List of articles (by subject) Structural Mechanics
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Open Access Article
1 - Investigating the Effect of Using Multistory Pipe Dampers and their Combination with Braces on Structure Performance
Sated Behzad Talaeitaba Erafn JalaliResearchers have combined passive control systems of differing stiffness with each other to provide multistory passive control systems. Each system absorbs and dissipates the applied energy according to its stiffness. This study investigates the multistory control syste MoreResearchers have combined passive control systems of differing stiffness with each other to provide multistory passive control systems. Each system absorbs and dissipates the applied energy according to its stiffness. This study investigates the multistory control system with the modern pipe in pipe passive damper, and combining them with braces, which are able to change stiffness and absorb energy under various loads to reduce seismic structural vibrations. Their performance in 5, 10 and 15 story 3D steel structures on type 1, 2 and 3 soil was evaluated with nonlinear time history analysis and referred to as the structure’s seismic responses. Results showed that using a combination of dampers and braces in 5, 10 and 15 story steel structures can be a suitable substitute for traditional bracing systems. For example, using pipe in pipe dampers instead of dual structures in 5, 10 and 15 story structures on type 3 soil reduced base shear by 45%, 51%, and 55%, and roof acceleration by 39%, 35% and 50%. Compared to dual structures, a combination of dampers in lower stories and braces in higher stories on type 3 soil reduced base shear by 36%, 36% and 46%, and roof acceleration by 38%, 32% and 41% in the 5, 10 and 15 story structures. Manuscript profile -
Open Access Article
2 - Seismic Fragility Analysis of Base-Isolated Buildings resting on Sloping Ground under real earthquake ground motions
RAMA DEBBARMAMost of the hilly regions are situated in high seismic zones of India. Such a threat compels the need to keep a check on the performance of buildings that suffer extensive damages or even collapse during strong ground shaking on account of near-fault pulses. The present MoreMost of the hilly regions are situated in high seismic zones of India. Such a threat compels the need to keep a check on the performance of buildings that suffer extensive damages or even collapse during strong ground shaking on account of near-fault pulses. The present research work is related to the construction of an ensemble of fragility curves for buildings lying on 15⁰, 30⁰ and 45⁰ slopes. In order to mitigate the damages caused by near-field earthquakes, base isolation system using lead rubber bearing has been provided at the foundation level. The responses of the buildings are obtained by incremental dynamic analysis and linear regression is performed to obtain the probabilistic seismic demand models to find out the median intensity and the uncertain parameters. All the buildings are analysed for slight, moderate, extensive and collapse damage states for which the corresponding fragility curves are obtained. Base isolator was able to significantly reduce the seismic demand measures by imparting flexibility to the system and therefore can be recommended as an alternative to conventional fixed base type buildings located on sloping terrain experiencing near-fault motions. Manuscript profile -
Open Access Article
3 - The effects of pre-compress on the mortar/concrete bond and their in-situ compressive strength using “pull-off” and “twist-off” methods
Ali Saberi Varzaneh Mahmood NaderiThe paper aimed to quantify the compressive strength of cementitious materials using in-situ “pull-off” and “twist-off” tests. Apart from determining the correlation coefficient, calibration plots and equations are presented to convert the result MoreThe paper aimed to quantify the compressive strength of cementitious materials using in-situ “pull-off” and “twist-off” tests. Apart from determining the correlation coefficient, calibration plots and equations are presented to convert the results of in-situ tests to mortar compressive strength. The crack distribution was calculated in the tests using the nonlinear ABAQUS software. Additionally, the methods mentioned above were used to investigate the effect of pre-compression on mortar/concrete shear and tensile adhesion strength. Thus, the effect of pre-compression on the tensile and shear adhesion strength of mortar/substrate concrete was investigated using the scanning electron microscopy (SEM) method and physical adsorption theory. The results indicated that pre-compression positively affected adhesion and could be measured using the simple twist-off machine instead of the other machine. By applying 0.1 kg/cm2 of pre-compress, the tensile and shear adhesion between the mortar and concrete layers increased by 5.8% and 8.8%, respectively, after 90 days. Additionally, a linear relationship between the results of “twist-off” and “pull-off” tests and those obtained from experimental tests was observed. Manuscript profile -
Open Access Article
4 - Cold rolling techniques in mechanical splices: Experimental investigations
mohamad reza shokrzadeh Fariborz Nateghi Allahe taleb sadeghianThis study presents a comprehensive evaluation of the performance of oversize threaded splices under cyclic loading conditions. The research includes monotonic tensile testing and cyclic loading experiments to investigate the seismic behavior of the splices. The experim MoreThis study presents a comprehensive evaluation of the performance of oversize threaded splices under cyclic loading conditions. The research includes monotonic tensile testing and cyclic loading experiments to investigate the seismic behavior of the splices. The experimental results demonstrate that the splices exhibit lower values of εu (strain at peak load) in cyclic loading compared to monotonic tensile testing. This suggests that the cyclic response can serve as a conservative lower bound for the mechanical performance of the splices. The findings highlight the importance of considering cyclic loading conditions when determining conservative lower bounds for the design and evaluation of threaded splices. Understanding the behavior and performance of threaded splices under cyclic loading is crucial for ensuring their reliable and safe operation in seismic regions. Manuscript profile -
Open Access Article
5 - Performance Evaluation and Comparison of Schools with Masonry System Treated by Braces, FRP Strips and Friction Dampers Using Fragility Curves (Case Study: Khorram Abad)
Saeed BahariPour Mahdi Nani Mojtaba Hosseini Abdolreza sarvghad Moghadam Mehran Mehran S. RazzaghiDue to the importance of seismicity in the region of Iran, the improvement and retrofitting of structures has always been the focus of competent employers and engineers. In order to achieve the goals of this research, a three-story concrete school structure in need of i MoreDue to the importance of seismicity in the region of Iran, the improvement and retrofitting of structures has always been the focus of competent employers and engineers. In order to achieve the goals of this research, a three-story concrete school structure in need of improvement has been selected. Then, the investigation of possible improvement options (three improvement options: 1 with braces, 2 with friction damper, 3 using FRP in the columns) has been done in Opensees software. In the following, incremental nonlinear dynamic modeling and analysis under selected earthquake records using the recommended FEMA P695 accelerometers for co-based seismic records (5 acceleration maps for the far field and 5 acceleration maps for the near field) has been performed. Then a comparison between the fragility curves for different states has been made. In this research, the behavior of the building against different earthquake intensities is shown According to the results obtained from other non-linear analyses, it can be seen that the maximum capacity obtained is in good agreement with the results of these analyzes and this method is very suitable for evaluating the behavior of buildings and ultimate capacities against earthquakes. Also, it can be a good alternative method for approximate methods such as pushover analysis to determine the performance level of the building and to determine the behavior of the building. Manuscript profile -
Open Access Article
6 - The effect of different arrangements of longitudinal reinforcements on the capacity of wide concrete beams
Javad Mahdian pari alireza faroughiA beam that has a width greater than the width of the column connected to it is called a wide beam. Due to the reduction in the height of the beams in this type of system, many advantages are created, including reducing the costs of molding and construction, increasing MoreA beam that has a width greater than the width of the column connected to it is called a wide beam. Due to the reduction in the height of the beams in this type of system, many advantages are created, including reducing the costs of molding and construction, increasing the execution speed, reducing the height of the floor and of course increasing the number of floors in high-rise buildings, as well as including Other advantages of these beams from the architectural point of view are the hiding of the beams in the roof of the structure. In concrete structure design, ductility is one of the important parameters. The ductile behavior of the structure has a significant effect in reducing the design forces caused by the earthquake due to its energy absorption and loss. The role of reinforcement in the ductility of concrete is very important. In this article, a concrete beam with six different types of longitudinal rebar arrangement has been selected for study and four-point loading has been applied to the models. All models have been analyzed in ABAQUS finite element software. The results indicate that; The pattern of placing the rebar crosswise and diagonally has less hardness, ductility and resistance than other models. The highest amount of energy absorption was related to the model with six bars in a trapezoidal arrangement. Manuscript profile -
Open Access Article
7 - Implementation of Higher Order Shear Theory on Isotropic Material and Liu's Bending Part on Laminated Composite Flat Shell Elements
