Journal of Structures The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Stress-Strain Compression of AA6082-T6 Aluminum Alloy at Room Temperature Thu, 13 Nov 2014 09:31:12 +0000 Short cylindrical specimens made of AA6082-T6 aluminum alloy were studied experimentally (compression tests), analytically (normalized Cockcroft-Latham criteria—nCL), and numerically (finite element analysis—FEA). The mechanical properties were determined with the stress-strain curves by the Hollomon equation. The elastic modulus obtained experimentally differs from the real value, as expected, and it is also explained. Finite element (FE) analysis was carried out with satisfactory correlation to the experimental results, as it differs about 1,5% from the damage analysis by the nCL concerning the experimental data obtained by compression tests. Alexandre da Silva Scari, Bruno Cesar Pockszevnicki, Jánes Landre Junior, and Pedro Americo Almeida Magalhaes Junior Copyright © 2014 Alexandre da Silva Scari et al. All rights reserved. Finite Element Analysis of Structures Using -Continuous Cubic B-Splines or Equivalent Hermite Elements Thu, 13 Nov 2014 08:05:56 +0000 We compare contemporary practices of global approximation using cubic B-splines in conjunction with double multiplicity of inner knots (-continuous) with older ideas of utilizing local Hermite interpolation of third degree. The study is conducted within the context of the Galerkin-Ritz formulation, which forms the background of the finite element structural analysis. Numerical results, concerning static and eigenvalue analysis of rectangular elastic structures in plane stress conditions, show that both interpolations lead to identical results, a finding that supports the view that they are mathematically equivalent. Christopher Provatidis Copyright © 2014 Christopher Provatidis. All rights reserved. Influence of the Parameterization in the Interval Solution of Elastic Beams Wed, 24 Sep 2014 08:55:25 +0000 We are going to analyze the interval solution of an elastic beam under uncertain boundary conditions. Boundary conditions are defined as rotational springs presenting interval stiffness. Developments occur according to the interval analysis theory, which is affected, at the same time, by the overestimation of interval limits (also known as overbounding, because of the propagation of the uncertainty in the model). We suggest a method which aims to reduce such an overestimation in the uncertain solution. This method consists in a reparameterization of the closed form Euler-Bernoulli solution and set intersection. Stefano Gabriele and Valerio Varano Copyright © 2014 Stefano Gabriele and Valerio Varano. All rights reserved. Hybrid Recentering Energy Dissipative Device for Seismic Protection Tue, 23 Sep 2014 00:00:00 +0000 A hybrid recentering energy dissipative device that has both recentering and energy dissipation capabilities is proposed and studied in this paper. The proposed hybrid device, referred to as the hybrid shape memory alloy (SMA) recentering viscous fluid (RCVF) energy dissipation device, connects the apex of a chevron brace to an adjoining beam using two sets of SMA wires arranged in series on either side of the brace and a viscous fluid damper arranged in parallel with the SMA wires. The viscous damper is used because being a velocity-dependent device it does not exert any force that counteracts the recentering force from the SMA wires after the vibration of the frame ceases. In the numerical study, the Wilde’s SMA constitutive model is used to model the SMA wires, and the Maxwell model is used to simulate the viscous fluid damper. To demonstrate the viability and effectiveness of the proposed hybrid device, comparative studies are performed on several single-story shear frames and a series of four-story steel frames. The results show that the frames equipped with the hybrid device have noticeably smaller peak top story displacements and residual story drifts when subjected to ground motions at three different intensity levels. Wenke Tang and Eric M. Lui Copyright © 2014 Wenke Tang and Eric M. Lui. All rights reserved. Prediction of Progressive Failure Behaviour of Composite Skewed Hypar Shells Using Finite Element Method Tue, 16 Sep 2014 00:00:00 +0000 Progressive failure behaviour of laminated composite skewed hypar shells is investigated in this paper through finite element approach. For composite materials which are weak in transverse shear, failure may initiate at any inner lamina or interface and may remain undetected and unattended to. Such latent damages may progress gradually and lead to a sudden total ply failure. An iterative method is adopted using the various failure theories