Experimental Investigation on Shear Property of RC Beams with Aramid Fiber Mesh Stirrups

2011 ◽  
Vol 255-260 ◽  
pp. 20-24 ◽  
Author(s):  
Er Jun Wu ◽  
Jian Long Xing ◽  
Zhao Quan Zhu
Keyword(s):  
High Performance ◽  
Aramid Fiber ◽  
Rc Beam ◽  
Rc Beams ◽  
Rc Structures ◽  
High Durability ◽  
Shear Property ◽  
Shear Bearing Capacity ◽  
Fiber Mesh ◽  
Better Than

This paper develops a new-typed high-durability RC structures in which the steel stirrups are replaced by mesh stirrups weaved with soft high performance fiber belt. The experiments are carried out to investigate the shear property of six beams with soft aramid fiber mesh stirrups and one common RC beam and the results show that the failure state in the slope sections of the RC beams with fiber belt mesh stirrups is similar to the common RC beam. It was also found the shear property of beams with lean fiber mesh stirrups is better than that with vertical and horizontal mesh stirrups, and with the high-elastic- modulus fiber stirrups better than the low-elastic-modulus’s. In addition, the distributions of fiber stirrups strain at slope section are also observed. Based the experimental results, a model for beams with fiber mesh stirrups was established and the formula of shear bearing capacity was suggested.

Repair of Severely Damaged Reinforced Concrete Beams with High-Strength Cementitious Grout

2020 ◽  
Vol 2674 (6) ◽  
pp. 372-384
Author(s):  
Antoine N. Gergess ◽  
Mahfoud Shaikh Al Shabab ◽  
Razane Massouh
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Rc Structures

High-strength cementitious materials such as high-performance concrete are extensively used for retrofit of reinforced concrete (RC) structures. The effectiveness of these materials is increased when mixed with steel fibers. A commonly used technique for strengthening and repair of RC beams consists of applying high-performance fiber-reinforced concrete jackets around the beam perimeter. This paper investigates the jacketing method for repairing severely damaged RC beams. Four 2 m (6 ft 63/4 in.) long rectangular RC beams, 200 × 300 mm (8 ×12 in.) were initially cast and loaded until failure based on three-point bending tests. The four beams were then repaired by thickening the sides of the damaged RC beams using a commercially available high-strength shrinkage grout with and without steel fibers. Strain and deformation were recorded in the damaged and repaired beams to compare structural performance. It is shown that the flexural strength of the repaired beams is increased and the crack pattern under loading is improved, proving that the proposed repair method can restore the resistance capacity of RC beams despite the degree of damage. A method for repair is proposed and an analytical investigation is also performed to understand the structural behavior of the repaired beams based on different thickening configurations.

Analysis of Shear Capacity of Stirrup Corroded RC Beam Based on the Truss-Arch Theory

2012 ◽  
Vol 204-208 ◽  
pp. 2865-2873
Author(s):  
Ke Bo Zhang ◽  
Zhi Zhang ◽  
Jian Ren Zhang ◽  
Bin Liu
Keyword(s):  
Strength Criterion ◽  
Shear Capacity ◽  
Control Group ◽  
Rc Beam ◽  
Arch Model ◽  
Rc Beams ◽  
Diagonal Reinforcement ◽  
Steel Bars ◽  
Shear Bearing Capacity ◽  
Crucial Parameter

On the basis of truss-and-arch model and the concrete softening strength criterion under ultimate state, a formula for shear capacity of reinforced concrete (RC) beam with diagonal reinforcement was established and verified. Accordingly, six RC beams with diagonal reinforcement and corroded stirrup were tested along with control group, the tested results were analyzed by liner regression to modify the formula given. Hence a formula for inclined section shear capacity of stirrups corroded RC beam with diagonal reinforcement was proposed and compared with a preceding formula without a consideration of diagonal reinforcement in corroded RC beam .The results showed that the existence of diagonal reinforcing steel bars enhanced the behavior of vertical compression web member in truss institutions, therefore increasing the shear force shared by truss mechanism. The inclination of diagonal web member is a crucial parameter of truss model. As the stirrup corrosion aggravating, the shear bearing capacity of such RC beams does not decrease drastically.

