| In today’s society,urban construction land is becoming more and more tight.In order to obtain the maximum land utilization rate and use value,and in order to meet its various use functions,the height of urban buildings is constantly increasing,and a large number of over-limit buildings are formed.The aspect ratio will affect the stiffness,displacement,overall stability and economic indicators of the building structure.Due to the small deformation of the pile foundation under the action of the seismic force and the good stability and reliability,most high-rise buildings currently widely use the pile foundation as its foundation form.This paper analyzes the internal force of the foundation of a large aspect ratio building project under the action of earthquake,and mainly performs the following work:(1)Several methods for calculating the aspect ratio of high-rise buildings are introduced,and their characteristics and deficiencies are compared.It is recommended that the aspect ratio be calculated using the equivalent width method.The influence of the aspect ratio on the structure is expounded.(2)This article mainly studies the force of the pile foundation under the earthquake,and introduces several analytical models of shear wall structure and the lower pile foundation.According to the actual situation of the model in this paper,select the appropriate analysis model and calculation method,the calculation of the pile-soil effect using M method,explained the determination of M value.According to the characteristics of the model used in this paper,the simulation unit types of various components of SAP2000 finite element analysis software are introduced.(3)Using SAP2000 finite element software for simulation analysis,the line element simulation is used for the lower pile foundation,the spring element acts on the line element of the simulated pile foundation,and the effect of soil on the pile is simulated by the stiffness of the additional spring The M method is used to calculate the stiffness.The shell element model is adopted for the upper shear wall and floor slab members,and the line element is adopted for the beam and slab members.When performing elastoplastic analysis on the model,the shear wall is divided into layered shells and plastic hinges are applied to the beam tosimulate the nonlinear behavior of the structure.(4)Establish a model with an aspect ratio of 7,select three seismic waves,and adjust the amplitude of the seismic waves.Compare the reaction force and shear force of pile top under different earthquakes.The outermost piles are more sensitive to earthquakes than the inner piles.The reaction force and shear force of the pile top of the large aspect ratio building structure are positively correlated with the earthquake action,and the outermost pile will produce tension in the event of rare earthquake action.(5)Change the aspect ratio by changing the height of the structure to obtain two models with aspect ratios of 5 and 9,respectively.Compare the internal force changes of the piles with different aspect ratio structures under different earthquakes.The basic design of the high aspect ratio building provides references and suggestions. |
