Effect Of Reinforcement Ratio Research Articles

Serviceability Assessment of Continuous Beams Strengthened by SMA Strands under Cyclic Loading

Since the wide cracks or large deflections can have a significant effect on the appearance of concrete elements and may cause some uncommon behavior, therefore, serviceability of concrete structures requires investigation. The main objective of this paper is to study experimentally the serviceability of continuous reinforced concrete (RC) beams strengthened by Ni-Ti strands. In addition, some building code provisions were used to calculate crack width and deflection. The current study presents the experimental results to verify the accuracy of building codes’ provisions for continuous RC beams strengthened by SMA strands. Although a pattern of smaller width cracks was monitored for strengthened beams, more than 50% of the crack widths were recovered because of super elastic SMA strands. The performance of crack width provisions illustrates an overestimated crack width for SMA RC beams. Moreover, the predicted values for immediate deflections based on building codes provided a good agreement, although the effective reinforcement ratio (steel reinforcement and SMA strands) had a significant effect on immediate deflections of reinforced concrete beams strengthened by SMA strands under service loads.

Effect of Reinforcement Ratio on Physical and Mechanical Properties of Cu-W Composites Synthesized by Ball Milling

Effect of Reinforcement Ratio on Physical and Mechanical Properties of Cu-W Composites Synthesized by Ball Milling

Reliability research analysis on crack control standard for steel lined reinforced concrete penstocks

In view of the insufficiency of research about steel lined reinforced concrete penstocks in hydropower station crack control standard, the Monte Carlo method was combined with the crack width calculation formula of Dong Zhe-ren method to establish a reliability calculation method. According to the engineering example and model test parameters, the reliability index of the crack control standard for steel reinforced concrete penstocks in China were calculated, and the main influence factors were concluded. Studies indicates that the reliability level of crack control for steel lined reinforced concrete penstocks is of medium level or slightly lower. The influence of crack width limit, cover thickness and the effective reinforcement ratio on reliability level of crack control standard is significant.

Homogeneous Substitute Material Model for Reinforced Concrete Modeling

Abstract This paper outlines a method of determining the deformation and strength parameters for a hypothetical, homogeneous, substitute material which approximates the properties of heterogeneous materials in reinforced concrete elements. The model of the substitute material creates a concrete reference model, in which the static - strength - deformation parameters were modified on the basis of the homogenizing function with the homogenization coefficient assumed as the effective reinforcement ratio of the reinforced concrete structural elements. The results of the comparative analysis of the numerical models using the hypothetical substitute material with experimental results for statically loaded beams and deep beams taken from the literature are presented.

Study on crack development of concrete beams in bending reinforced with FRP bars

The comparatively high tensile strength and low elastic modulus of fiber reinforced polymer (FRP) bars result in deflection and crack width requirements controlling the design of concrete beams reinforced with FRP bars. Consequently, when it comes to the design of such members, the deflection and crack width are first calculated at serviceability limit state, and then are checked at ultimate limit state. In this paper, five concrete beams reinforced with different FRP reinforcement ratios were tested and the crack development and pattern as well as the effect of reinforcement ratio on crack width and spacing were analyzed. The experimental results were compared with the calculation results using design guidelines recommended by Japan JSCE code, American ACI440.1R-03 code and China GB50608-2010 code. Several design suggestions were proposed for bending concrete beams reinforced with FRP bars.

Effect of reinforcement ratio on the flexural performance of hybrid FRP reinforced concrete beams

Abstract Fiber reinforced polymer (FRP) is widely used in concrete structures due to its high tensile strength and superior corrosion resistance. However, the FRP reinforced concrete (FRPRC) shows a less ductile behavior compared to the conventional steel reinforced concrete. In order to improve the strength and flexural ductility simultaneously, a hybrid reinforcement system composed of FRP and steel bars has been proposed and adopted in design recently. In hybrid FRPRC beams, FRP and steel reinforcements play different roles in improving strength and ductility. The hybrid reinforcement ratio between FRP and steel, Af/As, has a significant influence on the flexural performance of hybrid FRPRC beams as it affects the balance between strength and ductility in the flexural design. Here, the effect of hybrid reinforcement ratio on the flexural performance of concrete beams in both under- and over- reinforced scenarios is studied using three-dimensional finite element models. The results from the finite element models show that a preferable strength and ductility performance can be obtained through an appropriate design of hybrid reinforcement ratio. Such information helps us determine an appropriate range of hybrid reinforcement ratio and provide a design guideline for hybrid FRPRC beams for optimizing the strength and ductility performance.

