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Squat-reinforced concrete (RC) shear walls with an aspect ratio of less than two are considered effective structural members, where shear is the dominant failure mechanism. Squat shear walls are widely used in nuclear power plants and building construction and feature optimal cost and outstanding performance, due to their lateral strength and high rigidity to resist lateral loads. However, since the accurate evaluation of the shear strength of squat shear walls must meet the design specifications, its calculation may be very complex, challenging, and inaccurate using experimental and theoretical equations due to many influential and overlapping design factors, so it takes more time and higher cost to determine it. This study uses machine learning (ML) methods to build a shear strength prediction efficient model for squat RC walls to address these issues. First, a huge dataset of 1424 RC squat wall test specimens gathered from the literature is utilized for developing an ML model, by employing XGBoost, to predict the shear strength. Results verified that the XGBoost model had the best accuracy and least error while assessing the squat walls' strength at shear. Moreover, an XGBoost optimum algorithm fared better than the empirical models based on mechanics, with a 99.2% accuracy. Finally, to prove that the model can identify the most important variables that significantly affect the shear strength, parameter and sensitivity analyses were performed and the results showed that the wall length is the factor that contributes most to the ultimate shear strength of the squat shear wall as a percentage (7.62%), followed by the yield strength. For the web as a ratio. (6.88%), concrete strength (6.75%), reinforcement ratio information (6.56%), and geometric properties (6.01%), while the axial load represents the smallest contribution, reaching (4.16%).

Earthquakes are sudden and unpredictable natural activity that causes severe damage. As a result of the increasing seismic activity in Iraq, it has become necessary to conduct a study on the impact of earthquakes and methods of damping them. Since traditional seismic damping methods for construction are very expensive, alternative solutions are necessary. Therefore, this research proposes a new damping method that depends on surrounding the piles with rubber crumbs, as the rubber works to dampen the seismic force before it reaches the piles before moving to the structure. This method is considered a type of sustainability. The study included a set of variables, including (the thickness of the rubber that surrounds the piles, and the position of placing the rubber that sleeved the piles). The tests were carried out using the shaking table device. The results showed that surrounding the piles with rubber gave distinct results in damping the seismic force and it is considered an easy damping method due to its ease of implementation, as well as its economic feasibility. The results showed for the models that surround the rubber in the upper part of the pile, an increase in the values of the acceleration of the structure and a decrease in the values of the movement speed of the structure, the values of the lateral displacement of the structure. The models in which the rubber surrounds the middle and bottom part of the pile, the results were close to the reference model.

Textile reinforced mortar (TRM) is mainly used for strengthening of existing structural members whereas, on the other hand Textile reinforced concrete (TRC) is a technology implied in construction of new members for enhancing the structural behaviour. Application of TRM on the tension zone of the reinforced concrete (RC) slabs to improve the flexural capacity has been investigated by many researchers in the past. However, the effectiveness of textile fabrics, used as internal reinforcement in the RC slab (TRC technology) needs to be studied. The paper, therefore, presents the experimental research conducted on three one-way RC slabs specimens reinforced using textile grid. An innovative Polyacrylonitrile (PAN) based carbon textile grid was used as internal reinforcement in combination with the steel bars. Two textile-reinforced RC slabs having one and two layers of textile grid (SRC + 1T and SRC + 2T respectively) and one reference slab (SRC) was fabricated to investigate the flexural behaviour under a four-point loading system. The internal textile reinforcement layer(s) was confirmed to be effective, particularly in terms of improving the cracking load, ductility, deformability and toughness. The material ductility of SRC + 1T and SRC + 2T slabs were increased by 41% and 44% compared to SRC slab. Also, the deformability ratio was found to be greater than 4, indicating a ductile failure of textile-reinforced slabs. Further, based on the load-deflection relation, moment-curvature curves were derived. Moreover, these curves were also developed using Eurocode two prediction model. The experimental and the predicted moment-curvature curves showed good agreement.

