scholarly journals Parametric Study on Mixed Torsional Behavior of U-Shaped Thin-Walled RC Girders

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Jianchao Xu ◽  
Bo Diao ◽  
Quanquan Guo ◽  
Yinghua Ye ◽  
Y. L. Mo ◽  
...  
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Test Results ◽  
Height Ratio ◽  
Calculating Method ◽  
Concrete Girders ◽  
Flexural Failure ◽  
Parametric Studies ◽  
Thin Walled ◽  
Shear Failures

Nowadays, U-shaped thin-walled concrete girders have been widely applied in the urban construction of rail viaducts in China as well as worldwide. However, the mixed torsional behaviors of these structures are not well understood. In this paper, the mixed torsional behaviors of the U-shaped thin-walled RC girders are theoretically analyzed, and a method predicting failure modes and ultimate torques is proposed. Nonlinear FE models based on ABAQUS to simulate the mixed torsional behaviors are built and calibrated with the test results. Parametric studies considering three crucial parameters (boundary condition, span length-section height ratio, and ratio of longitudinal bars to stirrups) are conducted based on both the above suggested calculating method and the FE modeling. The calculated and the simulated results agree well with each other and with the test results. It is found that the failure modes of the U-shaped thin-walled RC girders under torsion are influenced by all the three parameters. Three kinds of failure modes are observed: flexural failures dominated by warping moment, shear failures caused by warping torque and circulatory torque, and flexural-shear failures in the cases where flexural failure and shear failure appear almost at the same time.

Experimental Study on Interlaminar Shear Properties of T300/BMI Composite Laminates

2013 ◽  
Vol 718-720 ◽  
pp. 157-161
Author(s):  
Zong Hong Xie ◽  
Hai Han Liu ◽  
Jian Zhao ◽  
Jun Feng Sun ◽  
Fei Peng ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Shear Test ◽  
Failure Modes ◽  
Shear Failure ◽  
Test Method ◽  
Test Results ◽  
Shear Properties ◽  
Test Fixture ◽  
Iosipescu Shear Test ◽  
Interlaminar Shear

A modified test fixture to measure the shear properties of composite laminates was designed and manufactured based upon Iosipescu shear test method. Tests on interlaminar shear propertis of T300/BMI composite laminates were conducted according to ASTM D 5379 test standard. Interlaminar shear stress/strain curves and shear failure modes were obtained. The test results showed that the modified shear test fixture and test method were effective in measuring the shear properties of composite laminates.

Analysis of Bending Loads on Bamboo-Balsa and Bamboo-Polypropylene Honeycomb Composite Sandwiches

2015 ◽  
Vol 1125 ◽  
pp. 94-99 ◽  
Author(s):  
Aldyandra Hami Seno ◽  
Eko Koswara ◽  
Hendri Syamsudin ◽  
Djarot Widagdo
Keyword(s):  
Failure Modes ◽  
Shear Failure ◽  
Numerical Models ◽  
Future Research ◽  
Test Results ◽  
Bending Tests ◽  
Bending Loads ◽  
Bending Behavior ◽  
Honeycomb Cores ◽  
Load Deflection Curve

This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.

scholarly journals Structural Behavior of Composite Floor System Using Cold-Formed Thin-Walled C Steel Channel Embedded Foam Concrete

2021 ◽  
Vol 11 (21) ◽  
pp. 9888
Author(s):  
Dianzhong Liu ◽  
Feng Fu ◽  
Wanjuan Liu
Keyword(s):  
Failure Modes ◽  
Concrete Slab ◽  
Structural Behavior ◽  
Test Results ◽  
Foam Concrete ◽  
Flexural Capacity ◽  
Composite Slab ◽  
New Type ◽  
Thin Walled ◽  
Floor System

