Numerical and experimental analysis of the behavior of structural elements composed of double lattice panels filled with cast-in-place concrete

AbstractAn experimental and numerical investigation was conducted into the factors that interfere in the shear strength of the concrete-concrete interface in structures composed of double lattice panels subjected to direct shear stress. The experimental program consisted of testing 26 direct shear models with varying widths of concrete filling of 7 cm, 9 cm and 13 cm, with smooth and rough interfaces, as well as different concrete compressive strengths in the filled region. The numerical modeling, which was performed with ANSYS software, employed solid finite elements, bar elements and contact elements, taking into account the non-linearity of the materials involved. The analyses of the experimental results under direct shear indicated that the transfer of stresses at the interface occurred with loss of adhesion. The numerical simulations indicated that the higher the geometric ratio of reinforcement the higher the direct shear strength of the structural model. In general, the slip of the models with smooth interfaces was 2 or 3 times greater than the models with rough surfaces. Numerically, the models with smooth interfaces showed a 36.61% gain in shear strength when the compressive strength in the region filled with concrete increased from 20 MPa to 28.4 MPa.

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Analysis of the suction evolution during direct shear test in a silty sand soil

E3S Web of Conferences ◽

10.1051/e3sconf/202019503031 ◽

2020 ◽

Vol 195 ◽

pp. 03031

Author(s):

Omar AL-Emami ◽

Gabriela M Medero ◽

Fernando A M Marinho ◽

Melis Sutman

Keyword(s):

Shear Strength ◽

Water Content ◽

Large Scale ◽

Matric Suction ◽

Vertical Stress ◽

Silty Sand ◽

Experimental Program ◽

Direct Shear ◽

Initial Void Ratio ◽

Study Results

Shear strength of soils is one of the essential parameters for analysing and solving divers geotechnical problems (e.g. the bearing capacity of shallow footings pile foundations, slope stability and earth embankments). In this study, a series of conventional large-scale (300 X 300 mm) direct shear tests were carried out on saturated and constant water content silty sand specimens at ei = 0.6 and 1.0 tested under applied vertical stresses of 100, 200, or 400 kPa to investigate the influence of matric suction on the shear strength characteristics of the tested material. A loading steel cap was modified to allow the direct measurements of the matric suction using two commercial available Equitensiometer suction probes (EQ3). The experimental program indicated that, for both studied void ratios, the obtained shear strength of specimens under constant water content is found to be distinctly greater than those obtained from saturated samples. The results showed that the samples compacted at ei = 1.0 exhibited collapse behaviour during saturation stage, whereas same samples did not show any volume change during stabilisation stage when tested under constant water content condition. The study results also showed that the matric suction reduction during consolidation stage depends on initial void ratio of the tested samples as well as the level of applied vertical stress. Moreover, the matric suction evolution during shearing process of both studied void ratios specimens decreased with increasing the level of applied vertical stress.

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Effect of temperature on the shear strength of soils and the soil–structure interface

Canadian Geotechnical Journal ◽

10.1139/cgj-2015-0355 ◽

2016 ◽

Vol 53 (7) ◽

pp. 1186-1194 ◽

Cited By ~ 46

Author(s):

Neda Yavari ◽

Anh Minh Tang ◽

Jean-Michel Pereira ◽

Ghazi Hassen

Keyword(s):

Shear Strength ◽

Soil Structure ◽

Shear Behaviour ◽

Effect Of Temperature ◽

Temperature Control System ◽

Direct Shear ◽

Ultimate Shear Strength ◽

Direct Shear Tests ◽

Direct Shear Apparatus ◽

Concrete Interface

In the present work, the shear behaviour of soils and the soil–concrete interface is investigated through direct shear tests at various temperatures. A conventional direct shear apparatus, equipped with a temperature control system, was used to test sand, clay, and the clay–concrete interface at various temperatures (5, 20, and 40 °C). These values correspond to the range of temperatures observed near thermoactive geostructures. Tests were performed at normal stress values ranging from 5 to 80 kPa. Results show that the effect of temperature on the shear strength parameters of soils and the soil–concrete interface is negligible. A softening behaviour was observed during shearing of the clay–concrete interface, which was not the case with clay specimens. The peak strength of the clay–concrete interface is smaller than the ultimate shear strength of clay.