The application of textile reinforcement to the tension zone of the reinforced concrete slabs as a means to enhance flexural capacity has been investigated by researchers in the past. However, the effectiveness of adding short carbon fibers as internal reinforcement in the textile-reinforced concrete one-way slab needs to be studied. The paper presents the experimental research conducted on four full-scale (1500×500×50) mm one-way slabs. An innovative Polyacrylonitrile (PAN) textile grid was used as internal reinforcement in combination with short carbon fibers. The first one consists of fine-grained concrete and short carbon fibers. Two textile-reinforced RC slabs have eight layers of fabric (textile-reinforced concrete (TRC) 8 L) with two percentages of short carbon fiber (0.264% and 0.528%), and one reference textile-reinforced concrete slab without short carbon fiber was fabricated to investigate the flexural behavior under a four-point loading system. The findings indicate that TRC + short carbon fiber showed significantly improved flexural capacity, load-deflection, and load-concrete strain behaviors compared with TRC. The new TRC+ 0.264% short carbon fibers (SCF) and TRC+ 0.528%SCF improved the load-bearing capacity by about 24.19% and 31.56%, respectively, as compared with TRC. Also, the intensity of the crack pattern was measured to compare the ductility of TRC+ short carbon fiber to that of traditional TRC.

This paper represents experimental and numerical study the behavior of the rubberized steel frame connections. One single-bay, one-story without elastic buckling are cyclically tested. The experimental specimens are simulated and analyzed by the ABAQUS program. Four specimens of steel plane portal frame are investigated under horizontal reversed cyclic loads. The specimen connections are developed by using different diameters of composite steel bolts/rubber instead of conventional steel bolts to connect the beams with columns. The yield and ultimate strength, ductility, envelope curves, and damping ratio of these specimens are analyzed and compared. The finite element method is used to establish and verify the results of the laboratory test. The results of the experimental and numerical tests gave a large load-carrying capacity, reduction in the stresses, excellent ductility and energy dissipation capacity, and remarkably improved damping ratio.

An earthquake is a dangerous natural phenomenon that exposes buildings to collapse and human life to danger. Due to the weakness and cost of design and implementation by seismic design requirements. Therefore, a way must be found to reduce the impact of the earthquake risk, by using the smart joints technology in steel structures. Two experimental models were analyzed theoretically, The results showed a great convergence between the experimental and theoretical programs. The case study is a numerical study containing four rigid specimens that were analyzed in the ABAQUS / CAS (2017) program with applied a horizontal quasi-static cyclic load. The difference between these samples is the difference in thickness of the rubber washer used in the specimen where it is placed under the bolt head in the beam-column connection of the rigid steel frame. Two bolts connect the column with the angle, and the beam with the angle at the top, bottom, in both sides, and two bolts that connect the beam with the shear tab (ST), and in both sides too. Thus, the total number of bolts is twenty and the total number of rubber washer are forty. The results showed that the resistant load of the model containing rubber washer with the thickness (1,2,3 mm) in the beam-column connection increased by (11.5%, 33.8%, and 47.3%), respectively, as well as a significant improvement in the cumulative energy, the ductility residual displacement, The ductility index, The drift ratio, and the equivalent viscous damping compared to the model without rubber.

Textile reinforced concrete (TRC) has gained attention from the construction industry due to several characteristics such as its lightweight, high tensile strength, design flexibility, corrosion resistance and remarkably long service life. Some structural applications that utilize TRC components include precast panels, structural repairs, waterproofing elements and façades. TRC is produced by incorporating textile fabrics into thin cementitious concrete panels. However, in order to use this strengthening method in construction practice, a design model is required. Investigating the combined effect of conventional steel and textile reinforcement on the ductility behavior of composite TRC/RC one-way slab is vitally important. Therefore, the current study describes the proper methods of calculating the ductility of the composite concrete reinforced by a direct combination of conventional steel and textile reinforcement. Four methods are presented to calculate the ductility of the three considered one-way slab specimens. The three slabs having dimensions 1500 mm × 500 mm × 50 mm were reinforced by steel bars (SRC), by steel with one layer of carbon fabric (SRC + 1T), and by steel with two layers of carbon fabric (SRC + 2T). The three slab specimens were cast by the hand lay-up method, removed from the molds, cured, and then tested in flexure after 28 days using the four-point bending method. The obtained results and calculations revealed the non-reasonability of using the conventional method based on yielding of steel reinforcement as the only criterion in the ductility determination. The results also confirmed the suitability of using the energy-based method over other discussed methods in the calculation of the ductility for the hybrid reinforced members.

