Seven half-scale beams were tested to explore the impact of adding steel fiber (SF) on the flexural behavior of concrete beams reinforced with hybrid schemes. Key parameters included SF volume (0.00%, 0.50%, and 1.00%) and the steel-to-GFRP ratio in hybrid schemes (1.0 and 0.69). The presence of SF in the concrete beams, reinforced with hybrid schemes, enhances ductility while simultaneously increasing load capacity and stiffness. Load capacity increased by 13% and 21% for 0.50% and 1.00% SF, respectively. Toughness enhancements were 97.7% and 161% for the same SF volumes. SF presence led to higher strains in GFRP bars at ultimate levels, enhancing ductility and extending the warning range before failure. The experimental results underscore the effectiveness of combining hybrid schemes with steel fibers in RC beams. The flexural capacity of the tested beams and an additional 41 specimens from the literature was determined through a modified approach based on first principles. Experimental flexural capacities were compared to theoretical ones, with an average ratio of about 1.05, indicating a reliable measure for predicting flexural capacity.

The most frequent cause of reinforced concrete deterioration is corrosion of the steel reinforcement, especially in harsh weather. One of the promising materials for structural applications is fiber-reinforced polymer (FRP) material because of its non-corrosive nature. One of the most productions of FRP material is FRP bars which are used in reinforced concrete structures. FRP bars have many advantages such as high strength to weight ratio. This research aims to evaluate the ultimate capacity of reinforced concrete beams with FRP bars by using available specimens in the literature against Eurocode 2 (EC2) specifications and compared with ACI-440.1R-06 code. The results showed that EC2 code overestimates the ultimate moment capacity for 5 samples only (4% of the examined specimens) for normal strength concrete, while EC2 code overestimates the ultimate moment capacity for 16 samples (14% of the examined specimens) for high strength concrete. Therefore, EC2 is more conservative for predicting moment capacity of reinforced concrete beams with FRP bars for normal strength concrete than high strength concrete. On the other hands, ACI 440.1R-06 underestimated the ultimate moment of all concrete beams reinforced with FRP bars. Accordingly, ACI 440.1R-06 is more conservative for predicting moment capacity than EC2.

The evaluation of torsion investigations is based on the increasing demand for the creative design of curved structural members; yet, they are limited concerning lightweight concrete beams.Lightweight concrete has many and diverse utilizations, including multistory building frames and floors, curtain walls and bridges.This paper investigated the effect of fiber on torsional behavior of lightweight concrete beam.Many variables were studied such as compressive strength of lightweight concrete, fiber type, fiber volume ratio, spacing between stirrups, diameter of stirrups and CFRP reinforcement.The numerical results showed that the increment in fiber content resulted in better mechanical properties and torsional resistance of lightweight concrete beams.The effect of carbon fiber and steel fiber is evident from the volume ratio 2%, which produced the highest ultimate torque enhancement to 77.64% and 76 % respectively.In addition, a rational approach is proposed to predict ultimate torque to develop the torsion design of lightweight concrete beams.

The flexural behavior of concrete beams reinforced with hybrid reinforcing schemes is investigated experimentally in this work.The effects of steel fibers inclusion on the flexural behavior of concrete beams reinforced using hybrid schemes were investigated using four half-scale beams.The steel fibers content (0.00%, 0.50%, and 1.00%) was the main important parameter.The experimental results demonstrated that steel fibers inclusion significantly improved the ultimate load, stiffness, and toughness of concrete beams.Load capacity was enhanced by 13% and 21% for steel fibers volume ratios of 0.50% and 1.00%, respectively.Toughness improvements were 97.7% and 161% for steel fibers volume ratios of 0.50% and 1.00%, respectively.A non-linear finite element analysis (NLFEA) was performed to simulate the flexural behavior of RC beams reinforced with hybrid schemes.The loaddeflection responses and crack patterns of experimental specimens and numerical models were compared.The comparison showed a good agreement between the experimental and numerical results.The overall average value of the ratio between the experimental flexural capacities to the predicted capacities is about 0.94 and the standard deviation was of 0.028.

