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CONTENTS
Volume 45, Number 5, March10 2013
 

Abstract
This paper aims to compare three collocation point methods associated with the odd order stochastic response surface method (SRSM) in a systematical and quantitative way. The SRSM with the Hermite polynomial chaos is briefly introduced first. Then, three collocation point methods, namely the point method, the root method and the without origin method underlying the odd order SRSMs are highlighted. Three examples are presented to demonstrate the accuracy and efficiency of the three methods. The results indicate that the condition that the Hermite polynomial information matrix evaluated at the collocation points has a full rank should be satisfied to yield reliability results with a sufficient accuracy. The point method and the without origin method are much more efficient than the root method, especially for the reliability problems involving a large number of random variables or requiring complex finite element analysis. The without origin method can also produce sufficiently accurate reliability results in comparison with the point and root methods. Therefore, the origin often used as a collocation point is not absolutely necessary. The odd order SRSMs with the point method and the without origin method are recommended for the reliability analysis due to their computational accuracy and efficiency. The order of SRSM has a significant influence on the results associated with the three collocation point methods. For normal random variables, the SRSM with an order equaling or exceeding the order of a performance function can produce reliability results with a sufficient accuracy. The order of SRSM should significantly exceed the order of the performance function involving strongly non-normal random variables.

Key Words
stochastic response surface method; collocation points; reliability analysis; probability of failure; performance function

Address
Dian-Qing Li, Shui-Hua Jiang, Yong-Gang Cheng and
Chuang-Bing Zhou: State Key Laboratory of Water Resources and Hydropower Engineering Science,Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering (Ministry of Education),
Wuhan University, Wuhan, P.R. China

Abstract
In this article we will present a method to directly evaluate the critical point of a non-linear system by using the solution of a polynomial eigenvalue approximation as a starting point for an iterative non-linear system solver. This method will be used to evaluate out-of-plane buckling properties of truss structures for which the lateral displacement of the upper chord has been prevented. The aim is to assess for a number of example structures whether or not the linearized eigenvalue solution gives a relevant starting point for an iterative non-linear system solver in order to find the minimum positive critical load.

Key Words
truss structures; out-of-plane buckling; non-linear iterative solver; polynomial eigenvalue problem

Address
Alexis Fedoroff: Department of Civil and Structural Engineering, Aalto University, Rakentajanaukio 4 A, Otaniemi, Espoo, Finland
Reijo Kouhia: Department of Engineering Design, Tampere University of Technology, Korkeakoulunkatu 10, 33720 Tampere, Finland

Abstract
In this paper, the problem of axisymmetric deformation of the circular membrane fixed at its perimeter under the action of uniformly-distributed loads was resolved by exactly using power series method, and the solution of the problem was presented. An investigation into the so-called Hencky transformation was carried out, based on the solution presented here. The results obtained here indicate that the well-known Hencky solution is, without doubt, correct, but in the published papers the statement about its derivation is incorrect, and the so-called Hencky transformation is invalid and hence may not be extended to use as a general mathematical method.

Key Words
axisymmetric deformation; membrane; power series method; Hencky transformation; Hencky solution

Address
Jun-yi Sun: College of Civil Engineering, Chongqing University, Chongqing 400045, PR China; Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400030, PR China
Yang Rong: College of Civil Engineering, Chongqing University, Chongqing 400045, PR China
Xiao-ting He: College of Civil Engineering, Chongqing University, Chongqing 400045, PR China; Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400030, PR China
Xiao-wei Gao: College of Civil Engineering, Chongqing University, Chongqing 400045, PR China
Zhou-lian Zheng: College of Civil Engineering, Chongqing University, Chongqing 400045, PR China; Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400030, PR China

Abstract
Optimum cost design of columns subjected to axial force and uniaxial bending moment is presented in this paper. In the formulation of the optimum design problem, the height and width of the column, diameter and number of reinforcement bars are treated as design variables. The design constraints are implemented according to ACI 318-08 and studies in the literature. The objective function is taken as the cost of unit length of the column consisting the cost of concrete, steel, and shuttering. The solution of the design problem is obtained using the artificial bee colony algorithm which is one of the recent additions to metaheuristic techniques. The Artificial Bee Colony Algorithm is imitated the foraging behaviors of bee swarms. In application of this algorithm to the constraint problem, Deb\'s constraint handling method is used. Obtained results showed that the optimum value of numerical example is nearly same with the existing values in the literature.

Key Words
optimization; metaheuristic; artificial bee colony algorithm; reinforced concrete columns

Address
Hasan Tahsin Ozturk and Ahmet Durmus: Faculty of Engineering (Civil), Karadeniz Technical University, Trabzon, Turkey

Abstract
In this study, strength reduction factors and inelastic displacement ratios are investigated for SDOF systems with period range of 0.1-3.0 s considering soil structure interaction for earthquake motions recorded on soft soil. The effect of stiffness degradation on strength reduction factors and inelastic displacement ratios is investigated. The modified-Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. The effect of negative strain – hardening on the inelastic displacement and strength of structures is also investigated. Soil structure interacting systems are modeled and analyzed with effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an inhouse computer program. New equations are proposed for strength reduction factor and inelastic displacement ratio of interacting system as a function of structural period (T̃, T), ductility (u) and period lengthening ratio (T̃/T).

