Review on impact response of reinforced concrete beams: Contemporary understanding and unsolved problems

2021 ◽  
pp. 136943322199771
Author(s):  
Thong M Pham ◽  
Wensu Chen ◽  
Hong Hao
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Structural Response ◽  
Impact Testing ◽  
Reinforced Concrete Beams ◽  
Impact Response ◽  
Analytical Models ◽  
Impact Loads ◽  
Rc Beams ◽  
The Impact

Designing protective reinforced concrete (RC) beams against impact loadings is a challenging task. It requires a comprehensive understanding of the structural response of RC beams subjected to impact loads. Significant research efforts have been spent to unveil the impact response of RC beams by using analytical models, experimental testing, or numerical investigations. However, these studies used various assumptions in the analytical derivations and different test setups in the impact testing, which led to significantly different responses and observations of similar structures and similar loading conditions. For example, a minor change in contact surface can triple the maximum impact force of identical RC beams. This study provides a review of the contemporary understandings of the RC beam responses to impact loads, and explains the different observations and conclusions. Some unsolved issues for protective structures, that is, RC beams to resist impulsive loads are also discussed. It is suggested that future studies should take into consideration the conditions of the test setup, simplifications and assumptions made in analytical derivations for better interpretations of the obtained results.

Improving the Impact Resistance of Reinforced Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1924-1929 ◽  
Author(s):  
Husain Abbas ◽  
Tarek Almusallam ◽  
Yousef Al-Salloum
Keyword(s):  
Reinforced Concrete ◽  
Split Hopkinson Pressure Bar ◽  
Impact Resistance ◽  
Concrete Structures ◽  
Material Behavior ◽  
Analytical Models ◽  
Impact Loads ◽  
Hopkinson Pressure Bar ◽  
Hybrid Fibers ◽  
The Impact

The strategic concrete structures are often required to resist impact loads arising from the projectile strike, falling weight, blast generated missile etc. The existing structures found deficient in resisting these loads are required to be retrofitted whereas the upcoming structures are required to be designed for expected impact loads. This paper explores the ways of strengthening existing reinforced concrete (RC) structures using externally bonded carbon fiber reinforced polymer (CFRP) sheets and improving the impact resistance of concrete by mixing hybrid fibers in its production. The impact response of concrete structures is assessed using experiments involving the impact of projectiles of different nose shapes on slab specimens. The material behavior at high strain rate is established using split Hopkinson pressure bar (SHPB) testing at varying strain rates. Analytical models are developed for predicting penetration depth, scabbing thickness, ballistic limit velocity and ejected mass. The experimental results were also validated through numerical modeling using LS-DYNA.

Recommendations for Designing Reinforced Concrete Beams Against Low Velocity Impact Loads

2018 ◽  
Vol 18 (09) ◽  
pp. 1850104 ◽  
Author(s):  
Piyapong Wongmatar ◽  
Chayanon Hansapinyo ◽  
Vanissorn Vimonsatit ◽  
Wensu Chen
Keyword(s):  
Reinforced Concrete ◽  
Impact Load ◽  
Reaction Force ◽  
Reinforced Concrete Beams ◽  
Low Velocity Impact ◽  
Inertia Force ◽  
Impact Loads ◽  
Rc Beams ◽  
Low Velocity ◽  
Velocity Impact

This study investigates the behaviors of simply supported reinforced concrete (RC) beams subjected to impact loads. A numerical model of RC beams has been calibrated and a total of 18 RC beams with varying longitudinal reinforcement, transverse shear reinforcement, span and effective depth are investigated, subjected to different input impact energy. It is found that inertia force plays an important role in resisting an impact load at the starting time. The slenderness of the beam can cause increased downward reaction force and also amplifies the upward reaction force. Based on the numerical results, recommendations are made for designing RC beams under low velocity impact load. A formula is derived to predict the maximum mid-span deflection under low velocity impact load with respect to the kinetic energy and static bending capacity. The maximum spacing and the diameter of stirrups are also recommended so as to avoid the brittle failure under impact load.