to predict the first ply failure load. After the first ply failure, the stiffness of the failed element is totally discarded from the laminate and the remaining laminate is considered for further analysis. The developed finite element code is validated through solution of a benchmark problem. Numerical experiments are carried out to obtain the first ply and progressive failure of simply supported hypar shells under transverse distributed load. While obtaining the failure loads, the shell is considered to be under plane stress condition and in linear elastic range. Results are studied meticulously to extract a set of conclusions of practical significance regarding the failure characteristics of composite hypar shells. Arghya Ghosh and Dipankar Chakravorty Copyright © 2014 Arghya Ghosh and Dipankar Chakravorty. All rights reserved. Application of Artificial Immune System in Structural Health Monitoring Wed, 20 Aug 2014 06:40:52 +0000 A large number of methods have been proposed in the area of structural health monitoring (SHM). However, many of them rely on the prior knowledge of structural-parameter-values or the assumption that the structural-parameter-values do not change without damage. This dependence on specific parameter values limits these methods’ applicability. This paper proposes an artificial immune system- (AIS-) based approach for the civil structural health monitoring, which does not require specific parameter values to work. A linear three-floor structure model and a number of single-damage scenarios were used to evaluate the proposed method’s performance. The high success rate showed this approach’s great potential for the SHM tasks. This approach has merits of less dependence on the structural-parameter-values and low demand on the training conditions. Jiachen Zhang and Zhikun Hou Copyright © 2014 Jiachen Zhang and Zhikun Hou. All rights reserved. Seismic Behavior of Steel Off-Diagonal Bracing System (ODBS) Utilized in Reinforced Concrete Frame Thu, 10 Jul 2014 08:35:16 +0000 The introduction of an eccentricity in this system results in a geometric nonlinearity behavior. The midpoint of the diagonal member is connected to the corner joint using a brace member with a relatively low stiffness, thus forming a three-member bracing system in each braced panel. An iterative method of analysis has been developed to study the nonlinear load-deflection behavior of ODBS. The results indicate that the load-deflection behavior of this system follows a nonlinear stiffness-hardening pattern with two yielding points, which reflect the tensile failure of different bracings; the present study aims to investigate the efficiency of applying off-diagonal steel braces to reinforced concrete frames. To achieve this, three types of 2-story, 6-story, and 15-story structures without and with X-bracing and off-center bracing systems were modeled using SAP2000 software, and for micromodeling ANSYS software was used to achieve finite element results for an exact comparison between various retrofitting systems. The results showed that the structures strengthened by toggle bracing system revealed better behavior for low oscillation periods. Moreover, this type of bracing system is quite suitable for 10-story structures but not for higher ones. Its main problem, which requires special contrivances to solve, is the existence of a soft ground floor. Keyvan Ramin Copyright © 2014 Keyvan Ramin. All rights reserved. Thermal Effect on Vibration of Tapered Rectangular Plate Tue, 08 Jul 2014 12:39:51 +0000 A mathematical model is constructed to help the engineers in designing various mechanical structures mostly used in satellite and aeronautical engineering. In the present model, vibration of rectangular plate with nonuniform thickness is discussed. Temperature variations are considered biparabolic, that is, parabolic in x-direction and parabolic in y-direction. The fourth-order differential equation of the motion is solved by Rayleigh Ritz method for three different boundary conditions around the boundary of plate. Numerical values of frequencies for the first two modes of vibration are presented in tabular form for different values of thermal gradient, taper constants, and aspect ratio. Anupam Khanna and Ashish Singhal Copyright © 2014 Anupam Khanna and Ashish Singhal. All rights reserved. Numerical Analysis of Eccentrically Loaded Cold-Formed Plain Channel Columns Tue, 24 Jun 2014 06:50:43 +0000 Finite element analysis of pinned cold-formed plain channel columns of different width-to-thickness ratios is presented in this paper. The study is focused not only on axially loaded columns, but also on eccentrically loaded columns. The general purpose finite element