Effect of reinforcement ratios on shear behavior of concrete beams strengthened with CFRP sheets

Carbon fiber reinforcement polymer (CFRP) sheets are the most commonly materials that are used to strengthen reinforced concrete members due to high strength-to-weight ratio, excellent mechanical strength, and good fatigue properties. In this research program seven reinforced concrete beams were tested under four points loading with different shear span-to-depth ratios avd, longitudinal and vertical reinforcement ratios. A numerical analysis using ANSYS software program was done by modeling 27 reinforced concrete beams with and without CFRP sheets. The beam dimensions, concrete strength, strengthening configuration of the CFRP sheets (full wrapped, U shape, and side bonding), and FRP thickness were considered as the main parameters of the numerical analysis. A comparison between the finite element (FE) results and the ACI standard code demonstrated the validity of the computational models in capturing the structural response of FRP contribution with variation varied from (10–16)%, (12–20)% and (13–19)% for full wrapping, U-jacketing, and side bonding, respectively. The finite element models were able to accurately predict the load capacities for the simulated RC beams strengthened in shear with CFRP composites. The results obtained using ANSYS finite element are relatively identical to the experimental ones, showing reasonable agreement with variation not more than 5% in all the specimens.

An Experimental Study of the Dynamic Split Tension Properties of Reinforced Concrete

Dynamic split tensile tests of reinforced concrete were carried out using the split Hopkinson pressure bar experimental technique to determine the failure modes of reinforced concrete at different strain rates, and the effect of reinforcement ratio and reinforcement layouts on the dynamic performance. The specimens with nine reinforcement ratios were used in the tests. Experimental results show that the tensile strength of reinforced concrete exhibits a critical strain rate, beyond which a larger increase in dynamic strength of specimens occur. The dynamic split tension strength of reinforced concrete is demonstrated to be greater than the plain concrete with the same strength grade over the range of tested strain rates. The results also indicate that the dynamic split tension strength of specimens enhances with the increase in the reinforcement ratio. These findings are instrumental to guide the structural design of reinforced concrete in engineering applications.

Finite Element Modeling of GFRP-Reinforced Concrete Interior Slab-Column Connections Subjected to Moment Transfer

A finite element model (FEM) was constructed using specialized three-dimensional (3D) software to investigate the punching shear behavior of interior slab-column connections subjected to a moment-to-shear ratio of 0.15 m. The FEM was then verified against the experimental results of full-scale interior slab-column connections reinforced with glass fiber reinforcement polymer (GFRP) bars previously tested by the authors. The FEM results showed that the constructed model was able to predict the behavior of the slabs with reasonable accuracy. Afterward, the verified model was used to conduct a parametric study to investigate the effects of reinforcement ratio, perimeter-to-depth ratio, and column aspect ratio on the punching shear behavior of such connections. The test results showed that increasing the tested parameters enhanced the overall behavior of the connections in terms of decreasing deflections and reinforcement strain and increasing the ultimate capacity. In addition, the obtained punching shear stresses of the connections were compared to the predictions of the Canadian standard and the American guideline for FRP-reinforced concrete structures.

Microstructural characterization and wear properties of in situ AlB2–reinforced Al–4Cu metal matrix composite

Aluminium matrix composites have been extensively studied for several decades due to the potential advantages over classical low-density materials. Low-density composites can offer high wear and corrosion resistance, high strength, and favorable thermal electrical properties that attract the attention of various industries such as aerospace and automotive. This study investigates the dry sliding wear behavior of AlB2–Al–4Cu composites with 5, 10, 20, and 30% weight reinforcement. In situ developed AlB2 flakes were incorporated as the reinforcing compound in the Al–4Cu matrix. The composite samples were tested against a steel disk using a pin-on-disk wear rig. The effect of reinforcement ratio, applied load, sliding velocity on the wear rate and friction coefficient of the composite samples was investigated. In addition, the worn surfaces have been characterized in terms of wear patterns. Compared to the matrix alloy, composite samples exhibited better wear resistance and lower friction coefficient to varying degrees of magnitudes.

