scholarly journals Effect of CFRP Shear Strengthening on the Flexural Performance of the RC Specimen under Unequal Impact Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Yanhui Liu ◽  
Khalil Al-Bukhaiti ◽  
Hussein Abas ◽  
Zhao Shichun
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Shear Failure ◽  
Impact Load ◽  
Concrete Strength ◽  
Impact Behavior ◽  
Parameter Study ◽  
Dynamic Amplification Factor ◽  
Flexural Performance ◽  
The Impact

Strengthening with externally bonded CFRP reinforcement is widely used in structural reinforcement and attractive to stakeholders and engineers because of ease and speed of construction, corrosion resistance, lightweight, high strength, and versatility stiffness which can be oriented according to the need. Numerous research studies were carried out to explore RC beams’ flexural and shear performance when subjected to dynamic impact loading. The results were auspicious in using such a technique of strengthening. Regular square section reinforced concrete frame members strengthened by CFRP material is taken as the research object. However, little attention to the impact behavior of CFRP-shear-strengthened square reinforced concrete (RC) specimens has been paid. The dynamic response of CFRP to reinforced concrete members under unequal cross-impact is discussed. This paper investigates the effectiveness of CFRP strengthening on the square RC specimen in preventing shear failure and evaluation of the flexural performance of the strengthened specimen under the impact load. The drop hammer impact test is firstly conducted on RC specimens with and without CFRP strengthening. The results show that using CFRP to strengthen the RC specimen in shear is very effective at preventing shear failure and leading the specimen’s response to flexural domination. This result is also the motivation for developing a numerical model supported by experimental tests to study the flexural performance of strengthened RC specimens. It is found that the strengthened specimen is prone to exhibit pure bending deformation under the impact load in terms of dynamic amplification factor (DAF) for section moment. Then, an extensive parameter study is carried out to evaluate further the influence of impact velocity, reinforcement ratio, and concrete strength on the flexural performance of the strengthened specimen and CFRP layers. Such a holistic study may provide preliminary research regarding the use of CFRP to strengthen RC specimens in shear under impact loads and will enhance the current state of knowledge in this area; also, the optimal value of the CFRP reinforcement layer was proposed.

scholarly journals Impact Behavior of Composite Reinforced Concrete Beams with Pultruded I-GFRP Beam

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 441
Author(s):  
Teghreed H. Ibrahim ◽  
Abbas A. Allawi ◽  
Ayman El-Zohairy
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Loading ◽  
Static Loading ◽  
Reinforced Concrete Beams ◽  
Impact Behavior ◽  
Drop Height ◽  
Concrete Compressive Strength ◽  
Shear Connectors ◽  
The Impact

The present study experimentally and numerically investigated the impact behavior of composite reinforced concrete (RC) beams with the pultruded I-GFRP and I-steel beams. Eight specimens of two groups were cast in different configurations. The first group consisted of four specimens and was tested under static load to provide reference results for the second group. The four specimens in the second group were tested first under impact loading and then static loading to determine the residual static strengths of the impacted specimens. The test variables considered the type of encased I-section (steel and GFRP), presence of shear connectors, and drop height during impact tests. A mass of 42.5 kg was dropped on the top surface at the mid-span of the tested beams from five different heights: 250, 500, 1000, 1500, and 1900 mm. Moreover, nonlinear Finite Element (FE) models were developed and validated using the experimental data. Static loading was defined as a displacement-controlled loading and the impact loading was modeled as dynamic explicit analysis with different drop velocities. The validated models were used to conduct a parametric study to investigate the effect of the concrete compressive strength on the performance of the composite beams under static and impact loadings. For the composite specimen with steel I-sction, the maximum impact force was 190% greater than the reference specimen NR-I at a drop height of 1900 mm, whereas the maximum impact forces for the specimens composite specimens with GFRP I-sction without and with shear connectors were 19% and 77%, respectively, more significant than the reference beam at the same drop height. The high stiffness for the steel I-beams relative to the GFRP I-beam was the reason for this difference in behavior. The concrete compressive strength was more effective in improving the impact behavior of the composite specimens relative to those without GFRP I-beams.

