| Earthquake is one of the most dangerous natural disasters to human life and economy in the world.Since the beginning of the last century,people began to study the theory of structural earthquake resistance continuously.In the previous seismic studies of engineering structures,it is generally believed that the magnitude and direction of ground motion action received by each support in the structure at the same time point are the same,so the assumption of uniform excitation of ground motion is made.However,with the continuous development of China’s economy and technology,the construction industry has made great progress.The improvement of people’s aesthetic appreciation for architecture has also made the current building structure more complex,and there are more and more super-high and super-long buildings.After the research of many scholars found that: when the structure span is large or the site changes obviously,the seismic action of each support has obvious difference,this difference is called "the spatial change effect of ground motion".In order to ensure the safety of buildings,it is necessary to take into account the influence of space specificity on building structure.Although many scholars have realized the importance of spatial specificity,the current research on spatial specificity in China is still in the exploratory stage due to the restriction of technology.Due to the complexity of spatial specificity,no general general rules have been summarized in previous studies.In order to study the influence of multi-point excitation traveling wave effect on the complex ultra-high structure supported by a single side mountain,this paper takes the actual project "Jiuxiang Dianhong Ladder Project" as an example.This project belongs to a complex over-limit structure supported by a special single side mountain.The project is simplified and simulated to study the influence of multi-point excitation traveling wave effect on the complex ultra-high structure.This paper conducts research from the following three aspects:(1)This paper introduces the significance of spatial specificity to the research of mountainous buildings in Yunnan Province.After reading a large number of domestic and foreign literatures,it summarizes the spatial characteristics of ground motion and seismic response analysis methods of large-span spatial structures and the current research status of spatial specific multi-point excitation in China.The simulation and solution of multi-point excitation are very complicated.In the finite element analysis software,the commonly used simplified solution and time-history analysis methods of multi-point excitation mainly include three kinds: absolute displacement method,large mass method and large stiffness method.Among the four spatial effects,the most obvious one is the traveling wave effect,and the traveling wave effect is affected by the apparent wave velocity,so this paper introduces two methods to determine the apparent wave velocity.(2)In this paper,the author studies on construction project the location,the structure form and purpose is very special,in order to ensure the accuracy of the simulation analysis and the safety of structures,according to the geological situation of the mountain,geotechnical properties and hydrogeological condition such as information to infer the possibility of geological disasters,and supported by the left side of the mountain is reasonable simplified simulation,using Flac3 d to mountain alone modeling,simulation analysis the stability of the mountain under the general condition and seismic conditions,obtained the general conditions and earthquake mountain natural gravity,under the condition of maximum stress and maximum shear and the stability coefficient of the mountain,so the mountain is stable.On this basis,a method of mountain simplification is proposed,which uses steel frame and viscous damper to simulate mountain.After modeling in SAP2000,the mountain model and building structure model are combined for analysis.(3)Analyze the model of building structure and mountain combination in SAP2000.After reasonable selection of seismic waves,conduct modal and time history analysis of multi-point excitation and uniform excitation respectively for the overall model.According to the data obtained from the finite element analysis,the influence coefficient of traveling wave effect is calculated.Based on the variation rule of the influence coefficient of traveling wave effect,the influence range and variation rule of multi-point excitation traveling wave effect on the complex ultra-high structure supported by unilateral mountain are summarized.Because the project is over 100 m high,there is a mild topical torsion is irregular,floor discontinuity and bearing capacity of floor mutation overrun situation,combined with the impact of the traveling wave effect,put forward the corresponding countermeasure,provides the actual project design,construction reasonable opinion,the ground can better guide the actual project,which guarantees the safety of building structure. |
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