The existing buildings can be improved under the seismic effect by adding rubber to the bolts in the connection. The buildings when maintenance work is happening there is a problem many times and it should be evacuated and requires high cost. This study aims to maintain the building without having to remove it and at a very low cost compared to other methods. This study includes six models divided into two groups. The two groups differ in terms of the number of bolts in the contact area between the column and the beam in the steel frame. The first group models contain four bolts in the connection area and the second group forms contain five bolts in the contact area. Each group includes three models representing the first form of a reference model that has not rubber material around the bolts in the connection area, the second model contains 150% rubber than a bolt diameter around one bolt of the connection area, and all the bolts in the connection area in the third model are warped with rubber. The presence of rubber around one bolt gave a load, displacement, drifting, damping ratio, ductility index energy dissipation close to models where all contact bolts are warped with rubber material. Conclusion Based on the results presented in this research and the observations obtained from the numerical analysis, the conclusions drawn from this work can be summarized as follows: • When comparing the load and displacement value of the reference model and that contain rubber, note that the displacement value and the load value have increased significantly because the rubber is a hyperelastic material, and one of the properties of this material is to make the rubber within the elastic phase, as the model is deformed and then returns to its original position, where this principle is called (deformation recovery) and the rubber continues in this case until it reaches the stage of yield and then to the ultimate stage and failure occurs. • The presence of rubber around one bolt gives a similar drift rate to the case of wrapping all the fixing bolts with rubber • The ductility of the model that contains one rubber-coated bolt in the case of the 4 bolts is not very different from the model that contains 4bolts coating with rubber, but in the case of the 5 bolts, the ductility of the model that contains 5 rubber-coated bolts is higher than the model that contains one bolt is rubber-coated due to the increase in the displacement of the model. • For damping, the addition of rubber around all bolts in the connection improved the damping ratio a little more compared to the model containing rubber around one bolt in each contact of the models. • Rubber around one bolt can dissipate a sufficient percentage of energy compared to wrapping all fixing bolts with rubber. • Finally, through all the above calculations, can verify the validity of this study, which enables us to maintain the buildings by wrapping one bolt with rubber to make the building resistant to seismic effects, and this method will give a greater saving of time and cost than the other method used in building maintenance.

The aim of this research is to investigate experimentally the effect of adding shear connectors to the composite deck slabs which have various geometries of steel sheeting. The behavior and resistance of composite slab is basically depending on the development of longitudinal shear resistance. In this study six specimens of composite deck slabs which have different types of geometries of steel sheets (trapezoidal, triangle and T-shapes) with dimensions (1850mm x 500mm x 110mm) were casted and tested under four-point load in presence and absence of shear connectors in order to evaluate the behavior and longitudinal shear resistance of composite slabs. The results show that the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to increase ultimate load capacity by 22.2% and 17.8% respectively as compared with composite slabs without shear connectors while effect of adding shear connectors to the composite slab with T-shape was very little or can be neglected. As well as the adding shear connectors to composite slabs with trapezoidal shape and triangle shape act to decreasing the deflection as compared with the same load also act to enhance the general performance of slabs. Conclusion From the results of the tested composite slabs specimens, the following conclusions can be drawn: - • The presence shear connectors in composite slabs with trapezoidal shape and triangle shape act to increase ultimate load capacity by (22.2% and 17.8%) respectively as compared with composite slabs without shear connectors while the effect of adding shear connectors to the composite slab with T-shape was very little or can be neglected. • The adding shear connectors to the composite slabs with trapezoidal shape and triangle shape lead to decrease the deflection after slip happened as compared with the same load while the deflection in the composite slabs with T-shape was approximately same in presence and absence of shear connectors. • The development of strain in composite slabs with trapezoidal shape and triangle shape in presence shear connectors were more than absence of shear connectors while the ultimate strain in composite slab with T-shape was approximate same in presence and absence of shear connectors. • The adding shear connectors to composite slabs in specimens with trapezoidal shape and triangle shape act to development of maximum end slip to 6.404mm and 10mm respectively while the slip in specimens with T-shape was zero in all the stage o loading. • The composite slabs which have Triangle shape failed by flexural failure and showed full interaction whereas the composite slabs which have trapezoidal shape and triangle shape failed by horizontal shear failure and showed partial interaction.

