Influence of Chained Masonry on the Seismic Response of Reinforced Concrete Buildings

The influence of chained masonry walls, which represents a special case of masonry infill without gap, on the seismic response of reinforced concrete buildings is extremely important due to their wide use in this type of building. We can consider the period of building as the key parameter to study this influence. In this article, we had carried out a comparative study of several 2D models of a multi-storey reinforced concrete building with a brick chained masonry wall using the response spectrum method in the ETABS finite element software, following the prescriptions of the current Algerian seismic code. This study included the use of the number of spans, the span length, the number of storeys, the thickness of the chained masonry wall, the ground soft storey, the openings in the walls, and the short column for studying the influence of these to the walls. The values from the numerical simulation were compared with those from the formula of the period of building, provided by both the Algerian and European codes. Based on the results obtained, we were able to assess the influence of chained masonry walls on the seismic response on this type of buildings. Through this article, we have concluded that these walls have a great influence on the overall behavior of reinforced concrete buildings under seismic loading. HIGHLIGHTS Clarify the importance of numerical simulation of chained masonry walls in the design of reinforced concrete buildings Give recommendations to the current Algerian seismic code for properly design the infilled buildings with chained masonry Know the great danger marked in the current conceptions, which neglect these walls in the phase of conception Give to the infilled reinforced concrete buildings an adequate design in case of earthquake loadings GRAPHICAL ABSTRACT

Mechanical analysis of a portal steel frame when subjected to a post-earthquake fire

Although current design code can manage the separate action of a fire or an earthquake, which causes a significant threat to the human life and to the integrity of the structures, the dual effect of a Post- Earthquake Fire (PEF) stands as a major hassle to designers and rescuers alike. Algerian seismic design code, RPA99v2003, with no exception does not consider the possibility of a subsequent fire after an earthquake, whose effect can significantly weaken the steel frame and destroy its fire protection. This paper presents the evaluation of the fire resistance for a two-storey steel portal frame, damaged by an earthquake simulated through spectrum response of Chlef, scaled three in the Algerian Seismic Code. First, the design of the steel structure considers seismic actions by a static nonlinear analysis. Second, it is followed by a fire analysis using an ISO834 standard fire model, considering that the structure is partially damaged. The finite element simulation and numerical analysis of the structure in post-earthquake fire condition yield the bilinear capacity curve at ambient temperature and the variation of local and global displacement at high temperature. A final comparison of the damaged (PEF) and undamaged (FIRE) frames subjected to the different fire scenarios is done.

Relevant lessons learned from the earthquakes El Asnam, 10/10/1980 and Zemmouri, 05/21/2003 on the paraseismic prevention in Algeria

In the field of seismic risk prevention in Algeria, the earthquake of El Asnam, 10/10/1980 is the triggering event and that of Zemmouri 21/05/2003 the accelerating element of the policy already in place. These two major events have been rich in information, as they are among the most studied internationally. The approaches and the development of methods for seismic risk reduction are based largely on feedback. The fundamental goal of seismic risk reduction is to avoid loss of life, which is mainly due to the partial or total collapse of structures. Exploiting lessons learned from past earthquakes is reflected in code requirements for new projects and approaches to vulnerability estimation for existing structures. In this paper, we give a description of the characteristics of the two events. The analysis of pathologies observed and the impact on the Algerian seismic code is discussed.

Behaviour of Reinforced Concerete Infilled Frames Under Seismic Loads

A significant portion of the buildings constructed in Algeria is structural frames with infill panels which are usually considered as non structural components and are neglected in the analysis. However, these masonry panels tend to influence the structural response. Thus, these structures can be regarded as seismic risk buildings, although in the Algerian seismic code there is little guidance on the seismic evaluation of infilled frame buildings. In this study, three RC frames with 2, 4 and 8 storey and subjected to three recorded Algerian accelerograms are studied. The diagonal strut approach is adopted for modeling the infill panels and a fiber model is used to model RC members. This paper reports on the seismic evaluation of RC frames with brick infill panels. The results obtained show that the masonry panels enhance the load lateral capacity of the buildings and the infill panel configuration influences the response of the structures.

The Effects of Building Characteristics and Site Conditions on the Damage Distribution in Boumerdès after the 2003 Algeria Earthquake

This study highlights the major contributing factors to the observed damage distribution in the city of Boumerdès after the 2003 Algeria earthquake. The results of field investigations and statistical analyses show that a majority of the damaged buildings, mostly mid-rise reinforced concrete (RC) moment-frame systems, were located on steep slopes and small hilltops, along river valleys. The horizontal-to-vertical (H/V) ratios from free-field microtremor measurements at these sites did not show clear results. In contrast, buildings with the same structural characteristics located on flat ground did not suffer much damage, and clear peaks were observed from the H/V ratio curves. The amplification effects of topography have not been incorporated into the revised Algerian seismic code, but the results from this study show the importance of considering this factor when designing new buildings for earthquake resistance.