scholarly journals Experimental Study and Failure Criterion Analysis on Combined Compression-Shear Performance of Self-Compacting Concrete

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 713 ◽  
Author(s):  
Jingrong Wang ◽  
Faxiang Xie ◽  
Chuanlong Zhang ◽  
Jing Ruan
Keyword(s):  
Residual Stress ◽  
Shear Strength ◽  
Axial Compression ◽  
Failure Modes ◽  
Shear Failure ◽  
Experimental Results ◽  
Compression Stress ◽  
Self Compacting Concrete ◽  
Cohesive Stress ◽  
Shear Performance

To investigate the combined compression-shear performance of self-compacting concrete (SCC), eight groups of concrete specimens under different axial compression ratios were designed, and the composite performance under different axial stresses was carried out by hydraulic servo machine. The uniaxial and tensile splitting strength of SCC were also included in the study. The failure modes of SCC were presented, discussed, and compared with normal concrete (NC). The characteristic points of stress-strain curves of SCC specimens from the experiments were extracted and analyzed under different axial compression stress. Based on the experimental results, the shear strength of compression-shear load was divided into cohesive stress and residual friction stress. The variation of residual stress and cohesive stress under the combined compression-shear stress was analyzed, and the relationship was obtained by numerical regression. Research results indicated that the residual stress increases linearly with the compression stress while the cohesive stress increased at first and then decreased. The research found that the friction coefficient of SCC was much smaller than NC due to the lack of interlocking effect. Utilizing the compression-shear strength of SCC, the material failure criteria of SCC were proposed from the view of shear failure strength and octahedral stress space, which could fit the experimental results confidently following the mathematical regression analysis. The comparison with data from other literature shows favorable consistence with the obtained criteria. The results of the study could be beneficial complement in engineering practices where SCC was applicable.

Investigation into Impact of Column Rectangularity on Shear Strength of No-Stirrup Rc Members in General Shear

2010 ◽  
Vol 163-167 ◽  
pp. 1456-1459
Author(s):  
Da Ren ◽  
Chao Yang Zhou
Keyword(s):  
Shear Strength ◽  
Regression Analysis ◽  
Lower Bound ◽  
Failure Modes ◽  
Shear Failure ◽  
Unified Model ◽  
Design Equation ◽  
Physical Explanation ◽  
New Approach ◽  
Practical Concern

Based on the links among various shear failure modes and the unified model for beam-like shear and symmetrical punching previously proposed, a new approach is presented to allow for the effect of column rectangularity on the shear capacities of members in general shear, which includes punching and beam-like shear as two particular extremes. In succeeded regression analysis, linear metric form is selected out of practical concern, and a lower-bound design equation is finally developed that can not only measure the influence of this variable on members in general shear, but can give a clear physical explanation to the measurement, as is absent in certain codes.

Implication of Unbondedness in Reinforced Concrete Beams

2012 ◽  
Vol 587 ◽  
pp. 36-41 ◽  
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.

scholarly journals Test on Hysteretic Behaviour of Prestressed Composite Joints with Concrete-Encased CFST Columns

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Kun Wang ◽  
Huihui Luo
Keyword(s):  
Energy Dissipation ◽  
Axial Compression ◽  
Compression Ratio ◽  
Failure Modes ◽  
Shear Failure ◽  
Hysteretic Behaviour ◽  
Axial Compression Ratio ◽  
Flexural Failure ◽  
Composite Joint ◽  
Cfst Columns

Four composite joint specimens consisted of concrete-encased steel beams and concrete-encased concrete-filled steel tube (CFST) columns were tested under lateral cyclic loading, in which three specimens were prestressed and the other was not. In the tests, crack distributions and failure modes of the joint specimens were acquired, and the energy dissipation, rigidity degeneration, ductility, and residential deformation were investigated. Meanwhile, the strain variation of longitudinal rebars and I-steel flanges at beam ends as well as steel tubes in panel zones were analysed. The experimental results showed that a type of mixed mode consisting of shear failure in the panel zone and flexural failure at beam ends was found for three prestressed joint specimens, whilst only flexural failure at beam ends was observed for the non-prestressed one, and all joint specimens showed good hysteretic behaviour. In addition, as can be seen from the skeleton curves, the lateral peak loads of prestressed joint specimens could be enhanced to some extent by increasing the prestressing level, and the axial compression ratio had little effect on lateral loads; meanwhile, the ductility and energy dissipation for prestressed joint specimens also could be reduced by increasing the prestressing level and axial compression ratio.