Taufiq Rochman Agoes Soehadjono Achfas ZacoebPlate and shell analysis using classical plate theory (CPT) has a lack of accuracy in predicting the influence of transverse deformation, because of its assumption that the line normal to the surface is remain straight and normal to the midplane before and after deforma MorePlate and shell analysis using classical plate theory (CPT) has a lack of accuracy in predicting the influence of transverse deformation, because of its assumption that the line normal to the surface is remain straight and normal to the midplane before and after deformation. The next revision by constant shear deformation theory or famous as first order shear deformation theory (CSDT/FOSDT) still suffer a disadvantage that have a constant value in the shear term that called shear locking phenomenon. This matter have been corrected by higher order shear deformation theory (HOSDT) using refined assumption that the line normal to the surface should be in a parabolic function and not normal to the midplane, but normal to the surfaces so it fulfill the zero strain in the surfaces. The analysis of bending part of laminated composite flat shell element is applied by higher order lamination theory (HOLT) that adopted from HOSDT. This model is accurate for thicknesses variation and complex material. HOLT model is implemented into finite element procedure to find deflection, stresses and internal forces. It can be concluded that the displacement and stresses in HOLT model is higher than FOLT ones (first order lamination theory) in small ratio of a/h dan its result almost the same value for a/h ratio more than 10. In a square plate case, the displacement get smaller if the fiber arranged into cross-ply sequence. Interlaminar stresses along thickness is not distributed continuously, but they have certain modes that depend on the depth of point position, the lamina or layer number, fiber orthotropic angle of each layer and a/h ratio. Manuscript profile -
Open Access Article
8 - Numerical investigation of a new structural configuration of a concrete barrier wall under the effect of blast loads
Ahmed K. Taha Zhengguo Gao Dahai Huang M. S. ZahranAbstractIn this study, a non-linear three-dimensional hydrocode numerical simulation was carried out using AUTODYN-3D, whichis an extensive code dealing with explosion problems. A high explosive material (comp-B) is blasted against several concretewall barriers. The mod MoreAbstractIn this study, a non-linear three-dimensional hydrocode numerical simulation was carried out using AUTODYN-3D, whichis an extensive code dealing with explosion problems. A high explosive material (comp-B) is blasted against several concretewall barriers. The model was first validated using referenced experimental tests and has shown good results. Several numericalmodels were carried out to study the effect of changing the shape of wall barrier from flat to convex curve and concavecurve, and also investigated the effect of changing the angle of curvature. The results showed that changing the shape of awall barrier from flat to convex curve has the best performance in mitigating the effect of blast waves. It is also concludedthat convex walls with 60° angle of curvature have the best performance compared to other barrier walls. Manuscript profile -
Open Access Article
9 - Behavior of Reinforced Concrete Short Columns with Fiber Reinforced Polymer Bars
Ehab. M LotfyThis paper presents the results of an experimental investigation of the axial behavior of small scale square reinforced concrete columns with fiber reinforced polymer (FRP) bars, as a solution to overcome the corrosion problems, where this material represents a relative MoreThis paper presents the results of an experimental investigation of the axial behavior of small scale square reinforced concrete columns with fiber reinforced polymer (FRP) bars, as a solution to overcome the corrosion problems, where this material represents a relatively new technology; therefore much research is needed to determine its characteristics and gain confidence to be accepted by engineers for practical application.A series of 8-column was tested in a vertical position and under compressive axial static loading. Where all columns had the same dimensions 250*250mm and 1250mm height, main reinforcement 4#12mm, 6#12mm, and 8#12mm, the transverse reinforcement was ø6@120mm closed stirrups along columnThe major parameters included in this research were the main reinforcement ratios, the main reinforcement types, the transverse reinforcement ratios in the column, and the charac-teristic strength of concreteResults from a series of tests on small-scale specimens showed that increasing main reinforcement, transverse reinforcement ratios in the column ends and increasing characteris-tic strength of concrete have a significant effect on the behavior of reinforced concrete col-umns with GFRP. Manuscript profile -
Open Access Article
10 - Cellular Automata in Optimum Shape of Brick Masonry Vault under Dynamic Loads
Kaveh Kumarci Afsaneh Banitalebi Dehkordi Pooya Khosravyan DehkordiThis paper deal with optimum shape brick masonry vaults under dynamic loads by cellular automata. In this paper, vaults are modeled. Then they are analyzed and optimized under acceleration–time components of Elcentro earthquake. For vault response optimization, th MoreThis paper deal with optimum shape brick masonry vaults under dynamic loads by cellular automata. In this paper, vaults are modeled. Then they are analyzed and optimized under acceleration–time components of Elcentro earthquake. For vault response optimization, the results were used in cellular automata computational model. Then vaults are analyzed and optimized by modeling rules. The results of error range and time of analysis in automata cellular model and FEM software compared. Finally, comparing the results of CA (Cellular Automata) method and FEM (Finite Element Method) method, shows that although precision is less in CA method, but the time of analysis and optimization is so much smaller in it. Manuscript profile -
Open Access Article
11 - Comparative Study of Seismic Response of Base Isolated Building with Plan Eccentricities and Elevation Eccentricities
Lavkesh Rameshrao WankhadeBase isolation is one of the most widely accepted techniques to protect structures and to mitigate the risk to life and property from strong earthquakes. In this paper, the effect of mass asymmetry in symmetric building with unidirectional and bidirectional eccentriciti MoreBase isolation is one of the most widely accepted techniques to protect structures and to mitigate the risk to life and property from strong earthquakes. In this paper, the effect of mass asymmetry in symmetric building with unidirectional and bidirectional eccentricities and asymmetric building with upward and downward eccentricities in elevation is studied. To study the effect of torsion in seismic behavior of base isolated structures, a symmetric and asymmetric thirteen story concrete building is chosen as reference model. These models with mass eccentricity of 5%, 10%, 15% and 20% of greatest dimension of building in unidirection and bidirection are considered. The response spectrum and linear time history analysis of this eccentric model of fixed base and base isolated building using ETABS software is done. The symmetric and asymmetric fixed base and base isolated building having eccentricity in plan and elevation are compared for parameters such as maximum shear force, torsion, bending moment, lateral displacement, storey drift, storey acceleration and base shear. It is concluded that base isolation is very effective for various mass eccentric models. Response of base isolated mass eccentric model even in large mass eccentricity reduces as compared to fixed base building. Manuscript profile -
Open Access Article
12 - Seismic Vulnerability Evaluation of Pipe Rack Supporting Structures in A Petrochemical Complex
Mohammad Karimi Naghdali Hosseinzadeh Farshid Hosseini Navid Kazem Hamid KazemSeismic evaluation of pipe rack supporting structures in a petrochemical complex as one of the most important parts of structural systems for safe and stable production processes have been studied in this paper. The behavior of these supporting structures is similar to MoreSeismic evaluation of pipe rack supporting structures in a petrochemical complex as one of the most important parts of structural systems for safe and stable production processes have been studied in this paper. The behavior of these supporting structures is similar to steel or reinforced concrete frame supporters for elevated processes pipes. Qualitative and quantitative methods of seismic vulnerability evaluations have been used according to the ASCE-1998 standard. In qualitative evaluation, the seismic vulnerability factors are determined by visual inspection and walk down the structural systems. Computer modelings have been used in quantitative evaluation of the supporting structures, including equivalent static analysis and linear dynamic analysis by considering torsion and P-∆ effects. Site specific earthquake records and design spectrum have been used as input seismic forces. Also, gravity and thermal loads based on the existing documents and design calculation sheets and specification notes have been considered in analyses. Gravity and lateral load combinations have been considered for seismic evaluation of foundation systems. Overturning stability of structures and uplifting of foundation systems due to gravity and lateral loads, and also, lateral displacements, frame element and connection capacities, have been investigated. However, different methods of seismic strengthening and retrofitting of structural system have been proposed. Manuscript profile -
Open Access Article
13 - Numerical Investigation of the Effect of Concrete Injection on the Concrete Joints of the Arched Dam, Under the Applied Stresses
Mohammadhossein Mansourghanaei Alireza MardookhpourNumerical Investigation of the Effect of Concrete Injection on the Concrete Joints of the Arched Dam, Under the Applied StressesAbstract Investigating the safety of dams is of great importance given their critical role in the industry and economy of countries and the ca MoreNumerical Investigation of the Effect of Concrete Injection on the Concrete Joints of the Arched Dam, Under the Applied StressesAbstract Investigating the safety of dams is of great importance given their critical role in the industry and economy of countries and the catastrophic consequences of their failure. Hence, the present paper examines the impact of incomplete contraction joint injection in the Karun 4 double-curvature arch dam as a case study. In this article, the Abaqus 6.12 finite element software was used to model and analyze 3 numerical models of the Karun 4 dam. These models consist of a linear, integrated, and homogeneous model and two nonlinear models considering the nonlinear behavior resulting from two different types of common contraction joints in the dam's body. The results indicated that a lack of injection led to a significant increase in the maximum principal stresses (MPa) at the upstream section of the dam, such that a large part of this section, which originally worked under compression, is now under tension. The tensile stresses at the upstream abutment and the downstream crest also increased. Moreover, a lack of injection considerably increased the vertical compressive stresses between the contact surfaces (µ). These stresses were increased almost twofold near the injection stop level such that the stresses between monolith zero and one increased from a maximum of 5.13 under complete injection to 11.3. According to the results, with an increase in the joint thickness under the absence of joint injection, considerable amounts (of stress) are added to the maximum principal stresses, minimum principal stresses, dam displacement, and the vertical compressive force between the contact surfaces. Manuscript profile -
