The Experts below are selected from a list of 61494 Experts worldwide ranked by ideXlab platform
Panagiotis E Mergos - One of the best experts on this subject based on the ideXlab platform.
-
Efficient optimum Seismic Design of reinforced concrete frames with nonlinear structural analysis procedures
Structural and Multidisciplinary Optimization, 2018Co-Authors: Panagiotis E MergosAbstract:Performance-based Seismic Design offers enhanced control of structural damage for different levels of earthquake hazard. Nevertheless, the number of studies dealing with the optimum performance-based Seismic Design of reinforced concrete frames is rather limited. This observation can be attributed to the need for nonlinear structural analysis procedures to calculate Seismic demands. Nonlinear analysis of reinforced concrete frames is accompanied by high computational costs and requires a priori knowledge of steel reinforcement. To address this issue, previous studies on optimum performance-based Seismic Design of reinforced concrete frames use independent Design variables to represent steel reinforcement in the optimization problem. This approach drives to a great number of Design variables, which magnifies exponentially the search space undermining the ability of the optimization algorithms to reach the optimum solutions. This study presents a computationally efficient procedure tailored to the optimum performance-based Seismic Design of reinforced concrete frames. The novel feature of the proposed approach is that it employs a deformation-based, iterative procedure for the Design of steel reinforcement of reinforced concrete frames to meet their performance objectives given the cross-sectional dimensions of the structural members. In this manner, only the cross-sectional dimensions of structural members need to be addressed by the optimization algorithms as independent Design variables. The developed solution strategy is applied to the optimum Seismic Design of reinforced concrete frames using pushover and nonlinear response-history analysis and it is found that it outperforms previous solution approaches.
-
optimum Seismic Design of reinforced concrete frames according to eurocode 8 and fib model code 2010
Earthquake Engineering & Structural Dynamics, 2017Co-Authors: Panagiotis E MergosAbstract:Traditional Seismic Design, like the one adopted in Eurocode 8 (EC8), is force-based and examining a single level of Seismic action. In order to provide improved control of structural damage for different levels of Seismic action, the new fib Model Code 2010 (MC2010) includes a fully fledged displacement-based and performance-based Seismic Design methodology. However, the level of complexity and computational effort of the MC2010 methodology is significantly increased. Hence, the use of automated optimization techniques for obtaining cost-effective Design solutions becomes appealing if not necessary. This study employs genetic algorithms to derive and compare optimum Seismic Design solutions of reinforced concrete frames according to EC8 and MC2010. This is important because MC2010 is meant to serve as a basis for future Seismic Design codes. It is found that MC2010 drives to more cost-effective solutions than EC8 for regions of low Seismicity and better or similar costs for regions of moderate Seismicity. For high-Seismicity regions, MC2010 may yield similar or increased structural costs. This depends strongly on the provisions adopted for selecting the set of ground motions. In all cases, MC2010 provides enhanced control of structural damage.
Wael W Eldakhakhni - One of the best experts on this subject based on the ideXlab platform.
-
Seismic Design parameters for special masonry structural walls detailed with confined boundary elements
Journal of Structural Engineering-asce, 2014Co-Authors: Bennett R Banting, Wael W EldakhakhniAbstract:AbstractIn this paper, the results from a test program focusing on the behavior of eleven fully grouted reinforced masonry (RM) structural walls containing confined boundary elements are analyzed and presented according to force, displacement, and performance-based Seismic Design considerations. To be consistent with current force-based Seismic Design codes, analysis is presented to predict the strength, stiffness, displacements, and ductility-related force modification factors using the eleven test specimens. A new estimate of the plastic hinge region for displacement calculations is also proposed which considers the inherent planes of weakness in masonry mortar joints as well as the angle of inclination of shear cracks. Finally, within the context of performance-based Design methodologies, the occurrence of specific damage states is identified. A methodology is proposed to estimate crack width in the walls based on curvature measurements which is also verified using digital image correlation analysis. T...
-
plastic hinge model and displacement based Seismic Design parameter quantifications for reinforced concrete block structural walls
Journal of Structural Engineering-asce, 2014Co-Authors: Marwan T Shedid, Wael W EldakhakhniAbstract:AbstractA practical alternative to the traditional rectangular cross sections of reinforced masonry structural wall systems is to alter the wall ends to allow for smaller compression zone depths, and thus higher curvatures to develop under increased Seismic lateral loads. Despite the significantly enhanced Seismic performance of flanged and end-confined masonry structural walls compared with their rectangular counterparts, Seismic Design parameters related to the former two types of walls have not been widely investigated. In addition, prescriptive Design requirements for rectangular walls are under continuous development to meet the ongoing research findings in this area. The focus of the current study is to extract specific Seismic Design parameters of these three types of masonry walls having different end configurations for different aspect ratios when tested under reversed cyclic loads. The parameters investigated include the equivalent plastic hinge lengths, lp, the hysteretic damping levels and the...