Hollow sections of steel are widely used in many engineering applications as structural members. This paper aims at studying the flexural behavior of a composite beams with steel tubes sections through a series of bending tests in order to study and examine the influence of the steel tube section shape, (square, rectangular and hexagonal) with the same shear connector type (headed stud or angle or perfobond) on its flexural behavior and the bending properties of these sections. As well as study the effect of different shear connectors types (headed stud, angle and perfobond) in the same steel tube sections (hexagonal, square, or rectangular) on the flexural behavior of the composite beams. The experimental program (in this work) has been divided into two groups, the first consists of nine specimens tests focusing on three types of steel section. Using shear stud first, angle at second, and perfobond at third as shear connector type. The second group consists of testing nine specimens of composite beams too. This group focuses on testing every steel section (hexagonal, square and rectangular) alone when using three types of shear connectors with it. All the specimens are of the same length, width and height (2000, 400 and 130) mm respectively. The tested steel tubes thickness was 2 mm, yield stress of 322 MPa and the ultimate strength was 390 MPa. The results showed that these shapes of hollow steel sections (hexagonal, square and rectangular) sustain the quality of services for the buildings, and these tested specimens are applicable by giving a distinctive strength and stiffness starting from 114 kN as ultimate load reaching to 170 kN. The experimental results proved that the perfobond and angle connector types are clearly effective shear connectors. Shear connector of the perfobond type increased the ultimate load of the composite beams by (6.25-9.74) % compared with the stud shear connector.

The present study aimed at evaluating the mechanical performance under bending loads of circular hollow sections of steel. Different bending tests have been carried out by applying two-point loads, to determine and examine the effects of the diameter, the thickness of the section, and the span of the beam on the performance of the steel tube. The effects of square opening and variation in the number of openings on the performance of these sections have also been examined. Ten samples of hollow circular beams of varying thickness (2 mm, 3 mm, and 6 mm), varying diameter (76.2 mm, 101.6 mm, and 219 mm), and varying span (1000 mm, 1500 mm, and 2000 mm) were fabricated and tested for pre-failure and post-failure stages. The dimensions of the reference specimen considered were 3 mm in thickness, 101.6 mm in diameter, and 1500 mm in span. The results have shown that on increasing the section thickness by 200%, ductility and bearing strength were enhanced by 58.04% and 81.75%, respectively. Meanwhile, decreasing the section thickness by 67%, ductility and bearing strength were reduced by 64.86% and 38.87%, respectively. Moreover, on increasing the specimen diameter and on decreasing span, a significant increase in bearing strength and stiffness was observed; however, ductility was reduced. Meanwhile, on increasing the span of the specimen, all the parameters observed, i.e., bearing strength, stiffness, and ductility, decreased. On observing the ultimate strength of each specimen with square opening, the ultimate strength was reduced by 17.88%, 19.71%, and 14.23% for one, two-, and three-square openings, respectively. Moreover, the ductility was significantly reduced by 72.40%, 67.71%, and 60.88% for one, two-, and three-square openings/apertures, respectively, and led to the sudden failure of these specimens. The local buckling failure dominated for specimens having a D/t ratio more than 50 and showed very negligible levels of ovalization of the cross-section. Local buckling failure was observed to be prevented after providing the circular rings in the specimen, since bearing strength increased compared with the specimen without rings.

In recent years, steel-concrete composite shear walls have been widely used in enormous high-rise buildings. Due to their high strength and ductility, enhanced stiffness, stable cycle characteristics and large energy absorption, such walls can be adopted in auxiliary buildings, surrounding the reactor containment structure of nuclear power plants to resist lateral forces induced by heavy winds and severe earthquakes. The current study aims to investigate the seismic behaviour of composite shear walls and evaluate their performance in comparison with traditional reinforced concrete (RC) walls when subjected to cyclic loading. A three-dimensional finite element model is developed using ANSYS by emphasising constitutive material modelling and element type to represent the real physical behaviour of complex shear wall structures. The analysis escalates with parametric variation in reinforcement ratio, compressive strength of the concrete wall, layout of shear stud and yield stress of infill steel plate. The modelling details of structural components, contact conditions between steel and concrete, associated boundary conditions and constitutive relationships for the cyclic loading are explained. The findings of this study showed that an up to 3.5% increase in the reinforcement ratio enhanced the ductility and energy absorption with a ratio of 37% and 38%, respectively. Moreover, increasing the concrete strength up to 55 MPa enhanced the ductility and energy absorption with ratios of 51% and 38%, respectively. Thus, this improves the contribution of concrete strength, while increasing the yield stress of steel plate (to 380 MPa) enhanced the ductility (by a ratio of 66%) compared with the reference model. The present numerical research shows that the compressive strength of the concrete wall, reinforcement ratio, layout of shear stud and yield stress of infill steel plate significantly affect ductility and energy absorption. Moreover, this offers a possibility for improving the shear wall’s capacity, which is more important.

