Side Splitting Failure of RC Beams and Columns under Seismic Action As a Form of Shear Failure

This research paper present the experimental study of reinforce concrete beams strengthened by FRCM system in the shear area. All samples are without transverse reinforcement at the shear distance. First beams tested as control sample, with shear distance a/d=2. Another three beams tested with strengthening by FRCM system. Variable parameter is the level of initial load, before strengthening. The initial load values were 0, 0.3, 0.5 from carrying capacity of control samples. All RC beams were designed to fail in shear, even strengthened samples. In the result of this research we determined that fracture toughness of RC beams increases with a decrease of span to the effective depth ratio. Results are comparable with the increasing of bearing capacity. The first inclined crack opend in mid-height cross section at the load 50 kN at an angle equal to 450 and it does not depend on the shear span. The maximum width of inclined cracks decrease with decreasing of shear span. The maximum width of inclined cracks decrease with decreasing of the shear span. The maximum values of width of inclined cracks are fixed at the value of 0.55 - 0.85 mm. Using the limit crack opening width as criteria of exhaustion of serviceability (SLS) we saw that about 16 - 29% of bearing capacity still remains before the danger of shear failure of the beam.

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Embedded Connector in Severe Optimization of Steel Plate for Shear Strengthening of RC Beam: Experimental and Numerical Investigations

Advances in Civil Engineering ◽

10.1155/2018/4721431 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Md. Ashraful Alam ◽

Suliman A. Bakkar ◽

Shahnawaz A. Onik ◽

Kamal N. Mustapha

Keyword(s):

Shear Failure ◽

Steel Plate ◽

Maximum Load ◽

Rc Beams ◽

Reinforced Concrete Structure ◽

Shear Strengthening ◽

Maximum Increase ◽

Numerical Investigations ◽

Externally Bonded ◽

Major Factors

Environmental impact has become one of the major factors taken into consideration for recent civil engineering studies and projects. Thus, researchers have been concentrating on shear strengthening of existing reinforced concrete structure as an upgrade method instead of demolishing and reconstructing. In general, shear strengthening of RC beams using externally bonded steel plate has gained huge popularity. However, premature debonding of plates is the main drawback of the system, which could be mitigated using embedded connector; thus, the dimension of steel plate could be reduced significantly. Furthermore, numerical analysis on shear strengthening of beams using embedded connector would provide a great insight on the structural behavior. The aim of this research is to severely reduce the dimension of the steel plate using embedded connector for shear strengthening of RC beams and to investigate the performances of optimized shear-strengthened beams through experimental and numerical investigations. The results showed that the dimension of plate was reduced without debonding of the plate if the beam was designed for shear strengthening with the consideration of yield strength of steel plate and shear link. Experimental results showed a maximum increase in failure of 24%. The numerical results predicted accurately the structural performance of beams. The embedded connector had a great effect in deferring and minimizing the debonding failure and accordingly increasing the maximum load of shear failure between 14.5% and 24% compared to control beam.

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

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455419500913 ◽

2019 ◽

Vol 19 (08) ◽

pp. 1950091 ◽

Cited By ~ 2

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.

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Fire Resistance Investigation of Simple Supported RC Beams with Varying Reinforcement Configurations

Advances in Civil Engineering ◽

10.1155/2019/8625360 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Yamin Song ◽

Chuanguo Fu ◽

Shuting Liang ◽

Ankang Yin ◽

Longji Dang

Keyword(s):

