APPLICATION OF DYNAMIC NONLINEAR ANALYSIS ON RETROFITTED RC FRAMED STRUCTURE WITH FRP MATERIALS

U okviru diplomskog rada provodila se nelinearna statička analiza, odnosno metoda postupnog guranja i nelinearna dinamička analiza zapisima potresa za ravninske i prostorne AB okvirne modele konstrukcija koji su se međusobno razlikovali u vrsti FRP materijala koji je služio za ojačanje konstrukcije i mjestu na kojem je konstrukcija bila ojačana. Nelinearnost modela konstrukcije prikazana je kroz materijalnu nelinarnost betona i armaturnog čelika i kroz plastifikaciju elementa. Osnovni model konstrukcije za obje analize bio je bez ojačanja dok su ostali modeli bili ojačani FRP-om. U metodi postupnog guranja, ravninski modeli bili su opterećeni inkrementalnim opterećenjem i kontinuiranim opterećenjem na gredama, dok su u nelinearnoj dinamičkoj analizi zapisima potresa modeli bili opterećeni kontinuiranim opterećenjem na gredama i sa 7 potresnih zapisa definiranih spektrom odgovora na osnovi maksimalnog ubrzanja tla iznosa 0,3g. Rezultati nelinearne statičke analize predstavljeni su u obliku histereznih krivulja koje daju uvida o granici popuštanja, otpadanju zaštitnog sloja i lomu konstrukcije, a rezultati nelinearne dinamičke analize zapisima potresa predstavljeni su u obliku maksimalnih međukatnih pomaka konstrukcije. Usporedbom dobivenih rezultata donešen je zaključak kako ojačanje pomoću FRP materijala utječe na ponašanje konstrukcije prilikom potresnog opterećenja.In this master’s thesis, a nonlinear static pushover analysis and nonlinear dynamic time-history analysis were performed for plane and spatial RC frame models. The models differed from each other in the type of FRP material used to reinforce the structure and the place where the structure was reinforced. The nonlinearity of the structure model is shown through the material nonlinearity of concrete and of reinforcing steel and through the plasticization of the elements. The basic construction model for both analysis was without reinforcement while the other models were reinforced with FRP materials. In the pushover analysis, plane models were loaded with incremental load and continuous load on beams, while in time-history analysis the models were loaded with continuous load on beams and with 7 seismic records defined by response spectrum based on maximum soil acceleration of 0,3g. The results of pushover analysis are presented in the form of hysteresis curves that provide insight into the yield strength, protective layer failure and structural fracture, and the results of nonlinear dynamic time-history analysis are presented in the form of interstory drift ratios. By comparing the obtained results, a conclusion was reached for how reinforcement of structure with FRP materials influences the behavior of construction under seismic load