Open Access Article
14 - Seismic Evaluation and Strengthening of Vertical and Horizontal Pressure Vessels in a Refining Complex
Hossein Kazem Mahmood MinavandPressure vessels are one of the most important equipment in the refining of the crude oil. For this reason, these equipment must be resist against the loads resulting from the earthquake.Pressure vessels are found in different units of refineries and in different vertic MorePressure vessels are one of the most important equipment in the refining of the crude oil. For this reason, these equipment must be resist against the loads resulting from the earthquake.Pressure vessels are found in different units of refineries and in different vertical and horizontal shapes. These equipment are locating on different foundation and their seismic behavior are quite different. For seismic study of pressure vessels, at first this equipment must be screened and categorized in order to find their real behavior. The selected sample should be a sample that in comparing to others must have critical condition in terms of seismic vulnerabilities.According to the qualitative studying, mechanical specifications such as dimensions, temperature, weight, and the dimensions of the foundation will be determined.After analytical modeling and calculations the amount of vessel vulnerabilities will be found. All the modeling is done with the SAP2000 and SAFE2000 softwares. For modal and spectrum dynamic analysis shell elements and frame elements is used.After analysis is done, the stresses and the displacement in the body of vessel and also stresses in pedestal and bolts will be determined and then compared to the allowable values. At the end those elements which have no adequate strength, will be retrofitted and all drawing and details will be presented. Manuscript profile -
Open Access Article
15 - Investigating the effect of increasing the height of bridge piers on seismic behavior of isolation systems in urban bridges (A case study on the Hesarak Bridge)
Mehdi Firoozbakht Aliakbar EdalatiBridges are vital to modern transportation infrastructure, providing convenient and efficient access to different locations. Because of their structural simplicity and low degree of indeterminacy, bridges tend to be particularly vulnerable to damage and even collapse wh MoreBridges are vital to modern transportation infrastructure, providing convenient and efficient access to different locations. Because of their structural simplicity and low degree of indeterminacy, bridges tend to be particularly vulnerable to damage and even collapse when subjected to earthquakes. The costs of their construction and retrofitting are high, so the maintenance of these capitals is one of the necessities of urban management. This paper investigates the influence of increasing the height of bridge piers on seismic behavior of isolation systems in urban reinforce concrete (RC) bridge. For this purpose, the seismic performance of the Hesarak Bridge constructed in Karaj city, Iran with two isolation systems; i.e. the existing elastomeric rubber bearing (ERB) and a proposed lead rubber bearing (LRB) are discussed by changing three times the height the bridge piers as compared with the existing situation. The numerical model was implemented in the well-known FEM software CSiBridge. The isolated bridge has been analyzed using nonlinear time history analysis (NTHA) method with seven pairs of earthquake records and the results are compared for the two isolation systems in both height modes. The results showed that with the increase in the height of the bridge piers, the natural period of the LRB isolated system changes from 2.7 to 2.77 seconds and on the other hand, this value increases from 1.37 to 1.62 in the ERB isolated system. The ratio of maximum base shear force for the bridge with the LRB to the ERB isolators under given ground motions in longitudinal and transverse directions showed higher values with increasing the height of bridge piers in comparison with the current situation, which indicates the weaker seismic performance of LRB isolators. Also, the results of the numerical Analysis illustrate the pier head relative displacement of columns increases in the longitudinal direction of the bridge with increasing height of bridge piers. Manuscript profile -
Open Access Article
16 - Response of the Wind Excited Benchmark Building Upgraded with SAEMFDs
Veeranagouda B. PatilDynamic behavior of the wind-excited-benchmark-building using Semi-Active Electromagnetic Friction Dampers (SAEMFDs), with modulated homogeneous friction algorithm is presented. The performance of the benchmark building is studied under across wind loads by installing t MoreDynamic behavior of the wind-excited-benchmark-building using Semi-Active Electromagnetic Friction Dampers (SAEMFDs), with modulated homogeneous friction algorithm is presented. The performance of the benchmark building is studied under across wind loads by installing the SAEMFDs with smooth boundary layer semi-active friction (SBLSAF) algorithm. The governing equations of motion are solved by employing state space formulation. Initially, one damper in each of the upper 26 storeys of the building is installed and later on the optimization of the location and the number of dampers required is carried out till the comparable performance criteria are obtained. The criterion selected for optimality was controllability index, obtained with the help of root-mean-square (RMS) value of the inter-storey drift. The performance of SAEMFDs is compared with that of passive friction dampers. Further, a parametric study is carried out by varying the value of controller gain (β). For each value of β, a parametric study of SAEMFDs by varying the value of the parameter representing the measure of the thickness of the boundary layer α is carried out. From the numerical study, it is found that SBLSAF algorithm is quite effective in enhancing the quality of the performance of the benchmark building. Optimization of location of dampers gives an economical solution to the vibration control of the benchmark building. Manuscript profile -
Open Access Article
17 - Practical Engineering Approach for Generating the Torsional Earthquake Excitation from Translational Components
Sandeep C. Potnis Raviji S. Desai I.D GuptaWorldwide networks of seismic recording instruments mostly record only translational ground motion in two or three orthogonal directions. Rotational component of earthquake is not commonly recorded. Several theories are available to estimate a torsional component from r MoreWorldwide networks of seismic recording instruments mostly record only translational ground motion in two or three orthogonal directions. Rotational component of earthquake is not commonly recorded. Several theories are available to estimate a torsional component from recorded translational components of ground motion. In this paper detailed investigations are made to study the relative performance of some available methods. This paper suggests a practical approach for obtaining true SH (S-wave having particle motion in horizontal direction) component from two recorded horizontal components of ground excitation. This new approach will help to obtain optimum torsional time histories from translational time histories. Manuscript profile -
Open Access Article
18 - Analysis On Response Of Dynamic Systems To Pulse Sequences Excitation
Li Shuang Zhai Changhai Xie LiliNear-fault ground motions with long-period pulses can place severe demands on structures near an active fault. These pulse-type ground motions can be represented by pulse sequences with simple shapes. Half-sinusoidal pulse sequences are used to approximate recorded grou MoreNear-fault ground motions with long-period pulses can place severe demands on structures near an active fault. These pulse-type ground motions can be represented by pulse sequences with simple shapes. Half-sinusoidal pulse sequences are used to approximate recorded ground motions and dynamic responses of SDOF system under the excitation of these pulse sequences are studied. Four cases are considered: (1) variation in duration of successor sub-pulse; (2) variation in duration of predecessor sub-pulse; (3) variation in amplitude of successor sub-pulse; and (4) variation in amplitude of predecessor sub-pulse. The corresponding acceleration, velocity and displacement response spectra of these pulse sequences are studied. The analysis on SDOF system shows that in some cases the responses are strongly affected by the changes of duration and/or amplitude of the sub-pulse. The study can be useful to understand the influences of sub-pulse in the near-fault pulse-type ground motions. Manuscript profile -
Open Access Article
19 - Finite Element Analysis of the Pseudo-elastic Behavior of Shape Memory Alloy Truss and Beam
Kamal M. Bajoria Surajit DasThe pseudo-elastic behavior of Shape memory alloy (SMA) truss and cantilever beam are investigated. Brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to MoreThe pseudo-elastic behavior of Shape memory alloy (SMA) truss and cantilever beam are investigated. Brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the SMA stress-strain characteristics. This material model also incorporates different young’s modulus for austenitic and martensite phase to represent the true SMA characteristics. In this model, a cosine function was used to express the evolution of the stress induced martensite fractions during the forward and reverse martensite phase transformation. A finite element formulation for the SMA truss member considering the geometric nonlinearity is proposed and the results are compared with the corresponding linear analysis. As a step forward, a finite element formulation for an SMA cantilever beam with an applied end moment is proposed. The load displacement characteristic for both the loading and unloading phases are considered to check the full pseudo-elastic hysteretic loop. In the numerical investigation, the stress-strain variation along the beam depth is also examined during the loading and unloading process to investigate the forward and reverse martensite phase transformation phenomena. Newton-Raphson’s iterative method is applied to get convergence to the equilibrium for each loading steps. During a complete loading-unloading process, the temperature is kept constant as the model is essentially an isothermal model. Numerical simulation is performed considering two different temperatures to demonstrate the effect of temperature on the hysteretic loop. Manuscript profile -
