Study On Low Intervention Seismic Reinforcement Of Village Dwellings In Yunnan Province

Yunnan Province is located in an area prone to frequent earthquakes.Due to aging materials or improper construction methods,the seismic capacity of residential buildings in villages or towns cannot meet the current standard requirements,which will reduce the service life of buildings and threaten the safety of life and property.Therefore,seismic reinforcement is urgently needed.There are various building types in Yunnan Province,and the statistics show that the three types of houses with the largest proportion in villages and towns are masonry houses,perforated timber frame filled wall houses and RC frame filled wall houses.The reinforcement methods for these house types are divided into 8 kinds,and the engineering cement-based composite materials(ECC)are finally selected for reinforcement after analysis and screening.ECC material has the characteristics of high toughness,high durability and so on.Due to its own cement matrix characteristics,the reinforced interface has good bonding performance,and the material has low carbon emission,convenient construction and has no great impact on the original building appearance,so it is a low-intervention seismic reinforcement material.At present,the ECC reinforced structure has been mature at home and abroad,but the reinforcement research on nonstructural components such as filled walls is still relatively limited,and there is a certain blank for structural reinforcement under different damage states.In this paper,the general large nonlinear finite element software ABAQUS and its own CDP are selected first,and the appropriate material constitutive relationship is selected through screening,comparative analysis and other methods,and the tensile constitutive relationship of ECC material is determined by ECC uniaxial tensile test.The effects of integral model,simplified micro model and refined micro model on the simulation results are compared and analyzed.The results show that the modeling method has little influence on the simulation results.Different modeling methods can be used for different components or different analysis targets.The three types of structural specimens with the largest proportion were modeled and compared with the test to verify the correct reliability of the modeling method.After that,relevant specimens were designed according to the actual situation of rural dwellings in Yunnan province.ECC surface layer was used for single-side reinforcement and in-plane pseudo-static loading was carried out.Hysteretic curve,skeleton curve,peak bearing capacity,stiffness degradation and energy dissipation were analyzed to analyze the improvement effect of this reinforcement method on inplane seismic performance of each component.At the same time,the influence of different reinforcement methods on the seismic performance of the structure is analyzed,and it is determined that the ECC surface reinforcement is a more suitable reinforcement method,and this method is taken as the basic reinforcement method for subsequent research.The residual bearing capacity was used to define the different damage states of each specimen,and the in-plane seismic performance of masonry bearing wall strengthened with ECC surface layer and the out-of-plane seismic performance of perforated wood frame filling wall and RC frame filling wall were analyzed under different damage states.Through comparative analysis of the peak bearing capacity,cumulative energy consumption and other indicators of each specimen,the reinforcement effect of each structure type under various damage states was comprehensively evaluated,and the relevant reinforcement suggestions and suggestions were put forward.At the same time,the influence of in-plane damage on the external bearing capacity of the opposite side is analyzed,and the relationship between the inter-plane displacement and the percentage decline of the external bearing capacity is obtained by fitting,and a complete set of reinforcement system is formed.Finally,a rural house in Ninglang Shuiqing Township,Ninglang Yi Autonomous County,Lijiang City is selected as a reinforcement pilot.ECC surface layer singleside reinforcement method is adopted to reinforce it.Modal analysis method is used to analyze the natural vibration period of the structure before and after reinforcement to judge the influence of reinforcement on the structure stiffness.Further evaluation is made on the enhancement effect of ECC surface single-plane reinforcement method on seismic performance of structures,which shows that this method is suitable for low-intervention seismic reinforcement of rural dwellings in Yunnan province.