Modeling of the Prediction of Densification Behavior of Powder Metallurgy Al–Cu–Mg/B4C Composites Using Artificial Neural Networks

Al–Cu–Mg/B4Cp metal matrix composites with reinforcement of up to 20 wt% were produced using the powder metallurgy technique. The effects of reinforcement ratio, reinforcement size, milling time, and compact pressure on the density and porosity of the composites reinforced with 0, 5, 10, and 20 wt% B4C particles were studied. Moreover, an artificial neural network model has been developed for the prediction of the effects of the manufacturing parameters on the density and porosity of powder metallurgy Al–Cu–Mg/B4Cp composites. This model can be used for predicting the densification behavior of Al–Cu–Mg/B4Cp composites produced under reinforcement of different sizes and amounts with various milling times and compact pressures. The mean absolute percentage error for the predicted values did not exceed 1.6%.

Discussion of “Effect of Reinforcement Ratio on Transverse Early-Age Cracking of GFRP-RC Bridge Deck Slabs” by Amir Ghatefar, Ehab El-Salakawy, and M. T. Bassuoni

Discussion of “Effect of Reinforcement Ratio on Transverse Early-Age Cracking of GFRP-RC Bridge Deck Slabs” by Amir Ghatefar, Ehab El-Salakawy, and M. T. Bassuoni

Closure to “Effect of Reinforcement Ratio on Transverse Early-Age Cracking of GFRP-RC Bridge Deck Slabs” by Amir Ghatefar, Ehab El-Salakawy, and M. T. Bassuoni

Closure to “Effect of Reinforcement Ratio on Transverse Early-Age Cracking of GFRP-RC Bridge Deck Slabs” by Amir Ghatefar, Ehab El-Salakawy, and M. T. Bassuoni

Effects of reinforcement ratio and arrangement on the structural behavior of a nuclear building under aircraft impact

This study presents the effectiveness of the rebar ratio and the arrangement of reinforced concrete (RC) structures on the structural behavior of nuclear buildings under aircraft impact using a finite element (FE) approach. A simplified model of a fictitious nuclear building using RC structures was fully modeled. The aircraft model of a Boeing 767-400 was used for impact simulation and was developed and verified with a conventional impact force–time history curve. The IRIS Punching test was used to validate the damage prediction capabilities of the RC wall under impact loading. With regard to the different rebar ratios and rebar arrangements of a nuclear RC building, the structural behavior of a building under aircraft impact was investigated. The structural behavior investigated included plastic deformation, displacement, energy dissipation, perforation/penetration depth and scabbing area. The results showed that the rebar ratio has a significant effect on withstanding aircraft impact and reducing local damage. With four layers of rebar, the RC wall absorbed and dissipated the impact energy more than once with only two layers of rebar for the same rebar ratio.

스터럽이 없는 GFRP 보강근 콘크리트 보에 대한 실험적 연구

This paper evaluates the shear strength, behavior and failure mode of reinforced concrete beams with deformed GFRP reinforcing bar. Four concrete beam specimens were constructed and tested. It was carried out to observe failure behavior and load-deflection of simply supported concrete beams subjected to four-point monotonic loading. In order to eliminate of the uncertainty by the shear reinforcements, any stirrups were not used. Variables of the specimens were shear span-depth ratio, effective reinforcement ratio. The dimensions of specimen is 3,300 or . Clear span and shear span were 2,900mm, 1,000mm respectively. Shear span-depth ratios were 6.5 and 2.5. Effective ratios of Longitudinal GFRP reinforcing bar were , , and . All beam specimens were broken by diagonal-tension shear and the ACI 440.1R, CSA S806 and ISIS, which was used to design test beams, showed considerable deviation between prediction and test results of shear strengths.