Key Words
soil-structure interaction; stiffness degradation; strength reduction factor; inelastic displacement ratio; ductility demand; structural analysis

Address
Muberra Eser Aydemir: Department of Civil Engineering, Istanbul Aydin University, Istanbul, Turkey

Abstract
A semi-analytical finite strip method is developed for analyzing the post-buckling behavior of rectangular composite laminated plates of arbitrary lay-up subjected to progressive end-shortening in their plane and to normal pressure loading. In this method, all the displacements are postulated by the appropriate harmonic shape functions in the longitudinal direction and polynomial interpolation functions in the transverse direction. Thin or thick plates are assumed and correspondingly the Classical Plate Theory (CPT) or Higher Order Plate Theory (HOPT) is applied. The in-plane transverse deflection is allowed at the loaded ends of the plate, whilst the same deflection at the unloaded edges is either allowed to occur or completely restrained. Geometric non-linearity is introduced in the strain–displacement equations in the manner of the von-Karman assumptions. The formulations of the finite strip methods are based on the concept of the principle of the minimum potential energy. The Newton–Raphson method is used to solve the non-linear equilibrium equations. A number of applications involving isotropic plates, symmetric and unsymmetric cross-ply laminates are described to investigate the through-thickness shearing effects as well as the effect of pressure loading, end-shortening and boundary conditions. The study of the results has revealed that the response of the composite laminated plates is particularly influenced by the application of the Higher Order Plate Theory (HOPT) and normal pressure loading. In the relatively thick plates, the HOPT results have more accuracy than CPT.

Key Words
post-buckling; pressure load; Classical Plate Theory (CPT); Higher Order Plate Theory (HOPT); Finite Strip Method (FSM); composite laminated plates

Address
Mohammad H. Sherafat: Department of Mechanical Engineering, McGill University, 817Sherbrooke West, Montreal, Canada H3A 2K6
Seyyed Amir M. Ghannadpour: Aerospace Engineering Department, Faculty of New Technologies and Engineering,
ShahidBeheshti University, G.C, 1983963113 Tehran, Iran
Hamid R. Ovesy: Aerospace Engineering Department and Centre of Excellence in Computational Aerospace Engineering,
Amirkabir University of Technology, Tehran, Iran

Abstract
Recently, artificial intelligence tools are most used for structural engineering and mechanics. In order to predict reserve prices and prices of awards, this study proposed a novel regression prediction model by the intelligent Kalman filtering method. An artificial intelligent multiple regression model was established using categorized data and then a prediction model using intelligent Kalman filtering. The rather precise construction bid price model was selected for the purpose of increasing the probability to win bids in the simulation example.

Key Words
construction project and management; intelligent fuzzy regression; Kalman filtering; prediction model

Address
Jeng-Wen Lin: Department of Civil Engineering, Feng Chia University, Taichung 407, Taiwan, R.O.C.
Cheng-Wu Chen: Department of Maritime Information and Technology, National Kaohsiung Marine University, Kaohsiung, Taiwan, R.O.C.; Global Earth Observation and Data Analysis Center, National Cheng Kung University, Tainan, Taiwan 701, R.O.C.
Ting-Chang Hsu: Department of Civil Engineering, Feng Chia University, Taichung 407, Taiwan, R.O.C.

Abstract
In this paper a study about concrete arch bridges built by lattice cantilevers is presented. Lattice cantilevers are partial structures composed of deck, arch, piers and provisional steel diagonals, organized as reticular cantilever girders, in order to build arch bridges without the use of centrings, supports or temporary towers. Characteristics of this construction methodology with its variants are explained together with their implications in the erection sequence. Partial elastic scheme method is implemented in order to find initial forces of temporary cables and a forward analysis is carried out to follow the actual sequence of construction, by extending a procedure already applied to concrete cable–stayed bridges and to arches built by the classical suspended cantilever method. A numerical application on a case–study of a concrete arch bridge is performed together with a comparison between different methodologies followed for its construction sequence. Differences between erection by lattice cantilevers and cable-stayed cantilevers, are discussed. Results can be useful for designers in conceptual design of concrete arch bridges.

Key Words
arch bridge; lattice cantilever; partial elastic scheme; staged construction; cable-stayed

Address
Michele Fabio Granata, Piercarlo Margiotta and Marcello Arici: Universita di Palermo, DICAM, Viale delle Scienze, Palermo, Italy
Antonino Recupero: Universita di Messina, DIC, Contrada Di Dio, Messina, Italy


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