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Direct shear strength test on rocks along discontinuities, under laboratory conditions

Pollack Periodica ◽

10.1556/pollack.9.2014.3.15 ◽

2014 ◽

Vol 9 (3) ◽

pp. 139-150 ◽

Cited By ~ 5

Author(s):

Ildikó Buocz ◽

Nikoletta Rozgonyi-Boissinot ◽

Ákos Török ◽

Péter Görög

Keyword(s):

Shear Strength ◽

Strength Test ◽

Direct Shear ◽

Shear Strength Test ◽

Laboratory Conditions

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Use of the Finite Element Analysis Method in Pedodontics

Materiale Plastice ◽

10.37358/mp.18.4.5097 ◽

2018 ◽

Vol 55 (4) ◽

pp. 666-675

Author(s):

Mihaela Tanase ◽

Dan Florin Nitoi ◽

Marina Melescanu Imre ◽

Dorin Ionescu ◽

Laura Raducu ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Structural Model ◽

Analysis Method ◽

Ansys Software ◽

Concentrated Force ◽

Element Analysis ◽

Finite Element Analysis Method ◽

The Finite Element Analysis ◽

Solid Type

The purpose of this study was to determinate , using the Finite Element Analysis Method, the mechanical stress in a solid body , temporary molar restored with the self-curing GC material. The originality of our study consisted in using an accurate structural model and applying a concentrated force and a uniformly distributed pressure. Molar structure was meshed in a Solid Type 45 and the output data were obtained using the ANSYS software. The practical predictions can be made about the behavior of different restorations materials.

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Study on the Strength Performance of Recycled Aggregate Concrete with Different Ages under Direct Shearing

Materials ◽

10.3390/ma14092312 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2312

Author(s):

Xin Liang ◽

Fang Yan ◽

Yuliang Chen ◽

Huiqin Wu ◽

Peihuan Ye ◽

...

Keyword(s):

Shear Strength ◽

Shear Force ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Displacement Curve ◽

Direct Shear ◽

Replacement Ratio ◽

Aggregate Concrete ◽

Concrete Failure ◽

Load Displacement

In order to study the mechanical properties of recycled aggregate concrete (RAC) at different ages, 264 standard cubes were designed to test its direct shear strength and cube compressive strength while considering the parameters of age and recycled aggregate replacement ratio. The failure pattern and load–displacement curve of specimens at direct shearing were obtained; the direct shear strength and residual shear strength were extracted from the load–displacement curves. Experimental results indicate that the influence of the replacement ratio for the front and side cracks of RAC is insignificant, with the former being straight and the latter relatively convoluted. At the age of three days, the damaged interface between aggregate and mortar is almost completely responsible for concrete failure; in addition to the damage of coarse aggregates, aggregate failure is also an important factor in concrete failure at other ages. The load–displacement curve of RAC at direct shearing can be divided into elasticity, elastoplasticity, plasticity, and stabilization stages. The brittleness of concrete decreases with its age, which is reflected in the gradual shortening of the elastoplastic stage. At 28 days of age, the peak direct shear force increases with the replacement ratio, while the trend is opposite at ages of 3 days, 7 days, and 14 days, respectively. The residual strength of RAC decreases inversely to the replacement ratio, with the rate of decline growing over time. A two-parameter RAC direct shear strength calculation formula was established based on the analysis of age and replacement rate to peak shear force of RAC. The relationship between cube compressive strength and direct shear strength of recycled concrete at various ages was investigated.

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Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

Sustainability ◽

10.3390/su13147758 ◽

2021 ◽

Vol 13 (14) ◽

pp. 7758

Author(s):

Biao Qian ◽

Wenjie Yu ◽

Beifeng Lv ◽

Haibo Kang ◽

Longxin Shu ◽

...

