In-plane shear resistance of structural frame - wall system: influence of eccentric confined window opening in masonry infill wall

Jedan od najčešćih oblika građenja na našim područjima, također i u svijetu, su armiranobetonski okvirni sustavi s nearmiranim ispunskim ziđem, sa ili bez otvora u njima. Zidanom ispunom određuje se arhitektonsko oblikovanje građevine, te se najčešće u njima nalaze otvori za vrata ili prozore. Samo ispunsko ziđe smatra se nekonstruktivnim elementom koji nosi svoju vlastitu težinu, te se podrazumijeva da će prilikom potresnog djelovanja najprije doći do otkazivanja nekonstruktivnih elemenata, dok armiranobetonski okviri preuzimaju djelovanja ostalih konstrukcijskih elemenata, posebice potresnog djelovanja te moraju osigurati globalnu nosivost, stabilnost i sigurnost cijele konstrukcije. Izvedba zidane ispune često se ne izvodi po pravilima struke, te se samo ispunsko ziđe zida uz konstrukcijske armiranobetonske elemente te stvara vezu s istima. Što dovodi do zaključka da se nosivost armiranobetonskog okvirnog sustava s ispunskim ziđem može promatrati kao jedinstvena konstrukcijska cjelina, iako se utjecaj ispune na nosivost konstrukcije najčešće zanemaruje. Ispunsko ziđe se najčešće modelira pomoću dijagonalnog tlačnog štapa, debljina štapa pri proračunima je jednaka debljini zida, dok se širina štapa određuje, a upravo širina štapa stvara najveći izazov inženjerima jer postoji više pristupa pomoću kojih se može odrediti, ali se još uvijek određuje koji je najprikadniji. Ovim radom prikazan je proračunski mikromodel izrađen pomoću metode konačnih elemenata u računalnom programu Atena 2D Engineering. Nelinearan proračun podrazumjeva modeliranje nelinearnog ponašanja materijala, odnoso elemenata. Budući da su proračunski mikromodeli vrlo zahtjevni kod modeliranja materijala, oni zahtijevaju pažljiv unos ulaznih podataka kako bi rezultati proračuna bili što točniji u odnosu na rezultate ispitivanja stvarnog eksperimenta. U sklopu rada istraženo je ponašanje i posmična otpornost konstrukcijskog sustava okvir ziđe s omeđenim izmještenim otvorom za prozor opterećenog potresnim djelovanjem u vlastitoj ravnini. Kako bi se odredila posmična otpornost sustava okvir – ziđe s omeđenim otvorom za prozor, izradit će se nelinearni proračunski mikromodel u računalnom programu Atena 2D Engineering. Rezultati dobiveni proračunskim mikromodelom usporedit će se s rezultatima ispitivanja stvarnog eksperimenta.One of the most common types of construction in our area, but also in the whole world, are reinforced concrete systems with unreinforced filled walls, with or without openings in them. Architectural formation of the building is defined by its masonry infill and it most often contains openings for doors or windows. The filled walls are considered as a non-constructive element which carries its own weight and it is implied that during seismic action the first to fail are non-constructive elements, while the reinforced concrete frames take on the impact of other constructive elements, especially seismic action and must secure global load, stability and safety of the whole construction. Building of masonry infill is oftenly not done by the rules of the profession and only the filled walls are built adjacent to the constructive reinforced concrete frame system and are connected to it. That leads to the conclusion that the load of a reinforced concrete frame system with filled walls can be observed as a unique constructive unit even though the influence of the infill on the load of the construction is most often ignored. Filled walls are most often modeled by using a diagonal pressure rod. The thickness of the rod during calculations is equal to the thickness of the wall while the width of the rod is determined, and that width of the rod gives engineers the biggest challenge as there are several approaches to determine the width of the rod, but the most appropriate approache is still being determined. This thesis shows a micromodel calculation made by using the method of finite elements in Atena 2D Engineering CAD software. Nonlinear calculation implies modeling of nonlinear behaviour of the materials, i.e. elements. Because the micromodel calculations are very demanding when modeling materials, they require careful entry of input data so the results of the calculation would be as accurate as possible in regards to the results of the actual experiment. As part of this thesis the behaviour and shear resistance of the constructive system frame - walls with bounded displaced opening for window under load of seismic activity in own plane was investigated. To determine the shear resistance of the system frame – walls with bounded opening for windows, a nonlinear micromodel calculation will be made in Atena 2D Engineering CAD software. Results from the micromodel calculation will be compared with results of the actual experiment