜拉索的水平拉力相当于对混凝土梁施加的预压力，有助于提高梁的抗裂性能，并充分发挥高强材料的特性。桥梁的竖向刚度和抗扭刚度较强，抗风稳定性要好，且便于采用悬臂法施工和架设，施工安全可靠，适合在城市中建造。3.3上承式拱桥图3.3.1上承式拱桥初步拟定拱桥桥梁跨径为98m，矢跨比为1/7，采用上承式布置行车道。拱圈采用钢管混凝土拱肋，钢筋混凝土拱桥的矢跨比一般为1/5-1/8。拱桥构造简单，造型美观，造价低，能充分就地取材，拱桥最大的优点就是将桥面系传来的压力转化为轴向压力，所以不需要像其他桥梁一样要考虑受拉和受弯等情况。与梁式桥相比上承式拱桥的建筑高度较高，与中、下承式拱桥相比,上承式拱桥的桥面位置较中、下承式拱桥高。但其自重较大，相应的水平推力较大，随着跨径和桥高的增大，支架或其他辅助设备的费用大大无增加，从而增大了拱桥的施工困难，提高了拱桥的总造价。3.4方案比选表3.4.1方案比选方案类别比较项目方案一方案二方案三自锚式悬索桥桥（100m）地锚式独塔斜拉桥(77m+23m)（推荐方案）上承式拱桥（98m)工艺技术要求先梁后缆，塔梁同步，索夹抗滑移要求高，结构需要进行体系转换，受力复杂，造价较高。适应在城市桥梁中应用，兼顾桥墩施工难度和施工量、岸坡稳定、结构刚度、跨越能力等。工艺技术经验比较成熟，占用施工场地大，自重较大，需要用大量吊装设备和劳动力，水平推力较大。造价及用材工期较长、造价高、用钢量较高工期适中、造价适中、耗钢量较大工期较长、造价较高、用钢量较小美观造型美观整体造型美观，可能成为城市中观赏性建筑自重较大，不适合城市桥梁使用从上表可以看出，方案一虽然造型美观但工期较长、造价较高、施工较复杂，因为位于城市，施工简易程度是我们应该考虑的因素并且方案一相对方案二来说造价太高，工期太长。第二方案从工期和造价方面看都比较适中，适合作为城市桥梁，施工方法也较为成熟，抗风抗震性能好，整体造型美观。第三方案自重较大，需要人工较多，工期较长，造价较高，不经济。故经过了较为综合的比较后，决定对方案二进行推荐。3.5推荐方案调整前期报告推荐方案为地锚式独塔斜拉桥，桥梁总跨径为100m，主跨设置为77m，锚固跨设置为23m，索塔选用倒Y形，高度30m。但是在建模过程中发现调索难以达到要求，难以实现工程建造，所以将初拟方案调整为双跨连续梁桥。跨径组合为50m+50m，梁高3m，墩柱的直径定为2m。本桥采用满堂支架施工方法，此方法施工工艺简单，便于施工、可以平行作业，地基经过简单加固处理即可以满足承载力要求，投入少、有利于保证安全质量。图3.5.1荆山南路大桥立面图截面为单箱双室箱梁，箱梁全宽20.2m（0.75米护栏+8.85米车行道+1米中央分割带+8.85米车行道+0.75米护栏）。桥台处1m范围内和桥墩处2m范围内均为实心截面（如图1.2），主梁高度300cm，之后变为单箱双室底板渐变截面，梁高300cm，底板由80cm变为40cm，腹板由200cm变为100cm，均按线性变化，过渡段长度为12m，之后在24m范围内为跨中区段截面，箱梁底板厚度均为40cm，梁高300cm。图3.5.2桥台处实心箱形截面图3.5.3桥台处加厚截面图3.5.4跨中段截面4桥梁模型的建立1）选择单位体系：kN,m2）定义材料特性C50混凝土选用Midas中规范JTG3362-18（RC）中数据库相应的材料类型。预应力钢筋选用用户定义类型材料，规范JTG3362-18（S）数据库的Strand1860材料。3）定义截面特性将拟定好的截面尺寸，输入到midas中，定义好截面。4）节点、单元的建立桥长100m，离起点（0,0,0）0.48m处需设置活动支座因而在（0.48,0,0）处设置一个节点，距离起点1m处设置一个节点，往后每2m设置一个节点，中间支座处每1m设置一个节点（49m、50m、51m），且在每跨的0.125、0.25、0375、0.5、0.625、0.75、0.875处均设置一个节点，桥梁成对称结构节点也对称，均用梁单元模拟。共设置79个节点，66个梁单元。图4.1.1建立节点图4.1.2建立单元5）定义时间依存性材料定义混凝土的徐变收缩特性，建立时间依存性材料连接，并应用修改单元依存材料特性值功能计算构件的理论厚度。6）添加边界条件支座处设置六个一般支撑,同时设置六个弹性连接节点（68,0)(76,78)对应约束为（Dx,Dy,Rx,Rz);(67,71)（77,79）对应约束为(Dx,Rx,Rz)；（72,74）对应约束为（Dx，Dy，Dz，Rx，Rz）；（73.75）对应约束为（Dx,Dz,Rx,Rz)图4.1.3一般支承桥墩在与主梁连接处采用刚性连接，刚性连接的功能是强制从属节点的自由度从属于主节点。包括从属节点的刚度分量在内的从属节点的所有属性(节点荷载或节点质量)均将转换为主节点的等效分量。主节点为相交处主梁上的节点，从属节点为桥墩最上端节点。图4.1.4刚性连接7）添加荷载工况（1）箱梁自重Midas程序中默认混凝土容重为25kN/m3，实际取混凝土容重为26kN/m3。所以在定义自重荷载时，自重系数=26/25=1.04,考虑Z轴方向为-1.04。（2）二期恒载二期恒载为桥面铺装和护栏的重力，以梁单元荷载进行加载。单个护栏每延米混凝土体积取0.15m3，沥青混凝土重度取24kN/m3。q护栏=0.15×25×4=30KN/mq铺装=0.5×（0.02+0.15275）×8.85×2×25+0.08×8.85×2×24=48.3549375KN/m二期恒载集度：q二期=q护栏+q铺装=78.3549375KN/m图4.1.5二期恒载（3）系统温度温度范围为-10℃～+34℃，计算温度+15℃～+20℃，取平均值17.5，整体升温17.5℃，整体降温-17.5℃。（4）梁截面温度计算桥梁结构由于竖向温度梯度引起的效应时，选用梁截面温度，取10cm沥青混凝土铺装时的温度基数。由通用规范可知，梁截面升温时距顶板h=0m处的温度为T1=14℃；h=0.1m,T2=5.5℃；h=0.3m,T3=5.5÷3=1.83℃，h=0.4m,T4=0℃。梁截面降温时竖向日照反温差为正温差乘以-0.5，故可知距顶板h=0m,T1=-7℃；h=0.1m,T2=-2.75℃，h=0.3m,T3=-0.917℃，h=0.4m,T4=0℃。梁截面降温时距顶板h=0m,T=-7℃；h=0.1m,T=-2.75℃；h=0.4m,T=0℃。8）移动荷载定义首先选择移动荷载规范中的中国规范China，然后添加四个车道荷载和一个车辆荷载，再添加移动荷载工况，标准车辆荷载选择中国城市桥梁荷载规范。9）定义支座沉降设置三个支座沉降组，均设为-0.01m。