scholarly journals Experimental investigation of Low velocity impact response of reinforced concrete beams without stirrups

2018 ◽  
Vol 183 ◽  
pp. 02038
Author(s):  
Yingqian Fu ◽  
Xinlu Yu ◽  
Xinlong Dong ◽  
Fenghua Zhou
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Beam ◽  
Shear Failure ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Low Velocity Impact ◽  
Experimental Program ◽  
Failure Model ◽  
The Impact

This paper presents an experimental program of reinforced concrete beam without stirrups tested by impact three-point-bending under different initial velocity (drop height). As the results shown, for the static events, the failure mode is bending firstly, and then translates to shearing. the longitudinal reinforcements play an important role for the increasing of loading during bending stage. For the impact events, reinforced concrete beams failed in a flexural failure model at slow rates of loading and in shear failure model at high impact loading rate relatively. Moreover, the shear failure and bending failure have developed during the peak stage of Force-deflection curves. That is different with the emergence sequence of cracks under static tests. So the mechanical parameters of peak stage should be considered for the resistance of concrete beam under impact loading.

The effect of assembling location on the performance of precast concrete beam under impact load

2017 ◽  
Vol 21 (8) ◽  
pp. 1211-1222 ◽  
Author(s):  
Qiushi Yan ◽  
Bowen Sun ◽  
Xuemei Liu ◽  
Jun Wu
Keyword(s):  
Reinforced Concrete ◽  
Impact Velocity ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Impact Load ◽  
Precast Concrete ◽  
Reinforced Concrete Beams ◽  
Impact Location ◽  
Weight Impact ◽  
The Impact

With incorporation of assembling joints, precast concrete beams could behave very differently in resisting both static and dynamic loads in comparison to conventional reinforced concrete beams. With no research available on the dynamic behavior of precast concrete beams under impact load, a combined experimental and numerical study is conducted to investigate the dynamic response of precast concrete beams under impact load. The results were also compared with reinforced concrete beams. Four groups of concrete beams were tested with all beams designed with the same reinforcement, but different assembling locations were considered for precast concrete beams. The effects of the assembling location in resisting drop weight impact of precast concrete beams were analyzed. The influence of impact mass and impact velocity on the impact resistance of precast concrete beams were also investigated. The results revealed that the further the assembling location is away from the impact location, the closer the mechanical performance of the precast concrete beam is to that of the reinforced concrete beam. When the assembling location and the impact location coincided, the assembling region suffered from severe local damages. With increased impact velocity and impact energy, the damage mode of the precast concrete beams may change gradually from bending failure to bending–shear failure and eventually to local failure. In addition, the bonding around the assembling interface was found to be effective to resist drop weight impact load regardless of the magnitude of the impact velocity and energy.

scholarly journals The SHEAR BEHAVIOR OF REINFORCED CONCRETE BEAMS STRENGTHENED BY CFRP STRIPS

2021 ◽  
pp. 1-9
Author(s):  
Lubna Mohammed Abd
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Experimental Program ◽  
Transverse Reinforcement ◽  
Maximum Deflection ◽  
Modes Of Failure ◽  
Different Shapes ◽  
Combined Failure

   In this research, (12) normal reinforced concrete beams are used with dimensions (110*10*20) cm, the compressive strength for all specimens is 30 MPa. Longitudinal steel is deformed bars 2Ø12mm with Ø6 mm transverse reinforcement which is deformed bars also for different spacing 5 cm, 10 cm and 15 cm. After casting  the specimens and removing them from the molds, they left for about 28 days. They tied by CFRP strips  with different shapes of tying (tied, inclined and X- shaped). They are all testing with two points load by a hydraulic machine for determining (Pu, P cr, maximum deflection and modes of failure) and compared among  their results with the specimens without CFRP strips. From the experimental program, the excellent behavior of the specimens with the X-shaped strips especially with the Pu which is 70% increment and maximum deflection is 39%  decrement. The addition of CFRP strips as a tying material helps to increase the strength of concrete and bearing against loads also, changes and decreases the flexural and shear failure and combined failure.

scholarly journals Assessing the Damage Mechanism in Reinforced Concrete Beams under Repetitive Low Velocity Impact Loading

2021 ◽  
Vol 9 (VI) ◽  
pp. 4412-4418
Author(s):  
Sajina K
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Beams ◽  
Experimental Studies ◽  
Damage Mechanism ◽  
Reinforced Concrete Beams ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Finite Elements Analysis ◽  
Ice Impacts

Reinforced concrete beams are widely used in various civil structures such as residential, industrial, and commercial buildings. The use of RC beams reduces the cost of the construction and the time of execution. Rockfalls, accidental events, explosions, projectile, missile or aircraft impacts, terrorist attacks and ice impacts are the typical examples of sudden loads. Experimental studies can be impractical and require expensive devices to observe crack pattern and failure due to impact loading. Similar results can be obtained through non-linear finite elements analysis. In this study, RC beam is modelled and analyzed for changing impact velocity. Beam properties like clear cover is varied to access the damage in beams.

scholarly journals Crack Detection of FRP-Reinforced Concrete Beam Using Embedded Piezoceramic Smart Aggregates

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1979 ◽  
Author(s):  
Tianyong Jiang ◽  
Yue Hong ◽  
Junbo Zheng ◽  
Lei Wang ◽  
Haichang Gu
Keyword(s):  
Reinforced Concrete ◽  
Stress Wave ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
The Other ◽  
Experimental Program ◽  
Active Sensing ◽  
Frp Bar

