Construction Simulation Analysis Of The Large Cantilevered Structure Of Hengqin Poly Square

In recent years,the large and complex construction rapid development momentum, it has more irregular, large span and cantilever structure characteristics of large cantilever steel truss structure is widely used, not only brought huge challenges to the construction process, but also will cause the redistribution of internal force of structures, cantilever steel members in the whole structure of the system has the particularity, the scene of the cantilever truss hoisting and uninstall, brings challenges to the construction, cause in the process of lifting and unloading structure internal force redistribution, which can cause serious engineering accidents, endangering public security. Therefore, in view of the large complex structure construction process to carry out the construction of the numerical simulation analysis, the research structure in construction process of the internal force, deformation, along with the development of the construction process is especially important for safe construction. It is based on Hengqin poly square, large cantilever structure as engineering background, first of all, using both the finite element software Midas Gen and SAP2000 established the structure of the three-dimensional finite element model and the finite element model to verify the analysis, then based on the verified numerical model of construction process on the influence law of structural internal force and deformation, the comparative study of different lifting scheme and supporting bracket in unloading way of large-span cantilever truss layer construction process, the influence of the research on mechanical properties of the whole structure to carry out the whole process of construction, and compared with the monitoring data analysis, further verify the accuracy of the simulation of construction. In this paper, the main research work and conclusions are as follows:1 It is based on software Midas Gen and SAP2000 contrast built by Hengqin poly square, the rationality of the finite element model. Separately using two software established the three-dimensional finite element model, on the modal analysis and construction simulation analysis. Comparison was carried out by cycle and vibration model, the structure of the main components of the error of the internal force and vertical displacement analysis. Results show that the two kinds of software to calculate the cycle and vibration model has good inosculation, modal analysis in the two biggest cycle which maximum error is 4.94%, two software in the first four were mode; Typical artifacts (bottom chord) on column, core tube, the accumulation of vertical displacement and axial force, shearing force, bending moment along with the advance of the construction phase of the process, with the change rule is a growing trend and two software numerical simulation data is close to, this project was verified by Midas Gen the rationality and validity of modeling, finite element model can be used in the structure of the simulation analysis of the follow-up work.2 In order to the construction scheme of the simulation in layer upon layer, carried out a comparative analysis of the two kinds of finite element software simulation to study the stress performance of different location component change rule. The results show that the same floor corner cantilever column cantilever central column vertical displacement, axial force and bending moment are larger than the internal column;Same floor corner vertical displacement of core tube is bigger than central core barrel.3 For the large cantilever truss hoisting and support bracket in unloading plan carried out the optimization analysis of construction process, and studied the whole nature, hoisting, assembled lifting truss layer, as well as the support bracket and a discharge, at the same time many times an uninstall unloading, partition, partition uninstall many times different lifting and unloading plan, such as the influence of the internal force and deformation of a typical component, the results show that the layer truss spell lifting scheme is better than that of the whole nature, lifting scheme and typical artifacts of axial force, shearing force, bending moment is small, and the vertical displacement change is smaller; The optimal support bracket in a discharge way, its influence on the internal force and deformation of the truss layer is minimal.4 It is conducted Hengqin poly square overall construction process simulation analysis, studies the different construction leveling floor number (two floors a leveling, three floors a leveling, five floors a leveling), the leading core tube frame construction layer (two, three, five leading layer) of post-cast strip, truss floor reserved or not on the influence law of structural internal force and deformation, the results showed that:in the ninth five layers before a leveling layer construction scheme optimum, followed by two layers of a leveling plan optimal, a minimal impact on layer truss vertical displacement change; In the ninth leading construction before the second construction scheme optimum, subsequently leading five layer construction scheme optimum, minimal impact on layer truss vertical displacement difference;Truss floor reserved after pouring belt can effectively reduce the cantilever end floor layer of bending moment and axial force, to ensure that the cantilever floor don't appear the crack.5 It is introduced the construction monitoring technology for stress, the vertical displacement of structure construction process of monitoring, verify the accuracy of the construction simulation analysis. Results show that the lower chord truss structure layer in support bracket in monitoring the vertical displacement values before and after unloading with the results of numerical simulation, the key components (bottom chord, pillar, oblique abdominal rod) on the stress value of measuring points are smaller than the theoretical value, and greatly improve the safety of the construction process.