SEISMIC ANALYSIS AND DEVELOPMENT OF FRAGILTY CURVE FOR AN RCC FRAME

Abstract

In recentzpast, severe earthquakes havezcaused substantial physical losses andzcasualties. Partszof India are inzhigh risk of facingzdevastating earthquakes. Since a majorityzof the populationzis living in earthquakezprone areas, it is probablezthat such terriblezevents may take placezagain in the nearzfuture. Moreover, it isznot easy to cope with thezsubstantial directzand indirect economiczlosses after each devastatingzearthquake for azdeveloping country likezIndia. Because in thiszcountry many reinforcedzconcrete buildings areznot designedzaccording to the currentzbuilding code, seismic behaviour is notztaken into considerationzduring selection of the structural systemzand in most caseszsupervision in the constructionzphase is not adequate whichzin turn induces deficiencieszlike poor concrete quality, inadequatezdetailing of reinforcement etc. It is, therefore,zvital to quantifyzthe earthquake riskzand to develop strategies forzdisaster mitigation. In order tozachieve this goal, anzextensive and inter-disciplinaryzstudy is required. This study describeszthe methods by which it iszpossible to determine thezvulnerability of existingzengineering structures andzbuilding stock. Theztool that is employedzto assess the seismiczperformance of reinforcedzconcrete framezstructures is the fragilityzcurve, By definition, fragilityzcurves provide estimates for thezprobabilities of reaching orzexceeding various limit stateszat given levels ofzground shaking intensity for anzindividual structurezor population ofzstructures. A limitzstate, which is in thezsame terms as thezresponse, usually representsza damage condition or azlimitation of usage. The seismiczvulnerability of these structureszfor different earthquakezcan be interpreted from thezdeveloped fragility curves.