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1

Study on the influence of stiffness of beam-column connections on the seismic behavior of composite moment resisting frames

Khemis Ahmed, Titoum Messaoud, Mazoz Aida, Louzai Amar

Architecture Civil Engineering Environment

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2021

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Vol. 14, no. 3

55--67

EN

In the design of steel or composite structures, the connections are usually considered infinitely rigid or perfectly pinned. However, the real behavior of these connections is semi-rigid. Consequently, this semi-rigidity can influence the overall behavior of the composite structures, especially the moment-resisting frames. Seismically, the most critical parameter that characterizes the frames behavior is the response factor R. In this context, the research work consists of studying the semi-rigidity effect of the connections on the behavior of the composite frames by evaluating the response modification factor R by using the Pushover method. To accomplish this task, three types of portal frames of 3, 4 and 5 storeys were analyzed for different degrees of connection (beam-column). An easy and practical solution has been proposed to determine the approximate value of the coefficient behavior R for the composite frames with semi-rigid connections.

2

Effect of setback irregularity location on the performance of RC building frames under seismic excitation

Mouhine Mohamed, Hilali Elmokhtar

Archives of Civil Engineering

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2020

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Vol. 66, nr 4

399--412

EN

The setback is a frequent type of irregularity expected in complex-shaped buildings. The main purpose of the present paper is to emphasize the influence of setback location on the performance of reinforced concrete building structures under seismic excitation. In this research study, 68 building models with setback values vary from 0.1 L to 0.5 L, located at various levels, are studied. Non-linear static (pushover) analyses were conducted. All building models are analyzed using a finite element calculation code. The outcomes show that setback irregularity location has a significant effect on the seismic behavior of the structure. Based on the regression analysis of the results obtained in the current study, a mathematical formula is proposed to quantify the effect of setback location on the performance of building structures. The results of this study would aid all professionals in the building sector to anticipate the response of these types of structures during the design phase.

3

Evaluation of seismic behaviour of railway bridges considering track-bridge interaction

Dehghani Ehsan, Najafi Zadeh Maryam, Nabizadeh Azam

Roads and Bridges - Drogi i Mosty

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2019

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Vol. 18, no. 1

51--66

PL

Mosty kolejowe wykazują dużą odporność na trzęsienia ziemi. Pomimo, że ich wytrzymałość była określana pod względem jakościowym w wielu opracowaniach, m.in. Stowarzyszenia AREMA (ang. American Railway Engineering and Maintenance of Way Association), dotychczas nie zaproponowano kryteriów ilościowych tej oceny. Celem niniejszej pracy jest przedstawienie kryteriów ilościowych oceny zachowania się mostów kolejowych poddanych działaniu obciążeń sejsmicznych. W artykule przedstawiono modele MES odpowiedzi dynamicznej mostów w warunkach sejsmicznych, w których uwzględniono oddziaływanie toru kolejowego z mostem lub to oddziaływanie nie było brane pod uwagę. Badane modele oceniane były z wykorzystaniem analizy pushover i dynamicznej analizy przyrostowej na podstawie czternastu zapisów trzęsień ziemi, które miały miejsce w przeszłości. Wyniki analiz wyraźnie pokazują, że zaproponowany model uwzględniający oddziaływanie toru z mostem zachowuje się w warunkach sejsmicznych lepiej pod względem wytrzymałościowym. W przypadku tego modelu parametry takie jak: przemieszczenie pomostu, siła ścinająca pomiędzy torem i pomostem oraz obrót plastyczny przegubów są mniejsze o odpowiednio 70-90%, 20-83% i 85-100%. W pracy zaproponowano równania do szacowania przemieszczenia pomostu oraz siły ścinającej w podstawie toru, bez uwzględnienia oddziaływania toru z mostem, wykorzystując metodę maksimów przyśpieszenia ziemskiego (ang. Peak Ground Acceleration, PGA), zarejestrowanych podczas wstrząsów sejsmicznych.

EN

Railway bridges have historically performed well in the previous earthquakes. Although this performance has qualitatively been studied in some references such as AREMA code, no quantitative criteria has been proposed for it. Thus, this study aims to present quantitative criteria for railway bridge performance under seismic loads. In the paper, seismic behaviour of railway bridges, with and without track-bridge interaction (TBI), is calculated through finite element modeling. Pushover and incremental dynamic analyses, are utilized to assess the proposed method, considering fourteen records of the past earthquakes. The results clearly show superior performance of the proposed model with track system, in which the deck displacement, base shear, and plastic rotation decrease by 70%-90%, 20%-83%, and 85%-100%, respectively. Finally, two equations are proposed to calculate deck displacement and base shear of railway bridges without performing track-bridge interaction (TBI) by Peak Ground Acceleration (PGA) of the applied record approximately.