Iman Hajirasouliha - One of the best experts on this subject based on the ideXlab platform.
-
a practical methodology for optimum Seismic Design of rc frames for minimum damage and life cycle cost
Engineering Structures, 2020Co-Authors: Payam Asadi, Iman HajirasoulihaAbstract:Abstract The Design criteria in current Seismic Design codes are mainly to control lateral displacements and provide adequate strength to sustain expected Design load combinations. However, to achieve the most economic Design solutions, the life-cycle total cost (TLCC), which includes both initial structural cost and expected damage cost, should be also considered for the probable earthquakes during the lifetime of the structure. In the present study, the TLCC of the buildings is used as the main objective function for optimum Seismic Design of reinforced concrete (RC) frames. First, it is demonstrated that the blind increase of the reinforcement ratios does not necessarily reduce the displacement demands and the damage costs. Subsequently, a practical methodology is developed for the optimum Seismic Design of RC frames based on the concept of uniform damage distribution (UDD). Using an adaptive iterative procedure, the distribution of inter-storey drifts and TLCC of the floors is modified along the height of the structure. To demonstrate the efficiency of the method, 5, 8 and 12 storey RC frames are optimized using the proposed algorithm. The results indicate that, while all predefined performance targets are satisfied, the maximum inter-storey drift ratio and TLCC of the frames are considerably reduced (up to 56% and 45%, respectively) only after a few steps. The proposed method should prove useful for more efficient performance-based Design of RC frames in practice.
-
optimum lateral load distribution for Seismic Design of nonlinear shear buildings considering soil structure interaction
Soil Dynamics and Earthquake Engineering, 2016Co-Authors: Behnoud Ganjavi, Iman Hajirasouliha, Ali BolourchiAbstract:Abstract The lateral load distributions specified by Seismic Design provisions are primarily based on elastic behaviour of fixed-base structures without considering the effects of soil-structure-interaction (SSI). Consequently, such load patterns may not be suitable for Seismic Design of non-linear flexible-base structures. In this paper, a practical optimisation technique is introduced to obtain optimum Seismic Design loads for non-linear shear-buildings on soft soils based on the concept of uniform damage distribution. SSI effects are taken into account by using the cone model. Over 30,000 optimum load patterns are obtained for 21 earthquake excitations recorded on soft soils to investigate the effects of fundamental period of the structure, number of stories, ductility demand, earthquake excitation, damping ratio, damping model, structural post yield behaviour, soil flexibility and structural aspect ratio on the optimum load patterns. The results indicate that the proposed optimum load patterns can significantly improve the Seismic performance of flexible-base buildings on soft soils.
-
new lateral force distribution for Seismic Design of structures
Journal of Structural Engineering-asce, 2009Co-Authors: Iman Hajirasouliha, Hassan MoghaddamAbstract:In the conventional Seismic Design methods, heightwise distribution of equivalent Seismic loads seems to be related implicitly on the elastic vibration modes. Therefore, the employment of such a load pattern does not guarantee the optimum use of materials in the nonlinear range of behavior. Here a method based on the concept of uniform distribution of deformation is implemented in optimization of the dynamic response of structures subjected to Seismic excitation. In this approach, the structural properties are modified so that inefficient material is gradually shifted from strong to weak areas of a structure. It is shown that the Seismic performance of such a structure is better than those Designed conventionally. By conducting this algorithm on shear-building models with various dynamic characteristics, the effects of fundamental period, target ductility demand, number of stories, damping ratio, postyield behavior, and Seismic excitations on optimum distribution pattern are investigated. Based on the results, a more adequate load pattern is proposed for Seismic Design of building structures that is a function of fundamental period of the structure and the target ductility demand.
Andre Filiatrault - One of the best experts on this subject based on the ideXlab platform.
-
integrated structural nonstructural performance based Seismic Design and retrofit optimization of buildings
Journal of Structural Engineering-asce, 2020Co-Authors: P Steneker, Andre Filiatrault, Lydell Wiebe, Dimitrios KonstantinidisAbstract:AbstractThe assessment of anticipated losses due to damage of both structural and nonstructural components is now recognized to be a key component in the performance-based Seismic Design or retrofi...