Open Access Article
20 - Analysis Of Reinforced Concrete Hollow Piers Behavior: Benefits Of Frp Confinement
Gian Piero Lignola Andrea Prota Gaetano Manfredi Edoardo CosenzaReliable stress-strain behavior of concrete is necessary particularly when a member is subjected to combine bending and axial load and confinement effects should be accounted for. A unified theory for confinement of circular hollow sections is proposed herein, that can MoreReliable stress-strain behavior of concrete is necessary particularly when a member is subjected to combine bending and axial load and confinement effects should be accounted for. A unified theory for confinement of circular hollow sections is proposed herein, that can be extended to the case of solid and noncircular sections. The main aim of the model is to trace step-by-step the evolution of the three dimensional stresses in confined concrete and confining devices (i.e. FRP externally bonded jackets). The iterative model is able to estimate confinement effectiveness and to plot stress-strain relationships, which are different in the case of solid and hollow sections. Through the proposed improved model, a simplified closed form solution has been also derived to directly determine ultimate confined concrete properties and stress-strain curves. At present, theoretical results based on the proposed concrete circular hollow sections confinement model, in satisfactory agreement with the experimental data available in scientific literature, show that FRP jacketing can enhance the ultimate load and ductility significantly, also in the case of hollow concrete cross sections. Manuscript profile -
Open Access Article
21 - An Efficient Auto Redundant Technique for Analysis of Single Layer Grid with Curved Mambers
Ashwin G. Hansora Mangubhai N. Patel Bharatbhai B. MistryThis paper presents an Auto Redundant Technique for analysis of grid with curved members.This technique is based on the force method, but in the technique choice of the redundant iscompletely eliminated. The analysis technique is found very effective, accurate andprogra MoreThis paper presents an Auto Redundant Technique for analysis of grid with curved members.This technique is based on the force method, but in the technique choice of the redundant iscompletely eliminated. The analysis technique is found very effective, accurate andprogrammable. A comprehensive C++ program has been developed to compute internalforces at the end of each member of the grid for different load cases and their combinations.Presently in this paper analysis of grid is carried out with fixed support when it is subjected toconcentrated point load, twisting moment, bending moment, full/partial uniformly distributedload and full/partial uniformly varying load. In this technique, any number of load cases canbe accommodated without creating any additional node(s) on the member. The power of theanalysis procedure is effectively demonstrated through the solution of one benchmarkproblem. The results obtained through the program for complementary load cases arecompared with the results from analysis software and are found to match. Manuscript profile -
Open Access Article
22 - Modal Identification Of A Tested Steel Frame Using Linear Arx Model Structure
Yavuz KayaThis study contains the identification of modal dynamic properties of a 3-story large-scale steel test frame structure through shaking table measurements. Shaking table test is carried out to estimate the modal properties of the test frame such as natural frequencies, d MoreThis study contains the identification of modal dynamic properties of a 3-story large-scale steel test frame structure through shaking table measurements. Shaking table test is carried out to estimate the modal properties of the test frame such as natural frequencies, damping ratios and mode shapes. Among many different model structures, ARX (Auto Recursive Exogenous) model structure is used for modal identification of the frame structure system. The unknown parameters in the obtained ARX model structure are estimated by Least-Square method by minimizing the AIC criteria with the help of a program coded in advanced computing software MATLAB®. The adopted model structure is then tested out in time domain to verify the validity of the model with the selected model parameters. Then the modal characteristics of test frame and the story stiffness are estimated using the white noise shakings. An attempt is done to determine the change of modal characteristics and the story stiffness of test frame according to the velocity, which the test frame structure experienced during the shaking schedule and also during the input shaking of El Centro 1940 NS. Results shows that there is an increase in damping ratio and a decrease in both story stiffness and natural frequency for all modes when the damage forms at cementitious device and the test frame structure itself during the shaking schedule. Manuscript profile -
Open Access Article
23 - Cyclic Testing of Steel Chevron Braces with Vertically Slotted Beam Connection
Rozlyn K. Bubela Carlos E. Ventura Helmut G.L PrionExperimental tests were performed to study the seismic behavior and performance ofmodified steel chevron braced frame systems, which incorporate a vertical slotted connection(VSC) detail between the top of the braces and the floor beam above. The VSC detail isintended t MoreExperimental tests were performed to study the seismic behavior and performance ofmodified steel chevron braced frame systems, which incorporate a vertical slotted connection(VSC) detail between the top of the braces and the floor beam above. The VSC detail isintended to prevent vertical load transfer to the beam and limit brace forces to thecompressive resistance of the members. Full-scale quasi-static cyclic tests were performed ontwo specimens with hollow tube braces, with one specimen having the braces filled withconcrete. Both frames exhibited stable, predictable behavior under cyclic loading. The VSCdetail provided free vertical movement of the brace assembly during both tests. However, itsflexibility created a moderate reduction in the overall lateral stiffness of the frame. Theconcrete-filled tube specimen sustained higher peak loads, demonstrated greater residualstrength and dissipated more energy than the hollow tube specimen due to the partialinhibition of local buckling by the concrete core. It was found that the VSC chevron bracedframe system is a suitable concept for use in buildings in high-risk seismic zones. Manuscript profile -
Open Access Article
24 - Seismic Assessment And Strengthening Of An Existing Steel Bridge In Portugal
Catarina Fernandes Humberto VarumThis article presents the seismic vulnerability assessment of the S. João de Loure bridge, inPortugal. The single span steel bridge has riveted joints, commonly affected by corrosion,which can lead to a significant stiffness reduction. With the objective of evalu MoreThis article presents the seismic vulnerability assessment of the S. João de Loure bridge, inPortugal. The single span steel bridge has riveted joints, commonly affected by corrosion,which can lead to a significant stiffness reduction. With the objective of evaluating theinfluence of the joints stiffness in the structural response of the bridge, a structural model ofthe bridge was created, and natural frequencies, maximum axial forces and maximum stresses,and maximum mid-span deflection were analysed. Four possible element rupture scenarioswhere also studied. Two of them where proved to be a risk for the structural safety of thebridge. A commonly used strengthening solution intending to reduce the bridge’s mid-spandeflection with external pre-stressing cables was studied. Manuscript profile -
Open Access Article
25 - Formulation of a new finite element based on assumed strains for membrane structures
Lahcene Fortas Lamine Belounar Tarek MerzoukiAbstractIn this paper, a new triangular membrane finite element with in-plane drilling rotation has been developed using the strainbasedapproach for static and free vibration analyses. The proposed element, having three degrees of freedom at each of thethree corner node MoreAbstractIn this paper, a new triangular membrane finite element with in-plane drilling rotation has been developed using the strainbasedapproach for static and free vibration analyses. The proposed element, having three degrees of freedom at each of thethree corner nodes, is based on assumed strain functions satisfying both compatibility and equilibrium equations. Numericalinvestigations have been conducted using several tests, including static and free vibration problems, and the obtained resultsare compared with analytical and numerical available solutions. It is found that efficient convergence characteristics andaccurate results can be achieved using the developed element. Manuscript profile -
Open Access Article
26 - An Analytical Solution for Cylindrical Concrete Tank on Deformable Soil
Shirish Vichare Mandar M. InamdarCylindrical concrete tanks are commonly used in wastewater treatment plants. These are usually clarifier tanks. Design codes of practice provide methods to calculate design forces in the wall and raft of such tanks. These methods neglect self-weight of tank material and MoreCylindrical concrete tanks are commonly used in wastewater treatment plants. These are usually clarifier tanks. Design codes of practice provide methods to calculate design forces in the wall and raft of such tanks. These methods neglect self-weight of tank material and assume extreme, namely ‘fixed’ and ‘hinged’ conditions for the wall bottom. However, when founded on deformable soil, the actual condition at the wall bottom is neither fixed nor hinged. Further, the self-weight of the tank wall does affect the design forces. Thus, it is required to offer better insight of the combined effect of deformable soil and bottom raft stiffness on the design forces induced in such cylindrical concrete tanks. A systematic analytical method based on fundamental equations of shells is presented in this paper. Important observations on variation of design forces across the wall and the raft with different soil conditions are given. Set of commonly used tanks, are analysed using equations developed in the paper and are appended at the end. Manuscript profile -
