钢网架屋盖顶升施工过程的数值模拟与监测

Numerical simulation and monitoring of steel grid roof structure jacking construction process

某高铁站房钢网架屋盖施工采用主体结构整体顶升,局部结构高空散拼的安装工艺,各施工步的结构、自重、支撑形式均有所变化,需要对其施工过程安全性进行计算分析和施工监测。本文对该网架施工过程进行了数值模拟计算,根据计算结果确定了各施工步中的关键受力杆件,对其在顶升施工过程中的应力响应进行了动态监测。计算结果表明:结构应力与位移最大值分别出现在施工步1与施工步4,为102.05MPa与–61.41mm,分别位于网架顶升支点附近和跨中,是顶升过程中的关键受力区域;千斤顶支反力最大值为422.06kN,达到了许用承载力的一半。监测结果表明:各施工步网架的内力分布和变形与数值模拟结果基本一致;由于千斤顶顶升不同步,造成网架空间姿态变化和内力分布对称性降低,在施工中应严格控制。

The construction of the steel roof structure of a high-speed railway station adopts the integral jacking of the main structure and high-altitude scattered assembly of the rest.The structure and support form of each construction step have changed,which requires numerical simulation and monitoring.This paper numerically simulated the construction process of the grid structure.The key load-bearing pipes in each step are determined by the results,and the stress changes during the jacking process are dynamically monitored.The calculation results show that the maximum values of stress and deformation occur in step 1 and step 4 respectively,which are 102.05MPa and–61.41mm.They are located near the lifting jack and in the middle of the grid span,which are the key areas in the jacking process;The maximum reaction force of the jack is 422.06kN,which reaches half of the bearing capacity;The monitoring results show that the stress and deformation of the grid structure in each construction step show the same trend with the simulation results.The unsynchronized jacking reduces the stress symmetry of the grid structure,which should be strictly controlled during construction.