Experimental Study on Strength and Failure Characteristics of Reinforced Concrete Plate under Complex Stresses Conditions

2013 ◽  
Vol 357-360 ◽  
pp. 699-704 ◽  
Author(s):  
Guang Yang ◽  
Zuo Zhou Zhao ◽  
Xiao Gang He
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Biaxial Tension ◽  
Reduction Factor ◽  
Failure Characteristics ◽  
Concrete Plate ◽  
Principal Tensile Stress ◽  
Force Ratio ◽  
Practical Engineering

To study the biaxial strength and failure characteristics of reinforced concrete in the state of biaxial tension-compression stresses and provide some suggestions for the practical engineering design, 3 one-third scale reinforced concrete (RC) plate specimens are tested. The results indicate that, in biaxial tension-compression stresses, reinforced concrete cracks in the direction normal to the principal tensile stress direction and presents the characteristics of shear failure modes. The test device could simulate the required stress condition. The compression strength of reinforced concrete is obviously lower than the uniaxial strength fc. The reduction factor k is about 0.55~0.75 which varies with different tension-compression force ratio. Concrete material takes part in the tension process of reinforced concrete and shares part of the tension, while the share ratio decreases as concrete cracks gradually.

Experimental Study and Numerical Simulation for Explosion and Phenomena of RC Slabs

2014 ◽  
Vol 501-504 ◽  
pp. 1096-1103
Author(s):  
Hong Xiao Wu ◽  
Hao Zhe Xing ◽  
Zhi Fang Yan
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Loading Condition ◽  
Damage Mechanism ◽  
Failure Characteristics ◽  
Explosion Pressure ◽  
Concrete Plate ◽  
Solid Models ◽  
Calculation Results ◽  
Rc Slabs

The blast impact dynamic experiment of reinforced concrete rectangular plate with simply supported boundary conditions was performed using explosion pressure simulator. With 3-D FEM software LS-DYNA, the separate solid models of concrete and steel were established and 3-D FEM dynamic analysis of the experiment process was carried out. Compared calculation results to experiment results synthetically, the damage mechanism and failure characteristics of reinforced concrete plate under explosion impact loading condition were got and it is also verified that the H-J-C model can approximately simulate the concrete properties well under explosion impact loading condition.

scholarly journals A Design Method to Induce Ductile Failure of Flexural Strengthened One-Way Reinforced Concrete Slabs

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7647
Author(s):  
Huy Q. Nguyen ◽  
Tri N. M. Nguyen ◽  
Do Hyung Lee ◽  
Jung J. Kim
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Design Method ◽  
Concrete Slab ◽  
Ductile Failure ◽  
Reinforced Concrete Slabs ◽  
Failure Loads ◽  
Ultimate Failure ◽  
Rc Slabs

Strengthening existing reinforced concrete (RC) slabs using externally bonded materials is increasingly popular due to its adaptability and versatility. Nevertheless, ductility reduction of the rehabilitated flexural members with these materials can lead to brittle shear failure. Therefore, a new approach for strengthening is necessary. This paper presents a methodology to induce ductile failure of flexural strengthened one-way RC slabs. Ultimate failure loads can be considered to develop the proposed design methodology. Different failure modes corresponding to ultimate failure loads for RC slabs are addressed. Flexural and shear failure regions of RC slabs can be established by considering the failure modes. The end span of the concrete slab is shown for a case study, and numerical examples are solved to prove the essentiality of this methodology.

scholarly journals Seismic Failure Modes and Deformation Capacity of Reinforced Concrete Columns under Cyclic Loads

2017 ◽  
Vol 62 (1) ◽  
pp. 80-91 ◽  
Author(s):  
Ma Ying ◽  
Gong Jin-xin
Keyword(s):  
Reinforced Concrete ◽  
Aspect Ratio ◽  
Axial Load ◽  
Failure Modes ◽  
Shear Failure ◽  
Hysteresis Loops ◽  
Load Ratio ◽  
Deformation Capacity ◽  
Static Test ◽  
Total Displacement

This paper investigates the seismic failure modes and horizontal deformation capacity of reinforced concrete square columns based on the pseudo-static test. The controlled variables include shear aspect ratio, axial load ratio and stirrup spacing. The seismic failure modes, the inelastic deformation capacity after yielding and the deformation components due to flexure, shear and anchorage slip of the RC columns were analyzed, especially flexural-shear failure. The results show that decreasing shear aspect ratio, or increasing axial load or stirrup spacing can result in the change of column failure mode from flexural failure to flexural- shear failure or shear failure, the pinching of hysteresis loops, the reductions of hysteresis loop area and deformation capacity. With the increase of total displacement, all three displacement components increased; the contribution of flexure displacement in total displacement reduced, the contribution of shear displacement increased, the contribution of anchorage slip displacement changed in the range of 30%- 40%.

scholarly journals Experimental Study and Damage Model on the Seismic Behavior of Reinforced Concrete L-Shaped Columns under Combined Torsion