Open Access Article
27 - Hysteretic Dissipators Made Of Aluminium And Steel: Optimal Design And Preliminary Characterization Tests
Mariella Diaferio Dora Foti Riccardo NobileIn this paper the optimal design of a dissipator made of aluminium and steel and principallysubjected to shear forces and the preliminary results of the characterization tests are described.The device has been designed on the basis of an optimization procedure with the MoreIn this paper the optimal design of a dissipator made of aluminium and steel and principallysubjected to shear forces and the preliminary results of the characterization tests are described.The device has been designed on the basis of an optimization procedure with the objective tomaximize the energy dissipated in the device. The response of a 3D frame equipped with thedevice and subjected to 7 earthquakes compatible with the response spectrum of Eurocode 8 isshown. The optimal response obtained from the characterization tests exhibits a gooddissipative behavior of the device, highlighted by a wide enough hysteresis cycle. Manuscript profile -
Open Access Article
28 - Dual-layer Multiple Tuned Mass Dampers for Vibration Control of Structures
Tanuja P. Bandivadekar Radhey S. JangidThe performance of dual-layer multiple tuned mass dampers (DL-MTMD) with uniformly distributed natural frequencies is investigated. The DL-MTMD consists of one large tuned mass damper (L-TMD) and an arbitrary number of small tuned mass dampers (S-TMD). The primary struc MoreThe performance of dual-layer multiple tuned mass dampers (DL-MTMD) with uniformly distributed natural frequencies is investigated. The DL-MTMD consists of one large tuned mass damper (L-TMD) and an arbitrary number of small tuned mass dampers (S-TMD). The primary structure is represented as a single degree-of-freedom system which corresponds to a specific vibration mode to be controlled in a real structure. The response of the structure with DL-MTMD is studied under harmonic excitation acting at the primary main system. The performance criterion used for assessing the optimum parameters and effectiveness of the DL-MTMD is selected as the minimization of the maximum dynamic magnification factor (DMF) of the displacement response of main structure. Two dynamic models of the DL-MTMD are proposed in the present study. The Model-I consists of S-TMD having the same mass and damping ratio and uniform distribution of natural frequencies. The Model-II consists of S-TMD with same stiffness and equal damping ratio and uniform distribution of natural frequencies. The comparative performance of the two models indicated that the performance of Model-II in comparison with Model-I is superior with respect to reduction in the displacement DMF. Manuscript profile -
Open Access Article
29 - Ductility-based Seismic Design Of Steel Plate Shear Walls: Practical Application Using Standard Sections
Mayank K. Gupta Swapnil B. Kharmale Siddhartha GhoshOver the past decade of extensive research works, the thin un-stiffened steel plate shear wall(SPSW) has now emerged as a promising lateral load resisting system. Considering thedemand of performance-based seismic design (PBSD) philosophy in current and futureseismic de MoreOver the past decade of extensive research works, the thin un-stiffened steel plate shear wall(SPSW) has now emerged as a promising lateral load resisting system. Considering thedemand of performance-based seismic design (PBSD) philosophy in current and futureseismic design codes, a ductility-based design was recently proposed for SPSW systems withpin-connected boundary beams. However, the effectiveness of that method was not testedusing standard steel sections. The focus of this paper is to check the applicability of thatPBSD procedure for practical designs of SPSW systems in the US and Indian context, usingstandard rolled steel sections available commercially in these countries. Based on sampledesign case studies on 4-story test buildings, the method is found to be a practicable solutionfor PBSD of SPSW systems. In addition, the distribution of inter-story drift over the height ofthe structure is also found to be suitable for adopting in design guidelines. The need forwidening the range of available Indian Standard sections for realistic PBSD applications is Manuscript profile -
Open Access Article
30 - Investigation on cold‑formed steel lipped channel built‑up I beam with intermediate web stiffener
P. Manikandan Manikandan M. ThulasiThe aim of the present study is to examine the behaviour of cold-formed steel (CFS) lipped channel built-up I-section withedge and intermediate web stiffeners under bending. Initially, the section dimension of length, width of the flange and depth ofthe sections are opt MoreThe aim of the present study is to examine the behaviour of cold-formed steel (CFS) lipped channel built-up I-section withedge and intermediate web stiffeners under bending. Initially, the section dimension of length, width of the flange and depth ofthe sections are optimized numerically and finally, it is validated with the test results. All the select cross-section dimensionshave satisfied the pre-qualified beam dimensions. Numerical analysis is carried out using the software ABAQUS. Totally,four section geometries are tested experimentally. After validation, a total of 75 parametric studies are carried out using theverified finite element model. All the results are compared with the direct strength method specifications for CFS structuresand the suitable design modifications are detailed. Manuscript profile -
Open Access Article
31 - Integrated User-friendly Environment For A 2-D Nonlinear Analysis Program
Hugo Rodrigues Xavier Romão Aníbal Costa Humberto VarumNonlinear analyses allow simulating, in a more realistic way, the behaviour of structuressubjected to several types of complex loading conditions such as earthquakes. However, it isrecognized that these analyses normally generate a considerable amount of results, a fact MoreNonlinear analyses allow simulating, in a more realistic way, the behaviour of structuressubjected to several types of complex loading conditions such as earthquakes. However, it isrecognized that these analyses normally generate a considerable amount of results, a factorthat difficult its interpretation. Over the last years, considerable progresses have been made instructural nonlinear behaviour modelling, associated to the fast growing development ofnumerical algorithms and computer capacities. Therefore, a number of computationalanalysis tools have been developed to meet the analysis requirements from the behaviourviewpoint. However, a similar growth in the development of graphical results visualizationtools has not been witnessed and the generalized use of such analysis programs is thus madedifficult. To face this, a graphical processor called VISUALANL was developed for anexisting nonlinear analysis program for plane frame structures. To observe the potentialitiesof such tool, an application example is presented illustrating both previously referred stages. Manuscript profile -
Open Access Article
32 - Seismic Upgrading of Non-ductile Steel Frames using Steel Plate Shear Walls
Vishal Bhatia Siddhartha GhoshMany old damaged and undamaged building structures do not meet the criteria of modern seismic design codes. Such structures need to be seismically enhanced. The main objective of this paper is to propose and validate the effectiveness of an upgrade scheme for non-seismi MoreMany old damaged and undamaged building structures do not meet the criteria of modern seismic design codes. Such structures need to be seismically enhanced. The main objective of this paper is to propose and validate the effectiveness of an upgrade scheme for non-seismic buildings using steel plate shear walls (SPSW). The upgrade is carried out considering a probability-based drift-based criterion, wherein incremental dynamic analysis is used for performance evaluation. The proposed upgrade procedure involves a static energy based scheme for the design of SPSW. It is tested on a 7- and a 5-story steel framed building structure. The results show substantial drift reduction overall, showing the effectiveness of the SPSW; however, selected target performance is not achieved exactly. Various reasons for the inability of the SPSW in meeting the probabilistic target are indicated. Overall, the proposed procedure is found to be effective for the upgrade of non-seismic steel frame structures to satisfy an inelastic drift-based probabilistic performance criterion. Need for future research works are indicated based on the shortcomings of the proposed procedure Manuscript profile -
Open Access Article
33 - Effect of Foundation Depth on Seismic Response of the Cable-stayed Bridge by Considering of Soil Structure Interaction
Siddharth Gopalkrishna Shah Chandresh H Solanki Jatin D. DesaiPost failure analysis of massive structure infers that Soil-structure interaction (SSI) is a crucial phenomena influencing seismic response of massive structures. Cable-stayed bridge’s popularity and numbers are increasing now-a-days because of economical longer s MorePost failure analysis of massive structure infers that Soil-structure interaction (SSI) is a crucial phenomena influencing seismic response of massive structures. Cable-stayed bridge’s popularity and numbers are increasing now-a-days because of economical longer span & aesthetic good look. The current paper examines the effect of depth of foundation on seismic response of cable-stayed bridge. Total 16 cases are solved with and without SSI by time history analysis with the Finite Element Program. Full 3D bridge model is developed and soil is model by assigning the spring and dashpots as Kelvin element to simulate SSI effects. The result yielded that SSI effects must be considered for soft soil conditions irrespective of the depth of foundation. The effects of SSI are site specific and cannot be generalized. However the fundamental time period is increasing as high as 28% due to SSI effects. The depth of foundation has also great role in seismic response of bridge; the medium depth foundation is proven critical compare to other cases. Manuscript profile -
Open Access Article