High Temperature ◽

Fire Resistance ◽

Room Temperature ◽

Shear Failure ◽

Failure Time ◽

Shear Capacity ◽

Reinforcement Ratio ◽

Longitudinal Reinforcement ◽

Rc Beams ◽

Vertical Deflection

To investigate fire-resistance behaviors of simple supported reinforced concrete (RC) beams with three faces exposed to fire, six full-scale specimens were designed in accordance with the principle of “strong bending and weak shearing.” One beam was treated as the control case of room temperature while the other five beams were exposed to high temperature. Parameters related to shear capacity were discussed, such as longitudinal reinforcement ratio and stirrup ratio. The experimental results show that brittle shear failure under room temperature may transfer to shear-bend failure at high temperature due to thermal expansion and strength degradation of concrete and steel. The greater the longitudinal reinforcement ratio, the longer the failure time of specimens. It indicates that the pinning action of longitudinal reinforcement can significantly improve the shear capacity of beams under high temperature. In addition, the configuration of stirrup reinforcement can effectively reduce the brittle change of vertical deflection when the beam enters the failure stage.

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Size Effect of Uniaxial Compressive Strength of Limestone

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.233 ◽

2012 ◽

Vol 229-231 ◽

pp. 233-238 ◽

Cited By ~ 1

Author(s):

Ze Hui Chen ◽

Chang Wu Liu ◽

Ji Wei Deng

Keyword(s):

Compressive Strength ◽

Elastic Modulus ◽

Size Effect ◽

Shear Failure ◽

Testing Machine ◽

Peak Strain ◽

Test Results ◽

Effect Model ◽

Splitting Failure ◽

Uniaxial Compressive Test

Using the MTS testing machine, the uniaxial compressive test of varisized da-qing limestones were undertaken, and the effect of dimensions about compressive strength, peak strain, elastic modulus and destructional forms of rock specimens were studied. It demonstrates that along with the increase of length-diameter ratio, peak strain and compressive strength turn smaller, elastic modulus gradually increases, the destruction of rock samples have a transformation from splitting failure to shear failure. Combined with the test results, Obert L model and Yang Shengqi model, the two size-effect models with extensive applications are analyzed and contrasted. And the conclusion is drawn that Obert L model has a relatively broad applicability, while Yang Shengqi model has a stronger Targeting and higher accuracy. Thus based on the Yang Shengqi model, the size-effect model of da-qing limestone is put forward, and the result indicates that this model corresponds well with the test results, having certain practical value.

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CONTRIBUTION OF CONCRETE TO SHEAR STRENGTH OF RC BEAMS FAILING IN SHEAR

Journal of Civil Engineering and Management ◽

10.3846/13923730.2012.757560 ◽

2013 ◽

Vol 19 (3) ◽

pp. 400-408 ◽

Cited By ~ 6

Author(s):

Guray Arslan ◽

Zekeriya Polat

Keyword(s):

Shear Strength ◽

Shear Failure ◽

Plastic Hinge ◽

Transverse Reinforcement ◽

Rc Beams ◽

Earthquake Resistant ◽

Earthquake Resistant Structures ◽

Shear Failures ◽

Beam Plastic Hinge ◽

Shear Demand

Reinforced concrete (RC) beams with light transverse reinforcement are vulnerable to shear failure during seismic response. In order to prevent brittle shear failures at beam plastic hinge regions of earthquake-resistant structures, the Turkish Earthquake Code and ACI318 require the use of sufficient transverse reinforcement to resist the total expected shear demand. These codes tend to be excessively conservative and, in some cases, the contribution of the concrete to the shear strength is neglected. The aim of this study is to investigate the contribution of concrete to shear strength of RC beams failing in shear experimentally. The beams were tested under monotonically increasing reversed cyclic loading to determine the concrete contribution to shear strength. It is observed that the concrete contribution to the shear strength at ultimate state ranges from 18% to 69% of the ultimate strength.