5主梁内力计算5.1恒载作用下主梁内力计算5.1.1自重下主梁内力图5.1.1自重作用下弯矩图图5.1.2自重作用下剪力图表5.1.1自重作用下控制截面的内力位置单元荷载轴向(kN)剪力-z(kN)弯矩-y(kN*m)左跨支点处2自重47.86-11938.35-239.43左跨1/410自重-12.32-3326.1586612.58左跨1/218自重47.863126.187837.49左跨3/426自重-98.569577.658460.22中墩支点34自重-1988.07-18154.83-162136.625.1.2二期恒载下主梁内力图5.1.3二期恒载作用下弯矩图图5.1.4二期恒载作用下剪力图表5.1.2二期恒载作用下控制截面的内力单元荷载轴向(kN)剪力-z(kN)弯矩-y(kN*m)左跨支点处2二期恒载6.68-1480.06-23.65左跨1/410二期恒载-3.05-538.2712106.79左跨1/218二期恒载6.68441.212713.38左跨3/426二期恒载-15.031420.571076.92中墩支点34二期恒载-261.01-2385.94-22802.85.2可变作用下主梁内力计算5.2.1正温度梯度下主梁内力图5.2.1正温度梯度下主梁弯矩图图5.2.2正温度梯度下主梁剪力图表5.2.1温度梯度升温作用下控制截面的内力单元荷载轴向(kN)剪力-z(kN)弯矩-y(kN*m)左跨支点处2温度梯度升温-18.23-401.8829.83左跨1/410温度梯度升温-25.47-401.494859.17左跨1/218温度梯度升温-18.23-401.889882.51左跨3/426温度梯度升温-12.07-402.1114906.1中墩支点34温度梯度升温26.8401.419930.525.2.2负温度梯度下主梁内力图5.2.3负温度梯度下弯矩图图5.2.4负温度梯度下剪力图表5.2.2温度梯度降温作用下控制截面的内力单元荷载轴向(kN)剪力-z(kN)弯矩-y(kN*m)左跨支点处2温度梯度降温9.12201-14.92左跨1/410温度梯度降温12.74200.8-2430.28左跨1/218温度梯度降温9.12201-4942.67左跨3/426温度梯度降温6.04201.11-7455.19中墩支点34温度梯度降温-13.4-200.76-9968.115.2.3移动荷载下主梁内力图5.2.9移动荷载作用下弯矩图图5.2.10移动荷载作用下剪力图表5.2.3移动荷载作用下控制截面的内力单元荷载轴向(kN)剪力-y(kN)剪力-z(kN)扭矩(kN*m)弯矩-y(kN*m)弯矩-z(kN*m)左跨支点处2移动荷载3.1715.49115.173258.071.044.02左跨1/410移动荷载6.1415.49293.412903.848158.88204.31左跨1/218移动荷载3.1715.49588.942927.619944.2346.32左跨3/426移动荷载3.6715.49906.13060.585955.16517.3中墩支点34移动荷载1.0515.568.543318.42362.49992.645.2.4支座沉降下主梁内力图5.2.11支座沉降作用下弯矩图图5.2.12支座沉降作用下剪力图表5.2.4支座沉降作用下控制截面的内力单元荷载轴向(kN)剪力-z(kN)弯矩-y(kN*m)左跨支点处2支座沉降4.13121.68.75左跨1/410支座沉降1.89121.651480.14左跨1/218支座沉降4.13121.63028.39左跨3/426支座沉降6.03121.524576.59中墩支点34支座沉降17.95122.626124.66内力组合为了进行预应力钢束的计算，在不考虑预加力引起的结构次内力及混凝土收缩徐变次内力的前提下，根据《公路桥涵设计通用规范》（JTGD60-2015）中的规定进行组合。1）承载能力极限状态组合γ0Sud=1.0×[1.2×（G1k（一期恒载）+G2k(二期恒载)）+0.5×G3k(基础变位)+1.4×Q1k(汽车荷载)+0.75×1.4×Q2k（温度梯度）]2）正常使用极限状态频遇组合Sfd=G1k（一期恒载）+G2k(二期恒载)+G3k(基础变位)+0.7×Q1k(汽车荷载不计冲击力)+0.8×Q2k（温度梯度）3）正常使用极限状态准永久组合Sqd=G1k（一期恒载）+G2k(二期恒载)+G3k(基础变位)+0.4×Q1k(汽车荷载不计冲击力)+0.8×Q2k（温度梯度）根据上述的组合要求，进行承载能力极限状态内力组合和正常使用极限状态内力组合，其结果见下表。表6.1基本组合截面位置最大最小剪力（KN）弯矩（KN*m）剪力（KN）弯矩（KN*m）左跨0.00L-26013.55-660.11-27676.25-1062.520.25L-6657.9200783.91-8034.96187596.570.50L8621.54198667.177275.40181161.590.75L23928.42783.2922456.41-10971.121.00L-42952.04-402716.55-44670.70-414121.53注：上述组合汽车荷载计冲击力表6.2频遇组合截面位置最大最小剪力（KN）弯矩（KN·m）剪力（KN）弯矩（KN·m）左跨0.00L-26319.86-904.51-27111.60-1096.130.25L-7097.76197231.42-7753.50190951.700.50L7967.60196582.447326.58188246.400.75L23044.436392.8122343.48-156.911.00L-42737.76-392303.39-43556.2-397734.00注：上述组合汽车荷载不计冲击力表6.3准永久组合截面位置最大最小剪力（KN）弯矩（KN·m）剪力（KN）弯矩（KN·m）左跨0.00L-25998.05-652.72-26463.70-688.130.25L-6891.12192797.56-7356.98187234.800.50L7973.39191796.807507.75180413.500.75L22835.75103.7122370.40-12099.801.00L-42677.61-389066.01-43143.20-412089.00注：上述组合汽车荷载不计冲击力；以上均为左边半桥的截面。7预应力钢筋面积估算与配置根据《公预规》，预应力混凝土连续梁应满足使用荷载下的正截面抗裂要求、正截面压应力要求和承载能力极限状态下的正截面强度要求。因此，预应力筋的数量可从这三个方面综合评定。根据正负弯矩分配在1到24单元只在下缘配筋，在25到26单元上下缘均需配筋，在27到34单元需在上缘配筋。