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CONTENTS
Volume 45, Number 3, February10 2013
 

Abstract
Beam-to-column connections behaviour plays an important role in the analysis and design of steel and precast concrete structures. The paper presents a computer-based method for geometrically nonlinear frames with semi-rigid beam-to-column connections. The analytical procedure employs modified stability functions to model the effect of axial force on the stiffness of members. The member modified stiffness matrix, and the modified fixed end forces for various loads were found. The linear and nonlinear analyses were applied for two planar steel structures. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks.

Key Words
geometrically nonlinear analysis; semi-rigid connection; plane frames

Address
H. Gorgun: Department of Civil Engineering, Dicle University, 21280, Diyarbakir, Turkey

Abstract
In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures, including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.

Key Words
dynamic soil-structure interaction; seismic behavior; lateral structural response; mid-rise moment resisting frames; soft soil deposit

Address
S. Hamid RezaTabatabaiefar, Behzad Fatahi and Bijan Samali: Centre for Built Infrastructure Research, University of Technology Sydney (UTS), Sydney, Australia

Abstract
With the ongoing development in the computer science areas of artificial intelligence and computational intelligence, researchers are able to apply them successfully in the construction industry. Given the complexities indeep beam behaviour and the difficulties in accurate evaluation of its deflection, the current study has employed the Adaptive Network-based Fuzzy Inference System (ANFIS) as one of the modelling tools to predict deflection for high strength self compacting concrete (HSSCC) deep beams. In this study, about 3668measured data on eight HSSCC deep beams are considered. Effective input data and the corresponding deflection as output data were recorded at all loading stages up to failure load for all tested deep beams. The results of ANFIS modelling and the classical linear regression were compared and concluded that the ANFIS results are highly accurate, precise and satisfactory.

Key Words
ANFIS; deflection; deep beams; fuzzy inference system; linear regression

Address
Mohammad Mohammadhassani, MohdZamin Jumaat, Mohammed Jameel, S.J.S.Hakim and Majid Zargar: Department of Civil Engineering, University of Malaya, 50063, Malaysia
Hossein Nezamabadi-Pour: Department of Electrical Engineering, Shahid Bahonar University of Kerman, Iran

Abstract
For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel\'s service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors, including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.

Key Words
shield TBM tunnel; segment joint; full-scale; mechanical model; joint test

Address
Wen-qi Ding, Yi-cheng Peng, Zhi-guo Yan, Bi-wei Shen, He-hua Zhu and Xin-xin Wei: Department of Geotechnical Engineering, Tongji University, Shanghai, China; Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai, China

Abstract
Single- and multi-span orthotropic functionally graded hollow cylinders subjected to axisymmetrical bending are investigated on the basis of a unified shear deformable shell theory, in which the transverse displacement is expressed by means of a general shape function. To approach the through-thickness inhomogeneity of the hollow cylinder, a laminated model is employed. The shape function therefore shall be determined for each fictitious layer. To improve the computational efficiency, we resort to a transfer matrix method. Based on the principle of minimum potential energy, equilibrium equations are established, which are then solved analytically using the transfer matrix method for arbitrary boundary conditions. Numerical comparisons among a third-order shear deformable shell theory, an exact elastic theory and the present theory are provided for a simply supported hollow cylinder, from which the present theory turns out to be superior in stress estimation. Distributions of displacements and stresses in single- and three-span hollow cylinders with different boundary conditions are also illustrated in numerical examples.

Key Words
axisymmetrical bending; multi-span; hollow cylinder; functionally graded material; unified shear deformable shell theory; transfer matrix method

Address
Z.G. Bian and Y.H. Wang: Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, P.R. China

Abstract
This paper presents the influence of incident angles of earthquakes on inelastic dynamic responses of asymmetry single story buildings under seismic ground motions. The dynamic responses such as internal forces and rotational ductility factor are used to evaluate the importance of the incident angles of ground motions in the inelastic range of structural behavior. The base shear and torque (BST) response histories of the resisting elements and of the building are used to prove that the shape of the BST surface of the building can be a practical tool to represent those of all resisting elements. This paper also shows that the different global forces which produce the maximum demands in the resisting elements tend to converge toward a single distribution in a definable intensity range, and this single distribution is related to the resistance distribution of the building.

Key Words
incremental dynamic analysis (IDA); angle of incidence; inelastic dynamic responses; rotational ductility factor; asymmetric-plan

Address
Van Tu Nguyen and Dookie Kim: Department of Civil Engineering, Kunsan National University, Republic of Korea

Abstract
A numerical method is presented here to detect and assess structural damages from changes in natural frequencies using Ant Colony Optimization (ACO) algorithm. It is possible to formulate the inverse problem in terms of optimization and then to utilize a solution technique employing ACO to assess the damage/damages of structures using natural frequencies. The laboratory tested data has been used to verify the proposed algorithm. The study indicates the potentiality of the developed code to solve a wide range of inverse identification problems in a systematic manner. The developed code is used to assess damages of beam like structures using a first few natural frequencies. The outcomes of the simulated results show that the developed method can detect and estimate the amount of damages with satisfactory precision.

Key Words
ant colony optimization; damage assessment; inverse problem; finite element method; natural frequency; stiffness reduction factor

Address
Aditi Majumdar and Dipak Kumar Maiti: Department of Aerospace Engineering, Indian Institute of Technology, Kharagpur-721302, India
Ambar De and Damodar Maity: Department of Civil Engineering, Indian Institute of Technology, Kharagpur-721302, India

Abstract
A well-designed mesh shape of the cable net is of essential significance to achieve high performance of cable-network antenna reflectors. This paper is concerned with the mesh design problem for such antenna reflector structure. Two new methods for creating the topological forms of the cable net are first presented. Among those, the cyclosymmetry method is useful to generate different polygon-faceted meshes, while the topological mapping method is suitable for acquiring triangle-faceted meshes with different mesh grid densities. Then, the desired spatial paraboloidal mesh geometrical configuration in the state of static equilibrium is formed by applying a simple mesh generation approach based on the force density method. The main contribution of this study is that a general technical guide for how to create the connectivities between the nodes and members in the cable net is provided from the topological point of view. With the new idea presented in this paper, multitudes of mesh configurations with different net patterns can be sought by a certain rule rather than by empiricism, which consequently gives a valuable technical reference for the mesh design of this type of cable-network structures in the engineering.

Key Words
cable network; mesh shape; mesh design; topological form; geometrical configuration

Address
Wang Liu, Dong-Xu Li and Jian-Ping Jiang: College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073, People


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