Study On Key Technologies Of Construction Control About Large-Span Steel Structure Based On Prestressed Foundation Beam

Against the characteristics of particular shape, complex force, large span and numerous space distorted components about large-span and profiled surface space steel structure based on prestressed foundation beams, this paper carried on analyzing the construction process which based on the construction program, discussed the principles and methods of construction monitoring of complex structures and monitored the parameters about stress and deformation of steel structures. Based on finite element theory to simulation the whole construction process of main steel structure. Prestress loss of the prestressed concrete foundation beams during construction process are simulated and analyzed using finite element software Midas/Civil. Prestress loss is grasped by the actual construction monitoring. Comparing and analyzing simulated values with measured values to verify the feasibility of the numerical simulation method of the construction process.The results showed that:change trend of analog values are same with the measured ones, but still existing some differences. The asymmetric construction sequence have great impact on the structure."Path" and "time" effect on structure during the actual construction process should be considered. Theoretical calculation in norm of prestress loss is maximum,followed by software simulation values, the measured prestress loss is minimize. Stress loss trend on both sides of prestressed foundation beams is same, length and tensile load size of the prestressed foundation beam have certain effect on the stress loss in numerical simulation.The longer the beams are, the greater the tensile load is, the more the internal force lose. Owing to frictional resistance of the surrounding soil, external environment, a variety of uncertainties and so on, the variation of the measured loss doesn’t match analog value.It proved that simulate the construction process of structure by the finite element software has some guiding significance for actual structural construction. It allows us to fully grasp the actual stress state and original design of the structure in construction process by construction process monitoring. It also provides real-time information of structural state and adequate technical support for the security and stability of the structure during construction. Gaps between software simulation values and the actual monitoring values are in the controllable range. Practice has proved that combining finite element simulation and the actual construction monitoring is an effective way to ensure security and stability of structural construction process. It can optimize structural design, save materials, enhance economic efficiency and provide a reference for the future design of similar structures.