2020 ◽  
Vol 10 (19) ◽  
pp. 7008
Author(s):  
Deyi Xu ◽  
Yang Yang ◽  
Zongping Chen
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Plastic Hinge ◽  
Combined Loading ◽  
Equivalent Viscous Damping ◽  
Axial Compression Ratio

Due to the advantage of saving indoor space, a special-shaped column frame attracted more attention of the engineers and researchers. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) L-shaped columns under compression-flexure-shear-torsion combined loadings to investigate the effect in the ratio of torsion to moment (T/M) and axial compression ratio (n) on their seismic performance. The results showed that the failure modes of L-shaped specimens included bending failure, bending-torsion failure, and torsion-shear failure with the hysteretic curves exhibiting S shape. With the increase of T/M ratio, cracks on the flange developed more fully, and the height of plastic hinge decreased and torsion bearing capacity improved. Besides, as the T/M ratio increased the twist ductility increased, while displacement ductility decreased. On the other hand, with a higher axial compression ratio, torsion bearing capacity and bending stiffness were both increased. Moreover, the equivalent viscous damping coefficient of bending and torsion were 0.08~0.28 and 0.13~0.23, respectively. The average inter-story drift ratio met the requirements of the Chinese standard. Finally, two modified models were proposed to predict the progression of damage for the L-shaped column under combined loading including torsion.

scholarly journals Failure Behaviour of Sandstone with a Preexisting Joint under Stepped Excavation

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Yinzhu Liu ◽  
Ping Cao ◽  
Liwen He ◽  
Qibin Lin
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Normal Load ◽  
Crack Coalescence ◽  
Tensile Failure ◽  
Type I ◽  
Failure Characteristics ◽  
Excavation Process ◽  
Spalling Failure ◽  
Shear Slip

Much geotechnical construction needs to be carried out under the condition of stepped excavation. However, there is still a lack of research on crack coalescence and failure modes of jointed rock mass under stepped excavation conditions. In order to simulate the stepped excavation test of the real project, the polylactic acid (PLA) material is selected as the filler for the excavation area. The stepped excavation tests are performed on sandstone specimens containing a preexisting joint under different normal load conditions. The dynamic stepped excavation of simulating excavate rock engineering is realised. The constant normal loads during the excavation process are determined to be 80 kN and 100 kN. The influence of the joint inclination on the failure characteristics of the excavation process is analysed. Four typical failure modes are summarised: (a) Mode I: crack coalescence of tensile failure; (b) Mode II: crack coalescence of mixed failure; (c) Mode III: without crack coalescence of mixed failure; (d) Mode IV: without crack coalescence of shear failure. Furthermore, the failure characteristics of the area above the excavation hole and the preexisting joint are analysed. The results show that there are three failure modes: (a) Type I: spalling failure; (b) Type II: shear slip failure; (c) Type III: shear slip and spalling mixed failure.

Experimental Researches on Fire Resistance of CFS Shear Strengthened Reinforced Concrete Beams

2011 ◽  
Vol 335-336 ◽  
pp. 1186-1189
Author(s):  
He Fan ◽  
Jun Yu Liu ◽  
Bao Kuan Ning
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Failure Modes ◽  
Shear Failure ◽  
Fire Retardant ◽  
Reinforced Concrete Beams ◽  
Insulation Material ◽  
Rc Beams ◽  
Fire Resistance Rating ◽  
Resistance Rating

Fire-resistance performance experiments with static loading-fire are investigated about one carbon fiber sheet（CFS） shear strengthened and one without CFS strengthened reinforced concrete (RC) beams exposed to the ISO834 standard fire. Shear strengthened RC beams are wrapped with fire insulation material- thick painted fire retardant coatings. Relationship between measure points temperature, displacement and time are achieved. The results suggest that: the ratio of shear-span is the main factor to fire-resistance rating and failure modes of CFS shear strengthened RC beams in fire; shear-failure fire-resistance rating are increased by thickening fire insulation to shear strengthened RC beams; mid-span deflection of shear failure is approximate one half of bending failure when shear strengthened RC beams.

scholarly journals Strength and Failure Characteristics of Saturated Sandstone Under Loading and Unloading

2021 ◽  
Author(s):  
Zhenhua Zhang ◽  
Huayan Yao ◽  
Hongguo Li ◽  
Hanbin Bian ◽  
Dayong Zhu
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Water Saturation ◽  
Triaxial Compression ◽  
Axial Direction ◽  
Confining Pressure ◽  
Stress Path ◽  
Failure Characteristics ◽  
Dry Conditions ◽  
Unloading Confining Pressure