An Effective Framework for Performance Evaluation of Reinforced Concrete Beams Under Impact Loadings

2020 ◽  
Vol 20 (11) ◽  
pp. 2050117
Author(s):  
Wuchao Zhao ◽  
Jihong Ye
Keyword(s):  
Performance Evaluation ◽  
Reinforced Concrete ◽  
Impact Analysis ◽  
Reinforced Concrete Beams ◽  
Effective Model ◽  
Rc Beams ◽  
Probabilistic Framework ◽  
Maximum Displacement ◽  
Damage Degree ◽  
The Impact

Extreme actions, such as impact loads, contain many uncertainties and hence, may not be analyzed by a deterministic approach. In this paper, an effective framework for performance evaluation of reinforced concrete (RC) beams subjected to impact loadings is proposed. For this purpose, a simple yet effective model considering the shear-flexural interaction is developed based on available impact test results. By incorporating the shear effect, both the maximum displacement and impact force are well predicted, by which the proposed model for the impact analysis of RC beams is validated. The joint probability density function (PDF) of two damage indexes, i.e. local drift ratio and overall support rotation, is used to represent the local shear damage degree and the overall flexural damage degree. Taking advantage of the probabilistic framework and the effective model, reliability analysis of the RC beams under different impact scenarios is performed. The damage, described in this study by the joint PDF, is highly affected by the combination of impact mass and velocity. Thus, the mass–velocity ([Formula: see text]–[Formula: see text] diagrams for various performance levels are generated for the damage assessment of the RC beams. Furthermore, the contribution of the local and global responses to the failure probability is quantified using the proposed probabilistic framework.

scholarly journals Behavior of fiber-reinforced polymer-strengthened reinforced concrete beams under static and impact loads

2016 ◽  
Vol 8 (1) ◽  
pp. 3-24 ◽  
Author(s):  
Thong M Pham ◽  
Hong Hao
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Impact Loads ◽  
Fiber Reinforced ◽  
Static Loads ◽  
Reinforced Polymer ◽  
Longitudinal Fiber ◽  
The Impact

This study investigates the behavior of fiber-reinforced polymer-strengthened reinforced concrete beams under static and impact loads. The experimental program includes six beams tested in static loads and seven beams tested against impact loads. Longitudinal fiber-reinforced polymer strips and fiber-reinforced polymer U-wraps were used to strengthen these beams. The section of four beams was modified to have a curved soffit in order to reduce the stress concentration of fiber-reinforced polymer U-wraps and provide confinement effect on longitudinal fiber-reinforced polymer strips. The experimental results showed that the proposed modification significantly increased the beam capacities as compared to their rectangular counterparts strengthened with the same amount of fiber-reinforced polymer material. In addition, this article also provides explanations and discussions on the phenomenon of shifting of the flexure failure mode under static loads to the shear–flexure failure mode under impact loads of all the beams tested in the study, as well as the proper interpretations of the measured impact forces in the tests. From the experimental results, it is recommended that the impact force and inertial force at the very early stage of an impact event should be used to design the impact resistance.

scholarly journals Investigation of Structural Response of Reinforced Concrete Beams Strengthened with Anchored FRPs

2013 ◽  
Vol 7 (1) ◽  
pp. 146-157 ◽  
Author(s):  
Constantinos B. Demakos ◽  
Constantinos C. Repapis ◽  
Dimitrios Drivas
Keyword(s):  
Reinforced Concrete ◽  
Load Capacity ◽  
Structural Response ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Anchorage System ◽  
Cfrp Sheet ◽  
Bending Capacity ◽  
Cfrp Strip ◽  
Lightly Reinforced Concrete

The beneficial effect of a composite material anchorage system (CMAS) upon the ductility and load capacity of reinforced concrete (RC) beams strengthened either with glass (GFRP) or carbon (CFRP) fabrics was investigated. The anchorage system consisted of U-shaped GFRP or CFRP strip (U-strip) at end of FRP. The U-strips were bonded around the beam section and further anchored by two tufts of glass fibres, each of them embedded at the opposite beam face and specifically in the region of compression zone of the beam web. Experimental evaluations in simply supported lightly reinforced concrete (RC) beams strengthened with one GFRP or a CFRP sheet anchored at its ends by the composite anchorage have shown that their bending capacity has increased by 8% and 17%, respectively, in relation to the capacity attained in similar RC strengthened beams without anchorage. On the other hand, their ductility was improved by an amount of 94% and 37%, respectively.