34 - Strengthening of reinforced concrete shear walls with openings using carbon fiber‑reinforced polymers
AbstractReinforced concrete shear walls are one of the most widely used lateral load structural resisting elements in high rise buildings.Introducing openings in existing shear walls may be due to remodeling or municipality considerations, such as placementof staircases MoreAbstractReinforced concrete shear walls are one of the most widely used lateral load structural resisting elements in high rise buildings.Introducing openings in existing shear walls may be due to remodeling or municipality considerations, such as placementof staircases, windows, doors and elevators. Making openings in existing shear wall decrease the overall structural capacityand integrity of the wall, in addition to stress concentrations around the openings. This necessitates the strengthening of theopening rim with FRP wraps. This paper focuses on developing a 3D high-reliability dynamic nonlinear finite element modelon ABAQUS theory manual and users’ manual, version 6.10 (2010) to simulate the behavior of shear walls with openingsstrengthened with FRP wraps to investigate their seismic response under the monotonic loads. The proposed FE model hasbeen validated using previous experimental data in literature. The FE results indicated that the proposed configuration ofCFRP laminates substantially increases the lateral load strength and deformation capacity of the shear wall with openingsand also improves the ductility and energy dissipation of the shear wall.Keywords Manuscript profile -
Open Access Article
35 - Nonlinear Analysis of Reinforced Concrete Columns with Fiber Reinforced Polymer Bars
Ehab M LotfyIn this paper, the results of an analytical investigation on the behavior of RC columns reinforced with fiber reinforced polymer bars FRP are presented and discussed. Nonlinear finite element analysis on 10-column specimens was achieved by using ANSYS software. The nonl MoreIn this paper, the results of an analytical investigation on the behavior of RC columns reinforced with fiber reinforced polymer bars FRP are presented and discussed. Nonlinear finite element analysis on 10-column specimens was achieved by using ANSYS software. The nonlinear finite element analysis program ANSYS is utilised owing to its capabilities to predict either the response of reinforced concrete columns in the post-elastic range or the ultimate strength of a reinforced concrete columns reinforced by FRP bars. An extensive set of parameters is investigated including different main reinforcement ratios, main reinforcement types (GFRP, Steel), the transverse reinforcement ratios, and the characteristic compressive strength of concrete.A comparison between the experimental results and those predicted by the existing models are presented. Results and conclusions may be useful for designers, have been raised, and represented. Manuscript profile -
Open Access Article
36 - Earthquake Vibration Control of Structures using Tuned Liquid Dampers: Experimental Studies
Pradipta Banerji Avik Samanta Sachin A. ChavanEarlier studies have shown conclusively that a Tuned Liquid Damper (TLD) is effective for controlling vibrations in structures subjected to narrow-banded wind excitations. A recent numerical study has shown that if the design parameters of a TLD are properly set, this d MoreEarlier studies have shown conclusively that a Tuned Liquid Damper (TLD) is effective for controlling vibrations in structures subjected to narrow-banded wind excitations. A recent numerical study has shown that if the design parameters of a TLD are properly set, this device could also be very effective for controlling structural vibration to broad-banded earthquake excitations. Here the results of a reasonably comprehensive set of experiments are presented to investigate the overall effectiveness of TLDs and the specific effect of TLD parameters (depth and mass ratios) for earthquake vibration control of structures. Effects of various earthquake ground motions parameters such as amplitude, frequency content, duration of excitation etc. are also evaluated. It is shown that there is good agreement between the numerical simulation and experimental results. This experimental study conclusively shows that a properly designed TLD reduces structural response to broad-band earthquake excitations. It is also observed that effectiveness of TLD increases with increase in mass ratio, depth ratio and amplitude of ground motion. Manuscript profile -
Open Access Article
37 - Reliability Index For Reinforced Concrete Frames Using Nonlinear Pushover And Dynamic Analysis
Ahmad A. Fallah Abdoreza S. Moghadam Saeed MohammadzadehIn the conventional design and analysis methods affecting parameters (loads, materials'strength, etc) are not set as probable variables. Safety factors in the current Codes andStandards are usually obtained on the basis of judgment and experience, which may beimproper o MoreIn the conventional design and analysis methods affecting parameters (loads, materials'strength, etc) are not set as probable variables. Safety factors in the current Codes andStandards are usually obtained on the basis of judgment and experience, which may beimproper or uneconomical. In technical literature, a method based on nonlinear static analysisis suggested to set Reliability Index on strength of structural systems. In this paper, a methodbased on Nonlinear Dynamic analysis with rising acceleration (or Incremental DynamicAnalysis) is introduced, the results of which are compared with those of the previous (StaticPushover Analysis) method and two concepts namely Redundancy Strength and RedundancyVariations are proposed as an index to these impacts. The Redundancy Variation Factor andRedundancy Strength Factor indices for reinforced concrete frames with varying number ofbays and stories and different ductility potentials are computed and ultimately, ReliabilityIndex is determined using these two indices. Manuscript profile -
Open Access Article
38 - Modal participation of fixed–fixed single‑walled carbon nanotube with vacancies
AbstractThis article presents an investigation of dynamical behaviors of perfect and defected fixed–fixed single-walled carbon nanotube(SWCNTs) model as a beam structures. The fundamental frequencies and modal participation factors for fixed–fixedsupportedSW MoreAbstractThis article presents an investigation of dynamical behaviors of perfect and defected fixed–fixed single-walled carbon nanotube(SWCNTs) model as a beam structures. The fundamental frequencies and modal participation factors for fixed–fixedsupportedSWCTS are considered through this analysis for the first time. Energy-equivalent model is implemented to finda relationship between the energy stored in atomic chemical bonding and potential energy of mechanical beam structure.Nanotube software modeler is exploited to create a geometrical structural of SWCNTs by defining its length of nanotube,bond distance between two atoms, and chiral angle. The tube of SWCNTs are simulated as fixed–fixed-supported structureat both ends, while bonding between each two atoms is modeled by 3D beam element with circular cross section. Parametricresults are illustrated to display the effects of vacancy on activation and deactivation of vibration modes, fundamentalfrequencies, and modal participation factors of SWCNTs.Keywords F Manuscript profile -
Open Access Article
39 - Qualitative and Quantitative Seismic Evaluation of Reinforced Concrete Structures in Petrochemical Plant
Fariborz Nateghi-A Ali Rezaei-TIn this paper the seismic evaluation of reinforced concrete structures in petrochemical facilities under sever conditions such as high pressure, high temperature and corrosive environment is studied. These structures were designed and constructed during 1976-78. The eva MoreIn this paper the seismic evaluation of reinforced concrete structures in petrochemical facilities under sever conditions such as high pressure, high temperature and corrosive environment is studied. These structures were designed and constructed during 1976-78. The evaluation procedure is basically performed in two phases namely; a) qualitative and b) quantitative methods. In the qualitative evaluation, all possible documentations including drawings, specifications, structural calculations, new additions and test results were studied. Collected data then was summarized in an evaluation checklist. When the needed requirements did not meet the specified entries, more detailed and quantitative analysis were performed and utilized in this study. Quantitative and numerical study was performed using finite element modeling under sever loading combinations. Based on the results of this evaluation, some important RC structures in this plant were highly vulnerable to seismic forces which required immediate attention. The methodology used and results obtained can be generalized and adapted for similar facilities. This paper will present details, procedure and conclusions obtained. Manuscript profile -
Open Access Article
40 - Stability Analysis Of 3-d Conventional Pallet Rack Structures With Semi-rigid Connections
Kamal M. Bajoria Keshav K. Sangle Rajshekar S. TalicottiThis paper describe the three dimensional finite element modeling and buckling analysis ofconventional pallet racking system with semi rigid connection. In this study threedimensional models of conventional pallet racking system were prepared using the finiteelement pro MoreThis paper describe the three dimensional finite element modeling and buckling analysis ofconventional pallet racking system with semi rigid connection. In this study threedimensional models of conventional pallet racking system were prepared using the finiteelement program ANSYS and finite element analysis carried out on conventional pallet rackswith the 18 types of column sections developed along with semi-rigid connections. Aparametric study was carried out to compare the effective length approach and the finiteelement method for accuracy and appropriateness for cold-formed steel frame design.Numerous frame elastic buckling analyses were carried out to evaluate the alignment chartand the AISI torsional-flexural buckling provisions. The parameters that influence the valueof Kx for column flexural buckling were examined in this study. The alignment chart and theAISI torsional-flexural buckling provisions, used to obtain the effective lengths and elasticbuckling load of members were also evaluated. Results showed that the elastic buckling loadobtained from the AISI torsional-flexural buckling provisions is generally conservativecompared to the results obtained from performing frame elastic buckling analysis. Resultsalso showed that, the effective length approach is more conservative than the finite elementapproach. Manuscript profile -