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Implication of Unbondedness in Reinforced Concrete Beams

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.587.36 ◽

2012 ◽

Vol 587 ◽

pp. 36-41 ◽

Cited By ~ 1

Author(s):

S.F.A. Rafeeqi ◽

S.U. Khan ◽

N.S. Zafar ◽

T. Ayub

Keyword(s):

Shear Strength ◽

Reinforced Concrete ◽

Failure Mode ◽

Shear Failure ◽

Concrete Beams ◽

Experimental Results ◽

Reinforced Concrete Beams ◽

Rc Beams ◽

Flexural Capacity ◽

Flexural Reinforcement

In this paper, behaviour of nine (09) RC beams (including two control beams) after unbonding and exposing flexural reinforcement has been studied which were intentionally designed and detailed to observe flexural and shear failure. Beams have been divided into three groups based on failure mode and unbounded and exposed reinforcement. Beams have been tested under two-point loading up to failure. Experimental results are compared in terms of beam behaviour with respect to flexural capacity and failure mode which revealed that the exposed reinforcement does not altered flexural capacity significantly and unbondedness positively influences shear strength; however, serviceability performance of beams with unbonded and exposed reinforcement is less.

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THE EFFECTS OF INCLINED SHEAR REINFORCEMENT IN REINFORCED CONCRETE BEAM

Malaysian Journal of Civil Engineering ◽

10.11113/mjce.v30.169 ◽

2018 ◽

Vol 30 (1) ◽

Cited By ~ 1

Author(s):

Nor Fazlin Zamri ◽

Roslli Noor Mohamed ◽

NurHafizah A. Khalid ◽

Kang Yong Chiat

Keyword(s):

Reinforced Concrete ◽

Concrete Beam ◽

Shear Failure ◽

Reinforced Concrete Beam ◽

Rc Beam ◽

Rc Beams ◽

Shear Reinforcement ◽

Strain Behaviour ◽

Different Types ◽

Loading System

This paper presents the findings of an experimental data on the effects of inclined shearreinforcement in reinforced concrete (RC) beam. Two types of shear reinforcement of RC beamwere investigated, conventional stirrups (vertical links) and inclined shear reinforcement (45degrees of inclined shear reinforcement). The RC beam with conventional stirrups wasdesignated as a control specimen. The RC beams with different types of shear reinforcementwere tested for shear under four-point loading system. Comparisons were made between bothtypes of RC beam on load-deflection, load-steel strain, load-concrete strain behaviour and modeof failure. The theoretical and experimental were calculated by using conventional formulation inaccordance to EC 2 in order to verify the experimental results. From the results, it was observedthat the RC beam with 45 degree inclined shear reinforcement improved structural performancein shear by approximately 20% and thus prolong the shear failure behaviour as compared to theRC beam with vertical links.

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Investigations of Coal-Rock Parting-Coal Structure (CRCS) Slip and Instability by Excavation

Shock and Vibration ◽

10.1155/2021/1715644 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Guang-Jian Liu ◽

Heng Zhang ◽

Ya-Wei Zhu ◽

Wen-Hao Cao ◽

Xian-Jun Ji ◽

...

Keyword(s):

Shear Failure ◽

P Wave ◽

Shear Behaviour ◽

Failure Zone ◽

Stick Slip ◽

Coal Structure ◽

P Wave Velocity ◽

Splitting Failure ◽

Shear And Tensile Cracks ◽

Coal Rock

Slip and instability of coal-rock parting-coal structure (CRCS) subjected to excavation disturbance can easily induce coal-rock dynamic phenomena in deep coal mines. In this paper, the failure characteristics and influencing factors of CRCS slip and instability were investigated by theoretical analysis, numerical simulations, and field observations. The following main results are addressed: (1) the slip and instability of CRCS induced by excavation are due to stress release, and the damage of the rock parting is partitioned into three parts: shear failure zone, slipping zone, and splitting failure zone from inside to outside with slip; (2) the slip and instability process of CRCS is accompanied by initiation, expansion, and intersection of shear and tensile cracks. The development of the cracks is dominated by shear behaviour, while the tensile crack is the main factor affecting fracture and instability of CRCS; and (3) slip and instability of CRCS are characterized by stick-slip first and then stable slip, accompanied with high P-wave velocity and rockburst danger coefficient based on microseismic tomography.

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