The Seismic Capability Anlaysis Of Typical Building With Regional And Characteristics In North-south Seismic Belt

It is found from past earthquake damage data that the seismic capability oftypical buildings with regional and specific characteristics is different during theearthquake. For example in Lijiang earthquake (M7.0) in1996the seismicdamage index of national wood house, i.e. mortised timber frame house is0.26,but the index of the general brick-and-timber house is0.51. It can be seen thatthe local economic losses and casualties caused by earthquakes are influencedby the seismic capability of houses with regional and specific characteristics.Therefore, the study on the seismic capability of typical buildings with regionaland specific characteristics is very signicant.The north-south seismic belt is a very important seismic belt in China,which has the characteristics of wide distribution, high frequency and geologicalcondition with extremely active movements. In this paper, the earthquakedamage of typical buildings in this belt are statistically analyzed, thevulnerability analysis results of various typical buildings are provided, and thehouse with the regional specificity charactersitics, i.e. the mortised timber framehouse is selected, whose corresponding seismic response analysis model is builtand the seismic capability of the house is analyzed. The main contents are asfollows:(1) Based on all the earthquakes occurred in the north-south seismic beltsince1996, whose magnitude is equal or greater than6.0are collected, and allthe earthquake damage after1993are systematized and counted. The damage ofvarious building types of different intensities in the north-south seismic belt areobtained, based on to the results of statistics, the comparative analysis andvulnerability analysis of seismic capability of various building types areimplemented. According to the analysis results, the differences among seismiccapabilities of all kinds of typical buildings in this belt are provided: the highestseismic capability among all of builgings is class C structure in past earthquakes,i.e. reinforced concrete frame structure, and whose level of earthquake damagein the actual statistical results is also the lightest; the second one is class Bstructure (masonry structure) and class A+structure (mortised timber framehouse); the most severely damage is class A structure which is made of woodand earth, stone, brick wall.(2) The force transfer mechanism, failure performance and seismic energydissipation mechanism of the mortise-tenon connection of mortised timberframe building are studied in this paper, and the conclusions are shown asfollowing:â‘ it is obtained from the force transfer mechanism of mortise-tenonconnection that the mortise-tenon joint is a special semi-rigid joint, which canreduce the stiffness and increase the ductility of the intergral structureeffectively;â‘¡by the study on the failure performance of the mortise-tenon connection, it is shown that the position of stress focus is generated in the neckof the tenon and the edge of mortise easily, which is also the failure position inmortise-tenon connection, and the mortise-tenon joint is closely related tomaterial mechanical properties of timber;â‘¢the mortise-tenon joint has theenergy dissipation mechanism similiar to the friction damper. The necessarytheoretical basis is provided by the study of this paper for establishing thesimplified mortise-tenon connection model, and the foundation is provided forthe seismic analysis of mortised timber frame house.(3) Depending on the study on earthquake damage and constructioncharacteristic of mortised timber frame house, the finite element (abbr. FE)analysis model and seismic behavior are studied. Because of the complexconstruction of mortised timber frame house, in order to ensure the feasibility ofnumerical simulation and finite element analysis, according to the constructioncharacteristics of houses, two kinds of FE analysis model are built, which are thesimplified FE model and non-simplified FE model, and the models areimplemented by the universal FE analysis software ABAQUS. By threeexamples calculated the rationality of the simplified model is verified. Theresults show that, by using the simplified model provided in this paper, themortise timber frame houses are well simulated in small deformation stage. Onthe other hand, because it is assumed the response of the semi-rigid joint is all inelastic stage, the error is increased with the increasing of PGA of ground motion,but the error value is acceptable. Based on this conclusion, a typical mortisedtimber frame house is selected as an example. The dynamic properties and theseismic capability of this structure are studied. The results show that thedisplacement and acceleration response of the house are increased in a nonlinearway with the increasing of PGA of ground motion, in which the seismicresponse of the structure on the site condition of II are maximum, and those onthe site condition of I are minimum.The study work of this paper is very important for understanding theseismic capability of buildings with regional and specific characteristics in thenorth-south seismic belt, which can be used as the basic work of establishingearthquake emergency foundation database of the belt, the necessary theoreticalbasis is provided for establishing seismic hazard assessment model and methodof the typical houses with regional specificity by this thesis, and it lays afoundation for making disaster prevention and reduction.