software ABAQUS 6.12 was used, and the force controlled loading was adopted. Geometric and material nonlinearities were incorporated in the finite element model. The ultimate loads are compared with the direct strength method (DSM) for axially loaded columns. Also, a parametric study is done by varying the length of the column and width of the unstiffened element. It is observed that the results correlate better with the DSM values for columns having unstiffened elements of lower ratios. The change in ultimate load is studied only in ABAQUS, as the position of load moves towards the free edge and the supported edge of the unstiffened element. A parametric study is done by varying the nonuniform compression factor for the columns. It is observed that the ultimate load increases as the position of load moves towards the supported edge and it is influenced by the ratio of the unstiffened element. A. P. Nivethitha, G. Vani, and P. Jayabalan Copyright © 2014 A. P. Nivethitha et al. All rights reserved. Damage Location Index of Shear Structures Based on Changes in First Two Natural Frequencies Sun, 22 Jun 2014 05:33:08 +0000 A method of detecting the location of damage in shear structures by using only the changes in first two natural frequencies of the translational modes is proposed. This damage detection method can determine the damage location in a shear building by using a Damage Location Index (DLI) based on two natural frequencies for undamaged and damaged states. In this study, damage is assumed to be represented by the reduction in stiffness. This stiffness reduction results in a change in natural frequencies. The uncertainty associated with system identification methods for obtaining natural frequencies is also carefully considered. Some simulations and experiments on shear structures were conducted to verify the performance of the proposed method. Hien HoThu and Akira Mita Copyright © 2014 Hien HoThu and Akira Mita. All rights reserved. Characterization and Degradation of Masonry Mortar in Historic Brick Structures Sun, 27 Apr 2014 13:46:54 +0000 This study characterized mortars from a masonry fortification in Charleston, South Carolina (USA), harbor where construction was during the period 1839–1860. This location for analysis was interesting because of the sea water impingement on the structure. The study was included as part of an overall structural assessment with restoration as an objective. The mortars were found to be cement, lime, and sand mixtures in proportions similar to ones expected from the historic literature, that is, one part binder to two parts of sand. The binder was found to be American natural cement, a substance analogous to the European Roman cement. The results suggest that the thermal history of the cement during manufacturing affected setting rate explaining why the cements were considered as variable during the mid-to-late 1800s. Fine pores were found in mortars exposed to sea water resulting from corrosion. Contemporary natural cement was shown to release calcium in aqueous solution. While this release of calcium is necessary for setting in natural and Portland cements, excessive calcium solution, as exacerbated by sea water contact and repointing with Portland cement mortars, was shown to result in brick scaling or decay through cryptoflorescence. Denis A. Brosnan Copyright © 2014 Denis A. Brosnan. All rights reserved. Analytical Modeling of Masonry Infilled RC Frames and Verification with Experimental Data Tue, 22 Apr 2014 00:00:00 +0000 The assessment of the response of masonry infilled RC frame structures has been a major challenge over the last decades. While several modeling approaches have been proposed, none can cover all aspects observed in the tests. The present paper introduces a simplified model built on the approach established by Crisafulli and Carr (2007) and addresses its calibration and implementation in a nonlinear analysis software for the evaluation of the in-plane lateral response of infilled RC frames. The proposed model uses a set of elements/springs to account separately for the compressive and shear behavior of masonry. The efficiency of the modeling approach is validated with available experimental data, yielding satisfactory matching. The most intricate issue encountered when attempting to represent a masonry panel is the plethora of the material parameters involved and the lack of complete and available test results. Thus, the numerical investigation is accompanied by a parametric study on the sensitivity of the model to the various parameters to identify the critical modeling quantities and provide guidance on their selection. S. Skafida, L. Koutas, and S. N. Bousias Copyright © 2014 S. Skafida et al. All rights reserved. Effect of Soil Flexibility on Seismic Force Evaluation of RC Framed Buildings with Shear Wall: A Comparative Study of IS 1893 and EUROCODE8 Sun, 30 Mar 2014 00:00:00 +0000 Conventional analyses of structures are generally carried out by assuming the base of structures to be fixed. However, the soil below foundation alters the earthquake loading and varies the lateral forces acting on structure. Therefore, it is unrealistic to analyse the structure by considering it to be fixed at base. Multistorey reinforced concrete framed buildings of different heights with and without shear wall supported on raft foundation incorporating the effect of soil flexibility are considered in present study to investigate the differences in spectral acceleration coefficient , base shear, and storey shear obtained following the seismic provisions of Indian standard code and European code. Study shows that the value of base shear obtained for symmetric plan building is lowest in buildings with shear wall at all the four corners. B. R. Jayalekshmi and H. K. Chinmayi Copyright © 2014 B. R. Jayalekshmi and H. K. Chinmayi. All rights reserved. Finite Element Modelling of Electrical Overhead Line Cables under Turbulent Wind Load Thu, 27 Mar 2014 11:20:58 +0000 This paper presents a finite element model of an overhead transmission line using so called cable elements which allow reproducing the cable’s nonlinear characteristics accurately employing only a few elements. Aerodynamic damping is considered in the equation of motion by taking into account the relative velocity between the flow of the wind and the moving structure. The wind flow itself is simulated by wave superposition making necessary assumptions on the lateral correlation between the wind velocities along the cable length. As result from the simulation, the following conclusions can be drawn. The first natural frequency of generally used wide spanning cables lies well below 1 Hz where also most of the energy content of the wind excitation is to be expected. Aerodynamic damping is significant for the moving cables holding very low structural damping which leads to a suppression of resonant amplification. This is particularly of interest regarding the support reaction which is dominated by the mean value and the so called background response. The latter is mostly influenced by the randomness of the wind flow, especially lateral to the main wind direction. Dominik Stengel and Milad Mehdianpour Copyright © 2014 Dominik Stengel and Milad Mehdianpour. All rights reserved. Seismic Hybrid Simulation of Stiff Structures: Overview and Current Advances Thu, 27 Mar 2014 08:48:16 +0000 Advances in the area of structural testing have in recent years led to hybrid simulation, that is, the advanced structural experimental method that encompasses the traditional pseudodynamic testing method and relies on substructuring to offer the advantage of combining the actual experimental testing of selected parts of the structure to the numerical treatment of the rest. The experimental part usually involves simplified test setups and structural elements with few degrees of freedom. Thus, issues of cross-coupling present in testing MDOF structures have not been treated adequately so far. In addition, it has been realized that when it comes to testing very stiff structures, in which the above phenomena are accentuated, further problems arise in relation to the quality of actuator control (accuracy of imposed displacements and stability of the test process). Few studies have focused on these issues, thus necessitating more work in the future. The present study provides an overview of the approaches that have been adopted so far, reports on recent advancements, and raises the points in which more research is needed. Stathis N. Bousias Copyright © 2014 Stathis N. Bousias. All rights reserved. Reassessing the Plastic Hinge Model for Energy Dissipation of Axially Loaded Columns Thu, 13 Feb 2014 10:05:39 +0000 This paper investigates the energy dissipation potential of axially loaded columns and evaluates the use of a plastic hinge model for analysis of hi-rise building column collapse under extreme loading conditions. The experimental program considered seven axially loaded H-shaped extruded aluminum structural section columns having slenderness ratios that would be typical of floor-to-ceiling heights in buildings. All seven test specimens initially experienced minor-axis overall buckling followed by formation of a plastic hinge at the mid-height region, leading to local buckling of the flanges on the compression side of the plastic hinge, and eventual folding of the compression flanges. The