This research aims to investigate flexural behaviour of high performance concrete beams reinforced with Basalt Fibers Reinforced Polymers (BFRP) bars. Twelve half-scale concrete beams were tested under four-points bending. The experimental parameters are BFRP reinforcement ratios (0.58%, 0.87%, and 1.16%), and Polyvinyl alcohol (PVA) fibers ratios (0.0%, 0.5%, and 1.0%).The test results showed significant improvement in the load-carrying capacity of high performance concrete beams with PVA fibers compared to non-fibrous concrete beams, the improvements are 29% and 48% for PVA ratio of 0.5% and1.0% respectively. In the presence of PVA fibers, the ultimate strain of BFRP bars is higher than that recorded in the absence of PVA fibers. It confirmed the contribution of PVA fibers to the flexural strength of the concrete beams and the better use of the tensile strength of the BFRP bars. Furthermore, an analytical investigation based on strain compatibility method was carried out to predict the moment capacity and effective moment of inertia of PVA concrete beams reinforced with BFRP bars.

In this manuscript, structural testing was conducted on high-strength concrete slab specimens to investigate the behavior of such specimens when reinforced with a locally produced GFRP reinforcement. Subsequently, a finite element model (FEM) was constructed and validated against the experimental results. In the experimental phase, a total of eleven specimens (nine were reinforced with GFRP, while two were reinforced with conventional steel) were constructed and tested. The slabs dimensions are 700 mm × 1750 mm with variable thickness from 100 mm to 150 mm and different reinforcement ratios using different diameters. The structural behavior of the tested slabs was investigated in terms of ultimate load, ultimate deflection, load–deflection relationship, and crack pattern. Additionally, a nonlinear finite element model using the software ANSYS 2019-R1 was constructed to simulate the structural behavior of slabs reinforced with GFRP bars. The results obtained from the finite element analysis are compared with experimental results. The outcomes showed that the contribution of GFRP rebars in concrete slabs improved slab ductility and exhibited higher deflection when compared with traditional steel rebars. Good agreement between experimental and nonlinear analysis was obtained.

A theoretical study of the train induced vibrations to the nearby soil surface is presented. A practical case of railway embankment that includes four existing tracks and a proposed new fifth one at Berlin, Germany is investigated. The analysis is performed utilizing a coupled Boundary Element – Finite Element (BE-FE) method. An impulsive type unit load as well as a harmonic sinusoidal type load is applied on each track, separately. The obtained results show that the proposed new fifth track causes the highest surface response and the surface displacements exhibit large differences in phase and amplitude. Moreover, the resonance at the embankment fundamental frequency strongly amplifies the surface response. The existence of a vertical wall at the right side of the embankment results in strong amplification of the surface response at the right side. On the other hand, the inclined left edge gives longer wave path inside the soil leading to relatively low surface response.

This paper investigates the strengthening techniques of lightweight concrete (LWC) flat slabs vulnerable to punching shear failure. Thirteen reinforced LWC flat slab specimens were experimentally tested. The main investigated parameters were the type of shear reinforcement (steel bars, high strength bolts, or glass fiber reinforced polymers (GFRP) rods), spacing, shear reinforcement configuration around the column and the fixation method of shear reinforcement. The test results showed that using radial shear reinforcement with spacing of (d/2) resulted in the most efficient strengthening technique. The punching shear capacities were improved by 77%, 61% and 54% by using steel bars, glass fiber rods and high strength bolts, respectively, compared to the reference specimen. Moreover, using high strength steel bolts fixed to the slabs with steel plates showed the highest ductility compared with the other strengthening techniques Also, the failure mode converted from being brittle shear failure to flexural-shear mode. Non-linear finite element analysis (NLFEA) was carried out for the numerical verification. The analysis adequately reflected the trend of experimental results. Finally, the experimental test results were evaluated with code equations. The evaluation showed that the ACI 318 code underestimated the punching shear capacity of the tested specimens. On the other hand, Euro Code showed good prediction of the punching shear strength of the tested slabs.