Keyword(s):

Shear Strength ◽

Void Ratio ◽

Soil Mass ◽

Direct Shear ◽

Test Results ◽

The Sustainable Development ◽

Direct Shear Tests ◽

Soil Cement ◽

Nano Clay ◽

New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

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Shear-friction behavior of concrete-to-concrete interface under direct shear load

Engineering Structures ◽

10.1016/j.engstruct.2021.112211 ◽

2021 ◽

Vol 238 ◽

pp. 112211

Author(s):

Jin Xia ◽

Kuang-yi Shan ◽

Xiao-hui Wu ◽

Run-li Gan ◽

Wei-liang Jin

Keyword(s):

Shear Load ◽

Direct Shear ◽

Friction Behavior ◽

Shear Friction ◽

Concrete Interface

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Impact of Reinforcement Ratio on Shear Behavior of I-Shaped UHPC Beams with and without Fiber Shear Reinforcement

Materials ◽

10.3390/ma13071525 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1525 ◽

Cited By ~ 1

Author(s):

Altug Yavas ◽

Cumali Ogun Goker

Keyword(s):

Shear Strength ◽

Failure Mode ◽

High Performance Concrete ◽

Shear Behavior ◽

Reinforcement Ratio ◽

Steel Fibers ◽

Experimental Program ◽

Shear Reinforcement ◽

Ultimate Shear Strength ◽

Loading Test

In the presented paper, the impacts of steel fiber use and tensile reinforcement ratio on shear behavior of Ultra-High Performance Concrete (UHPC) beams were investigated from the point of different tensile reinforcement ratios. In the scope of the experimental program, a total of eight beams consisting of four reinforcement ratios representing low to high ratios ranged from 0.8% to 2.2% were casted without shear reinforcement and subjected to the four-point loading test. While half of the test beams included 30 mm end-hooked steel fibers (SF-UHPC) with 2.0 vol%, the remaining beams were produced without the fiber to show possible effectiveness of the fiber use. The shear performances were discussed in terms of the load—deflection response, cracking pattern and failure mode, first cracking load and ultimate shear strength. In this sense, all the non-fiber beams were failed by shear with a dramatic load drop, regardless of the tensile reinforcement amount, before the yielding of reinforcement and they produced no deflection capability. The test results showed that while the inclusion of steel fibers to the UHPC mixture with low reinforcement ratios changed the failure mode from the shear to flexure, it significantly enhanced the ultimate shear strength in the case of higher reinforcement ratio through the SF-UHPC’ superior mechanical properties and fibers’ crack-bridging ability.

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Shear strength and dilative characteristics of an unsaturated compacted completely decomposed granite soil

Canadian Geotechnical Journal ◽

10.1139/t10-015 ◽

2010 ◽

Vol 47 (10) ◽

pp. 1112-1126 ◽

Cited By ~ 42

Author(s):

Md. Akhtar Hossain ◽

Jian-Hua Yin

Keyword(s):

Shear Strength ◽

Normal Stress ◽

Matric Suction ◽

Water Retention Curve ◽

Direct Shear ◽

Normal Stresses ◽

Soil Water Retention Curve ◽

Strength Data ◽

Decomposed Granite ◽

Completely Decomposed Granite

Shear strength and dilative characteristics of a re-compacted completely decomposed granite (CDG) soil are studied by performing a series of single-stage consolidated drained direct shear tests under different matric suctions and net normal stresses. The axis-translation technique is applied to control the pore-water and pore-air pressures. A soil-water retention curve (SWRC) is obtained for the CDG soil from the equilibrium water content corresponding to each applied matric suction value for zero net normal stress using a modified direct shear apparatus. Shear strength increases with matric suction and net normal stress, and the failure envelope is observed to be linear. The apparent angle of internal friction and cohesion intercept increase with matric suction. A greater dilation angle is found at higher suctions with lower net normal stresses, while lower or zero dilation angles are observed under higher net normal stresses with lower suctions, also at a saturated condition. Experimental shear strength data are compared with the analytical shear strength results obtained from a previously modified model considering the SWRC, effective shear strength parameters, and analytical dilation angles. The experimental shear strength data are slightly higher than the analytical results under higher net normal stresses in a higher suction range.

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Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

Advances in Civil Engineering ◽

10.1155/2018/9178140 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Yanhui Cheng ◽

Weijun Yang ◽

Dongliang He

Keyword(s):

Particle Size ◽

Shear Strength ◽

Internal Friction ◽

Direct Shear Test ◽

Shear Test ◽

Friction Angle ◽

Internal Friction Angle ◽

Direct Shear ◽

Stiffness Ratio ◽

Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

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