Effect of Reinforcement Ratio on Transverse Early-Age Cracking of GFRP-RC Bridge Deck Slabs

AbstractBecause concrete bridge deck slabs are much longer in the traffic direction, they experience transverse early-age cracks due to volumetric instability and restraint. In the last decade, the use of the noncorrodible fiber-reinforced polymer (FRP) bars in concrete bridges has significantly increased. This paper presents the experimental results of four full-scale, cast-in-place glass FRP–reinforced concrete (GFRP-RC) deck slabs, subjected to early-age shrinkage. The slabs measured 2,500 mm long×765 mm wide×180 mm thick. The longitudinal reinforcement ratio (0.30, 0.50, 0.70, and 1.1%) was the main parameter investigated in this study. The test results were presented in terms of cracking pattern, width and spacing, strains in both GFRP bars, and concrete over a period of 90 days after casting. The experimental results were compared with provisions and predictions from a published analytical model. It was concluded that the published numbers can reliably provide a minimum reinforcement ratio for br...

The Effect of Reinforcement Ratio on the Wear Behaviour of AlB2Flake Reinforced Metal Matrix Composites

Aluminium boride composites (Al AlB2) having two di erent volume fractions of reinforcing (AlB2), namely 4.0 and 10.0 per cent have been produced through synthesizing boron by reaction of boron oxide (B2O3) with liquid aluminium. Friction and wear characteristic of the composites have been investigated under dry sliding condition and results compared with pure aluminium. The wear rate increases with normal load and sliding speed and is signi cantly lower with the composites when compared to that of monolithic material. The coe cient of friction increased with increasing volume fraction of AlB2 reinforcement phase. The wear rate, however, decreased with increasing volume fraction of AlB2.

Effect of Reinforcement Ratio and Distribution on Penetration Resistance of Reinforced Concrete Panels: Numerical Simulation

Reinforced concrete protective layers of fortified structures are considered key points in resisting missiles penetration. Ferrocement is a highly versatile form of concrete reinforced with wire mesh reinforced in two directions. This type of reinforcement provides isotropic properties in two directions, high tensile strength, and high modulus of rupture. It also results in larger bond forces and reduces crack spacing and width compared to conventional reinforced concrete. Accordingly, concrete panels (550 x 550 x 300 mm) are reinforced with expanded steel mesh instead of the conventional steel bars and tested through numerical simulation to study the parameters affecting penetration resistance. A Nonlinearthree-dimensional hydrocode numerical simulation was carried out using AUTODYN 3D, which is an extensive code dealing with penetration problems. In the simulation, steel ogivenose projectile with a diameter of 23 mm is fired against concrete panels with striking velocity 990 m/s. Twelve numerical tests were carried out to study the parameters that significantly affect the penetration resistance of reinforced concrete panels. The parameters included are the reinforcement ratio; reinforcement position; and reinforcement distribution. The results showed that using the ferrocement wired mesh decreases the size of damage in the front and rear face of the panels. Increasing the reinforcement ratio has insignificant impact on the penetration resistance while the position and the distribution pattern of reinforcement proved to relatively enhance the penetration resistance.

Cracking of RC members revisited: influence of cover, ϕ/ρs, ef and stirrup spacing – an experimental and theoretical study

AbstractThis article describes an experimental programme aimed at studying the effect of cover, ratio between diameter and effective reinforcement ratio (ϕ/ρs, ef) and the influence of stirrup spacing on the cracking behaviour of reinforced concrete elements. The experimental programme was conceived in order to contribute to the debate – fuelled by the publication in recent years of Eurocode 2 EN1992‐1‐1 and the revision of the Model Code under way when the tests were carried out (and now published as a finalized document) – regarding the influence of these parameters on cracking. Important theoretical aspects are discussed, including where the crack width is estimated by current code formulations and what relevance this may have on the correlation between crack opening and durability of RC structures, especially with regard to structures with large covers. The effect of stirrup spacing, a variable absent from current codes, is also discussed.

Seismic Behaviour of RC Columns Strengthened with Steel Bar/Wire Mesh Mortar

In order to enhance the seismic behavior of reinforced concrete (RC) columns more efficiently, a thought to strengthen concrete columns by using steel bar/wire mesh mortar （FS）was proposed. An experimental study including five RC square columns strengthened with FS and steel bar mat mortar (S), respectively, under constant axial loading and lateral cyclic loading was carried out. Seismic bearing capacity, ductility, failure modes and hysteretic characteristics of all columns were tested, and the effect of reinforcement ratio and strengthening method to the tested columns was analyzed. The results showed that the energy dissipation capacity of FS strengthened columns was 73% higher than that of the S strengthened column, though the reinforcement ratio of the former was only 3.02% higher than that of the latter.