Egypt has many monumentality masonry minarets; most of them were constructed in the last two centuries 19th and 20th. Many of these minarets suffer from material aging, deterioration, adverse environmental conditions and lack of maintenance. Concerns regarding the safety limits of these heritage structures take place, and the necessity for structural assessment activities currently are going on and the need for proper analysis that will address the actual behavior of the minaret is required.This paper presents the condition assessment and structural analysis of a heritage masonry minaret (Al-Rifa’i minaret), that represents a typical example of these kind of structure in Egypt. Its current condition is studied including identification of the building materials, evaluation of the actual deteriorated material properties and estimation of the current loading conditions. A finite element model has been created using ANSYS v.15 program with its nonlinear capabilities, different loads have been considered such as the structure own weight, wind and seismic loads in accordance with the local codes, static and dynamic loads have been applied to determine the worst expected loading case in order to assess minaret structural efficiency, safety margin and serviceability limits. A comparison between static and dynamic analysis is performed, also linear and non-linear analysis have been compared and the obtained results regarding stresses, deformations and cracking within the structure indicates overall stability and safety of the structure in its current condition.

The self-compacting concrete (SCC) is the newest innovating category of high performance concrete. The shear behavior of Fiber Reinforced SelfCompacted Concrete (FRSCC) deep beams was investigated. The experimental program consisted of twelve simply supported beams tested up to failure under four-point load. The key parameters covered in this investigation were steel fibers ratios (0.0, 0.50, 0.75 & 1.00%) and the effective shear span to depth ratio; a/d that varied from 0.6 to 1.0. Also, the main flexure reinforcement ratio was variable (1.0, 1.60 and 2.20 percent). In addition, vertical and horizontal web reinforcement effect was investigated. The midspan deflection, cracks, reinforcement and concrete strains of the tested beams were recorded and compared. Test results pointed out that the steel fibers enhanced the cracking load, ultimate capacity, displacement and energy absorption of the tested FRSCC deep beams. The utmost enhancement in the performance of deep beams was achieved with steel fibers content of 1.0% within the range of the test parameters. The enhancement in the ultimate capacity was 40%. The test results indicated that both vertical and horizontal web reinforcement are efficient in shear capacity enhancement of FRSCC deep beams. The ultimate shear capacity was increased by about 47% with increasing the longitudinal steel ratio from 1.0% to 2.2%. Maximum strain in the extreme compression fiber of concrete section was 0.0019 and achieved at specimen tested at a/d ratio of 0.6. A non-linear finite element analysis (NLFEA) model was constructed to simulate the shear behavior of tested beams, in terms of crack pattern and load deflection behavior. It can be concluded that a good agreement between the experimental and numerical Maher A. Adam, Mohamed Said and Tamer. M. Elrakib http://www.iaeme.com/IJCIET/index.asp 26 editor@iaeme.com results was achieved. The ratio of the predicted to the experimental ultimate strength ranged between 0.98 and 1.04.

Cairo Metro Network is one of the major national projects in Egypt. It aimed at developing underground transportation system to solve the severe traffic problems in Greater Cairo which includes 3 crowded governorates; Cairo, Giza and Qalyubia. The project started in the last decades of the twentieth century where 2 lines were executed. In this century, the project is expanding and more lines are constructed. The tunnel constructed for Cairo Metro Line 3 has a circular cross section that consists of a precast segmental lining thickness of 0.40 m. This paper presents a parametric study on the effects of seismic waves on the tunnel structure through numerous simulations employing the finite-element analysis. Full dynamic analyses were performed employing three different earthquake motions as well as the effect of train-induced dynamic load. Also, the induced tunnel straining actions were studied. The analysis of soil-structure interaction was done using the commercial software PLAXIS. The results proved that the 0.40 m thick circular cross section can safely sustain the expected static, dynamic and seismic stresses.

This paper presents an experimental and analytical study on the shear behavior of concrete beams reinforced with lab produced glass fiber reinforced polymers (GFRP) bars and stirrups. The bars and stirrups are manufactured by double parts die mold using local resources raw materials at lab. A total of ten beams measuring 120 mm wide, 300 mm deep and 1550 mm long were casted and tested up to failure under four-point load. The main parameters were concrete compressive strength and the vertical GFRP web reinforcement ratio in the form of the number of GFRP stirrups (without stirrups and with 8 @ 215, 8 @ 150 and 8 @ 100 stirrups). The mid-span deflection, inclined crack load and GFRP reinforcement bars and stirrups strains of the tested beams were recorded and compared. The test results revealed that the shear capacity increasing by 41% and 82% of the shear carrying capacity of beam without stirrups by using web GFRP reinforcement of 8 @ 215 and 8 @ 100 respectively. The shear capacity increased by 49% and 104% as the concrete compressive strength increased from 25 MPa to 45 MPa and 70 MPa respectively. The maximum value of measured strain in GFRP stirrups reached 0.0095. New approach to calculate FRP stirrups shear strength was proposed and verified throughout an assessment of experimental results of current study and previous works. The shear capacities of the tested specimens were calculated using the strut and tie models (STM) and non-linear finite element analysis (NLFEA). The average ratio of experimental shear capacity to calculated (V-exp/V-pred) using NLFEA and STM were 1.2 and 0.9 respectively. (C) 2015 Elsevier Ltd. All rights reserved.