（以上均为最少配筋）表7.1正负弯矩对应单元与数值（单位KN·m）单元MsmaxMsminMkmaxMkmin2-652.72-688.13-654.64-977.4810198225186382.55200448.24185465.9414222059.71205741.2224590.89204349.6818198394.64178675.34200696.13176808.832520229.27-3422.2220790.03-6201.75269026.68-14726.599483.73-17544.3934-388837.12-417290.71-390734.23-421903.297.1预应力钢筋估算7.1.1按正常使用极限状态的正截面抗裂验算要求估束根据《公预规》第6.3.1条，预应力混凝土受弯构件应对正截面的混凝土拉应力进行验算，以满足正截面抗裂要求。－在作用（或荷载）短期效应组合下构件的抗裂验算边缘混凝土的法向拉应力，式中不含正负号；－扣除全部预应力损失后的预加力在构件抗裂验算边缘产生的预压应力。由于此处为估算预应力束，截面特性可以粗略地按毛截面特性计算。当截面承受正弯矩时当截面承受负弯矩时、－作用（或荷载）短期效应组合，弯矩的最大值和最小值；、－截面形心轴上侧和下侧配置的预应力筋的永存预应力；、－截面形心轴上侧和下侧配置的预应力束与形心轴之间的距离；、－截面上缘和下缘的抗弯模量，，，（、为截面的上、下核心距）若上下缘均需布置预应力钢筋，已知下缘布置钢筋根数时，可由下式求上缘布置钢筋根数：分别求解可得预应力筋根数估算：采用的每根钢绞线面积，抗拉强度标准值，张拉控制应力取，预应力损失按张拉控制应力的估算，取。取预应力钢筋重心距下缘距离为0.15m，ex=yx-0.15=1.6568-0.15=1.5068m。1)估算左跨跨中截面所需预应力筋数量Msmax=198394.64KN/m，Msmin=178675.34KN/m代入公式可得：694.5根≤nxy≤2616.7根2)估算正弯矩最大处所需预应力筋数量Msmax=222059.71KN/m，Msmin=205741.20KN/m代入公式可得：777.3根≤nxy≤3031.1根（2）只在截面上缘布置预应力筋1)左跨右支点处分别求解可得预应力筋根数估算：Msmax=-388837.12KN/m，Msmin=-417290.71KN/m，取预应力钢筋重心距上缘距离为0.15m，es=1.3432-0.15=1.1932m代入公式可得：1550.1根≤nys≤7505.1根2）左跨左支点处Msmax=-652.72KN/m，Msmin=-688.13KN/m代入公式可得：2.6根≤nys≤12.6根（3）在25、26单元处Msmax=20229.27KN/m，Msmin=-14726.59KN/m代入公式可得：nys≤-390.4根，nys≥54.7根（此处上下缘均需配筋）7.1.2按正常使用极限状态截面压应力要求估算根据《公预规》第7.1.5条使用阶段预应力混凝土受弯构件的压应力应符合下面规定：－由作用（或荷载）标准值产生的混凝土受压边缘的法向压应力，；－由预应力产生的混凝土法向拉应力；－混凝土轴心抗压强度标准值；－按作用（或荷载）标准值组合计算的弯矩值；－受弯侧的抗弯模量。由于此处为估算值，所有应力计算均可粗略地选用毛截面特性。与抗裂要求估算类似，可得到以下两个不等式：、－按作用（或荷载）标准值组合的计算弯矩最大值、最小值；其余各符号同上。（1）只在截面下缘布置预应力筋采用的每根钢绞线面积，抗拉强度标准值，张拉控制应力取，预应力损失按张拉控制应力的估算，取，混凝土轴心抗压强度标准值。估算左跨跨中截面下缘所需预应力筋数量由midas软件计算标准值组合Mkmax=200696.13KN/mMkmin=176808.83KN/m代入公式得：-1265.6根≤nyx≤1196.1根估算最大正弯矩截面下缘所需预应力筋数量由midas软件计算标准值组合Mkmax=224590.89KN/m,Mkmin=204349.68KN/m代入公式得：-985.7根≤nyx≤1273.2根（2）只在截面上缘布置预应力筋1)左跨右支点处由midas软件计算标准值组合Mkmax=-390734.23KN/m，Mkmin=-421903.29KN/m代入公式可得：-2650根≤nys≤2078.6根2）左跨左支点处由midas软件计算标准值组合Mkmax=-654.64KN/m，Mkmin=-977.48KN/m代入公式可得：-3849.6根≤nys≤919.4根7.1.3按承载能力极限状态的应力要求计算预应力梁达到受弯极限状态时，受压区混凝土应力达到混凝土抗压设计强度，受拉区钢筋达到抗拉设计强度。按破坏阶段估算预应力筋的基本公式是：（3.3.1）（3.3.2）联立解得：（3.3.3）（3.3.4）－－按极限承载能力估算的预应力筋数量的最小值；－－混凝土轴心抗压强度设计值；－－预应力筋抗拉强度设计值；－－桥梁结构重要性系数；－－受压翼缘宽度；－－截面的有效高度。（1）估算左跨跨中截面下缘所需预应力筋数量采用的每根钢绞线面积，抗拉强度设计值，混凝土轴心抗压强度设计值，结构重要性系数取γ0=1.0。M=259754.47KN/m，取预应力钢筋重心距下缘距离为0.15m，则有效高度h0=3-0.15=2.85，受压翼缘宽度b=20.2m。代入公式可得：nyx=536根(2)估算弯矩最大处截面下缘所需预应力筋数量M=284039.86KN/m代入公式可得：nyx=589根（3）估算左跨右支点截面上缘所需预应力筋数量M=-466153.04KN/m，取预应力钢筋重心距上缘距离为0.15m，则有效高度h0=3-0.15=2.85，受压翼缘宽度b=14.2m。代入公式可得：nys=1030.6根7.1.4估算结果左跨控制截面的预应力筋初步估算结果如下表表7.1左跨控制截面的预应力筋初步估算表截面位置上缘预应力筋（根）下缘预应力筋（根）左跨0L1000.25L07000.375L08000.5L07000.75L804007.2预应力钢筋布置位置经PSC设计验算后，发现初步估算的钢筋数量并不能满足抗弯、抗裂验算要求，因而适当增加钢筋数量，调整钢筋位置，得到符合验算要求的合理布置位置及数量。全桥关于跨中左右对称，限于篇幅，只列一半桥钢束坐标。