The composite shear wall has various merits over the traditional reinforced concrete walls. Thus, several experimental studies have been reported in the literature in order to study the seismic behavior of composite shear walls. However, few numerical investigations were found in the previous literature because of difficulties in the interaction behavior of steel and concrete. This study aimed to present a numerical analysis of smart composite shear walls, which use an infilled steel plate and concrete. The study was carried out using the ANSYS software. The mechanical mechanisms between the web plate and concrete were investigated thoroughly. The results obtained from the finite element (FE) analysis show excellent agreement with the experimental test results in terms of the hysteresis curves, failure behavior, ultimate strength, initial stiffness, and ductility. The present numerical investigations were focused on the effects of the gap, thickness of infill steel plate, thickness of the concrete wall, and distance between shear studs on the composite steel plate shear wall (CSPSW) behavior. The results indicate that increasing the gap between steel plate and concrete wall from 0 mm to 40 mm improved the stiffness by 18% as compared to the reference model, which led to delay failures of this model. Expanding the infill steel plate thickness to 12 mm enhanced the stiffness and energy absorption with a ratio of 95% and 58%, respectively. This resulted in a gradual drop in the strength capacity of this model. Meanwhile, increasing concrete wall thickness to 150 mm enhanced the ductility and energy absorption with a ratio of 52% and 32%, respectively, which led to restricting the model and reduced lateral offset. Changing the distance between shear studs from 20% to 25% enhanced the ductility and energy absorption by about 66% and 32%, respectively.

Circular hollow steel tube columns are widely used in high-rise buildings and bridges due to their ductility and lower weight compared to reinforced concrete. The use of this type of steel section has several advantages over using reinforced concrete members. The present study investigates the bending behavior of steel circular hollow sections when subjected to bending loads. The variations in material characteristics with regard to position along the cross-section of a steel tube member is first considered in this experimental study, providing for a more accurate definition of the material behavior in the model. A supported beam tested by two-point loads is the loading type that is used to study the bending performance of steel tubes. Ten circular hollow beam specimens were prepared and tested up to and post the failure stage with the following dimensions: thickness (2, 3, and 6 mm), diameter (76.2, 101.6, and 219 mm), and span (1000, 1500, and 2000 mm). A finite element analysis has been conducted for these ten specimens using the ANSYS program. The finite element model is compared to experimentally obtained data to verify that both local and global behaviors are correctly considered. The load-deflection results of this analysis showed a good agreement with the experimental results. A parametric study also was performed that considered two variables, which were the effect of the presence of circular rings and the change of opening location in the length direction on the specimens’ behavior. This study showed that the presence of the circular rings in the specimen led to an increase in its ultimate strength (of 53.24%) compared with the non-presence of these rings. In contrast, the presence of openings at 30, 40, and 50% from the specimen length reduced the strength capacity by 8.76, 14.23, and 17.88%, respectively.

The current paper aims to investigate the effect of steel tube thickness on the structural behavior of concrete composite beams with different steel tube sections. The experimental work of this study included a series of bending tests. The loading type used to study this effect on bending behavior of steel tubes was simply supported beam tested by two points load. Six composite beam specimens were performed and tested up to failure using three shapes of steel section (hexagonal, square and rectangular), every two specimens have the same shape of steel section. The type of shear connector was the headed stud for all specimens and to investigate the effect of thickness, this study used two thicknesses of steel tube sections of (2) mm and (3) mm. The tests showed improvement in the flexural behavior by increasing thickness of different steel section shapes, (50%) increasing in steel tube thickness led to increase the ultimate load by (32% - 34%). The ultimate slip at the ultimate load, for each specimen, is decreased by increasing the thickness of steel tube, the range of decreasing is ( 3.55% - 30.16% ).

Using Bubbles in the slab is a revolutionary method of eliminating concrete from the middle of conventional slab as this concrete does not perform any structural function, thereby dramatically reducing structural dead weight. This research presents experimental study to investigate the effect of construction type on the strength and behaviour of bubbled one-way slabs. The experimental program consists of testing four slabs with dimensions of 1850mm×460mm×110 mm. One1of the tested slabs was conventional slab (without bubbles), two bubbled slabs with different types of construction (simple and filigree bubbled slabs) and the remaining one is filigree bubbled slab strengthened with steel cage. The bubbles were made of recycled plastic balls. The experimental results show that the stiffness reduction factor for all the bubbled slabs was (0.87), this leads to decrease the ultimate strength of bubbled slabs and to be smaller than that of the solid slab by 4.4% 69% and 1.7% respectively. Also an increase in deflection at yield load (∆y) by about (10% to 12%), at the same time the crack load is found to be decreased by (13% to 40%). The simple bubbled slab is more efficient when compared with filigree bubbled slab. Also the results show that the use of steel cage in filigree bubbled slab gives an increase in the ultimate load by 69% and an increase in the ultimate deflection by about 77% when compared with filigree bubbled slab without steel cage.

