Study On Seismic Behavior And Retroffiting Method Of Existing Typical Rural Buildings In Beijing

Exsiting typical rural buildings in Beijing are mainly masonry-wooden frame structures,composed of 3-6 open rooms.Built for a long time,these structures are lack of seismic design and seismic construction measurement.Seismic hazard on masonry buidings shows that,masonry-wooden frame structures posses the problem of low material strength and unreasonable structural arrangement,and the seismic capacity of structures can hardly meet the seismic requirements.As a supportive study of local standards,this article studies the seismic capacity of the existing typical large-open room rural buildings in Beijing and proposes targeted retrofit recommendations.Finite element analysis and shaking table test of a 4-open rooms scale model are carried out to verify retrofit effect.Main research work and products are as follows:(1)Calibrating Finite element modeling method of the existing rural buildings in Beijing.Finite element model is established using general finite element software Msc.Marc,and the analysis results are compared with published experimental results.The comparison shows that used finite element modeling method can approximately simulate the seimic elastic-plasitc macro response of exsiting typical rural buidings.(2)Seismic capacity analysis of exsiting typical large-open room rural buidings.A elastic-plastic time-history seismic analysis of an existing typical 4-open rooms rural building structure is carried out including free vibration characteristic analysis,distribution of cracking strain and displacement response.The results show that structure can be seriously damaged even collapse under seismic load.Analysis on the Influence of numbers of open room and mortar strength on the seismic capacity of structures is also carried out.(3)Analysis on the characteristics of structural seismic response and the retrofit measurements.According to the features of structural arrangement and calculation results,seismic response characteristics of the structure is analyzed.After proposing targeted retrofit measurements,separate corresponding finite element models are established to verify the retrofit effect under isolated retrofit method through analysis on free vibration characteristic and elastic-plastic time-history response.Also an analysis on seismic capacity of a existing typical rural buildings with the combined retrofit methods is carried out.(4)Shaking table test of existing typical rural 4-open room one-storey rural buiding structure.To meet the seismic requirements that the structures can be repaired under fortification earthquake and not collapse under rare earthquakes,a retrofitted model of existing typical 4-open room rural building structure is designed,and is separately loaded under the case that the rods between the roof truss are tight and the case when the rods are loose.Through direct observation of structural damage under different seismic loads and analysis of the acceleration response,displacement response and strain response when the rods are tight under longitude and lateral seismic loads,seismic capacity of two retrofitted 4-open room building structures is assessed.Compared with finite element analysis results,feasibility and effectiveness of proposed retrofit method for exisiting rural buildings in Beijing are verified.