Research And Application On The Stability Of Existing Steel Frame Structures With Existing Damage Under Earthquake

Steel frame structures are often used in a lot of civil buildings of high-rise and super high-rise and industrial buildings.Steel frame structure of the existing will produce the accumulation damage gradually(such as environmental corrosion and component defects)under the influence of various factors such as manufacturing,construction,use and environment.Damage accumulation will reduce the bearing capacity of the structure and weaken the ability to resist natural disasters.If the earthquake occurs,steel frame structures with existing damage may collapse because they can not withstand earthquake.Therefore,according to the structure of the damage level,characteristics and use characteristics,the stability of existing steel frame structures with existing damage is studied under earthquake.The reasonable calculation method provides the theoretical basis for the identification and analysis of existing damaged steel frame structures.Therefore,it has practical significance to study the dynamic stability of structures.Through research on damage of steel show,weakened cross-section is an important reason for the damage of steel frame structure.The influence of cumulative damage on the ultimate bearing capacity of steel frame structure is analyzed under earthquake by steel frame engineering example.It is found that the instability o f the structure is more likely to occur when the structure is damaged.So it is necessary to introduce the damage factors in the analysis.Based on the theory of dynamic stability and comparison of various methods,the stability of a six-story steel frame structure under the condition of no damage and different damage degree was studied.The maximum displacement of the structure vertex is calculated under different seismic waves.The relationship between the maximum displacement of the structure and the seismic waves with different intensities seismic waves.Using the second kind of dynamic stability theory,we can see the critical value of the seismic load under the dynamic instability,and the structure is more prone to dynamic instability under the dama ge.The finite element method can be used to simulate the structural damage effectively and provide the basis for the seismic performance analysis of the existing steel frame structure.Scale model design of steel frame structure,the use of vibration table with four different mesa acceleration seismic load,and through dynamic strain gauge acquisition steel frame model of beam and column internal force is larger strain value of the control interface,and compared with the theoretical value obtained by the finite element analysis,the data are basically consistent.The test data have high authenticity.