experimental energy absorption, based on load-displacement relations, was compared to the energy estimates based on section plastic moment resistance based on measured yield stress and based on measured hinge rotations. It was found that the theoretical plastic hinge model underestimates a column’s actual ability to absorb energy by a factor in the range of 3 to 4 below that obtained from tests. It was also noted that the realizable hinge rotation is less than . The above observations are based, of course, on actual columns being able to sustain high tensile strains at hinge locations without fracturing. R. M. Korol and K. S. Sivakumaran Copyright © 2014 R. M. Korol and K. S. Sivakumaran. All rights reserved. Static, Vibration Analysis and Sensitivity Analysis of Stepped Beams Using Singularity Functions Mon, 20 Jan 2014 09:09:39 +0000 A systematic approach is presented in this paper to derive the analytical deflection function of a stepped beam using singularity functions. The discontinuities considered in this development are associated with the jumps in the flexural rigidity and the applied loads. This approach is applied to static and vibration analyses of stepped beams. The same approach is later extended to perform sensitivity analysis of stepped beams. This is done by directly differentiating the analytical deflection function with respect to any beam-related design variable. The particular design variable considered here is the location of discontinuity in flexural rigidity. Example problems are presented in this paper to demonstrate and verify the derivation process. Peng Cheng, Carla Davila, and Gene Hou Copyright © 2014 Peng Cheng et al. All rights reserved. Finite Element Modeling of Mode I Failure of the Single Contoured Cantilever CFRP-Reinforced Concrete Beam Sun, 22 Dec 2013 09:13:08 +0000 The single contour cantilever beam (SCCB) test method has been developed with the intent to capture Mode I opening failures of CFRP-reinforced concrete beams. Recent development in the method explores possible shifting damage into the concrete substrate by using the International Concrete Repair Institute (ICRI) Surface Profile Level Three (SP3) as the desired CFRP bonded interface to concrete. To validate and explain the interface fracture behavior, finite element analysis using special cohesive elements has been performed. The cohesive element allows separation of the concrete substrate from the CFRP. This paper presents the simulation of laboratory test results, where failure in the substrates has been successfully reproduced. The simulation results indicate that finite element method using cohesive elements can successfully replicate Mode I critical strain energy release rate and the peak capacity of the laboratory tests and may have the potential to simulate actual applications. T. Nicholas, D. Boyajian, S. E. Chen, and A. Zhou Copyright © 2013 T. Nicholas et al. All rights reserved. Dynamic Resonance of Curved Panels in Adverse Hygrothermal Environment Tue, 22 Oct 2013 09:31:35 +0000 The present paper deals with the dynamic resonance of composite curved panels subjected to periodic dynamic loadings. The effects of various parameters of four-sided clamped composite curved panels at elevated temperatures and moisture concentrations on the principal instability regions are investigated by finite element method which is used to study the antisymmetric angle-ply square plates. The results show that instability of composite plates occurs for different parameters in adverse hygrothermal environment. The experimental and numerical investigation is also carried out for four-sided clamped boundary condition for vibration and buckling of curved panels in hygrothermal environment. Manoj Kumar Rath Copyright © 2013 Manoj Kumar Rath. All rights reserved. Soil-Structure Interaction Analysis of Tall Reinforced Concrete Chimney with Piled Raft and Annular Raft under Along-Wind Load Mon, 21 Oct 2013 15:37:41 +0000 A three-dimensional (3D) soil-structure interaction (SSI) analysis of 300 m high reinforced concrete chimneys having piled annular raft and annular raft foundations subjected to along-wind load is carried out in the present study. To understand the significance of SSI, four types of soils were considered based on their flexibility. The effect of stiffness of the raft was evaluated using three different ratios of external diameter to thickness of the annular raft. The along-wind load was computed according to IS:4998 (Part 1)-1992. The integrated chimney-foundation-soil system was analysed by commercial finite element (FE) software ANSYS, based on direct method of SSI assuming linear elastic behaviour. FE analyses were carried out for two