钢筋布置位置及数量如下表：表7.2.1预应力钢束坐标表M18Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-0.4501001-0.4501.697001.697-0.483019.6320019.632-2.053020.3290020.329-2.08024.97950024.9795-2.08029.630029.63-2.08030.3270030.327-2.053048.2620048.262-0.483048.9590048.959-0.450500050-0.450M28Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-0.901001-0.901.697001.697-0.933016.3170016.317-2.213017.0140017.014-2.24024.9790024.979-2.24032.9440032.944-2.24033.6410033.641-2.213048.2610048.261-0.933048.9580048.958-0.90500050-0.90M38Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-1.3501001-1.3501.697001.697-1.383013.0030013.003-2.373013.70013.7-2.4024.980024.98-2.4036.260036.26-2.4036.9570036.957-2.373048.2630048.263-1.383048.960048.96-1.350M48Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)500050-1.3500000-1.801001-1.801.697001.697-1.83309.688009.688-2.533010.3850010.385-2.56024.97950024.9795-2.56039.5740039.574-2.56040.2710040.271-2.533048.2620048.262-1.833048.9590048.959-1.80500050-1.80M58Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-2.2501001-2.2501.697001.697-2.28306.373006.373-2.69307.07007.07-2.72024.97950024.9795-2.72042.8890042.889-2.72043.5860043.586-2.693048.2620048.262-2.283048.9590048.959-2.250500050-2.250M68Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-2.701001-2.701.697001.697-2.73303.058003.058-2.85303.755003.755-2.88024.9790024.979-2.88046.2030046.203-2.88046.90046.9-2.853048.2610048.261-2.733048.9580048.958-2.70500050-2.70T18Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-0.20500050-0.20T28Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)0000-2.80500050-2.80T38Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)350035-0.20500050-0.20T48Φ15.2X(m)Y(m)R(m)X(m)Z(m）R(m)490049-0.30500050-0.30具体布置位置详见图纸。8预应力损失的计算预应力混凝土构件在正常使用极限状态计算时，采用后张法张拉预应力钢束时应考虑以下五种引起预应力损失的情况：（1）预应力筋与管道壁间摩擦引起的应力损失（）（2）锚具变形、钢筋回缩和接缝压缩引起的应力损失（）（3）混凝土弹性压缩引起的应力损失（）（4）钢筋松弛引起的应力损失（）（5）混凝土收缩和徐变引起的应力损失（）上述预应力损失的计算公式参见《公路钢筋混凝土及预应力混凝土桥涵设计规范》（JTGD62-2004）6.2。由迈达斯对模型进行计算分析，可以得到不同施工阶段的预应力损失值，为节省本文的篇幅，在此以箱梁钢束组N为例，进行预应力损失的展示：表8.1预应力钢束张拉阶段预应力损失单元位置应力(考虑瞬时损失):A(kN/m^2)弹性变形损失:B(kN/m^2)比值(A+B)/A徐变/收缩损失(kN/m^2)松弛损失(kN/m^2)应力(考虑所有损失)/应力(考虑瞬时损失)端部有效钢束数2I1252237.483315.75751.0003-1963.4491-28230.43740.9761322J1252716.013326.21481.0003-1872.5521-28283.11280.9762323I1234841.655356.19721.0003-2574.7395-26337.28230.9769323J1258032.502408.20851.0003-2663.3056-28862.75650.9753324I1258032.502407.44591.0003-2678.9405-28862.75650.9753324J1269940.651430.38781.0003-2818.6363-30184.07750.9744325I1269940.651429.48481.0003-2832.086-30184.07750.9743325J1271960.23434.58411.0003-2937.2648-30409.09280.9741326I1271960.23433.5091.0003-2943.8599-30409.09280.9741326J1273897.518439.7511.0003-3023.2901-30625.74140.9739327I1273897.518438.72691.0003-3036.4168-30625.74140.9739327J1277857.118460.03461.0004-3273.5475-31074.58740.9735328I1277857.118459.62421.0004-3327.6591-31074.58740.9734328J1283986.152502.94861.0004-3652.1679-31771.46350.9728329I1283986.152504.79441.0004-3813.5284-31771