Open Access Article
41 - Study of Dynamic Infinite Element Used for Soil Structure Interaction
Anand M. Gharad R. S. SonparoteStarting from two-dimensional (2D) equations of motion, discretized formulations for transient behavior of soil-structure interaction problems have been derived. Two different dynamic infinite elements taking into account single and two-wave types are presented in trans MoreStarting from two-dimensional (2D) equations of motion, discretized formulations for transient behavior of soil-structure interaction problems have been derived. Two different dynamic infinite elements taking into account single and two-wave types are presented in transformed space. By coupling the infinite elements with standard finite elements, an ordinary finite element procedure is used for simulation of wave propagation in an unbounded foundation due to external forces. Manuscript profile -
Open Access Article
42 - Tsunami Propagation in Arabian Sea and Its Effect on Dwarka City of Gujarat, India
Vikram M. Patel H.S Patel A.P SinghIn Western Coast of Gujarat destructive tsunamis have been generated from large earthquakes along the Makran Coast, Chagos Ridge and Kutch Region in the past. Although the historical record is incomplete, it is believed that such Tsunamis were destructive on the coasts MoreIn Western Coast of Gujarat destructive tsunamis have been generated from large earthquakes along the Makran Coast, Chagos Ridge and Kutch Region in the past. Although the historical record is incomplete, it is believed that such Tsunamis were destructive on the coasts of India, Pakistan, Iran, Oman and Sri Lanka and possibly had significant effects on Islands. The most significant tsunamigenic earthquake in recent times was that of 28 November 194521:56 UTC (03:26 IST) with a magnitude of 8.1 (Mw). In this paper an attempt is made for a numerical simulation of the tsunami generation from the Makran Subduction Zone, and its propagation into the Arabian Sea and its effect on the Dwarka city of Gujarat, India, through the use of a numerical model. It is observed from the results that the simulated arrival time of tsunami waves at the Dwarka is in good agreement with the available data sources. In this study more importance has been given to the run up height of tsunami waves, arrival time and inundation map. Also effect of different fault parameters on basic data is also studied. Manuscript profile -
Open Access Article
43 - Shear resistance of masonry panel in infilled RC frames
The shear capacity of masonry-infilled reinforced concrete (RC) frames is determined experimentally by testing of five 2/3scale, one story, one bay infilled RC frame specimens with varying degrees of separation between upper and lower portionsof the masonry infill panel MoreThe shear capacity of masonry-infilled reinforced concrete (RC) frames is determined experimentally by testing of five 2/3scale, one story, one bay infilled RC frame specimens with varying degrees of separation between upper and lower portionsof the masonry infill panel. The main premise of this experimental study was to find the contribution of masonry panel inglobal resistance of infilled RC frames versus shear force. Based on the experimental results, a new method is proposedfor the determination of the shear resistance and the contribution of the masonry infill panel is derived. Comparisons ofexperimental and analytical results show that the proposed method for evaluating the shear resistance of the masonry panelsoffers a promising approach for the design of infilled RC frames. Furthermore, the results of this study indicate that the shearresistance of masonry panel in infilled RC frames is strongly influenced by the stiffness and lateral resistance of the RC frame.Keywords Manuscript profile -
Open Access Article
44 - Evaluation of the Performance of Visco-elastic Dampers in Near-fault Earthquakes using Nonlinear Time-history Analysis
Rasoul Sabe-ahd Kolsum Jafarzadeh Mohammad Ali Lotfollahi-YaghinRecords from near-fault earthquakes to close the distance where the wave propagation source is a special property that their behavior makes them different from other records. Mostly near-fault earthquakes have strong pulse velocity (pulsatile wave) with great period acc MoreRecords from near-fault earthquakes to close the distance where the wave propagation source is a special property that their behavior makes them different from other records. Mostly near-fault earthquakes have strong pulse velocity (pulsatile wave) with great period accompanied with permanent deformation of earth. Velocity pulse occurs in horizontal component perpendicular to the motion surface of fault which is resultant of directionality effect of fault rupture. The properties of pulse such as velocity record in near-fault earthquakes cause the response spectrum to show non-ordinary behavior in pulse period. Also, due to imposing much energy to structure in during short period by these pulses, most of earthquake energy is absorbed in first made hinges instead of extension of non-linear behavior and plastic hinges in height of structure and the extension of non-linear behavior is not observed. This absorption of energy causes large relative inter-story displacements. Considering today’s using energy dissipation systems is current due to reducing earthquake vibrations of structures, which one of these energy dissipation systems are passive viscoelastic dampers. In these dampers which their energy dissipation mechanism depends on velocity of motion or in other words, on loading frequency and to be active these dampers there is no need to determined level of external excitation and they act in every earthquake. For this purpose, a number of structural models have been modeled in 2D form in "OpenSees" software for different damping ratios due to the added viscoelastic damper, non-linear dynamic analysis has been done under acceleration of horizontal earthquake and the amount of reduction of displacement response and base shear have been studied. Manuscript profile -
Open Access Article
45 - Shear strength and stiffness enhancement of cross‑stiffened steel plate shear walls
AbstractNowadays, the use of steel plate shear walls, as an effective seismic resisting system, has been of great interest in enhancingthe lateral strength and stiffness of buildings both in renovation and seismic rehabilitation of existing concrete and steelstructures. MoreAbstractNowadays, the use of steel plate shear walls, as an effective seismic resisting system, has been of great interest in enhancingthe lateral strength and stiffness of buildings both in renovation and seismic rehabilitation of existing concrete and steelstructures. In the present research, the shear strength and stiffness of steel plate shear walls in various configurations ofstiffeners, including horizontal, vertical, and horizontal–vertical, were investigated by finite element method and finallysemi-empirical relations were presented in this regard. The results indicated that the shear strength and stiffness of stiffenedSPSWs were well predicted by the proposed relations, but increasing the number of stiffeners above a certain range will nothave a significant effect on enhancing the stiffness and strength.Keywords Manuscript profile -
Open Access Article
46 - Performance Characteristics of Carbon-nanofiber Blended Self Compacting Concrete
Sivakumar M V NSemiconducting carbon nanofibers (CNF) are prepared from three different sources, i.e., acetylene, ethanol, and cotton by the chemical vapor deposition (CVD) process. These fibers are having rich elastic, engineering and conductivity properties. Fresh self-compacting co MoreSemiconducting carbon nanofibers (CNF) are prepared from three different sources, i.e., acetylene, ethanol, and cotton by the chemical vapor deposition (CVD) process. These fibers are having rich elastic, engineering and conductivity properties. Fresh self-compacting concrete (SCC) flows into place and around obstructions under its own weight to fill the formwork completely and self-compact, without any segregation and blocking. To obtain maximum benefit from SCC, it has to be adopted in general concrete construction practice. Such practice requires inexpensive and medium strength concrete. This investigation aims to develop a medium strength carbon nanofiber self - compacting concrete (CNFSCC), which improves the fracture resistance characteristics of the concrete. In addition to that, the mechanical and structural properties of self-compacting concrete containing carbon nano-fiber with different concentration are experimentally studied by conducting suitable tests. The test results indicate that the presence of a reasonable concentration of CNF not only enhances mechanical performance, but also improves the structural characteristics of SCC. Manuscript profile -
Open Access Article
47 - Monitoring Process Of The Re-construction Of An Ancient Structure: The Baluarte Do Cavaleiro
Jorge Pinto Humberto Varum João Guedes Anibal CostaThe Baluarte do Cavaleiro is part of the stone masonry wall system existing in the city ofChaves of Portugal and it is a construction dated from the XVII century. The Baluarte doCavaleiro is formed by three walls (North-East, NE; South-East, SE; South-West, SW) andby tw MoreThe Baluarte do Cavaleiro is part of the stone masonry wall system existing in the city ofChaves of Portugal and it is a construction dated from the XVII century. The Baluarte doCavaleiro is formed by three walls (North-East, NE; South-East, SE; South-West, SW) andby two junction elements (designated here by cunhais). The SE wall has suffered twocollapses recently. The main objective of this research work is to describe the monitoringprocess adopted to control the stability of the Baluarte do Cavaleiro and the adjacentconstructions that could be affected during the last rebuilding process of this wall. Takinginto account that this rebuilding process included the total removal of this wall, it was alsopossible to identify the real geometry of the cross section of the wall, its building solution andthe type of the sustained soil. It was also possible to contribute for a better understanding ofthe structural behaviour of this kind of stone masonry construction. Manuscript profile -
Open Access Article
48 - Performance Evaluation of Viscoelastic and Friction Passive Damping Systems in Vibration Control of Tall Buildings