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 Experimental Study of the Shear Performance of Scrap Tire-Granular Material Composite Columns

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Fengchi Wang ◽  
Xiaomei Nie ◽  
Hanyu Zhao ◽  
Haiming Hu
Keyword(s):  
Shear Strength ◽  
Shear Failure ◽  
Lateral Displacement ◽  
Vertical Force ◽  
Scrap Tire ◽  
Stress Strain ◽  
Composite Columns ◽  
Failure Patterns ◽  
Loading Mode ◽  
Shear Performance

Scrap tires filled with granular materials can be used for geotechnical engineering. However, when subjected to earthquakes and other conditions, shear failure occurs between the tires. In this paper, eight groups of tire-sand composite columns are prepared and tested under shear strength tests. Different vertical forces, sand densities, and loading modes are considered to investigate the shear performance. The failure patterns, load-displacement curves, and stress-strain curves are observed. The results show that the shear failure of composite undergoes three typical stages: overall flexural lateral displacement, transverse compression, and relative interfacial slip. Under monotonic loading, the restriction of the transverse deformation of the composite column is enhanced with increasing vertical force. The overall antidisturbance ability of the composite is enhanced with increasing sand density. The cyclic loading mode can improve the lateral stiffness of the tire-sand composite. The relative motion between the tire-sand interfaces has two forms: elastic creep and interface sliding. Under the hoop effect of the tire, the pores between the particles produce a pseudocohesive force, which causes the shear strength of the tire-sand composite to be higher than that of common sand. A formula is obtained to describe the stress-strain variations in the composite under different vertical forces.

Shear Strength of Concrete and Gypsum Composite Walls

2013 ◽  
Vol 368-370 ◽  
pp. 976-983 ◽  
Author(s):  
Kang Liu
Keyword(s):  
Shear Strength ◽  
Glass Fiber ◽  
Shear Failure ◽  
Design Procedure ◽  
Green Product ◽  
Ultimate Shear Strength ◽  
Glass Fiber Reinforced ◽  
Shear Performance ◽  
Save Energy ◽  
Composite Walls

Gypsum walls are a green product that helps to save energy and protect the environment. This paper investigates the shear strength of glass fiber reinforced gypsum (GFRG) walls fully or partially filled with concrete in the hollow cores. Eight full scale GFRG walls were tested. The shear performance of the tested walls, including the shear failure mode, hysteresis responses, the ultimate shear strength were studied in the paper. A design procedure for the shear strength of the concrete filled GFRG walls is developed.

Copper, Silver, and PCC Wirebonds Reliability in Automotive Underhood Environments

2018 ◽  
Author(s):  
Pradeep Lall ◽  
Shantanu Deshpande ◽  
Luu Nguyen
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
Failure Modes ◽  
Shear Failure ◽  
High Reliability ◽  
Electrical Response ◽  
Process Window ◽  
Mechanical Degradation ◽  
Electric Response ◽  
Trade Offs

Wire bonding is popular first-level interconnect method used in the semiconductor device packaging. Gold (Ag) wire is often used in high-reliability applications. Typical wire diameters vary between 0.8mil to 2mil. Recent increases in the gold-price have motivated the industry to search for alternate materials candidates for use in wirebonding. Three of the leading candidates are Silver (Ag), Copper (Cu), and Palladium Coated Copper (PCC). The new material candidates are inexpensive in comparison with gold and may have better electrical, and thermal properties, which is advantageous for fine pitch-high density electronics. The transition, however, comes along with few trade-offs such as narrow process window, higher wire-hardness, increased propensity for chip-cratering, lack of reliability knowledge base of when deployed in harsh environment applications. Relationship between mechanical degradation of the wirebond and the change in electric response needs to be established for better understanding of the failure modes and their respective mechanisms. Understanding the physics of damage progression may provide insights into the process parameters for manufacture of more robust interconnects. In this paper, a detailed study of the electrical and mechanical degradation of wirebonds under high temperature exposure is presented. Four wirebond candidates (Au, Ag, Cu and PCC) bonded onto Aluminum (Al) pad were subjected to high temperature storage life until failure to study the degradation of the bond-wire interface. Same package architecture and electronic molding compound (EMC) were used for all four candidates. Detailed analysis of intermetallic (IMC) phase evolution is presented along with quantification of the phases and their evolution over time. Ball shear strength was measured after decapsulation. Measurements of shear strength, shear failure modes, and IMC composition have been correlated with the change in the electrical response. Change in shear strength and different shear failure modes for different wirebond systems are discussed in the paper.