.46350.9727329J1285581.016545.71921.0004-4119.691-31953.88510.97243210I1285581.016544.2591.0004-4146.3595-31953.88510.97233210J1286844.129564.48331.0004-4277.7885-32098.31990.97223211I1286844.129811.18961.0006-4286.9346-32098.31990.97243211J1291600.703820.2731.0006-4296.7828-32649.94790.9723212I1291600.703820.89321.0006-4296.786-32649.94790.9723212J1295130.695829.53931.0006-4307.7322-33059.95010.97183213I1295130.695830.03451.0006-4307.7376-33059.95010.97183213J1295716.033834.70171.0006-4308.2046-33126.18620.97183214I1295716.033834.82931.0006-4308.217-33126.18620.97183214J1295880.407836.04871.0006-4309.2283-33145.15260.97173215I1295880.407836.30531.0006-4309.2137-33145.15260.97173215J1296890.659848.36941.0007-4322.3268-33261.51670.97173216I1296890.659848.5081.0007-4322.3275-33261.51670.97173216J1297026.085863.75741.0007-4336.54-33275.58980.97173217I1297026.085863.83841.0007-4336.5402-33275.58980.97173217J1297025.873885.63421.0007-4359.6979-33274.1540.97173218I1296943.362885.33851.0007-4359.2906-33264.6130.97173218J1296943.646909.66261.0007-4389.7111-33266.07020.97173219I1296943.646909.44451.0007-4389.7109-33266.07020.97173219J1296943.931938.22631.0007-4444.5544-33267.94350.97163220I1296943.931937.92261.0007-4444.5534-33267.94350.97163220J1296313.639959.28961.0007-4532.7451-33196.11420.97163221I1296313.639958.92461.0007-4532.7541-33196.11420.97163221J1296205.003960.29261.0007-4547.7823-33183.65640.97163222I1296205.003959.96351.0007-4547.7695-33183.65640.97163222J1295927.297955.70851.0007-4688.583-33153.7150.97153223I1295927.297954.7321.0007-4688.577-33153.7150.97153223J1292432.909875.56871.0007-4922.4014-32746.88350.97153224I1292432.909938.16271.0007-4870.5413-32746.88350.97163224J1288031.768867.0561.0007-5129.7834-32235.85820.97173225I1288031.768548.62261.0004-5117.5984-32235.85820.97143225J1286768.334525.46941.0004-5005.895-32090.98670.97163226I1286768.334526.86411.0004-4974.1599-32090.98670.97163226J1285240.677490.50091.0004-4706.1552-31915.86470.97193227I1285240.677487.78871.0004-4507.5228-31915.86470.9723227J1279111.856462.7331.0004-4187.5755-31217.35480.97273228I1279111.856462.74041.0004-4120.9451-31217.35480.97273228J1275060.664453.99591.0004-3857.3441-30757.95310.97323229I1275060.664454.81311.0004-3841.7282-30757.95310.97323229J1273145.143450.04461.0004-3746.9125-30543.73620.97343230I1273145.143450.93611.0004-3739.203-30543.73620.97343230J1271192.935443.18631.0003-3606.1997-30325.97370.97373231I1271192.935443.81081.0003-3590.0922-30325.97370.97373231J1259065.467404.11111.0003-3398.8063-28980.72120.97463232I1259065.467404.421.0003-3379.8828-28980.72120.97463232J1218138.307314.16831.0003-3207.7498-24562.97550.97753233I1218138.3071109.781.0009-5908.5405-24562.97550.97593233J1217217.911639.54331.0005-3878.6867-24466.13770.977232表8.2桥面铺装阶段预应力损失单元位置应力(考虑瞬时损失):A(kN/m^2)弹性变形损失:B(kN/m^2)比值(A+B)/