In this paper, a new composite floor system using cold-formed thin-walled C steel channel embedment and a foam concrete slab is developed. This new type of floor system features lightweight, high fire-resistant, and high anti-corrosion features, and can be used for multi-story buildings, providing a promising new alternative floor system for the construction market. Two four-point bending tests were carried out to investigate the flexural capacity and failure modes of this new type of composite slab. Based on the test results, a nonlinear finite element model was developed using general software package ABAQUS. The model is validated using the test results. Using this model, parametric studies were performed to study the key parameters affecting the structural behavior of this new type of composite floor system. Different parameters such as density of the foam concrete, grade of the cold-formed thin-walled C steel channel embedment, and spacing of the cold-formed thin-walled C steel channel were investigated. Their contributions to the overall moment capacity and their effect on the failure modes of this type of composite slab were discovered. Based on experimental results and FE results, design formulas for ultimate flexural capacity of this new type of composite slabs were also developed which can accurately predict their flexural capacity.

scholarly journals Experimental Study on the Mechanical Behavior of Yunnan Limestone in Natural and Saturated States

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xutao Zhang ◽  
Mingyang Ren ◽  
Zhaobo Meng ◽  
Baoliang Zhang ◽  
Jinglong Li
Keyword(s):  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Water Content ◽  
Failure Modes ◽  
Shear Failure ◽  
Mechanical Response ◽  
Deformation Modulus ◽  
Confining Pressure ◽  
Hyperbolic Function ◽  
Test Results

Rock material is a kind of mineral assemblage with complex structural heterogeneity, whose mechanical behavior is strongly affected by water or moisture content. In this work, we carried out a series of laboratory tests to investigate the mechanical response (e.g., deformation, strength, and failure characteristics) of Yunnan limestone in natural and saturated states. Our test results show that (1) after saturation, the stiffness and strength of Yunnan limestone degenerate considerably. Compared with the natural condition, the elastic modulus, deformation modulus, and tensile modulus decrease by about 30% on average, and uniaxial compressive strength and tensile strength also decrease by about 15% and 20%, respectively. While Poisson’s ratio is less affected by water content, it can be regarded as a constant; (2) the elastic modulus and deformation modulus of Yunnan limestone are significantly affected by confining pressure, and the relationship between them and confining pressure satisfies the law of hyperbolic function; (3) the peak strength envelope of Yunnan limestone has significant nonlinear characteristics, which can be well described by generalized Hoek-Brown strength criterion. However, the generalized Hoek-Brown criterion does not apply to the residual strength, which shows a linearly increasing trend with the increasing confining pressure; (4) the failure modes of Yunnan limestone are significantly dependent on confining pressure but insensitive to water content. With the increasing confining pressure, the failure modes of Yunnan limestone transform from splitting failure, tension-shear mixed failure, single inclined plane shear failure to Y-shaped or X-shaped conjugated shear failure. The test results can provide important experimental data for the establishment of the constitutive model of Yunnan limestone, which will contribute to obtain more reliable results for stability assessment of Xianglu Mountain Tunnel.

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.

Analysis of Brick Wall’s Failure Modes under Earthquake Effect

2012 ◽  
Vol 226-228 ◽  
pp. 1066-1071
Author(s):  
Kai Qin ◽  
Wen Fang Zhang ◽  
Li Jun Niu
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Shear Failure ◽  
Brick Masonry ◽  
Width Ratio ◽  
Finite Element Models ◽  
Brick Wall ◽  
Flexural Failure ◽  
Earthquake Effect ◽  
Shear Bearing Capacity

Brick wall has large lateral sidesway stiffness and shear failure often occurs under horizontal earthquake effect, but the scourge surveys indicate that flexural failure can also occurs sometimes. Given that there are still few researches about masonry’s failure modes in China, Finite Element Models of non-reinforced brick masonry with different Depth-width Ratios and reinforced brick masonry whose Depth-width Ratio is 1.444 are established with the help of MSC.MARC to analyze its failure mode under horizontal action. The researching results indicate that: The larger the Depth-width Ratio of non-reinforced brick masonry is, the more flexural components it has and the better its ductility is; the smaller its Depth-width Ratio is, the larger the D-value of Bottom Shear and Ultimate Shear Bearing Capacity according to formulas from code before damage, and thereby the more easily the shear failure takes place; however, the ductility of brick wall’s flexural failure is improved evidently through making reasonable reinforcement schemes.

