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Concrete Buildings (concrete + building)
Selected AbstractsReserved Strength of Reinforced Concrete Buildings with Masonry WallsCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2005Nasreddin S. El Mezaini In this building, damage was limited to some cracks in the walls near the targeted zone. Other parts of the building remained intact. The building was analyzed using two different models. In one model, masonry walls were treated as nonstructural elements represented by applied loads. In the other model, walls were represented by membrane elements connected to concrete frames by link elements. Analysis was carried out for two cases, before and after damage. The study revealed that such buildings possess potential reserved strength. They have the ability to change their designated load path. The role of masonry walls is emphasized. In this case, masonry walls worked as a backup system that prevented major collapse of the building. It is estimated that, under normal conditions, masonry walls increase the building strength by 48%. [source] Empirical estimate of fundamental frequencies and damping for Italian buildingsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2009Maria Rosaria Gallipoli Abstract The aim of this work is to estimate the fundamental translational frequencies and relative damping of a large number of existing buildings, performing ambient vibration measurements. The first part of the work is devoted to the comparison of the results obtained with microtremor measurements with those obtained from earthquake recordings using four different techniques: horizontal-to-vertical spectral ratio, standard spectral ratio, non-parametric damping analysis (NonPaDAn) and half bandwidth method. We recorded local earthquakes on a five floors reinforced concrete building with a pair of accelerometers located on the ground and on top floor, and then collected microtremors at the same location of the accelerometers. The agreement between the results obtained with microtremors and earthquakes has encouraged extending ambient noise measurements to a large number of buildings. We analysed the data with the above-mentioned methods to obtain the two main translational frequencies in orthogonal directions and their relative damping for 80 buildings in the urban areas of Potenza and Senigallia (Italy). The frequencies determined with different techniques are in good agreement. We do not have the same satisfactory results for the estimates of damping: the NonPaDAn provides estimates that are less dispersed and grouped around values that appear to be more realistic. Finally, we have compared the measured frequencies with other experimental results and theoretical models. Our results confirm, as reported by previous authors, that the theoretical period,height relationships overestimate the experimental data. Copyright © 2008 John Wiley & Sons, Ltd. [source] Performance of Buildings under Earthquakes in Barcelona, SpainCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 8 2006Alex H. Barbat The seismic hazard in the area of the city is described by means of the reduced 5% damped elastic response spectrum. Obtaining fragility curves for the most important building types of an urban center requires an important amount of information about the structures and the use of nonlinear structural analysis tools. The information on the buildings of Barcelona was obtained by collecting, arranging, improving, and completing the database of the housing and current buildings. The buildings existing in Barcelona are mainly of two types: unreinforced masonry structures and reinforced concrete buildings with waffled slab floors. In addition, the Arc-View software was used to create a GIS tool for managing the collected information to develop seismic risk scenarios. This study shows that the vulnerability of the buildings is significant and therefore, in spite of the medium to low seismic hazard in the area of the city, the expected seismic risk is considerable. [source] Use of collision shear walls to minimize seismic separation and to protect adjacent buildings from collapse due to earthquake-induced poundingEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2008S. A. Anagnostopoulos Abstract The use of collision shear walls (bumper-type), acting transversely to the side subject to pounding, as a measure to minimize damage of reinforced concrete buildings in contact, is investigated using 5-story building models. The buildings were designed according to the Greek anti-seismic and reinforced concrete design codes. Owing to story height differences potential pounding in case of an earthquake will occur between floor slabs, a case specifically chosen because this is when pounding can turn out to be catastrophic. The investigation is carried out using nonlinear dynamic analyses for a real earthquake motion and also a simplified solution for a triangular dynamic force of short duration, comparable to the forces caused by pounding. For such analyses, nonlinear, prismatic beam,column elements are used and the effects of pounding are expressed in terms of changes in rotational ductility factors of the building elements. The local effects of pounding on the collision shear walls are investigated using a detailed nonlinear finite element model of the shear walls and results are expressed in terms of induced stresses. It is found that pounding will cause instantaneous acceleration pulses in the colliding buildings and will somewhat increase ductility demands in the members of the top floor, but all within tolerable limits. At the same time the collision walls will suffer repairable local damage at the points of contact, but will effectively protect both buildings from collapse, which could occur if columns were in the place of the walls. Copyright © 2008 John Wiley & Sons, Ltd. [source] Seismic design of RC structures: A critical assessment in the framework of multi-objective optimizationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2007Nikos D. Lagaros Abstract The assessment of seismic design codes has been the subject of intensive research work in an effort to reveal weak points that originated from the limitations in predicting with acceptable precision the response of the structures under moderate or severe earthquakes. The objective of this work is to evaluate the European seismic design code, i.e. the Eurocode 8 (EC8), when used for the design of 3D reinforced concrete buildings, versus a performance-based design (PBD) procedure, in the framework of a multi-objective optimization concept. The initial construction cost and the maximum interstorey drift for the 10/50 hazard level are the two objectives considered for the formulation of the