cases of SSI (I) chimney with annular raft foundation and (II) chimney with piled raft foundation. The responses in chimney such as tip deflection, bending moments, and base moment and responses in raft such as bending moments and settlements were evaluated for both cases and compared to that obtained from the conventional method of analysis. It is found that the responses in chimney and raft depend on the flexibility of the underlying soil and thickness of the raft. B. R. Jayalekshmi, S. V. Jisha, and R. Shivashankar Copyright © 2013 B. R. Jayalekshmi et al. All rights reserved. Elastic Stability of Annular Thin Plates with One Free Edge Thu, 26 Sep 2013 16:07:22 +0000 The elastic stability of annular thin plates having one free edge and subjected to axisymmetric radial edge loads at the other edge is investigated. The supported edge is allowed to be either simply supported or clamped against axial (transverse) deflection. Both compression buckling and tension buckling (wrinkling) are investigated. To insure accuracy, two methods of solving the appropriate eigenvalue problems are used and found to yield essentially identical results. A selection of these results for both compression and tension buckling is presented graphically and used to illustrate interesting aspects of the solutions. Nagarjuna Jillella and John Peddieson Copyright © 2013 Nagarjuna Jillella and John Peddieson. All rights reserved. Ultimate Seismic Resistance Capacity for Long Span Lattice Structures under Vertical Ground Motions Tue, 24 Sep 2013 09:47:14 +0000 Seismic resistance capacities of frame structures have been discussed with equilibrium of energies among many researchers. The early one is the limit design presented by Housner, 1956; that is, frame structures should possess the plastic deformation ability equivalent to an earthquake input energy given by a velocity response spectrum. On such studies of response estimation by the energy equilibrium, the potential energy has been generally abandoned, since the effect of self-weight or fixed loads on the potential energy is negligible, while ordinary buildings usually sway in the horizontal direction. However, it could be said that the effect of gravity has to be considered for long span structures since the mass might be concerned with the vertical response. In this paper, as for ultimate seismic resistance capacity of long span structures, an estimation method considering the potential energy is discussed as for plane lattice beams and double-layer cylindrical lattice roofs. The method presented can be done with the information of static nonlinear behavior, natural periods, and velocity response spectrum of seismic motions; that is, any complicated nonlinear time history analysis is not required. The value estimated can be modified with the properties of strain energy absorption and the safety static factor. Yoshiya Taniguchi Copyright © 2013 Yoshiya Taniguchi. All rights reserved. Strain Distribution Measurement of a Shear Panel Damper Developed for Bridge Structure Thu, 12 Sep 2013 08:30:05 +0000 A shear panel damper using low-yield steel is considered as one of cost-effective solutions to reduce earthquake damage to building structure. In this paper, we describe the development of a shear panel damper with high deformation capacity, which is a necessary condition for it to be a bridge bearing. The development is based on the measurement of strain distribution of the shear panels under cyclic loading test. For the measurement, an image processing technique is proposed to use with the two-dimensional finite element method, in which a constant stress triangular element is employed. The accuracy of the measurement is validated by comparing with the results acquired by strain gauges. Various shapes of shear panels are tested in the experiment to obtain the relationship between the strain distribution and the deformation capacity. Based on the results of the experiment, the shear panel damper is improved to achieve high seismic performance with large deformation capacity. Y. Liu, T. Aoki, and M. Shimoda Copyright © 2013 Y. Liu et al. All rights reserved. Comparison between Visibility and Diffraction Criteria on SIF and -Integral Value for Mode Crack Using RKPM Wed, 28 Aug 2013 10:41:57 +0000 Recently, mesh-free methods are increasingly utilized in solving various types of boundary value problems. Much research has been done on mesh-free methods for solving differential equation problems including crack and also obtained satisfactory results. Among these methods, reproducing kernel particle method (RKPM) has been used increasingly in fracture mechanic problems. The -integral and the stress intensity factor (SIF) are