scholarly journals Mechanical Characteristics of Steel Shear Keyed Joints in the Construction and Finished States

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Yu Zou ◽  
Dong Xu
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Mechanical Characteristics ◽  
Displacement Curve ◽  
Relative Deformation ◽  
Direct Shear ◽  
Confining Stress ◽  
Factors Affecting ◽  
Shear Key ◽  
Main Factors

Joints that represent locations of discontinuity were the prominent factors affecting the overall behavior of precast segmental bridges. In this study, the steel shear key was designed, which was used to transmit the shear stress of the joints. To study the mechanical characteristics of the steel shear keyed joints in the construction and finished states, direct shear experiments and numerical analysis were carried out. The experimental results showed that the steel shear keyed joints had a high bearing capacity and good ductility. Under the action of confining stress, the joints relied on the mechanical occlusion between the steel keys to transmit the shear forces. When the load-displacement curve entered the horizontal stage, it can still bore large relative deformation, and the bearing capacity did not decrease. In the construction state, the inelastic deformation of the steel shear key should be used to control the design value of the temporary load. In the finished state, the bearing capacity of joints should be controlled by the direct shear strength of the steel shear key, which can be calculated according to the shear formula. The shear strength of the material and size of the steel shear key are the main factors affecting the bearing capacity of steel shear keyed joints.

Experimental Study on Shear Mechanical Characteristics of Soil-Structure Interface under Different Normal Stress

2011 ◽  
Vol 243-249 ◽  
pp. 2332-2337 ◽  
Author(s):  
Hong Chun Xia ◽  
Guo Qing Zhou ◽  
Ze Chao Du
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Normal Stress ◽  
Soil Structure ◽  
Mechanical Characteristics ◽  
Shear Displacement ◽  
Interface Roughness ◽  
Displacement Curve ◽  
Direct Shear ◽  
High Normal Stress

The direct shear mechanical characteristics of soil-structure interface under different experimental condition were studied systematically using the DRS-1 high normal stress direct and residual shear apparatus. The results show that the normal stress is an important factor which determines the mechanical characteristics of soil-structure interface. The curve of shear stress-shear displacement presents strain softening when the normal stress<3MPa, linear hardening when =3~5MPa and strain hardening when12MPa, separately. At the same time, the volume of the soil expands when <3MPa and contracts when >3MPa. But the volume of the soil expands and contracts simultaneously during the process of direct shear when =3MPa.The roughness of the interface influences not only the shape of the shear stress-shear displacement curve but also the shear strength of the interface. Under same normal stress condition，the shear strength of interface increases with the roughness but the influence degree of interface roughness reduces gradually with the increase of normal stress. The grain breakage degree is different under different normal stress. It increases evidently with the increase of normal stress.

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

Materials ◽  
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.

scholarly journals Study on the Impact of Sand-Clay Bond in Geo-grid and Geo-Textile on Bearing Capacity

2016 ◽  
Vol 9 (6) ◽  
pp. 83 ◽  
Author(s):  
Mohammadehsan Zarringol ◽  
Mohammadreza Zarringol
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Tensile Force ◽  
Direct Shear ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Increased Strength ◽  
Reinforced Clay ◽  
The Impact ◽  
Total Shear

<p>This paper aims to determine the impact of sand-clay bond in geo-grid and geo-textile on bearing capacity. In doing so, we examined clay-geo-synthetics, sand-geo-synthetics and clay-sand-geo-synthetics samples using direct shear tests. The friction between clay and reinforcement was provided by encapsulated-sand system.</p><p>This method is used to transfer the tensile force mobilized in geo-synthetics from sand to clay and improve the strength parameters of clay. This study indicated that the provision of a thin layer of sand at both sides of the reinforcement significantly improved the shear strength of clay soil.</p>Bond coefficient computations indicated that the shear strength of clay-geo-synthetics samples was higher than non-reinforced clay. The increased strength was due to the impact of open meshes of geo-synthetics which provided some degree of resistance bearing. To determine the share of resistance bearing provided by geo-synthetic transverse members in the entire direct shear strength, we conducted a series of tests on geo-synthetics-reinforced samples with and without transverse members. The resistance bearing provided by geo-synthetic transverse members was almost 10% of total shear strength. The results indicated that encapsulated geo-grid and geo-textile sand system increased the bearing capacity of clay, with geo-grid being more efficient than geo-textile.

scholarly journals Comparative Study in Method of Compaction by Consolidated Drained and Direct Shear Test