multi-objective optimization problem. The solution of such optimization problems is represented by the Pareto front curve which is the geometric locus of all Pareto optimum solutions. Limit-state fragility curves for selected designs, taken from the Pareto front curves of the EC8 and PBD formulations, are developed for assessing the two seismic design procedures. Through this comparison it was found that a linear analysis in conjunction with the behaviour factor q of EC8 cannot capture the nonlinear behaviour of an RC structure. Consequently the corrected EC8 Pareto front curve, using the nonlinear static procedure, differs significantly with regard to the corresponding Pareto front obtained according to EC8. Furthermore, similar designs, with respect to the initial construction cost, obtained through the EC8 and PBD formulations were found to exhibit different maximum interstorey drift and limit-state fragility curves. Copyright © 2007 John Wiley & Sons, Ltd. [source] Seismic vulnerability assessment using regional empirical dataEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2006Ahmet Yakut Abstract This article presents a procedure developed for the seismic performance assessment of low- to mid-rise reinforced concrete buildings in Turkey. The past performance of reinforced concrete buildings during major earthquakes have been compiled and analysed comprehensively using statistical procedures in order to study the empirical correlation between the significant damage inducing parameters and the observed damage. A damage database of nearly 500 representative buildings experiencing the 1999 Kocaeli and Düzce earthquakes have been used and discriminant functions expressing damage score in terms of six damage inducing parameters have been developed. In order to extrapolate the procedure to other regions that are likely to be subjected to major earthquakes a new approach that takes into account different local soil conditions, site-to-source distance and the magnitude of the earthquake has been introduced. The procedure has been applied to a pilot area in Istanbul to estimate expected damage distribution under a credible scenario earthquake. Copyright © 2006 John Wiley & Sons, Ltd. [source] Elastic and inelastic drift performance optimization for reinforced concrete buildings under earthquake loadsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2004Chun-Man Chan Abstract This paper presents an effective optimization technique for the elastic and inelastic drift performance design of reinforced concrete buildings under response spectrum loading and pushover loading. Attempts have been made to develop an automatic optimal elastic and inelastic drift design of concrete framework structures. The entire optimization procedure can be divided into elastic design optimization and inelastic design optimization. Using the principle of virtual work, the elastic drift response generated by the response spectrum loading and the inelastic drift response produced by the non-linear pushover loading can be explicitly expressed in terms of element sizing design variables. The optimization methodology for the solution of the explicit design problem of buildings is fundamentally based on the Optimality Criteria approach. One ten-story, two-bay building frame example is presented to illustrate the effectiveness and practicality of the proposed optimal design method. While rapid convergence in a few design cycles is found in the elastic optimization process, relatively slow but steady and smooth convergence of the optimal performance-based design is found in the inelastic optimization process. Copyright © 2004 John Wiley & Sons, Ltd. [source] A displacement-based seismic design procedure for RC buildings and comparison with EC8EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2001T. B. Panagiotakos Abstract A procedure for displacement-based seismic design (DBD) of reinforced concrete buildings is described and applied to a 4-storey test structure. The essential elements of the design procedure are: (a) proportioning of members for gravity loads; (b) estimation of peak inelastic member deformation demands in the so-designed structure due to the design (,life-safety') earthquake; (c) revision of reinforcement and final detailing of members to meet these inelastic deformation demands; (d) capacity design of members and joints in shear. Additional but non-essential steps between (a) and (b) are: (i) proportioning of members for the ULS against lateral loads, such as wind or a serviceability (,immediate occupancy') earthquake; and (ii) capacity design of columns in flexure at joints. Inelastic deformation demands in step (b) are estimated from an elastic analysis using secant-to-yield member stiffnesses. Empirical expressions for the deformation capacity of RC elements are used for the final proportioning of elements to meet the inelastic deformation demands. The procedure is applied to one side of a 4-storey test structure that includes a coupled wall and a two-bay frame. The other side is designed and detailed according to Eurocode 8. Major differences result in the reinforcement of the two sides, with significant savings on the DBD-side. Pre-test calculations show no major difference in the seismic performance of the two sides of the test structure. Copyright © 2001 John Wiley & Sons, Ltd. [source] Vom Hofbräuhaus zum Deutschen Museum , Münchner Bauten aus Eisenbeton 1890 bis 1914 (2)BAUTECHNIK, Issue 12 2008Hartwig Schmidt Prof. i. R. Dr.-Ing. In diesem Jahr (2008) feiert München sein 850-jähriges Stadtjubiläum, und in den dazu erscheinenden Publikationen bemühen sich die Autoren, das speziell Münchnerische herauszuarbeiten. Wenig Beachtung findet dabei ein besonderes Kapitel der Münchner Baugeschichte , der Beginn des Bauens mit Eisenbeton um 1900. München kann für sich in Anspruch nehmen, diejenige Stadt gewesen zu sein, in der die neue Bautechnik erprobt wurde und schon früh bedeutende Bauten in Eisenbeton entstanden. Leider ist diese außergewöhnliche architektonische und bautechnische Entwicklung heute weitgehend in Vergessenheit geraten. From Hofbräuhaus to the German Museum , reinforced concrete buildings in Munich from 1890 to 1914. This year (2008) Munich celebrates its 850-year anniversary and in appropriate publications the authors try to work out the special Munich style. Little attention will be paid to a special chapter of Munich's history , the beginning of construction with reinforced concrete about 1900. Munich can claim that city to have been first in the new building technology and important buildings in reinforced concrete were designed and erected. Unfortunately, today this extraordinary architectural and engineering development is widely forgotten. [source] | ||||||||||