Papers by Abolfazl Arabzadeh
Advances in Civil Engineering
In most cases, openings are made in the Web of deep beams for installations to pass through. Thes... more In most cases, openings are made in the Web of deep beams for installations to pass through. These members require to be strengthened since the openings reduce load-bearing capacity. This study utilizes carbon fiber-reinforced polymer (CFRP) composites and steel protective frames (SPF) as strengthening configurations in reinforced concrete (RC) deep beams to improve the strength lost due to the square openings. To this end, eleven specimens with 10 × 50 × 120 cm in size were subjected to the three-point monotonic loading. In each beam, one or two square openings of 18 cm in each side are positioned either symmetrically or asymmetrically along the beam before it is strengthened with CFRP composites or SPFs. The strengthening composites were installed using externally bonded reinforcement (EBR) or externally bonded reinforcement on grooves (EBROG) techniques in two wrapped or inclined configurations. The obtained results indicate that specimens retrofitted by the SPF exhibited a super...
Using of composite materials in the structures has increased dramatically in the past two decades... more Using of composite materials in the structures has increased dramatically in the past two decades, due to the unique advantages of these materials such as high strength to weight ratio and selection of required material properties in desired directions. The composite materials commonly arecomposed frommultiplelaminates. Preciseknowledgeabout natural frequencies of the laminates is of particular importance for investigating their behavior. Classic theory is often used for analysing composite laminates whih does not onsider shear deformation. In this paper, several plates are modelled in ANSYS program and then frequency and mode shapes are calculated and compared with the exact solution in literature. After model validation, the laminates with different boundary conditions and different thickness are analyzed in ANSYS software and the result of Mindlin theory and classical theory are compared. The results show that for thickness to width ratioless than0.005, the fundamental frequency ...
The very early textbook of pediatrics: Tadbir-Al
Experimental study of fixed-ended RC deep beams under cyclic and monotonic loading
Canadian Journal of Civil Engineering, 2021
Reinforced concrete (RC) deep beams are commonly used in structural design to transfer vertical l... more Reinforced concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when there is a vertical discontinuity in the load path. Much experimental research has been conducted on simply supported deep beams, but little research has been carried out using monotonic loads. In our study, an experimental investigation was conducted to study fixed-ended reinforced concrete deep beams under cyclic and monotonic loads. Five specimens were experimentally tested. The specimens had similar geometry but different reinforcement details. Four specimens were tested under cyclic loads and one specimen under a monotonic load to observe the deflection of the mid-span where the load was applied, as well as the crack patterns, failure modes, and shear strengths. The results show that web reinforcements are more effective than longitudinal bars at increasing shear capacity in fixed-ended RC deep beams.
The Effects of Important Parameters on Buckling Strength of Continuous Beams with Monosymmetric I-Section in Bridges
Shear and Flexural Behaviour of Reinforced Conerete Continuous Deep Beams
The Effect of Opening on Mode Shapes and Frequencies of Composite Shear Wall
World Academy of Science, Engineering and Technology, International Journal of Civil and Environmental Engineering, 2014
Finite Element Study of Behavior of RC Bridge Beams Strengthened with CFRP
Plastic – Damage Modeling of RC Beams Under Torsion
Analisys of Deep Beams with Concrete of High-Strength Under Didtributed Loadng
A STM-based analytical model for predicting load capacity of deep RC beams with openings
Structures, 2021
Abstract Deep reinforced concrete beams constitute one of the most important structural members c... more Abstract Deep reinforced concrete beams constitute one of the most important structural members carrying large loads in long span structures that have been less investigated than ordinary beams due to their unconventional behavior. Due to their excessive height, deep beams often pose problems for the proper housing of mechanical and electrical installations that occupy rather large spaces or plumbing systems that pass through structural elements. As a remedy, openings are often needed in such beams that not only serve as a practical provision to house installations but also offer architectural advantages in the structure. Despite these advantages, the openings have serious adverse repercussion on the load-carrying capacity of the beams which, if not properly addressed, might cause grave damages to the structure. The present study introduces an analytical model based on the strut-and-tie method for estimating load-carrying capacity in simply-supported deep RC beams with rectangular or circular openings. The proposed model is capable of independently considering each of the different failure modes including that due to web crippling under load-bearing support sheets as well as flexural and shear failures to identify the dominant failure before it determines the failure mode of the specimen and to estimate, subsequently, the pertinent load-carrying capacity. Being based on the strut-and-tie method, the model relies for its accuracy on the accurate analysis of the strut model. Comparison of the model results and experimental measurements reported elsewhere reveals the accuracy of the proposed model in estimating the load-carrying capacity of deep RC beams. Verification of the model using measured results reported in the literature indicates mean predicted to measured load-carrying capacity ratios of 0.91 and 0.97 for beams with and without openings, respectively.