Y. M. Hashem, A. A. Mahmoud, M. Adam, and A.S. Shanour 1 Professor of R.C. Structures, Civil Eng. Dept., Faculty of Engineering, Shoubra, Benha Univ., Egypt. 2 Professor of R.C. Structures, , Civil Eng. Dept., Faculty of Engineering , Shoubra, Benha Univ., Egypt. 3 Associate Professor, Civil Eng. Dept., Faculty of Engineering, Shoubra, Benha Univ., Egypt. 4 Demonstrator, Civil Eng. Dept., Faculty of Engineering, Shoubra, Benha Univ., Egypt. ARTICLE HISTORY Received: xx/xx/2010 Accepted xx/xx/2010 ABSTRACT A numerical procedure for the nonlinear analysis of infilled frames based on the finite element method is presented. The infill panel material nonlinearities due to cracking and crushing are considered using ANSYS® Program. An extensive survey of published work on general concepts of infilled frames under cyclic loading is presented. Numerical parametric studies have been conducted to investigate different factors affecting the behavior of reinforced concrete infilled frames under cyclic loading. A rational approach for equivalent diagonal strut is developed which can help in the design of reinforced concrete infilled frames.

Glass fiber reinforced polymers (GFRP) reinforcement bars has a lower stiffness than steel reinforcement, which should be accounted for the ultimate and serviceability conditions, including the impact on member deflection and crack widths. This paper presents an experimental study of the flexural behavior of concrete beams reinforced with locally produced glass fiber reinforced polymers (GFRP) bars. The bars are locally produced by double parts die mold using local resources raw materials. A total of seven beams measuring 120 mm wide x 300 mm deep x 2800 mm long were caste and tested up to failure under four-point bending. The main parameters were reinforcement material type (GFRP and steel), concrete compressive strength and reinforcement ratio (µ b, 1.7 µ b and 2.7 µ b). The mid-span deflection, crack width and GFRP reinforcement strains of the tested beams were recorded and compared. The test results revealed that the crack widths and mid-span deflection were significantly decreased by increasing the reinforcement ratio. The ultimate load increased by 47% and 97% as the reinforcement ration increased from µ b to 2.7 µ b. Specimens reinforced by 2.7 µ b demonstrated an amount of ductility provided by the concrete. The recorded strain of GFRP reinforcement reached to 90% of the ultimate strains.

The study addresses the influence of local soft valley sediment on incident wave propagation and the relative response of two adjacent bridge structures. In contrast to previous studies the effect of various angles and dominant frequencies of the incident waves and soil-structure interaction (SSI) is considered. The investigation reveals that the local soft soil can significantly alter the spatial variation and also frequency content of the surface ground motions. The simultaneous effect of soil-structure interaction and the spatially varying ground excitations due to inclined incident waves are significant for an adequate estimation of the damage potential of bridge girders due to poundings and insufficient seat length.

A numerical investigation on the effectiveness of open and in-filled trenches in reducing the building vibrations due to passing trains is presented. Particularly, a two-dimensional soil-structure system containing the cross-section of a railway embankment, the underlying soil, a trench barrier and a nearby six-storey building is considered. For the analysis, a time domain coupled boundary element-finite element algorithm is employed. Unlike most of the previous formulations, this model completely considers the soil-structure interaction effects and directly determines the effect of the wave barrier on the structural response. The effects of geometrical and material properties of the trench and its backfill material on the structural response are investigated. The results point out that using a trench barrier, a reduction level up to 80% of the building vibrations and internal forces can be achieved. Increasing the depth or the width of a trench may improve its reduction effect and a softer backfill material results in a better isolation effect.