2020 ◽  
Vol 78 (2) ◽  
pp. 143-152
Author(s):  
Abdul Samad Abdul Rahman ◽  
N. Sidek ◽  
Juhaizad Ahmad ◽  
N. Hamzah ◽  
M. I. F. Rosli
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Triaxial Test ◽  
Direct Shear Test ◽  
Shear Test ◽  
Void Ratio ◽  
Direct Shear ◽  
Test Results ◽  
Stress Strain ◽  
Strain Behaviour

Soil compaction has been a common practice in the construction of highways, embankments, earth dams and other related structures where the condition of the soil is high in void ratio and therefore having a very low in bearing capacity. Therefore, the soil needs to be compacted in order to minimize the void ratio and in the same time would results in having a very high bearing capacity to sustain load. Nevertheless, only a few researches have been done to investigate the method of compaction using different energy on the behavior of shear strength by consolidated drained and direct shear test. In this research, the effect of different compaction in energy of 25 number of blows compared to 40 number of blows on the stress-strain behaviour of drained triaxial test has been done and findings of the data are to be compared with direct shear test. Results reveal that there is an increase in soil unit weight by using different energy in compaction with an increase of 5% from 1790 kg/m3 to 1880 kg/m3 for 25 and 40 number of blows respectively. However, the stress-strain behaviour of the specimens shows differently when compared between consolidated drained triaxial and direct shear test. The shear strength for direct shear-stress is at higher value compared to drained triaxial test. For drained triaxial test, results reveal that the effective friction angles are increase only about 1% from 37° to 38°. This is due to the soil particles rearranging itself with the different applied pressures thus eliminating the effects of different energy on the shear strength of the specimens. However, for direct shear test, the shear strength increases drastically from 29° to 32°. The increase of the shear strength is more likely influence by the soil particle arrangement due to the impact of the energy of the no of blows to the desired specimen.

scholarly journals Studi Eksperimen Pengaruh Penambahan Serabut Kelapa Terhadap Kohesi dan Sudut Geser Tanah Lempung

2021 ◽  
Vol 3 (2) ◽  
pp. 256-259
Author(s):  
Pebrinar Sangle
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Direct Shear Test ◽  
Shear Test ◽  
Clay Soil ◽  
Dry Weight ◽  
Strength Parameter ◽  
Direct Shear ◽  
Before And After ◽  
Coconut Fibers

This research is intended to study the shear strength of clay soil before and after adding coconut fibers. Shear strength is one of the factors that are taken into account to find the bearing capacity of the soil. Soil stability is a way to improve or change the nature of an unfavorable subgrade condition to be better in terms of the bearing capacity of the subgrade for the construction to be built on its Strength parameter testing shear using direct shear test equipment with total stress conditions. This research used coconut fiber variations of 0%, 1%, 2%, 3%, and 4% of the dry weight of the soil. The results of the direct shear test showed an increase in the value of soil cohesion (c) and shear angle (φ). This shows that the addition of coconut fibers to clay soil can increase the value of shear strength.

Prediction Method of Vertical Ultimate Bearing Capacity of Single Pile Based on Support Vector Machine

2010 ◽  
Vol 168-170 ◽  
pp. 2278-2282 ◽  
Author(s):  
Yong Jian Liu ◽  
Shi Hua Liang ◽  
Jia Wu Wu ◽  
Na Fu
Keyword(s):  
Support Vector Machine ◽  
Bearing Capacity ◽  
Mechanical Characteristics ◽  
Simple Structure ◽  
Prediction Method ◽  
Ultimate Bearing Capacity ◽  
Support Vector ◽  
Single Pile ◽  
Factors Affecting ◽  
Svm Model

By comprehensively analyzing the main factors affecting vertical ultimate bearing capacity of single pile, a prediction model of Support Vector Machine (SVM), which discusses the nonlinear relationship between vertical ultimate bearing capacity of single pile and influencing factors and analyzes the parameters on the performance of the model through sample knowledge learning, is established in this paper. The research results indicate that, SVM model, which is compared with BP neural networks model, possesses simple structure, flexible adaptability, high precision and powerful generalization ability, and can accurately reflect the actual mechanical characteristics of pile, therefore, SVM is an effective method for predicting vertical ultimate bearing capacity of single pile.

scholarly journals Study on Mechanical Characteristics of Composite Alkali-activated Materials-stabilized Gold Tailings Under Direct Shear

2021 ◽  
Author(s):  
Zhenkai Pan ◽  
Chao Zhang ◽  
Yuan Li ◽  
Shucheng Gan
Keyword(s):  
Shear Strength ◽  
Mine Tailings ◽  
Mechanical Characteristics ◽  
Confining Pressure ◽  
Gold Mine ◽  
Direct Shear ◽  
Type Curves ◽  
Direct Shear Tests ◽  
Gold Mine Tailings ◽  
Alkali Activated

