支架预压沉降观测分析实施报告

吉安赣江特大桥13#、14#墩三角形挂篮预压沉降观测分析总结报告编制审核审批监理工程师中铁二十二局集团第四工程有限公司

蒙华项目经理部

2017年10月23日吉安赣江特大桥13#、14#挂篮预压沉降观测分析总结报告一、 预压目的为了确保挂篮施工安全，减少挂篮的非弹性变形，获取弹性变形参数，得出压重与挂篮本身的变形关系，为挂篮施工和线性控制提供挂篮弹性挠度计算的可靠依据，保证施工质量和安全，对挂篮进行加载试验检验，消除整个挂篮的塑性变形，测量出挂篮的弹性变形。二、 预压方法a、 预压加载按照加压荷载的0%、20%、40%、60%、80%、100%、110%进行，布载截面形式应模拟梁体荷载分布。加载顺序尽可能模拟混凝土浇筑顺序。在加载前0%时先进行测量，第一次加载箱梁底板及腹板处，加载至20%，依次40%、60%、80%、100%、，加载至110%，采用1mX1mX0.62m类型混凝土预制块231块。具体加载顺序详见荷载布置断面图。b、 采用水准仪测量，分别测量加载前读数。加载时，按照加压荷载的0%、20%、40%、60%、80%、100%、110%分级进行，加载完成后观测记录，直至最后的平均沉降值＜2mm并满足24小时以上时方可卸载。然后逐级卸载至100%、80%、60%、40%、20%、0%。待总体沉降量稳定后，最后再测量一次卸载后读数。c、 在压载过程中采用水准仪实施全天候跟踪观测挂篮的变形情况并作好记录，待挂篮不再发生沉降，预压过程即告结束。在进行压载施工中，要边进行压载，边观测挂篮的变形情况，发现异常应立即停止压载作业，及时查找原因，处理正常后再进行压载。d、 挂篮标高调整：架体预压前，挂篮按照设计标高调整，通过

预压，观测计算得出挂篮弹性变形数值，调整梁底标高。梁底标高=设计梁底标高+挂篮弹性变形值+设计预拱度。挂篮预制块纵面布置图

三、预压过程表1 跨赣江特大桥13#墩挂篮预压记录表序号日期时间施工情况备注12017.10.188:00--8:30加载前22017.10.188:30--9:40加载至20%32017.10.1811:45--14:00加载至40%42017.10.1816:00--17:20加载至60%52017.10.196:30--8:20加载至80%62017.10.1910:20--11:25加载至100%72017.10.1913:00--13:35加载至110%82017.10.2015:35--16:10卸载至100%92017.10.2018:10--18:50卸载至80%102017.10.216:30--7:35卸载至60%112017.10.2110:20--11:25卸载至40%122017.10.2113:00--14:35卸载至20%132017.10.2116:50--18:10卸载至0%

表2 跨赣江特大桥14#墩挂篮预压记录表序号日期时间施工情况备注12017.10.1713:00--13:30加载前22017.10.1716:35--17:20加载至20%32017.10.187:00--7:35加载至40%42017.10.1810:00--10:25加载至60%52017.10.1814:00--14:35加载至80%62017.10.1818:15--18:40加载至100%72017.10.198:35--9:16加载至110%82017.10.209:15--9:45卸载至100%92017.10.2013:00--13:32卸载至80%102017.10.2017:20--17:50卸载至60%112017.10.219:40--10:06卸载至40%122017.10.2117:31--17:58卸载至20%132017.10.228:10--8:35卸载至0%四、预压结果汇总表1预压结果汇总墩号平均弹性变形13#15mm14#13mm五、成果应用本次观测较真实模拟箱梁施工的加载过程,达到了预压目的，验证了该挂篮结构的设计满足安全和质量要求。本次预压所得数据能够指导施工，预压结果合格，满足规范及设计要求.可运用该挂篮进行13#、14#主墩连续梁现浇施工。根据设计图纸，设计只提拱了成桥后预拱度，在挂篮施工过程中。还要考虑挂篮变形的因素。因此，施工预拱度为挂篮弹性变形值+设计预拱度，则：对于已预压的挂篮，根据如下公式调整底模标高：底模顶面标高二梁底设计标高+设计预拱度（1.5cm）+弹性变形即13#底膜顶面标高=62.312+0.015+0.015=62.34214#底膜顶面标高=62.312+0.013+0.015=62.340后附表：预压结果表格

