Haksever, Ataman2021-11-202021-11-2020172147-0308https://dergipark.org.tr/tr/pub/tujes/issue/31296/287772https://dergipark.org.tr/tr/download/article-file/387340https://hdl.handle.net/20.500.14551/7616Inthe eighties the work was particularly focused in SFB (SonderForschungsBereich: A special fire research activity forstructural elements in Braunschweig Technical University, 1971-1986) onthe development of a universal material model for normal concretes in case offire. Through a comprehensive mathematical description of the rheological phenomena at elevatedtemperatures, the relaxation behavior of restrained col­umns could besuccessfully predicted. It aimed at clarifying the difference, which took placebetween the deformation behavior as well as restraint forces of calculated andmeasured reinforced concrete columns (RFC) under fire conditions. Such amaterial model was developed, in fact, through close cooperation of subprojectsA and B3 of SFB. Naturally,the use of such material model requires an immense computational treatment.Theoretical studies have shown, however, that this is worthwhile, because onlyby this process the fire behavior of structural concrete elements can be takeninto account satisfactorily. It should be stressed here that a material modelcan gain confidence only if it has been tested successfully under differentboundary conditions. In particular, the model must apply for the assessment ofthe fire behavior of structural elements in large scale. Inthis regard relaxation tests on reinforced concrete columns under differentboundary conditions have been carried out in the special furnace of SFB. Theheating of the reinforced concrete columns have been made with respect to ISO830-fireas well as to a simulated natural fire condition. The following sectionsdescribe the tests and also their theoretical investigation.Inthe eighties the work was particularly focused in SFB (SonderForschungsBereich: A special fire research activity forstructural elements in Braunschweig Technical University, 1971-1986) onthe development of a universal material model for normal concretes in case offire. Through a comprehensive mathematical description of the rheological phenomena at elevatedtemperatures, the relaxation behavior of restrained col­umns could besuccessfully predicted. It aimed at clarifying the difference, which took placebetween the deformation behavior as well as restraint forces of calculated andmeasured reinforced concrete columns (RFC) under fire conditions. Such amaterial model was developed, in fact, through close cooperation of subprojectsA and B3 of SFB. Naturally,the use of such material model requires an immense computational treatment.Theoretical studies have shown, however, that this is worthwhile, because onlyby this process the fire behavior of structural concrete elements can be takeninto account satisfactorily. It should be stressed here that a material modelcan gain confidence only if it has been tested successfully under differentboundary conditions. In particular, the model must apply for the assessment ofthe fire behavior of structural elements in large scale. Inthis regard relaxation tests on reinforced concrete columns under differentboundary conditions have been carried out in the special furnace of SFB. Theheating of the reinforced concrete columns have been made with respect to ISO830-fireas well as to a simulated natural fire condition. The following sectionsdescribe the tests and also their theoretical investigation.eninfo:eu-repo/semantics/openAccessStructural fire safetyreinforced concrete columnsfire resistancerelaxationfire behaviorArticle182121136287772