A徐变/收缩损失(kN/m^2)松弛损失(kN/m^2)应力(考虑所有损失)/应力(考虑瞬时损失)端部有效钢束数2I1252237.483318.55541.0003-5432.7993-86498.06030.9268322J1252716.013318.69571.0003-5199.6357-86659.45760.9269323I1234841.655372.87371.0003-7314.3355-80697.4330.929323J1258032.5021373.59141.0011-7070.1477-88435.48590.9252324I1258032.5021368.86571.0011-7173.0877-88435.48590.9251324J1269940.6513135.01271.0025-6680.6262-92484.01330.9244325I1269940.6513122.99481.0025-6773.9707-92484.01330.9243325J1271960.234504.43811.0035-6371.4795-93173.46030.9253326I1271960.234487.40941.0035-6431.1379-93173.46030.9252326J1273897.5185405.83591.0042-6188.0074-93837.27170.9257327I1273897.5185385.53981.0042-6283.3047-93837.27170.9256327J1277857.1187987.76771.0063-5620.4729-95212.53580.9273328I1277857.1187958.54221.0062-5774.9736-95212.53580.9272328J1283986.15210775.43441.0084-5228.466-97347.76410.9285329I1283986.15210737.33791.0084-5515.2327-97347.76410.9283329J1285581.01612922.06251.0101-5193.5843-97906.70380.92993210I1285581.01612871.83221.01-5362.78-97906.70380.92973210J1286844.12913657.7841.0106-5302.0318-98349.25230.93013211I1286844.12914345.90641.0111-5042.5382-98349.25230.93083211J1291600.70316247.43681.0126-4058.3424-100039.44030.9323212I1291600.70316250.80131.0126-4057.1291-100039.44030.9323212J1295130.69517683.23321.0137-3322.8974-101295.68720.93293213I1295130.69517685.56181.0137-3322.0508-101295.68720.93293213J1295716.03318453.40591.0142-2907.6997-101498.63440.93373214I1295716.03318454.16791.0142-2907.4477-101498.63440.93373214J1295880.40718532.31361.0143-2867.5823-101556.74740.93373215I1295880.40718533.02751.0143-2867.2627-101556.74740.93373215J1296890.65918818.98211.0145-2738.0337-101913.28710.93383216I1296890.65918819.15721.0145-2737.9343-101913.28710.93383216J1297026.08518511.08961.0143-2922.8279-101956.40720.93343217I1297026.08518510.26671.0143-2923.0672-101956.40720.93343217J1297025.87317655.31521.0136-3421.4228-101952.00780.93243218I1296943.36217652.6041.0136-3421.3192-101922.77410.93243218J1296943.64616265.07121.0125-4219.8-101927.23910.93073219I1296943.64616261.86961.0125-4220.8755-101927.23910.93073219J1296943.93114395.95991.0111-5336.2524-101932.97880.92843220I1296943.93114391.84971.0111-5337.6339-101932.97880.92843220J1296313.63912140.65321.0094-6740.4346-101712.89380.92573221I1296313.63912137.76251.0094-6741.4514-101712.89380.92573221J1296205.00311840.62041.0091-6935.2598-101674.72320.92533222I1296205.00311837.90511.0091-6936.1562-101674.72320.92533222J1295927.2979710.84291.0075-8410.5996-101582.98280.92263223I1295927.2979704.97441.0075-8412.6206-101582.98280.92263223J1292432.9097360.82141.0057-10235.3461-100336.45090.92013224I1292432.9097499.09131.0058-10061.2328-100336.45090.92043224J1288031.7684842.05481.0038-12111.4534-98770.66950.91773225I1288031.7683993.16951.0031-12408.8053-98770.66950.91683225J1286768.3343286.25261.0026-12483.0878