附件1:沉降观测点横断面示意图挂篮预压测点布置图I左前吊测点A1点DU豳点B6点D12附件2:底版预压观测点平面布置图梁端(小里程墩13中心桥墩1，5，7，2，8，3，9，6，4，10，梁端(大里程)图113#墩底板和上横梁预压观测点平面布置图图214#墩底板和上横梁预压观测点平面布置图*1MIS*1o9007654321—1987654321成72.599872.608872.627872.634861.981961.988961.601961.628961.653961.6719到S72.599172.607872.626872.633661.981361.987661.601261.628161.653061.6711g72.586872.595872.616872.615861.971961.973961.587961.616961.638961.659972.581872.592872.611872.608861.966961.970961.579961.611961.633961.6519罗婵6O72.577872.588872.605872.604861.963961.969961.575961.601961.628961.6479婵00O72.574672.583972.597672.599861.960961.967961.573961.599961.625961.6419罗婵1OO72.570372.580172.592572.597661.957561.964561.571061.597961.621961.6389O72.570372.580372.592872.597761.957661.964561.570961.597661.621961.637572.570372.580172.592572.597661.957661.964561.570961.597961.621961.637972.572872.581872.595872.599861.959961.966961.573961.598961.623961.639972.575672.584872.599672.603061.961961.968561.576361.602161.627361.643500害W婵72.578172.587572.603672.606461.963661.970461.578661.605461.630561.6476建6O72.581272.5908|72.607272.609461.965961.971561.581461.608561.634461.6509111小里程端61.927961.927161.914961.909961.904961.899861.896261.896261.896261.898961.902561.906361.909712261.938961.938261.925961.918961.914961.912961.908761.908761.908761.910961.913561.916161.918713361.920961.920061.901961.895961.888961.884961.882461.882661.882461.884961.888761.892561.896314461.917961.917961.901961.895961.890961.890961.886561.886761.886561.888961.891961.894561.897915561.997961.996861.980961.977961.975961.972761.968961.968961.968961.970961.973561.976361.978716661.988961.988261.976961.971961.969961.967561.964861.964661.964761.966961.968761.970761.972617772.642872.642272.627872.619872.612872.609672.606472.606472.606472.609872.613672.617672.621218872.646872.646072.633872.629872.621872.613872.610472.610572.610372.612872.615872.618672.621819972.632872.632172.614872.608872.603872.599872.597572.597472.597372.599872.603472.607272.6104201072.624872.624072.610872.597872.592872.589772.581672.586372.586572.588872.592672.596672.6006表2跨赣江特大桥14#墩挂篮预压沉降观测数据记录序号编号布点位置加荷载'人刖荷载20%荷载40%荷载60%荷载80%荷载100%荷载110%卸载100%卸载80%卸载60%卸载40%0小时12小时24小时11，大里程端41.28141.27541.27341.27041.27041.26541.26341.26341.26241.26441.27141.27141.27122，41.29541.29041.28741.28241.28241.27941.27841.27741.27641.27941.28241.28241.28833，41.29441.28941.28641.28241.28041.27941.27741.27741.27641.27841.27941.28041.28444，41.23841.23541.23241.22641.22441.22241.22141.22141.22141.22141.22241.22341.22355，41.25841.25441.25141.24741.24441.24441.23541.23441.23441.23541.24241.24241.24366，41.26941.26241.26041.25841.25441.25241.24641.24641.24541.24641.24641.24241.25277，51.43551.43151.42751.42351.41951.41251.40851.40751.40651.40951.41151.41351.41588，51.54751.54251.53751.53151.52751.52151.51851.51751.51751.51851.51951.52051.52299，51.39751.39451.38951.38451.38151.37851.37651.37651.37551.37751.37951.38151.3841010，51.62751.62251.61951.61651.61251.61051.60951.60951.60951.60951.61051.61151.613

111小里程端61.38661.38161.37761.37261.36761.36461.36261.36161.36061.36361.36561.36961.37112261.36161.34861.34761.34561.34361.34261.33961.33861.33761.34061.34161.34361.34513361.38461.38261.38061.37761.37561.37361.37161.37061.36961.37161.37261.37561.37514461.41761.41061.40761.40361.39861.39661.39461.39361.39261.39661.39861.40161.40415561.35861.35361.34961.34661.34361.33961.33761.33761.33761.34061.34261.34561.34816661.37361.37061.36561.36261.35961.35561.35261.35161.35161.35461.35861.36161.36317771.34771.34371.34071.33671.33271.32871.32771.32671.32671.32971.33071.33571.33718871.29471.29171.28771.28271.27971.27671.27571.27571.27471.27771.27971.28271.28519971.26871.262