大跨空间轮辐式弦支桁架结构施工过程监测与模拟分析

大跨空间轮辐式弦支桁架结构施工过程复杂,不同施工方案及阶段结构刚度和荷载变化对结构安全影响不容忽视,但目前国内外对大跨空间结构多进行施工成型后的静力分析,缺乏对复杂结构施工过程中的受力监测与分析。为研究西安某体育馆大跨空间轮辐式弦支桁架结构在不同施工阶段的受力与变形性能,采用有限元程序MIDAS/Gen模拟该大跨空间结构旋转累积滑移施工过程的8个不同阶段,对辐射状倒三角桁架、加强桁架及“Y”型格构柱三类关键构件的应力与位移进行了仿真分析,并与实际监测数据进行对比。结果表明:数值仿真模拟结果与施工实际监测数据吻合较好,验证了数值仿真模拟的可行性; 通过预测不同施工阶段结构应力变化及最不利危险施工节点,可为施工阶段健康监测系统的分区建立及关键节点布测提供思路与依据,具有实际工程意义; 大跨空间轮辐式弦支桁架结构在不同施工阶段的内力变化较大,最大竖向位移常发生于桁架中间部位的下弦,为保证施工阶段安全性,应对外环桁架竖向腹杆、中心环桁架腹杆及上弦等关键节点进行重点监测及预警,避免施工阶段构件受损,保障施工安全。

Monitoring and simulation analysis of construction process for large-span spatial spoke chord-supported truss structure

The construction process of large-span spatial spoke chord-supported truss structure is complex. The influence of structural stiffness and load changes on structural safety in different construction schemes and stages cannot be ignored. However, at present, the static analysis of large-span space structure after construction is mostly carried out at home and abroad, and the stress monitoring and analysis in the construction process of complex structure are lacking. In order to study the stress and deformation performance of the large-span spatial spoke chord-supported truss structure of a gymnasium in Xi'an in different construction stages, the finite element program MIDAS/Gen was used to simulate the eight different stages of the rotation cumulative slip construction process of the large-span space structure. The stress and displacement of the three key components of the radial inverted triangular truss, the reinforced truss and the “Y” lattice column were simulated and analyzed, and compared with the actual monitoring data. The results show that the numerical simulation result is in good agreement with the actual monitoring data, which verifies the feasibility of numerical simulation. By predicting the structural stress changes and the most unfavorable construction nodes in different construction stages, it can provide ideas and basis for the zoning establishment of the health monitoring system and the layout of key nodes in the construction stage, which has practical engineering significance. The internal force of large-span spatial spoke chord-supported truss structure changes greatly in different construction stages, and the maximum vertical displacement often occurs in the lower chord of the middle part of the truss. In order to ensure the safety of the construction stage, the key nodes such as the vertical web member of the outer ring truss, the web member of the central ring truss and the upper chord should be monitored and warned to avoid the damage of the components in the construction stage and ensure the construction safety.