Numerical Simulation Theory And Spot Monitoring Technology For Construction Process Of Large Scale Steel Structures

With the flourishing development of economics in our country, the scale of many types of engineering construction are expanding and the amount of many important projects such as high-rising building, long-span building, super-high rising building and some other large scale and complex structures are increasing. The expanding of construction scale and the complexity of structure system bring out the complexity and safety problem in the construction process, which can result in that the construction procedures have great effect on the final state of structures. Presently, many researchers have attached importance to the mechanics problems confronted in the construction technology and process of long-span and high-rising buildings, Meanwhile the construction process analysis becomes an important component of the design of structure engineering, which can grantee the safety and reliability of project in the whole stage of construction and service process. And the construction process analysis is vital important both for the optimization of construction scheme and for the choice of reasonable construction sequence. The mechanical behavior of structure in the different stage of the whole construction process with the numerical method and spot timely monitoring means was studied in this paper, which provides reliable basis for the safety of the structures in the whole construction process.Firstly, this paper summarized the construction method and the characteristic of the construction process of large scale and complex steel structures, analyzed the research actuality in the field of construction analysis and spot monitoring for steel structures. Based on the nonlinear element theory, this paper provided the geometrical nonlinear beam and truss element as well as the finite element formula of space structures with semi-rigid joint that are suitable for the construction process analysis. According to the reality of the construction of project, this paper analyzed the numerical simulation method for tracing the whole construction of large scale and complex steel structures, designed the integral frame of the software for construction analysis, improved the pre-process and post-process programs using ObjectArx based on AutoCAD, which made the software more convenient and simple for the users.Based on the time-dependent model of reinforced concrete in CEB-FIP, the time-dependent model and finite element method for concrete filled steel tube (CFST) are provided in this paper which can be used for numerical simulation of the construction process of CFST structures. The spot timely monitoring test with vibrating strain gauge is conducted during the construction of Tongji teaching and researching building, the comparison of the test results and the numerical simulation results demonstrated that the method in this paper can precisely simulate the time-dependent inner force and deformation during the construction process of high-rising buildings, and the numerical simulation results showed that the deformation of the structure resulted from the shrinkage and creep of concrete during construction can not be ignored in the design.The prestress construction process of pre-tensioned steel structures is the emphasis and difficult issue in the steel structure engineering, knowing about the mechanical behavior of the structures for the different construction method and different construction stage using numerical simulation method can provide theoretical instruction both for the optimization of construction scheme and for the choice of reasonable construction sequence. The spot timely monitoring test is conducted during the construction of National Gymnasium of 2008 Olympics to study the construction mechanics of Bidirectional cable-stayed truss structures, the comparison of the test results and the numerical simulation results demonstrated that the method in this paper can precisely simulate the time-dependent inner force and deformation during the construction process of slipping and tension. Meanwhile, a reduced scale model test of hyperboloid cable net was conducted for the construction of Chinese Navigation Museum to prove the feasibility of the construction method for the cable net. According to the model test, some problems were found during the test and corresponding solving schemes were put forward in this paper. Finally the test results and the numerical results showed that the method in this paper was also suitable for the construction analysis of this type of structures.