scholarly journals Impact Resistance Behavior of Reinforced Concrete Beams Deteriorated due to Repeated Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yusuke Kurihashi ◽  
Yoshinori Nonomura ◽  
Hisashi Konno
Keyword(s):  
Propagation Velocity ◽  
Impact Resistance ◽  
Frost Damage ◽  
Rc Beam ◽  
Rc Beams ◽  
Residual Deflection ◽  
Rc Structures ◽  
Freeze Thaw ◽  
Ultrasonic Propagation ◽  
The Impact

Many existing reinforced concrete (RC) structures constructed more than 50 years ago now require maintenance. This is especially true in cold, snowy regions where significant frost damage deterioration of RC structures becomes a severe problem. In this study, falling-weight impact tests were performed to investigate the impact resistance behavior of RC beams degraded by frost damage. An RC beam was subjected to approximately 900 freeze-thaw cycles to emulate the frost damage before the execution of the impact test. The surface of the beam was remarkably scaled, and its coarse aggregate was exposed. The degree of deterioration was evaluated by the distribution of ultrasonic propagation velocity. The following conclusions were drawn. (1) The ultrasonic propagation velocity of RC beams was significantly reduced following 872 freeze-thaw cycles. At the upper edge of the RC beam, the ultrasonic wave propagation velocity decreased from 4,000 m/s to 1,500 m/s in some parts. This corresponds to a relative dynamic elastic modulus of approximately 14%. (2) The residual deflection of RC beams with frost damage increased at most by 20% compared with beams without frost damage. The increase in residual deflection was primarily related to the peeling of concrete at the collision site and the opening of multiple bending cracks. (3) According to the existing residual deflection calculation formula, an increase of 20% in the residual deflection corresponds to a decrease of about 17% in the bending capacity of the RC beam. When the relationship between the degree of frost damage deterioration and the impact resistance of RC structures is defined, existing structures subjected to accidental impact force from rockfalls are safer and can be maintained more efficiently.

scholarly journals Impact Resisting Mechanisms of Shear-Critical Reinforced Concrete Beams Strengthened with High-Performance FRC

2020 ◽  
Vol 10 (9) ◽  
pp. 3154
Author(s):  
Carlos Zanuy ◽  
Gonzalo S.D. Ulzurrun
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Environmental Cost ◽  
Interface Debonding ◽  
Rc Beams ◽  
Rc Structures ◽  
High Performance Fiber ◽  
The Impact

Reinforced concrete (RC) structures typically present brittle failures by shear or punching under impact loading. High-performance fiber-reinforced concrete (HPFRC) has great potential due to its superior strength and energy absorption. The higher price and environmental cost of HPFRC compared to conventional RC can be effectively overcome by partially strengthening impact-sensitive RC members with HPFRC. To study the feasibility of this technique, HPFRC was applied as a tensile layer at the bottom of RC beams. Drop weight impact tests were carried out on beams with two values (35 and 55 mm) of HPFRC thickness, in addition to companion RC beams. Results show that the impact response can be divided into two stages: a first stage governed by local effects and shear plug formation at midspan, and a second stage governed by global beam behavior with formation of shear web cracks. A new resisting mechanism was observed for beams strengthened with HPFRC, as the strengthening layer worked similarly to a stress ribbon retaining the damaged RC and reducing fragmentation-induced debris. Such mechanism was fully achieved by the specimens with 35 mm HPFRC layer but was limited for the specimens with 55 mm HPFRC layer due to impact-induced interface debonding.

scholarly journals Study on frost resistance and abrasion resistance of fiber mesh reinforced concrete

