Safety and stability analysis of variable cross-section disc-buckle type steel pipe high support system

Abstract

In order to solve the problems of poor safety and difficult determination of construction scheme in the construction process of variable cross-section disc-buckle type steel pipe high support system, based on the stress state of the normal working of the disc-buckle type formwork support, the stability bearing capacity of vertical poles under three working conditions of central pole, side pole and corner pole were experimentally carried out, and the correctness were verified by comparing with the results of the experiment and finite element analysis. Based on the verified finite element model and the characteristics of semi-rigid connection joints, the first-order buckling mode and nonlinear buckling analysis of the stability bearing capacity of the variable cross-section disc-buckle type steel pipe high support system were carried out in the construction period with special structure in practical engineering, the stability bearing capacity and deformation law of the variable cross-section disc-buckle type steel pipe high support system in the construction process were mastered. Through parametric analysis of the influencing factors such as the joint bending stiffness, the setting parameters and the initial imperfections, the influence law of the relevant parameters on the overall stability of the variable cross-section disc-buckle type steel pipe high support system was grasped. The results showed that the corner poles at the higher variable section and the lower variable section of the weak stiffness direction support system were prone to instability and failure. The overall stability bearing capacity was mainly affected by the lift height. The vertical diagonal bracing plays an important role in improving the overall stability, the larger the lift height was, the more obvious the improvement was. The overall stability bearing capacity decreases with increasing top extension length, and the top extension length should be controlled within 0.45 m. When the extension length of the top was greater than 0.45 m, the initial imperfection cannot control the overall stability bearing capacity, and the overall structural stability bearing capacity was determined by the buckling behavior of the top vertical pole. When the joint bending stiffness was greater than 2.0 K, the stability bearing capacity does not change. The higher the support system was, the smaller the influence of joint bending stiffness on the overall stability was.