The goal behind this research is to highlight on structural system using composite steel plate shear wall, this approach is widely used in many countries, due to its desired features. Composite steel plate shear wall are often considered essential in design of building to resist seismic action. This paper discuss the effect of concrete strength on behavior of CSPW, for this objective one story one bay model with different compressive strength (25, 28 , 45, 50, 55, 65)MPa ,this model formed by finite element code which is advanced by university of Amirkabir. The accuracy of the representation of the model by numerical analysis, numerical result contrast with valid experiment which explain suitable agreement. Result show increasing the compressive strength would advance the cycle behavior. By contrast the result in elastic region, it was seen initial stiffness is not enhance by varying the compressive strength.

In most designs of steel frames,beam-column connections are assumed either perfectly pinned or fully rigid. This assumption results in an incorrect estimation of the structural behavior of these frames. Practically, beam-column connections are between these two extreme assumptions and possess some rotational stiffness; therefore, it is called semi rigid connection. This research, presents a numerical analysis using finite element method to study the effect of semi-rigid connection on post buckling behavior of prismatic structural steel frames. The beam-column connection is modeled by linear elastic rotational spring element with specified rotational stiffness. The obtained results reveal that changing beam-column connection from rigid to semi rigid with different rotational joint stiffness values make the load-displacement curve of post buckling behavior less stiffer, the ultimate load decrease and ultimate vertical displacements increase with percentages depend on joint stiffness value and type of frame ;thus, semi-rigid connection should be considered in analysis and design of steel frames which exhibits post buckling behavior to obtain more realistic results.

The present research intended to determine thermal properties (thermalconductivity, thermal diffusivity and specific heat) of concrete manufactured by recycle waste of clay brick and thermostone for using it as aggregate after crushing process. For this purpose, three concrete mixes were prepared one of them using crushed clay brick as aggregate and two others were used crushed thermostone as aggregate too, these three mixes compared with reference normal concrete mix.Specific heat was measured by using semi-adiabatic calorimeter method whereas thermal diffusivity was measured by using heating-cooling system. Thermal conductivity was obtained by multiplying the thermal diffusivity, specific heat and density. From experimental laboratory work, it was concluded that the thermal diffusivity increase with concrete density increment, but the specific heat was decreased with concrete density increment. Thermal conductivity had a linear relationship with thermal diffusivity. Mixing ratio also had an influence on thermal properties of concrete.

Steel plate shear wall (SPSW) is commonly used in civil schemes because of its good deformability and stiffness. In this research, the numerical analysis of steel plate shear wall (SPSW) with unstiffened infill steel plate is conducted. This paper explains the effect of thickness variation of infill steel plate on behavior of steel plate. In this status, several samples are designed and checked by rigid frame and actuator. The experimental samples is joined to a rigid frame. 3 numerical specimens consist of steel plate shear wall with different thickness (1.5, 3, 4. 5) mm formed by finite element code which is advanced by the Amirkabir university. To confirm the model, numerical results were discussed with a valid experiment which explain suitable agreement. Numerical model tested under cyclic loading with frequency of 1/60 Hz. Results show that the increase of infill steel plate thickness enhance stiffness and ductility ratio of model. And so, would decrease energy absorption in comparison with the reference model

This paper presents an experimental investigation on the behavior of bubbled wide reinforced concrete beams with different shear steel plate spacing. Four specimens with the dimensions of 215x560x1800mm are investigated. The variables studied in this work is using the 10mm stirrups with 125mm spacing and 3mm thickness steel plate with spacing 125, 166 and 250mm instead of reinforcing stirrups. Shear steel plates is good alternative for replacing the stirrups and gives increasing in yield and ultimate loads with 17% and 18% respectively and decreasing the deflection by 8% at yield and 12% at ultimate. Moreover decrease the strain in longitudinal reinforcement by 8% at yield and 24% at ultimate, and reduced the total weight by 2.7%. By increasing the spacing of shear steel plate by 33% and 100%, the results showed that the yield load reduced to 3% and 4% respectively, but the deflection was increased with 37% and 20% (at yield). The strain in interior legs is more than the strain in exterior legs by 189%, 142% and 52% at yield for spacing 125, 166 and 250mm respectively. ACI 318-14 [1] and EC 2 [2] codes give a predicted deflection more than the experimental deflection by 26% and 30% on average respectively