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.

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.

The Impact Load on a Reinforced Concrete Beam

2021 ◽  
pp. 199-245
Author(s):  
Farzad Hejazi ◽  
Hojjat Mohammadi Esfahani
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Impact Load ◽  
Reinforced Concrete Beam ◽  
The Impact

scholarly journals The multiaxial behavior of filled polypropylene parts by drop-weight impact test

2018 ◽  
Vol 210 ◽  
pp. 05013 ◽  
Author(s):  
Ales Mizera ◽  
Martin Mizera ◽  
Milan Navratil ◽  
Stepan Sanda ◽  
Michal Opocensky
Keyword(s):  
Polymeric Material ◽  
Glass Fibre ◽  
Impact Loading ◽  
Material Properties ◽  
Impact Test ◽  
Impact Behavior ◽  
Suitable Choice ◽  
Penetration Test ◽  
Weight Impact ◽  
The Impact

This study deals with the multiaxial behaviour of reinforced polypropylene with 30 % of glass fibre (PP30GF) and virgin polypropylene (PP). The impact behavior of these two materials is very needed to know for the possible modification of these two materials to obtain the better material properties. The injection moulded PP, and PP30GF samples were subjected to the penetration test at different set potential energies, and the results were subsequently evaluated and discussed. It was found out that PP has better behaviour at the multiaxial stress than PP30GF. It is possible to claim that for the application more demanding to the impact loading, pure PP is more suitable choice of the polymeric material.

scholarly journals Nonlinear behaviour of reinforced concrete flat slabs after a column loss event

2018 ◽  
Vol 21 (14) ◽  
pp. 2169-2183 ◽  
Author(s):  
Justin M Russell ◽  
John S Owen ◽  
Iman Hajirasouliha
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Progressive Collapse ◽  
Nonlinear Behaviour ◽  
Dynamic Amplification Factor ◽  
Element Analysis ◽  
Flat Slab ◽  
Standard Design ◽  
Loss Event ◽  
Dynamic Amplification

Previous studies have demonstrated that reinforced concrete flat slab structures could be vulnerable to progressive collapse. Although such events are dynamic, simplified static analyses using the sudden column loss scenario are often used to gain an indication into the robustness of the structure. In this study, finite element analysis is used to replicate column loss scenarios on a range of reinforced concrete flat slab floor models. The model was validated against the results of scaled-slab experiments and then used to investigate the influence of different geometric and material variables, within standard design ranges, on the response of the structure. The results demonstrate that slab elements are able to effectively redistribute loading after a column loss event and therefore prevent a progressive collapse. However, the shear forces to the remaining columns were 159% of their fully supported condition and increased to 300% when a dynamic amplification factor of 2.0 was applied. It is shown that this can potentially lead to a punching shear failure in some of the slab elements.

Quasi-Static Lap Shear and Dynamic Impact of High Performance VHB™ Acrylic Foam and Adhesive Transfer Tape Bonded Aluminum Joints Subjected to Environmental Degradation

2005 ◽  
Author(s):  
Manoj Anakapalli ◽  
P. Raju Mantena ◽  
Ahmed Al-Ostaz ◽  
S. Jimmy Hwang
Keyword(s):  
High Performance ◽  
Shear Failure ◽  
Electrochemical Impedance ◽  
Impact Load ◽  
Bond Quality ◽  
Dynamic Impact ◽  
Impulse Frequency ◽  
Lap Shear ◽  
Failure Loads ◽  
The Impact

