scholarly journals Flexural Response and Failure Analysis of Solid and Hollow Core Concrete Beams with Additional Opening at Different Locations

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7203
Author(s):  
Ibrahim A. Sharaky ◽  
Ahmed S. Elamary ◽  
Yasir M. Alharthi
Keyword(s):  
Failure Modes ◽  
Concrete Beams ◽  
Load Capacity ◽  
Rc Beams ◽  
Hollow Core ◽  
Beam Length ◽  
Flexural Response ◽  
Beam Shear ◽  
Concrete Elements ◽  
Core Concrete

It is essential to make openings in structural concrete elements to accommodate mechanical and electrical needs. To study the effect of these openings on the performance of reinforced concrete (RC) elements, a numerical investigation was performed and validated using previous experimental work. The effect of the position and dimension of the opening and the beam length on the response of the beams, loads capacities, and failure modes was studied. The simulated RC beams showed different responses, loads capacities, and failure modes depending on the position and dimension of the opening. The transversal near support opening (TNSH) and longitudinal holes (LH) showed lower effects on the load capacities of the beams than the transversal near center opening (TNCH). The supreme reduction percentages of the load capacity (µu%) for beams with TNCH and TNSH were 37.21% and 30.34%, respectively (opening size = 150 × 150 mm2). In addition, the maximum µu% for beam with LH was 17.82% (opening size = 25% of the beam size). The TNSH with a width of less than 18.18% of the beam shear span (550 mm) had trivial effects on the beam’s load capacities (the maximum µu% = 1.26%). Although the beams with combined LH and TNCH or LH and TNSH showed different failure modes, they experienced nearly the same load reductions. Moreover, the length of the beam (solid or hollow) had a great effect on its failure mode and load capacity. Finally, equations were proposed and validated to calculate the yield load and post-cracking deflection for the concrete beams with a longitudinal opening.

scholarly journals ANALYTICAL AND EXPERIMENTAL STUDY ON REPAIR EFFECTIVENESS OF CFRP SHEETS FOR RC BEAMS

2013 ◽  
Vol 20 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Moatasem M. Fayyadh ◽  
H. Abdul Razak
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Load Capacity ◽  
Fe Model ◽  
Rc Beams ◽  
Shell Elements ◽  
Cfrp Sheets ◽  
Adhesive Interface ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents the results of both analytical and experimental study on the repair effectiveness of Carbon Fibre Reinforced Polymer (CFRP) sheets for RC beams with different levels of pre-repair damage severity. It highlights the effect of fixing CFRP sheets to damaged beams on the load capacity, mid-span deflection, the steel strain and the CFRP strain and failure modes. The analytical study was based on a Finite Element (FE) model of the beam using brick and embedded bar elements for the concrete and steel reinforcement, respectively. The CFRP sheets and adhesive interface were modelled using shell elements with orthotropic material properties and incorporating the ultimate adhesive strain obtained experimentally to define the limit for debonding. In order to validate the analytical model, the FE results were compared with the results obtained from laboratory tests conducted on a control beam and three other beams subjected to different damage loads prior to repair with CFRP sheets. The results obtained showed good agreement, and this study verified the adopted approach of modelling the adhesive interface between the RC beam and the CFRP sheets using the ultimate adhesive strains obtained experimentally.

Studies on Fire Resistance of FRP Shear Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 94-96 ◽  
pp. 1318-1321
Author(s):  
He Fan ◽  
Ze Fan
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Failure Modes ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Temperature Fields ◽  
Insulation Material ◽  
Rc Beams ◽  
Fire Resistance Rating ◽  
Resistance Rating

Fire-resistance performance experiments with static loading-fire are investigated about two carbon fiber sheet (CFS) shear strengthened reinforced concrete (RC) beams exposed to the ISO834 standard fire. Shear strengthened RC beams are wrapped with fire insulation material- thick painted fire retardant coatings. Relationship between measure points’ temperature and time are achieved. The results suggest that: the ratio of shear-span is the main factor to fire-resistance rating and failure modes of CFS shear strengthened RC beams in fire; shear-failure fire-resistance rating are increased by thickening fire insulation to shear strengthened RC beams. A computer program is developed to calculate the temperature fields of fire insulated concrete beams shear strengthened with CFS coated thick fireproof material. This program is validated comparing with experimental results. Researches can give a supplement to produce overall fire-resistance factors of CFS shear strengthened reinforced concrete beams at high temperatures.

scholarly journals Performance of Concrete Beams Reinforced with Various Ratios of Hybrid GFRP/Steel Bars

2020 ◽  
Vol 6 (9) ◽  
pp. 1652-1669
Author(s):  
Phan Duy Nguyen ◽  
Vu Hiep Dang ◽  
Ngoc Anh Vu
Keyword(s):  
Failure Modes ◽  
Concrete Beams ◽  
Peak Load ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Deformation Model ◽  
Rc Beams ◽  
Linear Deformation ◽  
Crack Patterns ◽  
Steel Bars