This paper investigates the ovalisation behavior of the Steel Circular Hollow Sections (CHSs) when subjected to bending moment. The experimental program included testing of ten specimens in four groups in order to examine the influence of changing the diameter, thickness, length and the presence of openings on the ovalisation phenomenon of these specimens.The experimental results showed that the ovalisation of the specimen cross-section appears clearly when the diameter to thickness ratio (D/t) is ranging from 17 to 50, while the ovalisation of the specimens that have D/t ratio greater than 50 is very little or unclear because the instability of these specimens are controlled by the local buckling. In addition, the change of the specimen length and the presence of openings didn’t cause the cross-section ovalisation

This research was conducted to investigate the effect of using internal steel plates for shear reinforcement on flexural behavior of SCC beams instead of using traditional reinforcement bars (stirrups) and to study the effect of their spacing and thickness on strength. The experimental work included destructive tests on six SCC beams under two-point load. The results showed that the yield loads in all of the beams with steel plates were lower than the reference beam by (5.21%) on average, the deflection at yield load was higher by (13.72%) on average and the ultimate loads were lower by (6.77%) on average except in one beam where it was higher by (0.37%). It was also found that the ultimate deflection in beams with internal shear steel plates was lower by (10.01%) on average except in the aforementioned beam where it was higher by (2.31%). Ductility in all beams with steel plates was lower by (20.08%) on average and the strain before a load of (200kN) was higher in the longitudinal reinforcement and lower in shear steel plates and vice versa after a load of (200kN). Theoretical analysis was also carried out for all beams using the finite element program ANSYS (version 15) where theoretical results of load versus mid-span deflection relations, longitudinal reinforcement strain, shear reinforcement strain, variations of neutral axis depths and cracks patterns showed good agreement with experimental ones. Finally, some specific further studies were recommended.

In the present study, three-dimensional nonlinear finite element analyses were conducted to investigate the effect of several important parameters on the behavior of the external prestressed continuous composite steel-concrete beam. These parameters included the effects of concrete compressive strength, ratio of effective prestressing to ultimate stress (fpe/fpu), external prestressing technique, ratio of thickness to width of concrete slab (T/B), transfer load point to mid span section, type of loading, full and partial interaction, tendon profile, and number of stiffeners. It had been found that, at increasing the concrete compressive strength from (20 to 60MPa) and the ratio of prestress to ultimate stress from (0.264 to 0.79), the ultimate load was increased by about (19.64%) and (9.05), respectively. The ultimate load of a continuous composite beam with external prestressing was increased by about (26.63%) than the same continuous beam without prestressing. The increase in the ultimate load of the continuous beam subjected to three point loads on each span was (25.93%) larger than that of the continuous beam with a single load on each span. It was noted that the ultimate capacity was increased by (7.32%) when draped tendon profile was used. Also it was noted that the ultimate load of beam with full interaction is (3.25%) greater than the same beam with partial interaction. Increasing the thickness to width of concrete slab ratio, from (0.1 to 0.25) with constant area of concrete, led to an increase in the ultimate load by about (6.60%). It was noted that the ultimate capacity increased by about (8.25%) when number of stiffeners were increased from three to seven.

This paper presents an experimental investigation of the behavior of wide reinforced concrete beams with different shear steel plate spacing. Four reinforced concrete wide beams with the dimensions of 215x560x1800mm are investigated. The variables studied in this work are using the 10mm stirrups with 125mm spacing and 3mm thick steel plate with spacing 125, 166, and 250mm instead of reinforcing stirrups. Shear steel plates are a good alternative for stirrups and give identical results in yield and ultimate loads and increase the ductility by 55% and reduced the strain on the exterior and interior legs by 17% and 46% respectively compared with stirrups also reducing the total weight of wide beams by 2.7%. By increasing the spacing of the shear steel plate by 33% and 100%, the results showed that the yield load reduced to 5% and 12%, respectively, but the deflection was increased by 2% and 16%, respectively (at yield). The strain on interior legs is more than the strain on the exterior legs (having a spacing of 125, 166, and 250mm) by 31%, 70%, and 1% respectively. ACI 318-14(1) and EC 2(2) codes are given a predicted deflection less than the experimental deflection by 19% and 21% on average, respectively.