-
performance based Seismic Design of nonstructural building components the next frontier of earthquake engineering
Earthquake Engineering and Engineering Vibration, 2014Co-Authors: Andre Filiatrault, T J SullivanAbstract:With the development and implementation of performance-based earthquake engineering, harmonization of performance levels between structural and nonstructural components becomes vital. Even if the structural components of a building achieve a continuous or immediate occupancy performance level after a Seismic event, failure of architectural, mechanical or electrical components can lower the performance level of the entire building system. This reduction in performance caused by the vulnerability of nonstructural components has been observed during recent earthquakes worldwide. Moreover, nonstructural damage has limited the functionality of critical facilities, such as hospitals, following major Seismic events. The investment in nonstructural components and building contents is far greater than that of structural components and framing. Therefore, it is not surprising that in many past earthquakes, losses from damage to nonstructural components have exceeded losses from structural damage. Furthermore, the failure of nonstructural components can become a safety hazard or can hamper the safe movement of occupants evacuating buildings, or of rescue workers entering buildings. In comparison to structural components and systems, there is relatively limited information on the Seismic Design of nonstructural components. Basic research work in this area has been sparse, and the available codes and guidelines are usually, for the most part, based on past experiences, engineering judgment and intuition, rather than on objective experimental and analytical results. Often, Design engineers are forced to start almost from square one after each earthquake event: to observe what went wrong and to try to prevent repetitions. This is a consequence of the empirical nature of current Seismic regulations and guidelines for nonstructural components. This review paper summarizes current knowledge on the Seismic Design and analysis of nonstructural building components, identifying major knowledge gaps that will need to be filled by future research. Furthermore, considering recent trends in earthquake engineering, the paper explores how performance-based Seismic Design might be conceived for nonstructural components, drawing on recent developments made in the field of Seismic Design and hinting at the specific considerations required for nonstructural components.
-
performance based Seismic Design of wood framed buildings
Journal of Structural Engineering-asce, 2002Co-Authors: Andre Filiatrault, Bryan FolzAbstract:An important advancement in structural engineering in recent years has been the development of performance-based Seismic Design. However, its application to engineered wood framed buildings remains largely unexplored. This paper discusses the application of performance-based Seismic Design to wood framed buildings through a direct-displacement methodology. In the first part of the paper, limitations of the current force-based Seismic Design procedure for wood framed buildings are outlined. Thereafter, the fundamentals of displacement-based Seismic Design are presented along with a description of the system parameters required for its application. For the purpose of evaluating these parameters for wood framed buildings, a simple numerical model capable of predicting the cyclic response and energy dissipation characteristics of wood shear walls under general quasi-static cyclic loading is presented. The generalization of this model to three-dimensional wood framed structures is also discussed. As an application example, the displacement-based Seismic Design of a simple one-story shear wall building is presented. In turn, this Design approach is validated by nonlinear dynamic time-history analyses using earthquake records representative of the hazard levels that were associated with the Design performance levels.
Ali Ruzi Ozuygur - One of the best experts on this subject based on the ideXlab platform.
-
performance based Seismic Design of an irregular tall building a case study
Structures, 2016Co-Authors: Ali Ruzi OzuygurAbstract:Abstract The structural Design of a 50-story tall reinforced concrete residential building, which was planned to be constructed in Istanbul and given up afterwards by the investor, has been completed in accordance with the draft version of Seismic Design Code for Tall Buildings in Istanbul that adopts performance-based Seismic Design as the basic approach as Tall Buildings Initiative Guidelines do. The Seismic Design of the building has formed the main part of the structural Design process due to high Seismicity of the proposed location and the extremely irregular floor plan not conforming to usual tall building structures. The building consists of two individual buildings linked through stronger link slabs at top 13 stories whereas relatively weak slabs at lower stories. The building has been Designed for Design basis earthquake by elastic response spectrum analysis and its Seismic performance has been checked for maximum considered earthquake by nonlinear time history analyses carried out using PERFORM-3D.
-
performance based Seismic Design of an irregular tall building in istanbul
Structural Design of Tall and Special Buildings, 2015Co-Authors: Ali Ruzi OzuygurAbstract:Summary Structural Design of a 50-story tall reinforced concrete residential building, which was planned to be constructed in Istanbul and given up afterwards by the investor, has been completed in accordance with the draft version of Seismic Design Code for Tall Buildings in Istanbul that adopts performance-based Seismic Design as the basic approach as Tall Buildings Initiative Guidelines do. Seismic Design of the building has formed the main part of the structural Design process due to high Seismicity of the proposed location and extremely irregular floor plan not conforming to usual tall building structures. The building consists of two individual buildings linked through sky floors at the top 12 stories whose Design was one of the most challenging works. The building has been Designed for Design basis earthquake by elastic response spectrum analysis, and its Seismic performance has been checked for maximum considered earthquake by nonlinear time-history analyses carried out using PERFORM-3D. Copyright © 2015 John Wiley & Sons, Ltd.
