Numerical Analysis Of Seismic Performance Of Separate Hydraulic Climbing Formwork

In recent years,the rapid development of super high-rise buildings has made hydraulic climbing formwork construction technology widely used.Climbing formwork have many advantages such as saving scaffolding materials,relying on their own equipment to lift,saving costs,shortening the construction period,etc.,and have achieved satisfactory result in the construction of super high-rise building core tube.The high-rise buildings in the seismic zone with high earthquake intensity have high seismic fortification intensity and long construction period,therefore,the seismic capacity of construction machinery during construction cann't be ignored.Due to the high-altitude operation and the load environment is complicated of the climbing formwork during the construction process,the safety and stability of the climbing formwork in the construction state and the climbing state are related to the progress,quality and safety of the whole project,if an earthquake occurs,the safety of the climbing formwork will inevitably be affected,and even pose a serious threat to the safety of construction workers on the climbing formwork,causing significant losses.This paper takes the super high-rise office building of Xishan Wanda Plaza in Kunming as the engineering background,takes the separation hydraulic climbing formwork used in the core tube of office building as the research object,and uses ANSYS finite element software to study the seismic performance of the hydraulic climbing formwork in the construction state and the climbing state.The main research contents and results are as follows:(1)Combining the climbing formwork system used in the construction of the core tube of the office building of Xishan Wanda Plaza in Kunming,introducing the climbing principle,tructural composition,model selection,assembling,disassembling and construction processes of the separated hydraulic climbing formwork system,providing a reference for similar projects.(2)Based on the structural dynamics theory,the core tube is simplified into a spring-constrained mass in ANSYS software.Compareing the vibration modes of the simplified core tube and the PKPM core tube model,found that the spring-constrained mass model can effectively simulate the translational and torsional motion characteristics of the core tube in the horizontal plane.(3)According to the different boundary conditions of the climbing formwork and whether to consider the influence of the core tube movement on the climbing formwork,four corresponding finite element models are established.Using the ANSYS modal analysis function to analyze the first 10 modes of the four models,and expounding the dynamic characteristics of the climbing formwork in the construction state and the climbing state.It is pointed out that the influence of the simplified core tube on the vibration mode of the Climb mode is mainly concentrated in the first 3 modes.(4)Analyze seismic response of the climbing formwork in the X-direction,Y-direction and XY-direction seismic waves by the response spectrum method.The displacement and equivalent stress law of the climbing formwork in the climbing state and the construction state are obtained,and it is pointed out that the Y-direction seismic waves makes the climbing formwork produce larger displacement and equivalent stress.It is recommended to strengthen the connection between the frame and the structure of the climbing frame.The difference of the seismic response of the climbing formwork in the construction statea and climbing state are compared.It is pointed out that the results of response spectrum method are larger than those of time history analysis method.(5)The elastic-plastic time-history analysis of the climbing formwork subjected to gravity load,construction load,wind load and 3-way seismic wave are carried out,it is concluded that the vertical pole on the main frame of the climbing formwork will yield in the construction condition.It is recommended to increase the section of the vertical pole on the main platform or to change the steel with stronger strength;the climbing formwork does not yield in the climbing condition;It is sensitive to Y-direction earthquakes of climbing formwork.