In this study, shear behavior of reinforced concrete wide beams was investigated experimentally. The experimental program consisted of four wide beams of 45 MPa concrete compressive strength tested with a shear span-depth ratio (a/d) equal to 4.52. One of the tested wide beams had web reinforcement as a control specimen, and the other three specimens had no transverse reinforcement but contained vertical shear steel plates. The flexure mode of failure was secured for all of the specimens to allow for shear mode of failure. The key parameters covered in this investigation were the effect of the existence solid and hollow vertical steel plates on the shear capacity of the tested wide beams. The study shows that the contribution of vertical steel plates to the shear capacity was significant and directly proportional to the existence and direction of the steel plates. The increase in the shear capacity ranged from 9.52% to 47.62% for the range of the tested beams compared with the control beam. Transverse vertical steel plates with voids were more effective in the contribution of the shear strength of wide beams and enhances the ductility of the wide beams.

This paper presents a numerical analysis using ANSYS finite element program to simulate the reinforced concrete slabs with spherical voids when subjected to five point load. Six slabs with length 1.0m, width 1.0m, height (0.1m and 0.125m) and simply supported were modeled. Nonlinear materials behavior, as it relates to steel reinforcing bars and plain concrete, and linear behavior for steel plate is simulated using appropriate constitutive models. The results showed that the general behavior of the finite element models represented by the load-deflection curves at mid-span, ultimate load, load-maximum concrete compressive strain curve, and crack patterns show good agreement with the test data from the experimental test. The finite element models represented by this work can be used to carry out parametric study for the BubbleDeck slab specimens

This paper presents a nonlinear finite element computer program. ANSYS version 12.0 developed for the analysis of composite steel-concrete beam. A three-dimensional finite element (FE) model has been developed in this work. The analytical results of load-deflection response have been compared with available experimental tests. In general good agreement between the finite element solutions and experimental results have been obtained. Parametric studies have been carried out to investigate the effect of some important material and geometrical parameters. These parameters included the effect of shear connectors number, concrete grade, thickness to width ratio of concrete slab, the ultimate load for shear connector and effect of yield strength of Steel beam. It was found that, as the compressive strength of concrete increases from 20 MPa to 70 MPa the ultimate load increases by about 20% and also an increase in the thickness to width ratio (t/B) of concrete slab from 0.1 to 0.3 lead to increase in the ultimate load by about 43%.

This paper presents the flexural capacities of R.C two way hollow slabs of plastic spherical voids, also known as BubbleDeck slab system. Recently, various types of slab systems which can reduce the self-weight of slabs have been studied as the height and width of building structures rapidly increase (1). A biaxial hollow slab system is widely known as one of the effective slab systems which can reduce the self-weight of slabs (1). A BubbleDeck slab has a two-dimensional arrangement of voids within the slabs to reduce self-weight (2). The behavior of BubbleDeck slabs is influenced by the ratio of bubble diameter to slab thickness. To verify the flexural behavior of this BubbleDeck slab such as ultimate load, deflection, concrete compressive strain and crack pattern, two-dimensional flexural tests were tested by using special loading frame. Six test of specimens were used. Two were a conventional RC slab and four were BubbleDeck slabs having void diameter to slab thickness ratios of (0.51, 0.64 and 0.80). Results have shown that the crack pattern and flexural behavior depend on the void diameter to slab thickness ratio. The ultimate load capacities for BubbleDeck slabs having bubble diameter to slab thickness of (0.٥1 and 0.64) were the same of solid slabs, while when bubble diameter to slab thickness of (0.80) the ultimate capacities were reduced by about (10%).

This paper focuses on the strengthening of reinforced concrete beams deficient in shear using external bonded Carbon Fiber Reinforced Polymer CFRP laminations. The CFRP laminations can be used to enhance the shear capacity of beams and to change the mode of failure from shear to flexure. The investigation is made in order to estimate the contribution of CFRP reinforcement to the shear capacity of strengthening reinforced concrete beams. The finite element method presented by ANSYS software used for modeling the reinforced concrete beam with CFRP strengthened. The model makes use of the ANSYS software abilities to evaluate the effects of number of parameters (CFRP strap height and thickness, carbon fiber direction with respect to beam longitudinal axis, concrete compressive strength, CFRP strip width and spacing) that are important in the response of the strengthened beam in shear. The numerical results are presented and discussed and conclusions drawn.