Abstract In this study, the traditional industrial waste residue and some alkaline activators were mixed to prepare a new composite alkali-activated materials (CAAMs), which was used to stabilize gold mine tailings (GMTs). Due to emissions of greenhouse gases and solid dust, alkali-activated materials have been widely used to replace Portland cement to solidify geotechnical materials to enhance their mechanical properties. Different admixture of CAAMs (i.e., 0, 3, 5, 8% ) and gold mine tailings were prepared, and the samples were cured in saturated water and under no air conditions. In order to investigate the mechanical characteristics of CAAMs-stabilized GMTs, laboratory direct shear tests were carried out on samples after curing them for 3, 7, 14 and 28 days, respectively. The test results showed that as the curing periods increased, the brittleness of the samples increased, and the stress-displacement curves for all the cured specimens changed from plateau-type to peak-type curves. The curing periods and the content of CAAMs are both beneficial for enhancing the shear strength of CAAMs-stabilized GMTs samples, but the increase rate decreased as the vertical confining pressure increased. Furthermore, the influence of CAAMs content on shear strength increment was larger than that of curing periods. An exponential growth model could be well used to describe the change of shear strength with the curing periods at different vertical stresses.

scholarly journals SCALE EFFECT ON THE SHEAR STRENGTH OF TWO-LAYER SOIL REINFORCED BY GEOGRID

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Sakine Tamassoki ◽  
Reza Z. Moayed ◽  
Mohammad Ashkani ◽  
Hamidreza Rahimi
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Scale Effect ◽  
Large Scale ◽  
Direct Shear ◽  
Shear Tests ◽  
Element Analysis ◽  
Direct Shear Tests ◽  
Granular Base ◽  
Shear Box

Geosynthetics are used to reinforce soils and improve their mechanical characteristics,especially when soft low-bearing capacity soils are encountered in civil engineering projects.Particularly, in roads, geosynthetics are placed between the interface of granular materials andsoft-soil sub grade to improve composite layers’ bearing capacity. This paper presents the resultsof the finite element analysis of the two-layer soil(granular base-clayey sub grade) reinforced bygeogrid and discusses the effect of the reinforcement on the shear strength. As the primary aim ofthe study, the numerical model was calibrated in comparison with the experimental results oflarge scale direct shear tests. The results showed that the shear strength improved in the two-layersoil which had been reinforced by geogrid. The predictions made by the developed model werefound to be in line with the experimental data obtained from large scale direct shear tests. Asanother aim of the study, different dimensions of shear box were used for modelling in order toinvestigate the scale effect on the shear strength of double-layered soil (clay-sand). The resultsshowed that the increase in the dimensions of the reinforced shear box leads to the enhancementof peak shear strength. Moreover, several analyses were conducted on geogrid in shear box withdifferent dimensions in fixed and unfixed states. The results demonstrated that the shear strengthof treated geogrid was higher than the shear strength of those in which untreated geogrid wasutilized.

scholarly journals Shear Properties of Cemented Paste Backfill under Low Confining Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Andrew N. Pan ◽  
Murray W. F. Grabinsky ◽  
Lijie Guo
Keyword(s):  
Shear Strength ◽  
Mining Industry ◽  
Binder Content ◽  
Environmental Benefits ◽  
Direct Shear ◽  
Cemented Paste Backfill ◽  
Curing Time ◽  
Confining Stress ◽  
Strain Property ◽  
Paste Backfill

Cemented paste backfill (CPB) plays an important role in the mining industry due to safety, cost efficiency, and environmental benefits. Studies on CPB have improved the design and application of paste backfill in underground mines. Direct shear is one of the most fundamental parameters for assessing backfill strength. This study harnesses direct shear tests to explore the low confining stress behavior of CPB. We perform all the tests in a standard apparatus on the combination of three binder contents of 4.2%, 6.9%, and 9.7% CPB with four curing times of 3, 7, 14, and 28 days, respectively. The applied confining stress levels vary in a range according to the in situ regime. Results are presented by strength envelope, stress-strain property, and shear strength with curing time and binder content. The data suggest that the shear strength follows the Mohr–Coulomb envelope in which the shear strength and behavior are time and binder content dependent. In addition, the results show that shear strength is strongly related to the binder content than the curing time, namely, the higher the degree of binder hydration, the higher the cementation binding force between CPBs.

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