Structures, 2020
The end support of deep beams could have different effects on behavior of the beams. In this pape... more The end support of deep beams could have different effects on behavior of the beams. In this paper, experimental results of 43 deep beams with span-to-depth ratio of less than 3, different reinforcement arrangements and boundary conditions were investigated and discussed. Results indicated that, boundary conditions have important effects on ultimate loads, modes of failure and deflections; but crack formation and their patterns are almost the same irrespective of applied boundary conditions. Furthermore, the ultimate loads of the beams with fixed ends are 1.2-6 times of simply supported and continuous deep beams, depending on amount of main bottom and top reinforcements. Furthermore, in fixed-end deep beams, modes of failure and ultimate loads mostly depend on top main reinforcement. To examine the beams theoretically, available standards and published proposed methods were used. Results indicated that, none of existing methods is suitable for fixed-end deep beams, except proposed method. However, the methods proposed by ACI 318-14 and CIRIA Guide 2 yielded very conservative results for simply supported deep beams.
Structures, 2020
Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical l... more Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when, there is a vertical discontinuity in the load path. Due to their deep geometry, force distribution within the RC deep beams is very different from RC shallow beams. There are some Strut-and-Tie Models (STM) developed for RC deep beams. However, most of these models are developed for RC deep beams with simply supported boundary condition, not applying for RC deep beams with fixed-ended condition. In this paper, a novel curved STM was developed to simulate load capacity and failure mode of fixed-ended RC deep beams subjected to monotonic and cyclic point loads. Curved STM has double main struts and fan-shaped sub struts to simulate force distribution within the RC deep beams. Parameters of curved STM were calibrated using 5 fixed-ended RC deep beams subjected to monotonic and cyclic loads. Then, Calibrated model was compared to responses obtained from 31 additional independent experimental tests. Results showed that newly proposed curved STM is able to simulate load capacity and failure mode of fixed-ended RC deep beams very well.
Structures, 2020
Few relations were presented in the literature for computing the shear strength of prestressed co... more Few relations were presented in the literature for computing the shear strength of prestressed concrete deep beams. However, these relations have shortcomings to predict the ultimate load of such members. In this study, a new simple model based on Strut-and-Tie Model (STM) was put forwarded to obtain the ultimate load of prestressed reinforced concrete deep beams and seven specimens were tested experimentally. The effects of prestressing were considered by using an equivalent load and added members of the truss in the proposed model. This model can control the flexural, bearing and shear modes of failure. In order to verify the suggested model, the results were compared with experimental data. The accuracy of the proposed model was shown by the comparison of results.
International Journal of Engineering, 2019
Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical l... more Reinforced Concrete (RC) deep beams are commonly used in structural design to transfer vertical loads when there is a vertical discontinuity in the load path. Due to their deep geometry, the force distribution within the RC deep beams is very different than the RC shallow beams. T here are some strut and tie model (STM) already been developed for RC deep beams. However, most of these models are developed for RC deep beams with the simply supported boundary condition, which do not apply for RC deep beams with the fix-ended condition. In this paper, five fixed-end RC deep beams have been tested experimentally which were subjected to monotonic and cyclic loads. Also, a simple ST M was proposed to simulate the load capacity and failure mode of fix-ended RC deep beams. T he proposed ST M has the main strut and sub struts to simulate the force distribution within the RC deep beams. T his ST M were verified using five fixed-end RC deep beams subjected to monotonic and cyclic loads and compared to the response of 31 additional independent experimental tests. T he result shows the newly proposed ST M can simulate the load capacity and failure mode of fix-ended RC deep beams very well.
Construction and Building Materials, 2019
h i g h l i g h t s EBR and EBROG methods have been utilized to install the FRP sheets on deep be... more h i g h l i g h t s EBR and EBROG methods have been utilized to install the FRP sheets on deep beams with openings. EBROG is the most effective method in preventing the debonding of sheets. The inclined orientation of sheets is the most effective configuration among the installation methods.
