Investigation On Seismic Performance And Analysis Method Of Damped Masonry Infill Wall Based On Seismic Resilience

Masonry infill wall(MIW)is an important non-structural component that undertakes building functions such as enclosure and separation.It is found that the post-earthquake damage of MIW is severe and the risk of collapse is high,leading to casualties,property losses and the hindering of the recoverability of the building using functions.Therefore,it is necessary to ensure the safety of MIW during the earthquake and the post-earthquake recoverability of MIW to realize the seismic resilence of MIW.Damped masonry infill wall(DMIW)is an innovative MIW,which is able to significantly weaken the stiffness and restraint effect of MIW that transmit to the structure.Also,the DMIW has the advantages of high deformation capacity,low damage,and offering damping to the structure.Thus,DMIW is deemed as a new solution to the problem of seismic resilience of MIW.In this dissertation,the main goal is to further study the seismic resilence-based analysis,calculation and design methods based on the existing research results of DMIW.To achieve this main goal,the in-plane(IP)seismic performance,out-ofplane(OOP)performance,effects of IP damages on OOP performance,mesoscale and macroscale modeling method for predicting the IP and OOP behavior of DMIW,seismic performance evaluation and design method of DMIW component and DMIW structure are studied respectively.The main research contents are as follows:(1)Shear hysteretic performance of damping layer joint(DLJ).A total of 17 types of specimens,which are composed of 4 kinds of materials of DLJ and 2 kinds of bonding glue for DLJ-brick interface(DBI),are designed and manufactured,and the shear hysteretic test is perform to investigate the performance of the specimens and study the reliability of the bonding glue.By comparing the results of hysteretic performance and the failure pattern,one type of DLJ specimen that has the superior DLJ material and the reliable DBI bonding glue is selected as the superior configuration for the DLJ.The macro-modeling method of the hysteretic performance of DLJ is developed,which is composed of Bouc-Wen model,Maxwell element and nonlinear spring element.The genetic algorithm is adopted to calibrate the parameters of the DLJ macro model and the test result of the superior configuration of DLJ is used to validate the DLJ macro model.(2)Seismic performance of the RC frame with DMIW.The quasi-static experiment is performed to test the IP seismic performance of one RC frame with MIW and one RC frame with DMIW.The IP working mechanism is revealed and the seismic performance in terms of hysteretic performance,stiffness characteristic,deformation pattern and failure patter.Furthermore,the shear deformation characteristics of DLJ,as well as the mechanical behavior of the flexible connection between masonry unit and column,are analyzed.The results indicate that the superior DLJ configuration is able to realize the expected mechanism that shear deformation of DMIW concentrating at the DLJ.Through the expected mechanism of DMIW,the stiffness effect of MIW is weakened significantly and the damages are eliminated.Furthermore,the DBI bonding remains reliable.Based on the existing seismic performance of DMIW,the definition of damage state(DS)of DMIW is proposed.The fragility curve of DMIW under different DSs are developed and the corresponding parameters are obtained.The economic loss of DMIW frame under different DSs is predicted.(3)The out-of-plane(OOP)performance of the DMIW.The airbag is used to simulate the OOP inertial loading being applied on the wall surface.One RC frame with MIW and three RC frame with DMIWs are investgated experimentally.The OOP mechanism of DMIW is revealed,the influence of the number of masonry units and the type of DLJ materials on the OOP performance of DMIW are analyzed,respectively.The results suggests that the main OOP working mechanism of DMIW with viscoelastic DLJ is the bending mechanism of masonry units and tie bars.The main OOP working mechanism of DMIW with low-strength-mortar DLJ is the bending mechanism composed of masonry units and tie bars coupled with two-way acrhing action.The the equivalent static methods given by seismic standards are used to evaluate the OOP seismic capacity of DMIW.The results show that DMIW possesses the capacity to resist the maximum considered earthquake in the highly seismic regions of the main seismic hazard countries.Furthermore,the OOP behavior of the DMIW and MIW with IP damage that is equal to the 1/50 IP story drift are studied,respectively.And the influence of IP damage on OOP performance of DMIW are investigated.The results indicates that the influence of IP damage on OOP performance of DMIW is significantly lower because of the low-damage characteristic during the IP cyclic loading,compared to MIW.The OOP capacity of DMIW decreases by 15% after IP damage while the OOP capacity of MIW decreases by 72%.(4)Mechanical performance and simulation methods of DMIW.A discrete element method(DEM)based mesoscale simulation method for predicting the IP and OOP behavior of DMIW is developed and validated.Based on the OOP mechanism of DMIW,the calculation methods of OOP initial stiffness and bearing capacity are derived.The existing IP macro-modeling method of DMIW is modified in terms of determining the hinge location of diagonal link element.The dynamic macro-modeling method of DMIW with viscoelastic DLJ is developed based on the lumped inelastic beam element models with distributed mass and lumped mass,respectively.The calculations of the equivalent section parameters and mass of the model are derived.Lastly,the Open Sees-based simulation methods for predicting the behavior of DMIW are developed.(5)Seismic performance and design method of the structure with DMIW.DMIWs are placed in the 1:5 scaled specimen which is a damaged slab conversion structure retrofitted by energy dissipation devices.The quasi-static is performed to experimentally study the IP and OOP performance of the DMIW in a real structure.The results suggests that the DMIWs in a real structure is able to realize the expected IP mechanism,which makes DMIW avoid being damaged.No OOP collapse of DMIW is observed under the OOP inter-story displacement that is equivalent to 0.56 times the wall thickness.At last,the existing research results of DMIW are summarized,the seismic design method as well as the design flow which considering seismic resilience are developed.