This paper aims to study the flexural behavior of concrete beams reinforced with hybrid combinations of GFRP/steel bars. To this purpose an experimental program was carried out on four concrete beams reinforced with Glass Fiber Reinforced Polymer (GFRP) and twelve hybrid GFRP/steel Reinforced Concrete (RC) beams. Flexural behavior of the tested beams such as stages of response, failure modes, crack patterns, stiffness, toughness and ductility were analyzed. The experimental results showed that depending on GFRP/steel reinforcement configurations, the behavior of hybrid GFRP/steel RC beams undergoes three or four stages, namely: pre-cracking stage; after concrete cracking and before steel yielding; post-yield stage of the steel bar until peak load and failure stage. Totally six failure modes of hybrid RC beams are reported depending on reinforcement rations and configuration. The effect of reinforcement configuration and ratio of GFRP to steel (ρg) on the crack patterns, stiffness, ductility and toughness of hybrid RC beams are significant. Based on the non-linear deformation model, an analytical model has been developed and validated to determine the steel yielding moment and ultimate moment of hybrid GFRP/steel RC beams. It could be seen that the experimental values were in good agreement with the predicted values.

RETROFIT STEEL CORRODING RC BEAMS USING CFRP COMPOSITES: NLFE ANALYSIS

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Rami H. Haddad
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Concrete Beams ◽  
Load Capacity ◽  
Concrete Cover ◽  
Cfrp Sheets ◽  
Cfrp Composites ◽  
Severe Reduction ◽  
Corrosion Of Steel ◽  
Repair Techniques

Corrosion of steel reinforcement is one of the main durability problems facing reinforced concrete infrastructures worldwide. Steel degradation and/or cracking of concrete both cause severe reduction in bearing capacity, leading ultimately to failure. The potential of repairing corroded concrete beams with two configurations of carbon-fiber reinforced polymeric (CFRP) composites was investigated with a nonlinear finite Element (NLFE) model. CFRP composites were assumed to be either bonded directly to existing concrete or to a new concrete cover; replacing the old one. The data generated showed that the load-bearing capacity and stiffness for concrete beams, as long as corrosion levels were below 10%, can be fully restored. However, the ductility in terms of deflection at failure would be reduced, especially for repair techniques that involved anchoring with CFRP sheets. For corrosion levels greater than 10%, attaching CFRP composites to a new concrete cover contributed to additional improvements in load capacity and stiffness ranging from 10 to 15% of that achieved from similar repairing on existing concrete. The failure modes indicated that debonding failure prevailed, and that the extent of debonding prior to failure depended upon the corrosion level and on whether the concrete cover was replaced or not.

Mechanical Behavior for RC Beams Strengthened with Near-Surface-Mounted Bars Considering Effect of Secondary Loading

2014 ◽  
Vol 638-640 ◽  
pp. 1360-1364
Author(s):  
Hai Xia Zhang ◽  
Jia Wei Pei ◽  
Lu Yuan He
Keyword(s):  
Failure Modes ◽  
Concrete Beams ◽  
Load Level ◽  
Rc Beams ◽  
Near Surface ◽  
Initial Load ◽  
Bond Property ◽  
Near Surface Mounted ◽  
Frp Bars ◽  
Strengthening Method

Compared with other strengthening methods, NSM FRP bars strengthening method has obvious advantages in bond property and fire prevention performance. In accordance with current experimental study and the theory of concrete beams strengthened in bending with FRP are introduced, and the effect of FRP bars strengthening quantity on failure modes of reinforcement beams and the initial load level influence on the ultimate bearing capacity are analyzed. It provides a basis for further research and application in China.

Experimental Research on the Flexural Performance of the Strengthened Concrete Beams with Prestressed CFRP

2011 ◽  
Vol 255-260 ◽  
pp. 105-108
Author(s):  
Guo Wen Yao ◽  
Yan Li Wei ◽  
Shi Ya Li
Keyword(s):  
Failure Modes ◽  
Concrete Beams ◽  
Flexural Stiffness ◽  
Load Carrying Capacity ◽  
Rc Beams ◽  
Flexural Performance ◽  
Load Carrying ◽  
Cycle Loading ◽  
Strengthened Beam ◽  
Three Stages

Three-bending experiments were performed on RC beams strengthened with prestressed CFRP under static and cycle loading. Prestressed CFRP obviously increases the load-carrying capacity and fatigue life of strengthened RC beam. And it greatly increases the flexural stiffness of strengthened beam. The failure modes of the beams go through concrete cracking, CFRP debonding from concrete and beam fractured. The vertical flexibility history at midspan is decomposed into three stages. And then fatigue damage is defined by flexural stiffness and its evolvement shows three stages of nucleation, growth and mutation.