Iranian Journal of Science and Technology, Transactions of Civil Engineering, 2016
Coupled walls are known to be efficient lateral load-bearing systems. Coupling beam and wall pier... more Coupled walls are known to be efficient lateral load-bearing systems. Coupling beam and wall piers are two important and effective elements in the general response of these structures. In this paper, stiffness effect of steel coupling beams on boundary elements in coupled shear walls has been investigated. The provisions of Iranian National Building Code for concrete structure (INBC-No. 9) for evaluating detailing requirements at wall boundaries are based on studies on uncoupled continuous walls, in which stress distribution across sections is assumed to be linear and in un-cracked sections. Due to the fact that there have been severe axial forces on wall piers resulting in the creation of cracks in sections of tension walls, the applicability of these provisions in coupled walls should be evaluated. Several coupled wall structures with different geometrical specifications, representative of various ratios of stiffness of the coupling beam to stiffness of the wall (RSBW), under equivalent lateral force, were designed, and efficiency of the code provisions was investigated in comparison with the results of the numerical analysis in Abaqus software. In this analysis, nonlinear behavior of material was considered. Results show that for structures with large and medium RSBW, code provisions are not appropriate in evaluating detailing requirements of tension wall boundaries, and a nonlinear stress distribution on the section should be used. For compression walls and structures with low RSBW, code provision is reliable.
Strut-and-Tie Model (STM) can be used to model the flow of compression within a concrete strut. C... more Strut-and-Tie Model (STM) can be used to model the flow of compression within a concrete strut. Concrete struts are formed in various shapes such as prismatic or bottle-shaped. In order to study the behavior of concrete struts, a series of simple tests were performed. Eighteen reinforced concrete isolated struts with compressive strength of 65 MPa were tested up failure under point loading in the plane of specimens. The tested specimens were reinforced by various reinforcement layouts. The behavior of tested beams was investigated. Observations were made on transverse displacement, primary cracking and ultimate failure load and distribution of strain on the face of tested panels. Based on these observations, the geometry of the concrete struts was examined. a new model to analysis of concrete struts was proposed based on modified compression field theory (MCFT). A database of 44 tested specimens was compiled to evaluate the proposed model. The results indicate that using the ACI and CSA codes expressions regarding the amount of minimum required reinforcement in a strut produces conservative but erratic results when compared with the test data. Conversely, the new proposed model presents a more accurate prediction for the strength of 44 tested struts.
Composite steel shear wall is a lateral load resisting system that consists of steel plate as a p... more Composite steel shear wall is a lateral load resisting system that consists of steel plate as a primary component with concrete wall (cover) attached to one side or both sides of the plate to prevent it from elastic buckling. The composite action of the system is ensured by using high-strength bolts. This paper investigates the effects of the distance between bolts on the behavior of the system. For this purpose, 14 one story one bay specimens with various distances between bolts were modeled and analyzed in the finite element software ABAQUS. To verify the ability of the model, numerical results were compared with a valid experiment, which shows very good agreement. Results demonstrate that increasing distance between bolts would improve the seismic behavior of the system. However, this increase in distance should be limited, since permission to widespread buckling of steel plate in free subpanels between bolts would result in no more improvement of the behavior. By comparing the results in elastic region, it was clearly observed that the initial stiffness of the system is not affected by changing the distance between bolts.
The Open Construction and Building Technology Journal, 2014
The performance of the interface between fiber reinforced polymer (FRP) composites and concrete i... more The performance of the interface between fiber reinforced polymer (FRP) composites and concrete is one of the key factors affecting the behavior of strengthened reinforced concrete (RC) structures. Existing laboratory research has shown that RC beams strengthened with FRP sheets usually fail because of either debonding of the impregnated fabric from the concrete substrate or fracture of the FRP. This work presents an experimental and analytical investigation of the effectiveness of FRP strengthening sheets on RC beams aiming at increasing their flexural strength and stiffness. Experimental results obtained from beam specimens tested under four-point bending are examined with main parameters being the resin type and the anchoring system. In addition, the procedure suggested by the EC8 - Greek Assessment & Retrofitting Code (EC8-GARC) provisions is applied and compared with the experimental results.
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Papers by Abolfazl Arabzadeh