Construction Monitoring And Analysis Of Long-span Prestressed Structures

With the continuous development of China’s economy and the continuous improvement of construction technology,more and more complex buildings appear in actual engineering,one of which is the long-span cantilever beam structure.During the entire construction process of a long-span cantilever beam structure,a temporary support system is required to ensure its safety.During the process of dismantling the temporary support system,in order to ensure the safety and feasibility of the long-span cantilever beam,the entire construction process needs to be monitored.The main research contents and results are as follows:1.This article takes Huazhiyi Fashion Art Center’s long-span prestressed cantilever beam structure as the object.First,it analyzes the related technology in the entire construction process,and then describes the monitoring scheme in detail.Selected from nine ones,four representative cantilever beams are monitored.Place instruments on four different sections ABCD of each cantilever beam.Each section equipped with two concrete strain gauges,two reinforced strain gauges,at the same time,Static levels are placed on the beam ends of the four beams.A static level,a static level is placed in the middle of the largest frame beam,and the static level at the root of the beam is used as the reference point.2.Construction monitoring of prestressed tensioning and four mold removal processes during the construction of long-span prestressed cantilever beams.(1)During the first stage of mold removal processes,the maximum stress values of the concrete and steel bars appear on section A,and the beam end displacement is the largest.The maximum monitored stress of concrete and of steel bars respectively are 0.253 MPa and 1.48 MPa,and the monitored displacement of static level 3 is 26.11 mm,which are all within the range of design requirements.(2)In the second stage of mold removal processes,the maximum stress values of the concrete and steel bars appear on the section B,and the beam end displacement is the largest.The maximum monitored stress of the concrete and of the reinforcing steel respectively are 0.7873 MPa and 4.914 MPa,and the monitored displacement of the static level 3 is 50.11 mm,which are all within the design requirements.(3)In the third stage of mold removal processes,the maximum stress values of theconcrete and steel bars appear on section C,and the beam end displacement is the largest.The maximum monitored stress of the concrete and of the reinforcing steel respectively are1.3654 MPa and 7.99 MPa,and the monitored displacement of the static level 3 is 52.23 mm,which are all within the design requirements.(4)In the fourth stage of mold removal processes,the maximum stress values of the concrete and steel bars appear on section D,and the beam end displacement is the largest.The maximum monitored stress of concrete and of the reinforcing steel respectively are1.4835 MPa and 10.69 MPa,and the monitored displacement of static level 3 is 66.66 mm,which are all within the range of design requirements.3.Finally,the finite element software was used to simulate the four mold removal processes of the long-span prestressed cantilever beam,and the numerically calculated stress values and deflection values were compared with the on-site monitoring stress values and deflection values.It was found that the two could be compared.The results show the correctness of the finite element analysis method.4.The research results of this paper have certain reference value and guiding significance for the analysis and application of the construction process of similar long-span prestressed cantilever beams in the future.Figure:48 Table:24 Reference:40...