Flexural Behaviors of RC Beams Strengthened with Post-Poured UHTCC Layer

2010 ◽  
Vol 150-151 ◽  
pp. 6-9
Author(s):  
Shi Lang Xu ◽  
Nan Wang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Load Capacity ◽  
Three Dimensional ◽  
Close Correlation ◽  
Composite Beams ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Strength Failure ◽  
Three Dimensional Finite Element

For studying the effectiveness of externally pouring Ultra High Toughness Cementitious Composites (UHTCC) in improving the flexural behaviors of existing reinforced concrete beams, four-point bending tests were conducted up to failure on seven RC beams and strengthening beams. The flexural strength, failure mode and crack propagation of composite beams were investigated. The results showed that pouring UHTCC on the bending surface of reinforced concrete beams properly to improve the ductility and load capacity of composite beams. It was also found that UHTCC layer restricted the development of cracks in upper concrete and dispersed them into multiple fine cracks effectively. Compared with post-poured concrete, UHTCC was more suitable for working together with reinforcement. The load-deflection plots obtained from three-dimensional finite-element models (FEMs) analyses were compared with those obtained from the experimental results, which showed close correlation.

scholarly journals Flexural and Shear Behavior of Beams Reinforced with GFRP Rebars

2021 ◽  
Vol 9 (5) ◽  
pp. 229-235
Author(s):  
Axetha Menam ◽  
K. Sunil Kumar ◽  
P. Rupa
Keyword(s):  
Concrete Beams ◽  
Load Capacity ◽  
Reinforcement Ratio ◽  
Reinforced Concrete Beams ◽  
Steel Beams ◽  
Rc Beams ◽  
Ultimate Load Capacity ◽  
Flexural Reinforcement ◽  
Shear Failures ◽  
Gfrp Rebars

A new inexperienced constructing material is glass fibre reinforced polymer (GFRP) rebar. GFRP rebars are noncorrosive, non-conductive, light-weight substances and have an excessive longitudinal tensile capacity that is beneficial for use in civil infrastructure applications. In this analysis, the overall performance of GFRP rebar-reinforced concrete beams was assessed. Full scale exams had been conducted underneath fourpoint bending on eight one hundred fifty x 250 x 1500 mm beams to inspect the influence of GFRP specimens reinforced through both GFRP or metal rebars with flexural reinforcement ratios (ρf ) ranging from 0.53 to 1.45 times the balanced ratio (ρfb). In phrases of crack pattern, load deflection behaviour, load strain conduct and peak capacity, the check facts used to be analysed to decide the flexure and shear conduct of GFRP RC beams. The find out about confirmed that the ultimate load capacity of beams is immediately proportional to the flexural reinforcement ratio, and for steel bolstered specimens, cracking moments had been greater, relative to GFRP. For GFRP RC beams, the peak carrying ability is extra than steel beams. GFRP beams confirmed greater deflections than bolstered beams of steel. The findings additionally confirmed that the building of GFRP bolstered beams in concrete with GFRP stirrups can be influenced by means of shear failures. The reinforcement ratio and shear design of GFRP bolstered concrete beams is affected by way of their behaviour.

Behavior of Strengthened RC Beams with CFRP Sheets under Combined Bending and Torsion

2020 ◽  
Vol 857 ◽  
pp. 109-119
Author(s):  
Abdul Muttalib I. Said ◽  
Qais H. Al-Shemmari
Keyword(s):  
Experimental Work ◽  
Failure Modes ◽  
Ultimate Load ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Loading Conditions ◽  
Pure Bending ◽  
Pure Torsion ◽  
Cfrp Sheets

The experimental investigations were carried out to study the behavior of reinforced concrete beams strengthened by CFRP sheets under different loading conditions (pure bending, combined bending and torsion and pure torsion). The experimental work included testing twenty RC beams of the rectangular cross-section of dimensions of 160×240 mm and of 2600 mm length with an area of the ordinary reinforcement being kept constant for all beams. Two parameters were taken into consideration (Twisting to bending moment ratio (T/M) and CFRP strengthening pattern). The tested beams are divided into five groups. Each group consists of four beams; the first beam is without CFRP strengthening, the other three are strengthened with CFRP sheets of different arrangements (U-stirrups, U-stirrups and longitudinal CFRP sheets in the bottom and Full U- stirrups wrapping). Each beam is loaded to a different loading conditions (pure bending, T/M = 0.5, T/M = 1.0, T/M = 2.0 and pure torsion). The CFRP sheets were attached externally to the beam. Test results were analyzed based on the influence of CFRP on the ultimate load, vertical mid-span deflection and failure modes. In the experimental work, it was found that all strengthening patterns of CFRP sheets exhibited a significant increase in ultimate strength. This increase reached up to 78.9% for tested beams, when the beam strengthened in the form of full U- stirrups wrapping pattern for T/M = 0.5. In this study, it is observed that the use of external CFRP sheets attached to the tension sides of beams (U-stirrups and longitudinal CFRP in the bottom) could enhance the ultimate load capacity by 32.7% over the capacity of the unstrengthen control beam for T/M = 1.0.

Sign in / Sign up

Export Citation Format

Share Document