-98326.78340.91643226I1286768.3343292.32651.0026-12179.2991-98326.78340.91673226J1285240.6771195.69171.0009-12561.0842-97790.20950.91513227I1285240.6771189.64481.0009-12019.9884-97790.20950.91553227J1279111.856-1525.5520.9988-12539.303-95649.97510.91423228I1279111.856-1533.13320.9988-12369.0414-95649.97510.91443228J1275060.664-3917.05830.9969-12869.37-94242.36830.91293229I1275060.664-3934.36960.9969-12761.9782-94242.36830.9133229J1273145.143-4662.50190.9963-12879.1443-93586.00770.91273230I1273145.143-4683.65790.9963-12819.1418-93586.00770.91273230J1271192.935-5673.70150.9955-12971.0167-92918.78330.91223231I1271192.935-5700.5350.9955-12866.8727-92918.78330.91233231J1259065.467-6468.90560.9949-12766.1686-88796.92980.91423232I1259065.467-6505.05590.9948-12652.0059-88796.92980.91433232J1218138.307-6152.78240.9949-12054.6644-75260.95680.92333233I1218138.307-9071.19860.9926-20019.0045-75260.95680.91433233J1217217.911-6457.88930.9947-13481.583-74964.24610.92232表8.3撤销施工支架阶段预应力损失单元位置应力(考虑瞬时损失):A(kN/m^2)弹性变形损失:B(kN/m^2)比值(A+B)/A徐变/收缩损失(kN/m^2)松弛损失(kN/m^2)应力(考虑所有损失)/应力(考虑瞬时损失)端部有效钢束数1I1251795.617521.62221.0004-2561.7911-56363.65280.9533321J1252237.483-16.05221-2534.0467-56460.87490.9529322I1252237.483-12.80831-2533.3453-56460.87490.9529322J1252716.013-54.83211-2426.7126-56566.22560.9529323I1234841.655-22.89761-3330.8553-52674.56460.9546323J1258032.502661.58431.0005-3316.841-57725.5130.952324I1258032.502658.68831.0005-3340.0203-57725.5130.952324J1269940.6512015.05041.0016-3257.7988-60368.15490.9515325I1269940.6512006.38891.0016-3277.8005-60368.15490.9515325J1271960.233102.65771.0024-3198.3592-60818.18560.9521326I1271960.233090.23481.0024-3209.263-60818.18560.9521326J1273897.5183821.86361.003-3167.8401-61251.48280.9524327I1273897.5183806.5191.003-3187.1018-61251.48280.9524327J1277857.1185891.40491.0046-3080.924-62149.17480.9536328I1277857.1185867.65651.0046-3081.4413-62149.17480.9535328J1283986.1528104.88611.0063-3047.1232-63542.9270.9545329I1283986.1528073.72241.0063-3121.8275-63542.9270.9544329J1285581.0169787.07211.0076-3149.6428-63907.77010.95553210I1285581.0169751.02351.0076-3330.6-63907.77010.95533210J1286844.12910357.97681.008-3374.4784-64196.63990.95553211I1286844.12910676.35351.0083-3282.5548-64196.63990.95593211J1291600.70312308.0831.0095-2945.9741-65299.89580.95673212I1291600.70312309.51591.0095-2945.8464-65299.89580.95673212J1295130.69513558.76871.0105-2690.451-66119.90030.95733213I1295130.69513559.81631.0105-2690.3527-66119.90030.95733213J1295716.03314274.22341.011-2532.8522-66252.37230.95793214I1295716.03314274.56961.011-2532.8406-66252.37230.95793214J1295880.40714349.35811.0111-2517.3336-66290.30510.9583215I1295880.40714349.751.0111-2517.261-66290.30510.9583215J1296890.65914682.79341.0113-2454.3761-66523.03340.95813216I1296890.65914682.99951.0113-2454.3476-66523.03340.95813216J1297026.08514