2020 ◽  
Vol 206 ◽  
pp. 02020
Author(s):  
Cheng Hu ◽  
Xingzhong Weng ◽  
Xiangcheng Yan ◽  
Pengcheng Liu ◽  
Tianxiong Guo
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Abrasion Resistance ◽  
Frost Resistance ◽  
Unit Area ◽  
Basalt Fiber ◽  
Aramid Fiber ◽  
Enhancement Effect ◽  
Fiber Mesh ◽  
Better Than

The frost resistance and abrasion resistance of the fiber mesh reinforced concrete under the simulated treatment of external environment were studied through the frost resistance test and abrasion test. The relative dynamic modulus, the amount of spalling per unit area, the amount of abrasion per unit area and abrasion depth were used as evaluation indexes. The result shows that the frost resistance and abrasion resistance of concrete can be enhanced by fiber mesh. For the frost resistance, enhancement effect of carbon fiber mesh is better than that of basalt fiber mesh, and better than that of aramid fiber mesh. For the abrasion resistance, enhancement effect of aramid fiber mesh is better than that of basalt fiber mesh, and better than that of carbon fiber mesh. On the whole, the frost resistance and abrasion resistance of basalt fiber mesh reinforced concrete are better. Therefore, basalt fiber mesh is recommended to strengthen the frost resistance and abrasion resistance of concrete in engineering practice.

scholarly journals FLEXURAL CAPACITY ASSESSMENT OF BRICK AGGREGATED PRE-CRACKED RC BEAM STRENGTHENED WITH CARBON FIBER POLYMER

2019 ◽  
Vol 31 (1) ◽  
Author(s):  
Niaz Md Mamun ◽  
G. M. Sadiqul Islam ◽  
Md Jahangir Alam
Keyword(s):  
Carbon Fiber ◽  
Failure Modes ◽  
Fiber Reinforced Polymers ◽  
Capacity Assessment ◽  
Rc Beam ◽  
Rc Beams ◽  
Flexural Capacity ◽  
Carbon Fiber Reinforced Polymers ◽  
Rc Structures ◽  
Fiber Sheet

Ageing and improvements to design code has led to many existing RC structures made of locally available brick aggregates are now found structurally deficient and are in need of rehabilitation. This research emphases on flexural capacity assessment and investigation of failure modes of Carbon Fiber Reinforced Polymers (CFRP) strengthened brick aggregated RC beams. Flexural performance of the RC beam specimens are evaluated using four point bending method. Six RC beams (initially cracked) with CFRP strengthening were tested by varying (i) type of CFRP, (ii) reinforcing area, (iii) anchorage type; and (iv) number of CFRP layers. Two beams were tested as control specimens. Unidirectional carbon fiber sheet (Tow Sheet) and individually hardened continuous fiber strands woven into sheet form (Strand Sheet) were used. Simple flexure failure was obtained for unstrengthened RC beams while end plate and interfacial debonding were observed for the initially cracked CFRP strengthened RC beams. Strengthening of pre-cracked beams using Strand Sheet gave better performance compared to Tow sheet. Overall flexural strength improvement of CFRP strengthened beams varied from 12% to 34% with respect to unstrengthened beams depending on strengthening methods.

scholarly journals Embodied Energy and Cost Optimization of RC Beam under Blast Load

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Runqing Yu ◽  
Diandian Zhang ◽  
Haichun Yan
Keyword(s):  
Unit Volume ◽  
Cost Optimization ◽  
Optimization Procedure ◽  
Embodied Energy ◽  
Cost Ratio ◽  
Rc Beam ◽  
Rc Beams ◽  
Rc Structures ◽  
Important Index ◽  
The Cost

Reinforced concrete (RC) structures not only consume a lot of resources but also cause continuing pollution. However, sustainable design could make RC structures more environmental-friendly. One important index for environmental impact assessment is embodied energy. The aim of the present study is to optimize the embodied energy and the cost of RC beam subjected to the blast loads. First, a general optimization procedure was described. Then, the optimization procedure was used to optimize the embodied energy and the cost of RC beams. Optimization results of the cost and the embodied energy were compared. It was found that the optimization results were influenced by the cost ratio nC (ratio of price of steel to price of concrete per unit volume) and the embodied energy ratio nE (ratio of embodied energy of steel to embodied energy of concrete per unit volume). An optimal design that minimized both embodied energy and cost simultaneously was obtained if values of nC and nE were very close.

