Experimental Study On Seismic Damage Of Masonry Bottom Piers Strengthened By Compressive-shear Metal Damper

The masonry structure has a long history and is still one of the most widely used structural forms,especially in the township buildings.Compared with other types of structures,the masonry structure has many advantages,but in terms of earthquake resistance,the masonry structure has major defects and deficiencies.Compared previous earthquake damages,it is found that the masonry structure piers are more likely to be damaged during an earthquake,and the bottom piers is the most severely damaged.Although the related research on the method of strengthening the damaged masonry structure has been done in the existing research,and preliminary results have been obtained,the research on the method of strengthening the damage mode of the piers of the masonry structure is still insufficient.In recent years,the concept of strengthening with energy dissipation as the core has been recognized by the majority of scholars,and all kinds of metal dampers have been widely studied and applied.Based on the existing reinforcement methods of masonry structure,combined with the concept of energy dissipation and vibration reduction of metal damper,according to the stress mechanism of piers masonry structure,this paper designs a bearing compressive-shear metal damper(CSMD)which can replace piers equivalently.Through the combination of quasi-static test and finite element simulation,the seismic performance of the test wall before and after reinforcement is compared and analyzed,and finally this reinforcement method is put forward the rationality of law.The main research contents of this paper include:(1)Analyzing the failure characteristics and stress mechanism of the damaged piers of masonry structure,and combined with the reinforcement idea of replaceable connecting beams in concrete structure,this paper proposes a pressure-resistant shear metal damper that can replace the damaged piers;(2)According to the research status of the metal damper,the design of the pressure-bearing shear metal damper that conforms to the stress characteristics of the piers is carried out,and the rationality of this design method is verified by finite element analysis;(3)Replace the damaged bottom piers of the masonry structure with a pressure-resistant and shear-type metal damper,conduct pseudo-static test research on the strengthened wall,compare the seismic performance of the wall strengthening,and focus on the wall;(4)The finite element software simulates the test wall and compares it with the test results to verify the rationality of the reinforcement method.The conclusions of this paper show that: Based on the stress mechanism piers of masonry structure,the metal damper designed in this paper meets the mechanical requirements of "bearing pressure and shear resistance".The bearing capacity of the wall can be restored to the undamaged state after the damaged piers is replaced by the compressive-shear metal damper.The energy dissipation capacity is significantly improved in the later stage of loading,and the seismic performance is improved.The numerical simulation results show that the failure of the strengthened wall model is more reasonable,which verifies the feasibility of the reinforcement method and provides reference for the improvement of the subsequent reinforcement method.