the most important parameters for crack problems. In this study -integral has been used to calculate the SIF in the crack tip. The mode SIF at the crack tip in a work-hardening material is obtained for various dilation parameters using RKPM. A comparison between two conventional treatments, visibility and diffraction on SIF and -integral value, is conducted. Visibility and diffraction methods increase the accuracy of RKPM results and effect on the -integral results at the crack tip. In comparing between the visibility and diffraction methods to modify the shape functions, the diffraction criterion seems to have better results for the -integral and SIF value. Masood Hajali, Caesar Abishdid, and Arash Nejadpak Copyright © 2013 Masood Hajali et al. All rights reserved. Effects of Side Ratio on Wind-Induced Pressure Distribution on Rectangular Buildings Mon, 12 Aug 2013 14:44:40 +0000 This paper presents the results of wind tunnel studies on 1 : 300 scaled-down models of rectangular buildings having the same plan area and height but different side ratios ranging from 0.25 to 4. Fluctuating values of wind pressures are measured at pressure points on all surfaces of models and mean, maximum, minimum, and r.m.s. values of pressure coefficients are evaluated. Effectiveness of the side ratios of models in changing the surface pressure distribution is assessed at wind incidence angle of 0° to 90° at an interval of 15°. Side ratio of models has considerable effects on the magnitude and distribution of wind pressure on leeward and sidewalls but it has very limited effect on windward walls at wind incidence angle of 0°. For building models with constant cross section, change in side ratio does not significantly affect the general magnitude of peak pressures and peak suctions, but rather the wind angle at which they occur. The regression equation is also proposed to predict the mean pressure coefficient on leeward wall and side wall of rectangular models having different side ratios at 0° wind incidence angle. J. A. Amin and A. K. Ahuja Copyright © 2013 J. A. Amin and A. K. Ahuja. All rights reserved. Investigations on Efficiently Interfaced Steel Concrete Composite Deck Slabs Sun, 04 Aug 2013 13:34:10 +0000 The strength of the composite deck slab depends mainly on the longitudinal shear transfer mechanism at the interface between steel and concrete. The bond strength developed by the cement paste is weak and causes premature failure of composite deck slab. This deficiency is effectively overcame by a shear transferring mechanism in the form of mechanical interlock through indentations, embossments, or fastening studs. Development of embossment patterns requires an advanced technology which makes the deck profile expensive. Fastening studs by welding weakens the joint strength and also escalates the cost. The present investigation is attempted to arrive at a better, simple interface mechanism. Three types of mechanical connector schemes are identified and investigated experimentally. All of the three shear connector schemes exhibited full shear interaction with negligible slip. The strength and stiffness of the composite slabs with shear connectors are superior about one and half time compared to these of the conventional reinforced concrete slabs and about twice compared to these of composite slabs without mechanical shear connectors. The scheme2 and scheme3 shear connector mechanisms integrate deck webs and improve strength and stiffness of the deck, which can effectively reduce the cost of formworks and supports efficiently. K. N. Lakshmikandhan, P. Sivakumar, R. Ravichandran, and S. Arul Jayachandran Copyright © 2013 K. N. Lakshmikandhan et al. All rights reserved. Parametric Instability of Square Laminated Plates in Hygrothermal Environment Thu, 01 Aug 2013 15:44:13 +0000 The present paper investigates the parametric instability of square laminated plates subjected to periodic dynamic loadings in hygrothermal environment. The effects of various parameters like the increase in static load factor and the degree of orthotropy of simply supported composite plates at elevated temperatures and moisture concentrations on the principal instability regions are investigated using finite element method. The effects of transverse shear deformation and rotary inertia are used to study the antisymmetric angle-ply square plates. A simple laminated plate model is developed for the parametric instability of square laminated plates subjected to hygrothermal loading. A computer program based on FEM in MATLAB environment is developed to perform all necessary computations. The results show that instability of square laminated plates occurs for different parameters with