A range of 3M™ VHB™ acrylic foam tapes and high performance adhesive transfer tapes were used to bond 1” × 1/8″ (25.4 mm × 3.175 mm) aluminum 2024 T-4 adherends in single-lap joint (SLJ) and three-point end-notched flexure (ENF) configurations. Three types of 0.045” thick double-coated acrylic foam tapes: Foam 41, 50 and 52 (firm, soft and softer), and three types of adhesive transfer tapes: Adhesives 69, 73 and 85 (0.005”, 0.01” and 0.005” thick, respectively) were used for this study. The samples were subjected to two types of aggressive environments simulating extreme service conditions: freeze-thaw cycling from 10°F to 50°F at 6 cycles per day (ASTM C666 Procedure A) for 21 days with samples immersed in water; heat-cool cycling (with 90% of maximum recommended temperature by the manufacturer of both acrylic foam and adhesive transfer tapes attained at 70% relative humidity) and 3 cycles per day for 21 days. Initially the impulse-frequency response vibration and electrochemical impedance spectroscopy (EIS) techniques were used for monitoring bond quality nondestructively and selecting the best out of 250 fabricated samples. After obtaining baseline data, the specimens were subjected to quasi-static lap-shear and dynamic impact loading to compare their lap-shear failure loads and shear energy along with the impact load and energy absorbed.

Dynamic Response and Shear Demand of Reinforced Concrete Beams Subjected to Impact Loading

2019 ◽  
Vol 19 (08) ◽  
pp. 1950091 ◽  
Author(s):  
Wuchao Zhao ◽  
Jiang Qian
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Parametric Study ◽  
Shear Failure ◽  
Impact Force ◽  
Rc Beams ◽  
Local Response ◽  
Shear Demand ◽  
The Impact ◽  
Peak Impact Force

Reinforced concrete (RC) beams under the impact loading are typically prone to suffer shear failure in the local response phase. In order to enhance the understanding of the mechanical behavior of the RC beams, their dynamic response and shear demand are numerically investigated in this paper. A 3D finite-element model is developed and validated against the experimental data available in the literature. Taking advantage of the above calibrated numerical model, an intensive parametric study is performed to identify the effect of different factors including the impact velocity, impact mass and beam span-to-depth ratio on the impact response of the RC beams. It is found that, due to the inertial effect, a linear relationship exists between the maximum reverse support force and the peak impact force, while negative bending moments also appear in the shear span. In addition, the local response of the RC beams can be divided into a first impact stage and a separation stage. A shear plug is likely to be formed near the impact point at the first impact stage and a shear failure may be triggered near the support by large support forces. Based on the simulation results, simplified methods are proposed for predicting the shear demand for the two failure modes, whereas physical models are also established to illustrate the resistance mechanism of the RC beams at the peak impact force. By comparing with the results of the parametric study, it is concluded that the shear demand of the RC beams under the impact loading can be predicted by the proposed empirical formulas with reasonable accuracy.

scholarly journals Axial Impact Load of a Concrete-Filled Steel Tubular Member with Axial Compression Considering the Creep Effect

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3134 ◽  
Author(s):  
Tao Lan ◽  
Guangchong Qin ◽  
Jinzhao Zhuang ◽  
Youdi Wang ◽  
Qian Zheng ◽  
...  
Keyword(s):  
Impact Load ◽  
Slenderness Ratio ◽  
Concrete Strength ◽  
Pressure Ratio ◽  
Impact Resistance ◽  
Axial Pressure ◽  
Axial Impact ◽  
Creep Effect ◽  
The Impact ◽  
Peak Value

The dynamic loads acting on concrete-filled steel tubular members under axial impacts by rigid bodies were studied herein by FEM. The whole impact process was simulated and the time history of the impact load was obtained. The effects of eight factors on the axial impact load were studied; these factors were the impact speed, mass ratio, axial pressure ratio, steel ratio, slenderness ratio, concrete strength, impact position, and boundary conditions. Besides this, the effects of concrete creep on the impact load were also considered by changing the material parameters of the concrete. The results show that axial impact load changes with time as a triangle. The peak value of impact load increases and the impact resistance improves with the growth of the axial pressure ratio, steel ratio, slenderness ratio, and concrete strength after creep occurs. As the eccentricity of the axial impact acting on a concrete-filled steel tubular member increases, the peak value of the impact load decreases. The enhancement of constraints at both ends of the member can improve the impact resistance. The creep reduction coefficients for the peak axial impact load of a concrete-filled steel tubular member under axial compression and considering the creep effect over 6 months and 30 years are 0.60 and 0.55, respectively. A calculation formula for the peak value of impact load was suggested based on the existing formula, and its accuracy was proved by finite element calculation in this study.

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