BEHAVIOR OF RC BEAM RETROFITTED USING ULTRA HIGH-PERFORMANCE CONCRETE UNDER IMPACT LOADS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohammed Ali Al-Osta
Keyword(s):  
Finite Element ◽  
Impact Loading ◽  
High Performance ◽  
High Performance Concrete ◽  
Rc Beam ◽  
Rc Beams ◽  
Ultra High Performance Concrete ◽  
Static Loads ◽  
Finite Element Software ◽  
The Impact

Several new types of materials have recently been used as retrofitting materials for structural elements such as ultra-high performance concrete with steel fiber reinforcement (UHPFRC). These materials are used as jacking to enhance the strength and ductility reinforced concrete (RC) beams. Considerable attention has been focused on the response of retrofitted RC beam under static loads but the behavior of such beam under impact loading is somewhat lacking. Therefore, in this study, a 3-D finite element model (FEM) of retrofitted RC beams under impact loading using non-linear finite element software (ABAQUS) was investigated. Since experimental work on this topic is scarce, the FEM is validated using the results of retrofitted RC beam under static loads. The impact load was applied in ABAQUS as equivalent to an initial velocity of 2500 mm/s. A parametric study was carried out to study the flexural response of RC beams retrofitted with different thicknesses and strengthening configurations of UHPFRC under impact loading.

Experimental Study on the Fatigue Properties of RC Beam Strengthened by Prestressed CFL

2008 ◽  
Vol 33-37 ◽  
pp. 169-173 ◽  
Author(s):  
Yi Yang ◽  
Pei Yan Huang ◽  
Jun Deng
Keyword(s):  
Experimental Study ◽  
Experimental Results ◽  
Fatigue Properties ◽  
Rc Beam ◽  
Rc Beams ◽  
Rc Structures ◽  
Reinforcing Effect

Bonding prestressed CFL to strengthen reinforced RC structures can improve the bending capability of structures and the working efficient of CFL. Base on the fatigue experiments of 4 RC beams strengthened by prestressed CFL, the present paper analyzes the fatigue properties of prestressed CFL reinforced RC beams. Comparing with the experimental results of strengthened RC beams without prestress, it can be concluded that the prestressed technology can improve the reinforcing effect and fatigue lives.

Structural Behaviors of Hybrid High Performance RC Beams with Web Openings Using Hybrid Fibers

2014 ◽  
Vol 1044-1045 ◽  
pp. 585-588
Author(s):  
Seung Jo Lee ◽  
Jung Min Park
Keyword(s):  
High Performance ◽  
Ultimate Load ◽  
Steel Tube ◽  
Flexural Behavior ◽  
Rc Beams ◽  
Test Results ◽  
Hybrid Fibers ◽  
Web Openings ◽  
Structural Behaviors ◽  
Better Than

The purpose of this study is to evaluate the flexural behavior of hybrid high performance RC beams with web openings (Hy-HPRWO) that are constructed by using circle steel tube, hybrid fibers and Garnet, Fly-ash. One regular RC beam with openings (HPRC) and four Hy-HPRWO specimens were manufactured and tested under monotonic loading. It was evaluated by flexural experiment of Hy-HPRWO through comparison of failure mode, load-deflection curves, ductility and ultimate load (Vu). Test results showed that the ultimate load of the Hy-FPSC3 specimens were approximately 5.82% better than that of the HPRC, in addition their ductility behavior was 68.1% better than the HPRC.

Sign in / Sign up

Export Citation Format

Share Document