In this paper, the authors present a stress wave-based active sensing method to detect the crack in FRP-reinforced concrete beams. The embedded smart aggregates (SAs), which utilize Lead Zirconate Titanate (PZT) as transducers, are employed in this research to generate and sense the stress wave. Three specimens are involved in the experimental program and each is made of concrete, longitudinal distributed reinforcement, steel stirrups, main bar (FRP bar or steel bar), and four SAs. A pair of SAs installed on the lower part of the main bar and the other pair of SAs mounted on the upper part of main bar are utilized to monitor the crack occurrence and development in the three test specimens. The signals received by the SA sensors are analyzed in both time domain and frequency domain. The wavelet packet energy is used to extract damage features. The applied load–vertical displacement curves of mid-span in the specimen are obtained. Experimental results show the test specimens experience crushing failure when the concrete compression exceeds its compressive strength. Increasing the contact area between FRP bar and concrete can effectively improve the cracking load of the FRP-reinforced concrete beam and reduce the cracking speed and depth of FRP-reinforced concrete beam; on the other hand, increasing the elastic modulus of the main bar can slow down the crack development of concrete on the upper side of the main bar and decrease the displacement of reinforced concrete beam during the loading test process. The research results show that the developed piezoceramic-based active sensing method, though low-cost, can monitor the crack-induced damage and estimate the process of damage degree in real-time, and has potentials to provide an early warning of crack occurrence and development for FRP-reinforced concrete beams.

Impact Resistance of Post-Tensioned Concrete

1990 ◽  
Vol 211 ◽  
Author(s):  
Nianzhi Wang ◽  
Sidney Mindess
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Beams ◽  
Impact Resistance ◽  
Plain Concrete ◽  
Reinforced Concrete Beams ◽  
Fibre Reinforced Concrete ◽  
Impact Tests ◽  
The Impact ◽  
Post Tensioned

AbstractImpact tests were carried out on post-tensioned beams, prepared both with plain concrete and fibre-reinforced concrete. It was found that post-tensioned beams might be less resistant to impact loading than were ordinary reinforced concrete beams. However, the addition of fibres to the concrete greatly increased the impact resistance of these beams.

A Time-Variant Reliability Analysis of Reinforced Concrete Beams Working with Cracks under High Temperature

2012 ◽  
Vol 197 ◽  
pp. 259-265
Author(s):  
Zhen Qing Wang ◽  
Mu Qiao ◽  
Yu Lai Han ◽  
Zhu Ju
Keyword(s):  
Reinforced Concrete ◽  
Reliability Index ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
First Order ◽  
First Order Second Moment ◽  
The Impact ◽  
Second Moment Method

The reliability of a reinforced concrete beam has been largely discounted when it under the action of fire. For a more accurate description of concrete beams’ reliability, the impact of cracks in reinforced concrete beams has been taking into account. Concrete is divided into elastic zone and plastic zone to calculate its strength. A simple and feasible time-variant model of reliability index of reinforced concrete beams under fire has been given. The effect of ISO834 temperature rising curve on the reliability index of concrete beam at different time has been analyzed. The reliability of a reinforced concrete beam under the ISO834 standard heating curve was assessed by first order second moment method.

scholarly journals Experimental study of the mechanical properties of steel fiber stainless-steel reinforced concrete (SFSRC) beams under low velocity impact conditions

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110449
Author(s):  
Xiwu Zhou ◽  
Wen Zhang ◽  
Xiangyu Wang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Steel Fiber ◽  
Concrete Beams ◽  
Impact Resistance ◽  
Reinforced Concrete Beams ◽  
Steel Reinforced Concrete ◽  
The Impact

In the present study, based on the previous impact resistance test study results regarding stainless steel reinforced concrete beams, six steel fiber stainless-steel reinforced concrete (SFSRC) beams were subjected to drop-hammer impact tests using an advanced ultra-high heavy multi-function drop hammer impact test system. The goal was to further investigate the mechanical properties of SFSRC beams under impact load conditions. The influencing effects of the steel fiber content and impact velocity levels on the impact resistance mechanical properties of SFSRC beams were analyzed. A digital image correlation method (DIC) was used to analyze the full-field strain and displacement values of the specimens. The results revealed that the steel fibers had significantly enhanced the overall energy dissipation and crack resistance capacities of the specimens, and also improved the brittleness of the stainless steel reinforced concrete beams. In addition, the addition of steel fibers effectively inhibited the local damages of the beam-hammer contact areas. In this study’s experiments, the impact resistance of the beams was observed to be the highest when the fiber content was 2.0%. The internal force formula of the local response stage of the beams showed that the shearing effects had significant impacts on the overall failure modes of the specimens. It was found that with the increases in impact velocity, the failure mode of the SFSRC beams transitioned from bending failure to shear failure, and then to a punching shear failure mode. The DIC results indicated that the addition of steel fiber improved the bonding performances between the concrete matrixes, along with inhibiting the crack development rates through the bond force between the fiber and the concrete.

Experimental Study on Flexural Behavior of Damaged Reinforced Concrete Beams Strengthened with CFRP

2014 ◽  
Vol 507 ◽  
pp. 306-310 ◽  
Author(s):  
Bin Jia ◽  
Jin Xue ◽  
Jun Mo ◽  
Chun Tao Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Failure Model ◽  
High Coherence

Abstract. In the view of the project problem that concrete strength grade is lower than C15in reinforced concrete beam, we consider a composite technology strengthened with CFRP, and do some monotonic loading experiments on these beams with eight different methods, and discuss the beam force behavior including ultimate bearing capacity, failure model and crack propagation. This paper finds out that the composite reinforced scheme, which with ticking trough, planting steel displaces concrete and gluing and then pasting CFRP, has a remarkable improvement than pasting CFRP immediately, and that there is a high coherence workability in the old and new concrete, so we can give full play to their role as the CFRP high strength.

Sign in / Sign up

Export Citation Format

Share Document