Potresni odziv pravokotnih armiranobetonskih sten povezanih s ploščami : magistrsko delo št.: 245/II. GR

Remec, Miha (avtor), Isaković, Tatjana (mentor), Janevski, Antonio (komentor)

V nalogi smo ugotavljali, kakšne so lastnosti potresnega odziva pravokotnih armiranobetonskih sten in učinek njihove povezanosti z gladkimi armiranobetonskimi etažnimi ploščami, brez gred. Tovrstne stene običajno projektiramo kot konzolne. Pri tem običajno predpostavimo, da plošče stene povezujejo le kot toge šipe na nivoju etaž, oziroma zanemarimo upogibno togost in nosilnost povezovalnih plošč, pod predpostavko, da je ta v primerjavi s stenami zanemarljivo majhna. V nalogi smo naredili parametrično študijo, s katero smo analizirali, ali je ta predpostavka upravičena in kako nanjo vplivajo različni geometrijski ter konstrukcijski parametri. V analizah smo upoštevali določila standardov Evrokod 8 in Evrokod 2. Stene smo najprej dimenzionirali na osnovi rezultatov linearne elastične modalne analize. Glede na to, da lahko s takšno analizo ugotovimo zgolj približek potresnega odziva obravnavanih konstrukcij, smo njihov potresni odziv ocenili tudi z nelinearno analizo, pri kateri smo uporabili N2 metodo. Obravnavane konstrukcije sten so predstavljale značilen izsek iz tipičnih stenastih stavb. Stene smo v enem primeru obravnavali kot konzolne, v drugem pa kot povezane. Upogibna armatura teh dveh sistemov se v obravnavanih primerih ni bistveno razlikovala, ker pri povezanih stenah znaten del prevrnitvenega momenta prevzamemo z momenti, ki jih v konstrukciji povzročajo osne sile v stenah. Zaradi različnega poteka upogibnih momentov vzdolž sten, pa so bile prečne sile dokaj različne. Posledično je bila potrebna prečna armatura v povezanih stenah pri večini primerov bistveno večja kot v konzolnih. V ploščah so bili v primeru povezanih sten upogibni momenti večinoma zelo veliki in posledično je bila potrebna razmeroma velika količina upogibne armature. Ugotovili smo tudi, da je lahko stopnja povezanosti sten le s ploščami zelo velika. Ključno vlogo pri tem ima sodelujoča širina plošče, ki se aktivira ob močnem potresnem odzivu in je lahko bistveno večja od tiste, ki jo običajno upoštevamo pri projektiranju. Ta parameter pomembno vpliva tudi na vrsto mehanizma odziva, ki se aktivira v nelinearnem območju.

• Jezik: Slovenski jezik
• Ključne besede: gradbeništvo, magistrska dela, GR, potresni odziv, armiranobetonske stene, armiranobetonske plošče, plastifikacija, gredni element, konzolne stene, povezane stene, nelinearna analiza
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: FGG - Fakulteta za gradbeništvo in geodezijo
• Kraj izida: Ljubljana
• Založnik: [M. Remec]
• Leto izida: 2022
• Št. strani: XVIII, 74 str., [5] str. pril.
• PID: 20.500.12556/RUL-141783-a6f236c4-bdc4-06f2-bf26-1e42db835e16
• UDK: 624.012.45:624.042.7(497.4)(043.3)
• COBISS.SI-ID: 132423427
• Datum objave v RUL: 08.10.2022

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Seismic response of rectengular reinforced concrete walls connected with slabs : master thesis no.: 245/II. GR

Izvleček

In the task, we determined the characteristics of the seismic response of rectangular reinforced concrete walls and the effect of their connection with reinforced concrete slabs, without beams. These types of walls are usually designed as cantilever walls. In such cases, we usually assume that the only »connection« between the walls are constraints in the horizontal direction at floor level (rigid diaphragms). In other words, we ignore the bending stiffness and load-bearing capacity of the connecting slabs, assuming that it is negligibly small compared to that of the walls. In the assignment, we made a parametric study, where we analyzed whether this assumption is justified and how it is affected by various geometric and structural parameters. In the analyses, we took into account the provisions of the standards Eurocode 8 and Eurocode 2. The walls were first dimensioned based on the results of the linear elastic modal analysis. Considering that with such an analysis we can only determine the approximation of the seismic response of the considered structures, we also evaluated their seismic response with a non-linear analysis, in which we used the N2 method. The considered wall constructions represented a characteristic part of typical wall buildings. In one case, we treated the walls as cantilever walls, and in the other as connected walls. The logitudinal reinforcement of these two systems did not differ significantly in the cases considered, because in the case of connected walls, a significant part of the overturning moment is absorbed by the moments caused in the construction by the axial forces in the walls. Due to the different redistribution of bending moments along the walls, the transverse forces were quite different. As a result, the required transverse reinforcement in connected walls were in most cases significantly greater than in cantilever walls. In the slabs, in the case of connected walls, the bending moments were mostly very large and, as a result, a relatively large amount of longitudinal reinforcement was required. We also found out that the degree of connection of walls only with the slabs can be very high. A key role in this is played by the participating width of the slab, which is activated in the case of a strong seismic response and can be significantly larger than what is usually taken into account in the design. This parameter also significantly affects the type of response mechanism that is activated in the nonlinear region.

• Ključne besede: civil engineering, master thesis, seismic response, reinforced concrete walls, reinforced concrete slabs, plastification, beam element, cantilever walls, connected walls, nonlinear analysis