基于施工全过程健康监测的装配式部分包覆钢-混凝土组合结构体系动力特性研究

Experimental study on dynamic response of prefabricated partially-encased composite structure system based on whole construction process health monitoring

为研究装配式部分包覆钢-混凝土组合结构的动力特性,基于世博文化公园双子山项目,采用全过程健康监测手段对装配式PEC结构体系施工全过程的应力、加速度进行监测,研究其阻尼比和自振频率在施工过程中的变化情况,将实测结果与有限元计算结果进行对比。结果表明:结构应力计算值、自振频率计算值等均与实测值吻合较好,验证了结构施工全过程仿真模拟计算的合理性。施工过程中PEC框架梁柱及节点后浇区的型钢及混凝土应力实际监测结果均满足强度要求。节点后浇区混凝土浇筑前后,结构自振周期和阻尼比差别较小;结构顶部覆土恒载施加完成后,结构的自振周期和阻尼比均较之前有所增大。结构设计时阻尼比取0.04,小于施工完成后的阻尼比实测值最小值0.046,阻尼比取值偏于安全,设计阻尼比取值合理。

In order to study the dynamic characteristics of prefabricated partially-encased composite structure,based on the Shuangzi mountain project of the Shanghai World Expo Cultural Park,the stress and acceleration of the entire construction process of the prefabricated PEC structural system were monitored using full process health monitoring methods.The changes in damping ratio and natural frequency during the construction process were studied,and the measured results were compared with the finite element calculation results.The results show that the calculated values of structural stress and natural frequency are in good agreement with the measured values,which verifies the rationality of the simulation calculation of the entire construction process of the structure.The actual monitoring results of the stress on the steel and concrete in the post pouring area of the PEC frame beams,columns,and nodes during the construction process meet the strength requirements.The difference in the natural vibration period and damping ratio of the structure before and after the pouring of concrete in the node pouring area is relatively small;After the permanent load of the soil covering the top of the structure was applied,the natural vibration period and damping ratio of the structure have increased compared to before.When designing the structure,the damping ratio is taken as 0.04,which is lower than the minimum measured value of 0.046 after construction.The damping ratio value is biased towards safety,and the design damping ratio value is reasonable.