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 Torsional Strengthening of Reinforced Concrete Beams with Externally-Bonded Fibre Reinforced Polymer: An Energy Absorption Evaluation

2020 ◽  
Vol 6 ◽  
pp. 69-85
Author(s):  
Mahir M. Hason ◽  
Ammar N. Hanoon ◽  
Ahmed W. Al Zand ◽  
Ali A. Abdulhameed ◽  
Ali O. Al-Sulttani
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Energy Absorption ◽  
Structural Damage ◽  
Absorption Capacity ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Concrete Compressive Strength ◽  
Externally Bonded ◽  
The Impact

The impacts of numerous important factors on the Energy Absorption (EA) of torsional Reinforced Concrete (RC) beams strengthened with external FRP is the main purpose and innovation of the current research. A total of 81 datasets were collected from previous studies, focused on the investigation of EA behaviour. The impact of nine different parameters on the Torsional EA of RC-beams was examined and evaluated, namely the concrete compressive strength (f’c), steel yield strength (fy), FRP thickness (tFRP), width-to-depth of the beam section (b/h), horizontal (ρh) and vertical (ρv) steel ratio, angle of twist (θu), ultimate torque (Tu), and FRP ultimate strength (fy-FRP). For the evaluation of the energy absorption capacity at different levels, Response Surface Methodology (RSM) was implemented in this study. Also, to fit the measured results, Quadratic and Line models were created. The results show that the RSM technique is a highly significant tool that can be applied not only to energy absorption-related problems examined in this research, but also to other engineering problems. An agreement is observed between Pareto and standardized charts with the literature showing that the EA capacity of the torsional FRP-RC beams is mostly affected by the concrete compressive strength, followed by the vertical reinforcement ratio. The newly suggested model in this article exhibits a satisfactory correlation co-efficient (R), of about 80%, with an adequate level of accuracy. The obtained results also reveal that the EA acts as a safety index for the FRP-strengthened RC beams exposed to torsional loadings to avoid sudden structural damage. Doi: 10.28991/cej-2020-SP(EMCE)-07 Full Text: PDF

scholarly journals Numerical Assessment of Reinforced Concrete Beams Strengthened with CFRP Sheets under Impact Loading

2021 ◽  
Vol 15 (58) ◽  
pp. 48-64
Author(s):  
Mohamed Emara ◽  
Nada Elkomy ◽  
Hilal Abdel Kader
Keyword(s):  
Reinforced Concrete ◽  
Impact Velocity ◽  
Impact Loading ◽  
Impact Load ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Rc Beams ◽  
Cfrp Sheets ◽  
Externally Bonded ◽  
The Impact

This paper investigates numerically the behavior of Reinforced Concrete (RC) beams, strengthened using Carbon Fiber Reinforced Polymers (CFRP) sheets, subjected to impact loading. Three-dimensional finite element analysis was performed and its results were verified against experimental ones available in the literature showing good agreement. Then, a comprehensive parametric study was performed to investigate the effect of studied parameters on the strengthened RC beams. The main studied parameters were type and size of reinforcing bars, geometric characteristics of externally bonded CFRP sheets (width, length, and thickness), impact velocity, and the position of the impactor with respect to the beam. Results showed that the use of externally bonded CFRP sheets enhanced the beam capacity and failure mode, and reduced the mid-span deflection. Moreover, a reduction in the mid-span deflection was observed due to the use of CFRP bars as internal reinforcement. On the other hand, the deflection was increased due to the increase of the impact velocity, and the change of the impact load position.

Sign in / Sign up

Export Citation Format

Share Document