scholarly journals Double-walled Pipe Preparation by Tensile Method and Experimental Verification of Safety

2021 ◽  
Author(s):  
Ruogu Zhang ◽  
Xiang Zan ◽  
Yinbo Zhu ◽  
HengAn Wu ◽  
Ping Gu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Transfer Function ◽  
Axial Compression ◽  
Experimental Verification ◽  
Special Kind ◽  
Experimental Results ◽  
Experimental Sample ◽  
X Ray Diffraction ◽  
X Ray

Abstract Double-walled metal pipe is a special kind of pipe that maintains both heat transfer function and safety. In this paper, a method of fabricating double-walled pipes using tensile stresses is presented. The residual stress of the experimental sample was measured by X-ray diffraction. The behavior of pre-cracked pipes under axial compression was tested both experimentally and simulatively. The buckling deformation of the pipe causes the outer pipe to bulge up at the crack and separate from the inner pipe. The experimental results demonstrated this method can be used to construct effective double-walled pipes with properties that prevent cracks from penetrating the interface between the two layers of pipe.

scholarly journals Shear strength of steel–concrete–steel sandwich deep beams: A simplified approach

2018 ◽  
Vol 22 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Yubing Leng ◽  
Xiaobing Song
Keyword(s):  
Shear Strength ◽  
Analytical Model ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Strength ◽  
Upper And Lower Bounds ◽  
Deep Beams ◽  
Concrete Core ◽  
Simplified Approach ◽  
Triangular Area

Steel–concrete–steel composite structure comprises a concrete core sandwiched between the outer steel plates. It combines the advantages of both steel and reinforced concrete structures. In thick steel–concrete–steel structural members, the shear performance becomes rather critical. Experimental works have been carried out to study the failure mode and shear strength of steel–concrete–steel deep beams, and an analytical model has been proposed. In this article, parametric studies are carried out on the original analytical model to discuss the influence of each geometric and material variable on the shear strength, and a simplified strength predicting method is developed. Different shear failure modes, identified as “top+bottom triangular area damage” or “bottom triangular area damage+horizontal cracking,” can be predicted with the method. The simplified approach shows good correlation with the experimental results, regarding to shear resisting pattern and failure modes. Through the simplified formulas, the upper and lower bounds of the shear resistance are obtained. The requirement on stud spacing to maintain full composite behavior in the top and bottom triangular areas and the requirement on concrete strength are proposed.

scholarly journals Experimental and numerical evaluations of composite concrete-to-concrete interfacial shear strength under horizontal and normal stresses

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252050
Author(s):  
M. Yahya Al-Fasih ◽  
M. E. Mohamad ◽  
I. S. Ibrahim ◽  
Y. Ahmad ◽  
M. A. Mohd Ariffin ◽  
...  
Keyword(s):  
Shear Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Zone Model ◽  
Normal Stresses ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Surface Textures ◽  
Roughened Surface

Effects of different surface textures on the interface shear strength, interface slip, and failure modes of the concrete-to-concrete bond are examined through finite element numerical model and experimental methods in the presence of the horizontal load with ‘push-off’ technique under different normal stresses. Three different surface textures are considered; smooth, indented, and transversely roughened to finish the top surfaces of the concrete bases. In the three-dimensional modeling via the ABAQUS solver, the Cohesive Zone Model (CZM) is used to simulate the interface shear failure. It is observed that the interface shear strength increases with the applied normal stress. The transversely roughened surface achieves the highest interface shear strength compared with those finished with the indented and smooth approaches. The smooth and indented surfaces are controlled by the adhesive failure mode while the transversely roughened surface is dominated by the cohesive failure mode. Also, it is observed that the CZM approach can accurately model the interface shear failure with 3–29% differences between the modeled and the experimental test findings.

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