| Through the analysis of earthquake investigation reports from countries around the world in recent years,it is found that the proportion of casualties and economic losses caused by the damage of non-structural components in the total losses in earthquakes is increasing.For this reason,our country pays more attention to the disaster prevention and mitigation of building subsidiary structures.Among them,the seismic resistance of building electromechanical engineering is one of the key areas of concern.Compared with the accumulation of seismic technology of main-structure of building,there are still many shortcomings in the development of seismic technology of building electromechanical engineering,especially the optimized design and intelligent monitoring is still blank in China.Based on a large number of test and finite element simulation data,this paper carries out a series of research on the design and monitoring of seismic braces and hangers around the goal of the anti-seismic optimization design and intelligent monitoring method of building electromechanical engineering.The main work is as follows:(1)Through the failure test of the whole body and components of the seismic braces and hangers,the weak of the bearing capacity and the failure mechanism of the anti-seismic suspension bracket are explored.The failure of the whole body and components of the anti-seismic hanger is brittle,and the weak of its bearing capacity is the fixed connection seat itself and the connection joint with C-channel steel;the main failure forms are: the connection part between the anti-seismic connection seat B(brace of bracket)and U-tube hanger is pulled off,the bolt of C-channel steel is torn by the anti-seismic connection seat B,and the adjustable hinge will be pulled off by itself,etc.the cause of the damage is the slippage at the joint between the fixed joint and the channel steel.Or self-destruction;It is found that the bolt torque at the connection between fixed connector and C-type channel steel has a great influence on the ultimate bearing capacity of the anti-seismic hanger.(2)Through a large number of finite element analysis simulations and compared with the experimental results,a simplified mode decomposition reaction spectrum method for Calculation of integral seismic action and a local seismic action analysis method based on ANSYS workbench are proposed.The acceleration power amplification factor of seismic braces and hangers based on floor acceleration can be taken as 1.2;the simplified mode decomposition response spectrum method can be used as a supplementary algorithm of the equivalent lateral force method,and its calculation results can be reduced by 30%~40% compared with the equivalent lateral force method,but slightly larger than the time history analysis method;seismic response analysis of local components shows that increasing the bolt tightening torque has an obvious effect on improving the bearing capacity of the fixed joint and the anti-seismic hanger,but should not exceed the limit value of the bolt head.(3)Based on the first-order characteristic frequencies of the seismic braces and hangers,a damage warning method of the seismic braces and hangers is established by using the integrated test platform of the main structure-the seismic braces and hangers.Compared with the intact state,the first-order frequency of the seismic braces and hangers in the loosened state decreases obviously.The frequency domain analysis method combined with wavelet transform and Fourier transform can accurately identify the change of the fundamental frequency of the seismic braces and hangers.The method of installing vibration motor and suspension weight can improve the discreteness of the monitoring data analysis results.The effect of installing the vibration motor is the best,and the distance between the excitation point and the loose bolt of the top plate is found.The farther away,the smaller the dispersion of the first-order frequency of the power spectrum,the more stable the analysis results. |
PDF Full Text Request