Behaviour of Reinforced Concerete Infilled Frames Under Seismic Loads

2013 ◽  
Vol 61 (3) ◽  
Author(s):  
A. Kadid ◽  
S. Noui ◽  
A. Zine ◽  
D. Yahiaoui

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.

Author(s):  
Ying-Hsiu Shen ◽  
Yin-Nan Huang ◽  
Ching-Ching Yu

Seismic probabilistic risk assessment (SPRA) has been widely used to compute the frequencies of core damage and release of radiation of a nuclear power plant (NPP). In 2011, Huang et al. (2011a, 2011b) published a SPRA methodology with the following characteristics different from the widely used Zion method: (a) seismic fragility curves are defined as a function of structural response parameters, such as floor spectral acceleration and story drift; (b) nonlinear response-history analysis is used to estimate statistical distributions of seismic demands for structural and non-structural components of NPPs; (c) Monte Carlo simulation is used to determine damage states of structural and non-structural components. In the study presented in this paper, the seismic risk of a sample NPP was evaluated using the methodology of Huang et al. (2011a, 2011b). The seismic risk was quantified using the annual frequency of unacceptable performance defined by a sample accident sequence for a sample NPP. The values of seismic risk computed using the methodology of Huang et al. (2011a, 2011b) and Boolean Algebra were compared to evaluate the accuracy and efficiency of the methodology of Huang et al. (2011a, 2011b). The two procedures generate similar risk values and the methodology of Huang et al. (2011a, 2011b) is more efficient than the procedure using Boolean Algebra.


2018 ◽  
Vol 149 ◽  
pp. 02040
Author(s):  
Yamina Ait-Meziane ◽  
Rania Souici ◽  
Farah Lazzali

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.


2018 ◽  
Vol 10 (12) ◽  
pp. 4659 ◽  
Author(s):  
Yabin Chen ◽  
Longjun Xu ◽  
Xingji Zhu ◽  
Hao Liu

For seismic resilience-based design (RBD), a selection of recorded time histories for dynamic structural analysis is usually required. In order to make individual structures and communities regain their target functions as promptly as possible, uncertainty of the structural response estimates is in great need of reduction. The ground motion (GM) selection based on a single target response spectrum, such as acceleration or displacement response spectrum, would bias structural response estimates leading significant uncertainty, even though response spectrum variance is taken into account. In addition, resilience of an individual structure is not governed by its own performance, but depends severely on the performance of other systems in the same community. Thus, evaluation of resilience of a community using records matching target spectrum at whole periods would be reasonable because the fundamental periods of systems in the community may be varied. This paper presents a GM selection approach based on a probabilistic framework to find an optimal set of records to match multiple target spectra, including acceleration and displacement response spectra. Two major steps are included in that framework. Generation of multiple sub-spectra from target displacement response spectrum for selecting sets of GMs was proposed as the first step. Likewise, the process as genetic algorithm (GA), evolvement of individuals previously generated, is the second step, rather than using crossover and mutation techniques. A novel technique improving the match between acceleration response spectra of samples and targets is proposed as the second evolvement step. It is proved computationally efficient for the proposed algorithm by comparing with two developed GM selection algorithms. Finally, the proposed algorithm is applied to select GM records according to seismic codes for analysis of four archetype reinforced concrete (RC) frames aiming to evaluate the influence of GM selection considering two design response spectra on structural responses. The implications of design response spectra especially the displacement response spectrum and GM selection algorithm are summarized.


2020 ◽  
Vol 10 (5) ◽  
pp. 1763
Author(s):  
Albert Albareda-Valls ◽  
Alicia Rivera-Rogel ◽  
Ignacio Costales-Calvo ◽  
David García-Carrera

Ceramic-reinforced slabs were widely used in Spain during the second half of the 20th century, especially for industrial buildings. This solution was popular due to the lack of materials at that time, as it requires almost no concrete and low ratios of reinforcement. In this study, we present and discuss the results of a real load-bearing test of a real ceramic-reinforced slab, which was loaded and reloaded cyclically for a duration of one week in order to describe any damage under a high-demand loading series. Due to the design of these slabs, the structural response is based more on shear than on bending due to the low levels of concrete and the geometry and location of re-bars. The low ratio of concrete makes these slabs ideal for short-span structures, mainly combined with steel or RC frames. The slab which was analyzed in this study covers a span of 4.88 m between two steel I-beams (IPN400), and corresponds to a building from the mid-1960s in the city of Igualada (Barcelona, Spain). A load-bearing test was carried out up to 7.50 kN/m2 by using two-story sacks full of sand. The supporting steel beams were propped up in order to avoid any interference in the results of the test; without the shoring of the steel structure, deflections would come from the combination of the ceramic slab together with the steel profiles. A process of loading and unloading was repeated for a duration of six days in order to describe the cyclic response of the slab under high levels of loading. Finally, vibration analysis of the slab was also done; the higher the load applied, the higher the fundamental frequency of the cross section, which is more comfortable in terms of serviceability.


2016 ◽  
Vol 847 ◽  
pp. 361-368 ◽  
Author(s):  
Daniele Perrone ◽  
Vincenzo Saponaro ◽  
Marianovella Leone ◽  
Maria Antonietta Aiello

The damages observed during the earthquakes occurred in the last decades have clearly shown as the influence of infill panels on the seismic behaviour of Reinforced Concrete (RC) buildings should be taken into account; the global stiffness and the strength of the RC frames are significantly modified by the infills. In the present study the influence of infills in terms of shear forces has been analyzed by means of linear static analysis; a parametric study has been carried out to evaluate the behavior of infilled frames varying both modelling approach and the mechanical properties of the masonry infills. In terms of modelling approach the single and multi-strut models have been adopted; the Young modulus of masonry infills have been varied in the common range proposed in literature. The results show that multi-strut approach is able to predict both global and local behavior. In addition, the importance of the mechanical properties of masonry infills in the evaluation of the elastic period and shear force in the columns is underlined.


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