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CONTENTS
Volume 2, Number 1, January 2017
 

Abstract
This paper presents a variant of the Harmony Search Algorithm (HS) and its application to discrete optimization. The main proposed modifications regarding original HS are related to stopping criterion and reinitialization of population, called Harmony Memory. In order to investigate the efficiency of the algorithm, it was applied for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression. To minimize the cost of the section, the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as design variables. The obtained results were compared to those generated by other optimization methods. Since, to the examples, Harmony Search reached the same results achieved by Simulated Annealing, some additional analysis are presented in order to compare these methods regarding success rate and number of iterations to reach the optimum.

Key Words
heuristics; modified harmony search; simulated annealing; columns; reinforced concrete

Address
Civil and Environmental Engineering Graduate Program, University of Passo Fundo, Passo Fundo, Brazil

Abstract
One of the major developments in seismic design over the past few decades is the increased emphasis for limit states design now generally termed as Performance Based Engineering. Performance Based Seismic Design (PBSD) uses Displacement Based Design (DBD) methodology wherein structures are designed for a target level of displacement rather than Force Based Design (FBD) methodology where force or strength aspect is being used. Indian codes still follow FBD methodology compared to other modern codes like CalTrans, which follow DBD methodology. Hence in the present study, a detailed review of the two most common design methodologies i.e., FBD and DBD is presented. A critical evaluation of both these methodologies by comparing the seismic performance of bridge models designed using them highlight the importance of adopting DBD techniques in Indian Standards also. The inherent discrepancy associated with FBD in achieving ´seismic regularity´ is highlighted by assessing the seismic performance of bridges with varied relative height ratios. The study also encompasses a brief comparison of the seismic design and detailing provisions of IRC 112 (2011), IRC 21 (2000), AASHTO LRFD (2012) and CalTrans (2013) to evaluate the discrepancies on the same in the Indian Standards. Based on the seismic performance evaluation and literature review a need for increasing the minimum longitudinal reinforcement percentage stipulated by IRC 112 (2011) for bridge columns is found necessary.

Key Words
displacement based design; force based design; performance-based design; seismic regularity; seismic design and detailing

Address
Department of Civil Engineering, National Institute of Technology Calicut, Kerala, India

Abstract
This study presents algorithms for determining the fuzzy critical loads of planar steel frame structures with fixity factors of beam - column and column - base connections are modeled as triangular fuzzy numbers. The finite element method with linear elastic semi-rigid connection and Response Surface Method (RSM) in mathematical statistic are applied for problems with symmetric triangular fuzzy numbers.The

Key Words
steel frame; critical load; fuzzy connection; response surface method; differential evolution algorithm

Address
Tran Thanh Viet: Department of Civil Engineering, Duy Tan University, K7/25 Quang Trung, Danang, Vietnam

Vu Quoc Anh: Department of Civil Engineering, Ha Noi Architectural University, Vietnam

Le Xuan Huynh: Department of Civil Engineering, National University of Civil Engineering, Hanoi, Vietnam

Abstract
The aim of this paper is to develop software for designing of steel reinforced elastomeric isolator (SREI) according to American Association for State Highway and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) Specifications. SREI is used for almost all bridge types and special structures. SREI-structures interface defines support boundary conditions and may affect the seismic performance of bridges. Seismic performance of the bridge is also affected by geometrical and materials properties of SREI. The selection of SREI is complicated process includes satisfying all the design constraints arising from code provisions and maximizing performance at the lowest possible cost. In this paper, design stage of SREI is described up to AASHTO LRFD 2012. Up to AASHTO LRFD 2012 analysis and design program of SREI performed different geometrical and material properties are created with C# object-oriented language. SREI-CAD, name of the created software, allows an accurate design for economical estimation of a SREI in a short time. To determine types of SREI effects, two different types of bearings, rectangular and circular with similar materials and dimension properties are selected as an application. Designs of these SREIs are completed with SREI-CAD. It is seen that ensuring the stability of circular elastomer bearing at the service limit state is generally complicated than rectangular bearing.

Key Words
C# programming language; steel reinforced elastomeric isolator; software engineering

Address
Karadeniz Technical University, Department of Civil Engineering, 61080 Trabzon, Turkey

Abstract
The composite plate to upgrade structures and, in particular, to extend the lives of reinforced concrete beams has wide applications. One of the main aspects of the bonded strengthening technology is the stress analysis of the reinforced structure. In particular, reliable evaluation of the adhesive shear stress and of the stress in the composite plates is mandatory in order to predict the beam

Key Words
finite element analysis; RC beam; interfacial stresses; strengthening; composite plate

Address
Tahar Hassaine Daouadji: Département de génie civil, Université Ibn Khaldoun Tiaret; BP 78 Zaaroura, 14000 Tiaret, Algérie

Tahar Hassaine Daouadji: Laboratoire de Géomatique et Développement Durable, Université Ibn Khaldoun de Tiaret, Algérie

Abstract
This study focuses on the efficiency and applicability of dynamic relaxation methods in formfinding of membrane structures. Membrane structures have large deformations that require complex nonlinear analysis. The first step of analysis of these structures is the form-finding process including a geometrically nonlinear analysis. Several numerical methods for form-finding have been introduced such as the dynamic relaxation, force density method, particle spring systems and the updated reference strategy. In the present study, dynamic relaxation method (DRM) is investigated. The dynamic relaxation method is an iterative process that is used for the static equilibrium analysis of geometrically nonlinear problems. Five different examples are used in this paper. To achieve the grading of the different dynamic relaxation methods in form-finding of membrane structures, a performance index is introduced. The results indicate that viscous damping methods show better performance than kinetic damping in finding the shapes of membrane structures.

Key Words
dynamic relaxation method; viscous damping; kinetic damping; form-finding; membrane structures

Address
S. Fatemeh Labbafi: Department of Civil Engineering, University of Birjand, Birjand, Iran

S. Reza Sarafrazi: Department of Architecture & Architectural Engineering, Seoul National University, Seoul, Korea

Thomas H.-K. Kang: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, USA


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