{"title":"Elongation in Ductile Seismic-Resistant Reinforced Concrete Frames","authors":"R. Fenwick, B. Davidson","doi":"10.14359/982","DOIUrl":"https://doi.org/10.14359/982","url":null,"abstract":"To survive a major earthquake, current practice requires seismic resistant frames to be designed to be ductile. To achieve the required level of ductility in multi-storey frames, the majority of the potential plastic hinge zones are located in the beams. The inelastic rotation, which may develop in these zones, arises predominantly from the tensile yielding of the reinforcement. The associated compressive strains are small and as a consequence elongation occurs. Test results show that elongations of the order of 2 to 4 percent of the member depth develop in plastic hinge zones of beams subjected to cyclic loading before strength degradation occurs. The factors influencing elongation are reviewed. The results of a time history analysis, in which elongation effects are modeled, shows that this action, which is neglected in current design practice, has important implications for the detailing of columns and the design of supports for precast components and external cladding.","PeriodicalId":305630,"journal":{"name":"SP-157: Recent Developments In Lateral Force Transfer In Buildings","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116894016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reinforced Concrete Buildings in Moderate Seismic Zones: Progress and Problems in Evaluation and Design","authors":"P. Gergely","doi":"10.14359/1010","DOIUrl":"https://doi.org/10.14359/1010","url":null,"abstract":"The questions and difficulties associated with introducing a seismic design code for the first time are discussed. The seismic risk to a populated region is not reduced much for many years after the code takes effect; only the rehabilitation of existing structures will reduce the risk significantly in a meaningful time frame. The overall behavior of buildings, especially of existing older r/c buildings, is often nearly elasto-plastic in nature because a mechanism forms soon after the formation of the first hinge and there is little or no over-strength. This may not be an optimum design in most cases. The response of r/c buildings to moderate ground motions designed only for gravity loads is better than expected, with moderate drifts and no premature brittle failures in most building types.","PeriodicalId":305630,"journal":{"name":"SP-157: Recent Developments In Lateral Force Transfer In Buildings","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132842323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}