an increase in temperature and moisture environment. The onset of instability occurs earlier, and the width of dynamic instability regions increases with a rise in temperature and moisture for different parameters. The effect of damping shows that there is a finite critical value of dynamic load factor for each instability region below which the square laminated plates cannot become unstable. Manoj Kumar Rath and Shishir Kumar Sahu Copyright © 2013 Manoj Kumar Rath and Shishir Kumar Sahu. All rights reserved. Enhancing Seismic Capacity of Pile-Supported Wharves Using Yielding Dampers Wed, 26 Jun 2013 09:16:30 +0000 This paper presents a numerical study on the seismic response of pile-supported wharves equipped with metallic yielding dampers. Using 20 ground acceleration records, the contribution of the yielding damper is examined, and its main parameters are optimized through a parametric study. In the current study, considering coupling effects of different parameters, a new optimization procedure is proposed. The obtained results indicate that the stability condition of the retaining wall (quay wall) behind the wharf, period of the soil-wharf system, and also maximum allowable ductility ratio of the damper are the key factors affecting the optimum damper parameters. A simplified design guideline is proposed for either the design or the retrofit purposes followed by a numerical assessment to evaluate the contribution of the proposed damper on the seismic behavior of a typical pile-supported wharf. The obtained results show that yielding dampers, through their nonlinear behavior, can dissipate a large portion of seismic input energy and mitigate piles damages which have been observed in earlier earthquake events. Seyed Amin Mousavi and Khosrow Bargi Copyright © 2013 Seyed Amin Mousavi and Khosrow Bargi. All rights reserved. Study of Magnetic Vibration Absorber with Permanent Magnets along Vibrating Beam Structure Wed, 05 Jun 2013 19:07:32 +0000 The vibration absorbers are frequently used to control and minimize excess vibration in structural system. Dynamic vibration absorbers are used to reduce the undesirable vibration in many applications such as pumps, gas turbines, engine, bridge, and electrical generator. To reduce the vibration of the system, the frequency of absorber should be equal to the excitation frequency. The aim of this study is to investigate the effect of magnetic vibration absorber along vibrating cantilever beam. This study will aim to develop a position of magnetic vibration absorber along the cantilever beam to adopt the change in vibratory system. The absorber system is mounted on a cantilever beam acting as the primary system. The objective is to suppress the vibration of the primary system subjected to a harmonic excitation whose frequencies are varying. It can be achieved by varying the position of magnetic vibration absorber along the length of beam. The advantage of magnetic vibration absorber is that it can be easily tuned to the excitation frequency, so it can be used to reduce the vibration of system subjected to variable excitation frequency. F. B. Sayyad and N. D. Gadhave Copyright © 2013 F. B. Sayyad and N. D. Gadhave. All rights reserved. Research on the Behavior of the Steel Plated Shear Wall by Finite Element Method Thu, 30 May 2013 17:48:52 +0000 From the early’ 70s till today, steel shear walls have been used as the primary lateral force resisting system in some of the significant buildings around the world. To assist understanding the behavior of this system, there have been research programs in USA, Canada, Japan, and UK. This research presents the dynamic and cyclic behavior of steel plated shear wall. In order to simulate the behavior of such a wall structure, finite element method of analysis is implemented. Several analytical models are implemented, in order to obtain the dynamic as well as cyclic behavior of such system. The material nonlinearity as well as geometrical nonlinearity along with the postbuckling behavior of steel plate subjected to cyclic loading has also been employed. The hysteresis diagrams of steel shear wall system in terms of storey shear drift are presented. The results obtained from the analyses are compared to some experimental results reported by other researchers previously. The nonlinear time history analysis of such system is carried out for different seismic response spectra. Finally, the significant factors and parameters of the steel plated shear wall which affect the overall behavior of such system are acknowledged and their effects were recognized. S. M. R. Mortazavi, M. Ghassemieh, and M. S. Ghobadi Copyright © 2013 S. M. R. Mortazavi et al. All rights reserved.