526.67861.0112-2494.8048-66551.17970.9583217I1297026.08514526.53921.0112-2494.788-66551.17970.9583217J1297025.87313894.11221.0107-2647.1421-66548.3080.95743218I1296943.36213893.06141.0107-2646.6969-66529.22590.95743218J1296943.64612802.9061.0099-2904.2019-66532.14040.95633219I1296943.64612801.84511.0099-2904.2478-66532.14040.95633219J1296943.93111303.79481.0087-3278.6299-66535.88690.95493220I1296943.93111302.4221.0087-3278.693-66535.88690.95493220J1296313.6399511.20121.0073-3756.0222-66392.22830.95323221I1296313.6399510.1611.0073-3756.1107-66392.22830.95323221J1296205.0039277.24921.0072-3822.6661-66367.31280.9533222I1296205.0039276.29011.0072-3822.7198-66367.31280.9533222J1295927.2977621.18091.0059-4338.9497-66307.430.95143223I1295927.2977619.0061.0059-4339.1493-66307.430.95143223J1292432.9095883.39631.0046-4986.5084-65493.76690.953224I1292432.9095954.89351.0046-4914.8352-65493.76690.95013224J1288031.7683929.30011.0031-5655.2131-64471.71640.94863225I1288031.7683522.50421.0027-5757.701-64471.71640.94823225J1286768.3342998.58761.0023-5722.8104-64181.97350.9483226I1286768.3343004.3771.0023-5496.9119-64181.97350.94823226J1285240.6771392.81051.0011-5497.5293-63831.72940.94713227I1285240.6771394.95391.0011-5340.8089-63831.72940.94733227J1279111.856-785.02510.9994-5374.4636-62434.70960.94643228I1279111.856-787.50010.9994-5357.7553-62434.70960.94643228J1275060.664-2773.55360.9978-5418.3663-61515.90620.94533229I1275060.664-2784.72920.9978-5394.358-61515.90620.94533229J1273145.143-3406.78640.9973-5399.1331-61087.47240.94513230I1273145.143-3421.44880.9973-5387.4433-61087.47240.94513230J1271192.935-4283.86060.9966-5393.9245-60651.94730.94473231I1271192.935-4302.82060.9966-5369.4062-60651.94730.94473231J1259065.467-5015.79020.996-5278.1248-57961.44240.94583232I1259065.467-5042.31530.996-5249.9469-57961.44240.94583232J1218138.307-4829.26850.996-5004.489-49125.95090.95163233I1218138.307-7313.28080.994-8812.6548-49125.95090.94643233J1217217.911-5034.00120.9959-5827.5787-48932.27550.950932表8.4收缩徐变阶段预应力损失单元位置应力(考虑瞬时损失):A(kN/m^2)弹性变形损失:B(kN/m^2)比值(A+B)/A徐变/收缩损失(kN/m^2)松弛损失(kN/m^2)应力(考虑所有损失)/应力(考虑瞬时损失)端部有效钢束数1I1251795.6171744.61071.0014-26204.0919-112727.30560.8904321J1252237.4831207.45971.001-26192.6297-112921.74970.8899322I1252237.4831217.04031.001-26182.7024-112921.74970.8899322J1252716.0131202.80911.001-25450.1636-113132.45120.8903323I1234841.6551006.81761.0008-38939.507-105349.12930.884323J1258032.5022054.78831.0016-38029.2915-115451.0260.8796324I1258032.5022066.02211.0016-39519.8457-115451.0260.8785324J1269940.6513869.3111.003-37795.0894-120736.30980.8782325I1269940.6513874.00731.0031-39167.0945-120736.30980.8771325J1271960.235269.27661.0041-37791.9131-121636.37120.8788326I1271960.235263.81821.0041-38712.4992-121636.37120.8781326J1273897.5186193.18931.0049-37875.5828-122502.96570.879327I1273897.5186192.56