薄壁大跨度箱体结构分层吊装防变形设计

Anti-deformation Design of Thin-wall Large-span Box Structure during Lifting by Layers

某项目薄壁大跨度箱体结构由于外形尺寸较大,传统的厂房外拼装后整体吊装就位的施工工艺周期较长,对工程施工关键路径影响较大,无法满足工程整体施工进度的要求,需研究对分层拼装、吊装就位的崭新工艺思路,实现土建施工与安装施工交叉并行,确保工程重大里程碑目标的顺利实现。为解决薄壁大跨度箱体结构刚度低、在分层吊装中易产生大变形的问题,本文从工装设计、平衡梁和吊点设计两个方向出发,对该项目薄壁大跨度箱体结构进行了防变形优化设计。对采取防变形工装后的吊装工况进行数值仿真,优化吊装过程中防变形控制措施;研究平衡梁的设计方案,改进吊点的空间排布。通过有限元分析和设计优化,最终得到了一套具有一定通用性的防变形设计方案,并在施工过程中安装传感器监测变形以作进一步验证。结果表明:防变形设计方案能优化薄壁大跨度箱体结构在吊装时的受力情况,减小由于整体受力原因产生的变形,克服薄壁大跨度箱体结构模块化施工的技术难题。

As a typical“super engineering”,the economy of nuclear power plant is an important indicator to determine its competitiveness in the global power market.Due to the large overall size of the thin-wall large-span box structure of a project,the traditional construction process cycle of integral lifting in place after external assembly of the plant is long.It has a great impact on the critical path of project construction and can not meet the requirements of the overall construction progress of the project.Therefore,it is necessary to study a new process idea of layered assembly and lifting in place.This process can realize the intersection and parallel of civil construction and installation construction,and ensure the smooth realization of major milestones of the project.But the thin-wall large-span box structure itself has some problems,such as low stiffness,instability,easy to produce large deformation in the lifting process,which is the key problem to be solved in the modular construction process.In order to solve this problem,the anti-deformation design of the whole lifting of a thin-wall large-span box structure was carried out from the two directions of fixture design,balance beam and lifting point design.In order to get the ideal anti-deformation tooling design and lifting point design,several times of simulation were carried out.According to the simulation results,the causes were analyzed and the design was optimized.After obtaining the preliminary design scheme,the overall deformation of the balance(lifting)beam and the local stress of the lifting point were analyzed by numerical simulation,so as to improve the design scheme of the balance beam,optimize the spatial arrangement of the lifting point,and obtain a simple and universal design scheme.After determining the optimal design scheme of balance beam and lifting point,combined with numerical simulation,the anti-deformation fixture was adjusted(such as:adjusting the arrangement and quantity of inclined brace,local reinforcement)to control the deformation of the overall lifting process,and ensure that the structure meets the requirements of safety and design deviation in the overall lifting process.Through finite element analysis and design optimization,a set of universal anti deformation design scheme was finally obtained,and sensors were installed in the construction process to monitor the deformation for further verification.The results show that the anti-deformation design scheme can optimize the stress of the thin-wall large-span box structure during lifting,reduce the deformation caused by the overall stress,and overcome the technical problem of modular construction of the thin-wall large-span box structure.