Ehsan Noroozinejad FarsangiThis paper provides a comparison of the maximum inter-story drifts and tip acceleration of both a 16 and 30 stories building each with different structural systems; hybrid R.C moment frame with shear walls and hybrid steel frame with shear walls and X bracing which are MoreThis paper provides a comparison of the maximum inter-story drifts and tip acceleration of both a 16 and 30 stories building each with different structural systems; hybrid R.C moment frame with shear walls and hybrid steel frame with shear walls and X bracing which are equipped by passive dampers. Each of the building models were analyzed as fully non-linear structures for variety of dampers placements and subjected to a total of 4 different earthquake excitations. Three-dimensional (3D) finite-element models have been developed in the (FE) code LUSAS to predict the effects of passive damping on the vibrating structures. The manuscript tries to presents a rational comparison for determining dynamic response of seismic-excited high-rise buildings installed with friction and viscoelastic dampers in the cut outs of shear walls in order to capture their advantages in creating efficient damping systems. The results have shown that it is possible to achieve seismic mitigation, under all earthquake excitations, for all the structures considered in this study, by using appropriate damper types suitably located within the structure. Manuscript profile -
Open Access Article
49 - Lateral strength and ductility of reinforced concrete columns strengthened with NSM FRP rebars and FRP jacket
Fiber-reinforced polymer (FRP) wrapping of reinforced concrete (RC) columns is an effective way to improve their shearcapacity and ductility and prevent buckling in their longitudinal reinforcements. Another strengthening method called the nearsurface mounted (NSM) rein MoreFiber-reinforced polymer (FRP) wrapping of reinforced concrete (RC) columns is an effective way to improve their shearcapacity and ductility and prevent buckling in their longitudinal reinforcements. Another strengthening method called the nearsurface mounted (NSM) reinforcement has been proven effective in improving the flexural strength of RC columns. In thisresearch, the strengthening of RC columns with the combined use of NSM rebars and FRP jacket was studied using a finiteelement modeling approach. After validating the numerical models with the existing experimental data, a comprehensiveparametric study was performed to determine the effect of axial load, implementing the FRP confinement around the base orover the entire height of the column, the number of plies of FRP jacket, the type of jacket fiber, the ratio of NSM reinforcement,and the compressive strength of the concrete on the behavior of the strengthened RC columns. The results show thatthe optimum number of plies of jacket for reaching a desirable level of ductility can be determined by setting the maximumcompressive strain in the confined concrete, ccu , to 0.008. Increasing the ratio of NSM reinforcement from 0.16% of the totalcross-sectional area to 1% led to approximately 28% increase in the lateral strength and 50% decrease in the ductility factor. Manuscript profile -
Open Access Article
50 - Static, free vibration, and buckling analysis of plates using strain‑based Reissner–Mindlin elements
AbstractA quadrilateral and a triangular element based on the strain approach are developed for static, free vibration and bucklinganalyses of Reissner–Mindlin plates. The four-node triangular element SBTP4 has the three essential external degrees offreedom at eac MoreAbstractA quadrilateral and a triangular element based on the strain approach are developed for static, free vibration and bucklinganalyses of Reissner–Mindlin plates. The four-node triangular element SBTP4 has the three essential external degrees offreedom at each of the three corner nodes and at a mid-side node; whereas the quadrilateral element SBQP has the samedegrees of freedom at each of the four corner nodes. Both elements use the same assumed strain functions which are in thelinear variation where bending and transverse shear strains are independent and satisfy the compatibility equations. The useof the strain approach allows obtaining elements with higher-order terms for the displacements field. The formulated elementshave been proposed to improve the strain-based rectangular plate element SBRP previously published. Several numericalexamples demonstrate that the present elements are free of shear locking and provide high-accuracy results compared to theavailable published numerical and analytical solutions. Manuscript profile -
Open Access Article
51 - Effects of roof slope and wind direction on wind pressure distribution on the roof of a square plan pyramidal low‑rise building using CFD simulation
AbstractRoof shape and slope are both important parameters for the safety of a structure, especially when facing wind loads. Thepresent study demonstrates the pressure variations due to wind load on the pyramidal roof of a square plan low-rise buildingwith 15% wall open MoreAbstractRoof shape and slope are both important parameters for the safety of a structure, especially when facing wind loads. Thepresent study demonstrates the pressure variations due to wind load on the pyramidal roof of a square plan low-rise buildingwith 15% wall openings through CFD (Computational Fluid Dynamics) simulation. Many studies on roofed structures havebeen performed in the past; however, a detailed review of the literature indicates that the majority of these studies focusedon flat, hip, gable and spherical roofs only. There is a lack of research that analyses these effects on pyramidal roof buildings.ANSYS (Analysis System) ICEM (Integrated Computer Engineering and Manufacturing)-CFD and ANSYS Fluentcommercial packages have been used for modelling and simulation, respectively, and ANSYS CFD Post was used to obtainthe results. A realizable k–ε turbulent model was used for the pressure distribution on the roof of the building model. Inthe present study, twenty-four models with different roof slopes (α), i.e. 0°, 10°, 20°, and 30°, with various wind incidenceangles (ϴ), i.e. 0°, 15°, 30°, 45°, 60° and 75° were investigated. The influence of roof slope and wind incidence angle areanalysed in this study. Results have been represented through pressure coefficient (Cp) contours on the roof surface andvelocity streamlines of the flow field of the different cases. The optimization of the roof slope may be achieved by consideringdifferent wind incidence angles for buildings so that they may better withstand wind force in a specific area. When windpressure coefficients from building models with openings were compared with pressure coefficients from building modelswithout openings, it was found that the pressure coefficients for building models without openings are almost twice or threetimes that of the pressure coefficients for models with openings. Manuscript profile -
Open Access Article
52 - Embedded carbon fiber‑reinforced polymer rod in reinforced concrete frame and ultra‑high‑performance concrete frame joints
Shahnaz Basim Farzad Hejazi Raizal Saifulnaz Bin Muhammad Rashid1Beam–column joints play an important role in providing lateral stiffness and integrity of frames during dynamic loadingsuch as earthquake. In the high humidity areas, during functioning of the building cracks occur, which leads to the corrosionof the reinforcement MoreBeam–column joints play an important role in providing lateral stiffness and integrity of frames during dynamic loadingsuch as earthquake. In the high humidity areas, during functioning of the building cracks occur, which leads to the corrosionof the reinforcement due to the environmental exposures. Therefore, one of the main failures mechanism of building duringan earthquake is caused by easily yielding of corroded steel reinforcement, which leads to reduce functionality of the framejoints in transferring the loads. This study proposed a new design to reinforce the beam-column joints with embedded carbonfiber-reinforced polymer (CFRP) rods, due to their extremely high strength and stiffness, along with the fact that they willnot rust or corrode and very light weight. CFRP rods are used in reinforced concrete (RC) frame and ultra-high-performanceconcrete (UHPC) frame subjected to dynamic load. The prototype of the proposed design is constructed as frame with conventionalconcrete and frame with UHPC material to conduct experiments Test as well as numerical analysis to evaluate theperformance of the proposed joints under dynamic loads. The results showed improvement in the performance of the framesreinforced with embedded CFRP in joints in terms of lateral load resistance capacity, ductility behaviour, overall stiffness,and failure mechanism. Manuscript profile -
Open Access Article
53 - INVESTIGATING THE SEISMIC PERFORMANCE OF THE HONEYCOMB YIELDING DAMPER(HYD)
peyman shadman heidari Mohammad Ghanooni Bagha Zeinolabedi MortezaaliToday, the use of energy-dissipating system such as yielding metal damper in structures can improve the seismic performance of structures. One of the characteristics of metal yielding dampers is the ability to dissipate high energy and increase the ductility of the stru MoreToday, the use of energy-dissipating system such as yielding metal damper in structures can improve the seismic performance of structures. One of the characteristics of metal yielding dampers is the ability to dissipate high energy and increase the ductility of the structural system, which can improve the ductility and energy absorption characteristics of the metal frame equipped with braces and prevent the brace from buckling during an earthquake. The purpose of this research is introduce a new form of yielding dampers called honeycomb yielding damper (HYD) with different dimensions and thickness along with evaluating and comparing the force-displacement diagrams and investigating the seismic parameters of this type of yielding damper. All modeling and validation of numerical samples were done by Ansys software. Non-linear analysis method is used in this research. The hysteresis curves are obtained under in-plane cyclic loads. The mechanical parameters such as ductility ratio, initial hardness, effective hardness and damping coefficient can be determin. The results of this research showed that the effective stiffness increases by increasing the length and thickness of the sample. The ductility ratio decreases by increasing the height of the sample. the effective stiffness decreases by increasing the height of the sample. The ductility ratio increases by increasing the height of the sample. Also, the effective damping coefficient decreases with the increase in the height of the samples, the effective damping coefficient increases with the increase in length and thickness of the samples. Manuscript profile