Abstract Water has effects on the strength and failure characteristics of the sandstone in natural environment. Conventional triaxial compressive or unloading confining pressure experiments were conducted on sandstone specimens. Experimental results indicate that the compressive strength of sandstone decreases significantly under saturated conditions in comparison with dry conditions, the strength parameters of saturated specimens under unloading confining pressure are also lower than those of dry rock samples; for the sandstone with the same water content, the strengths under triaxial unloading confining pressure is slightly higher than those under triaxial compressive condition; compared with the stress path of triaxial compression, the stress path of unloading confining pressure makes cracks propagate more easily along the axial direction, and the angle between fracture surface and axial direction is smaller. Under triaxial unloading confining pressure, there failure modes of dry sandstone are tension failure and shear failure, while that of saturated sandstone is mainly shear failure. In the process of water saturation, the bond and friction characteristics between grain particles are degraded due to water weakening the cementation between the grain particles and softening grains boundary, and the expansion of clay minerals in the sandstone, which leads to the decrease of macroscopic mechanical strengths.

Investigating the Load–Deflection of FRP Material in Concrete Beams Wrapped with CFRP in Universal Testing Machine (UTM)

2018 ◽  
Vol 15 (2) ◽  
pp. 744-751
Author(s):  
S. Margaret Jesse ◽  
V. M. Shanthi
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Testing Machine ◽  
Reinforced Concrete Beams ◽  
Flexural Failure ◽  
Reinforced Polymer ◽  
Cfrp Sheet ◽  
Strength And Stiffness

Strengthening Reinforced Concrete (RC) beams using FRP laminate becomes one of the main strengthening techniques. Failure of these beams is usually controlled by the bond strength between the laminate and the concrete. This paper presents the results of experimental investigation on six reinforced concrete beams, with various types, which were tested under two-point loading. The aim of the work was to study the efficacy of Carbon Fiber Reinforced Polymer (CFRP) sheets in enhancing the beam strength and stiffness from shear failure or flexural failure. The strengthening and deflection of the beams were carried out with cyclic loading. Experimental data on ultimate load, deflection and failure modes of each of the beams were obtained. For the comparison of CFRP sheet with cement concrete and the retrofitted specimens absorbs more energy, the CFRP beams yield a good result.

Experimental Behavior of Square Tubed-Reinforced-Concrete Column to RC Beam Joints with Internal Diaphragms under Cyclic Loading

2018 ◽  
Vol 763 ◽  
pp. 779-786 ◽  
Author(s):  
Dan Gan ◽  
Zheng Zhou ◽  
Xu Hong Zhou
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Failure Modes ◽  
Shear Failure ◽  
Steel Tube ◽  
Rc Beam ◽  
Reinforced Concrete Column ◽  
Current Test ◽  
Panel Zone ◽  
Test Parameters

This paper describes experimental investigation on three square tubed-reinforced-concrete (TRC) column to reinforced concrete (RC) beam joints with internal diaphragms subjected to cyclic loading, where width-to-thickness ratios of the steel tube in the panel zone and levels of axial load were selected as test parameters. Two failure modes, namely, joint shear failure and beam failure + bond failure were observed in the current test. Test results showed that the proposed composite joints exhibited favorable seismic performance.

scholarly journals The load-bearing behaviour of a reinforced concrete beam investigated by optical measuring techniques

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
Götz Hüsken ◽  
Stephan Pirskawetz ◽  
Detlef Hofmann ◽  
Frank Basedau ◽  
Klaus-Peter Gründer ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Failure Modes ◽  
Shear Failure ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Fibre Bragg Grating ◽  
Load Bearing ◽  
Measuring Techniques ◽  
Deformation Measurements

AbstractBending beams and slabs are typical examples for structural elements used for reinforced concrete structures such as bridge girders, T-beams and bridge decks. Their strength related failure modes at maximum loading can be divided into bending and shear failure. The failure of beams loaded in bending can occur with or without indication. Therefore, conventional design concepts aim on failure modes with sufficient indication (e.g. large deflections or cracks), as it occurs in the case of secondary flexural compression failure. These indicating factors can also be used for Structural Health Monitoring (SHM) of civil infrastructure systems (e.g. bridges) to identify structural changes. In this context, non-destructive testing (NDT) methods offer different techniques for measuring deflections or crack formation and opening. However, profound knowledge on the determining failure modes of bending beams and their detection by NDT methods is required for the reliable application of SHM. Different NDT methods have been used in this study for analysing the load-bearing behaviour of a reinforced concrete beam in bending. The different measuring techniques are briefly described and their applicability is discussed by means of experimental results. For this purpose, the load-bearing behaviour of a reinforced concrete beam having a span of 2.75 m was investigated in a four-point bending flexural test at laboratory scale. The focus is on the characterization of determining failure modes by optical NDT and the comparison with classical measuring techniques (e.g. deformation measurements by displacement transducers). The bending beam was equipped with two single-mode (SM) sensor fibres. One fibre served as Distributed Optical Fibre Sensor (DOFS), whereas the other fibre contained Fibre Bragg Grating (FBG) sensors. In addition, optical deformation measurements using Digital Image Correlation (DIC) and Stereophotogrammetry (SP) were conducted.

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