Experimental investigation of precast assembled bridge columns with UHPC-filled connections

2019 ◽  
Author(s):  
Yu Shen ◽  
Biao Ma ◽  
Ruilong Wang
Keyword(s):  
High Performance ◽  
Failure Modes ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Successful Implementation ◽  
Flexural Failure ◽  
Short Columns ◽  
Component Material ◽  
Damage Process ◽  
Ductility Capacity

<p>Accelerated bridge construction (ABC) has attracted substantial attentions around the world owing to advantages of minimizing construction delivery time, improving component material quality and promoting overall-economy performance. An essential factor in widespread and successful implementation of the ABC lies in the reliable connections between precast units. In this study, the distinction of seismic performance between the high and short precast reinforced concrete pier columns with a new column-to-footing (or cap beam) connection filled with ultra-high performance concrete (UHPC) were experimentally investigated through the quasi-static testing. Based on the observations of test results, although the phenomena of sliding and uplifting around the joints were obvious, the failure modes of high and short columns were the flexural failure and the shear failure on the non-joint zone, respectively. Moreover, the damage process, the ductility capacity, the resilience behavior and the hysteresis energy response of the two large-scaled prefabricated piers were described and discussed.</p>

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.

Damage Detection with FBG Sensors for Pre-Stress Concrete Girders

2017 ◽  
Vol 737 ◽  
pp. 454-458 ◽  
Author(s):  
Seong Cheol Lee ◽  
Kyung Joon Shin ◽  
Jae Min Kim ◽  
Hwan Woo Lee
Keyword(s):  
Prestressed Concrete ◽  
Shear Failure ◽  
Experimental Program ◽  
Test Results ◽  
Strain Variation ◽  
Concrete Members ◽  
Concrete Girders ◽  
Drastic Increase ◽  
Fbg Sensors ◽  
Tendon Strain

In this paper, possibility to detect damage on post-tensioned concrete girders was investigated through an experimental program with 6 m long specimens containing smart tendons where FBG (Fiber Bragg Grating) sensors were embedded. Total six specimens were fabricated and tested, and test variables were prestressing tendon’s profile and web thickness. All the specimens were subjected to 3-points loading, and they exhibited shear failure. Through the test, it was observed that tendon strains were successfully measured through FBG sensors regardless of the test variables. It was also observed that tendon strains within the pure span significantly increased while ones nearby the anchors beyond the pure span were constant. When the specimen was cracked, FBG sensors nearby cracks showed relatively drastic increase on tendon strain. Since strain variation along tendons cannot be detected by conventional equipment such as a load-cell, the test results indicated that actual tendon strains can be easily measured with FBG sensors. These results showed that FBG sensors can be useful to check whether prestressed concrete members were significantly damaged. In addition, it is expected that FBG sensors can be helpful on more reasonable maintenance of PSC girders.

scholarly journals Axial Uplift Behaviour of Belled Piers in Coarse-Grained Saline Soils

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Jian Xu ◽  
Jianwei Ren ◽  
Songhe Wang ◽  
Long Jin ◽  
Jun Yuan
Keyword(s):  
Bearing Capacity ◽  
Transmission Lines ◽  
Failure Modes ◽  
Shear Failure ◽  
Empirical Equation ◽  
Coarse Grained ◽  
Saline Soils ◽  
Test Results ◽  
Linear Change ◽  
Load Displacement

Bearing capacity of belled pier foundation is critical in designing transmission lines in coarse saline soil region. This paper describes model test results on belled pier foundations. Axial uplift behaviours including failure modes, load-displacement curves, and ultimate uplift bearing capacity were discussed. The failure planes in four cases were obtained from pulled out cone-shaped bodies. An empirical equation was developed with a critical parameter of an uplift angle in design. Results indicate the range where the ground uplift shows circular extension at higher loads and the overall shear failure finally occurred. The load-displacement curves are primarily softening, and the uplift bearing capacity for coarse-grained saline soils (CSS) in the crystalline state increases at larger thickness, higher than that in dissolved state. Failure planes all exhibit approximately linear change from bottom to up. The angles of uplift for soils in crystalline and dissolved states can be taken as 34° and 18°, while 32° for the conventional for the sake of safety. Uplift behaviour of belled piers in CSS was modelled incorporating a practical interface model, with both failure planes and plastic range.

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