• Geomechanics and Engineering
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• v.25 no.2
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• pp.89-98
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• 2021

The paper presents an experimental study on the strength behaviour of a coral gravelly sand from Vietnam subjected to monotonic and cyclic loading. A series of direct shear tests were carried out to investigate the shear strength behaviour and the factors affecting the shear strength of the sand such as relative density, cyclic load, amplitude of the cyclic load and loading rate. The study results indicate that the shear strength parameters of the coral gravelly sand include not only internal friction angle but also apparent cohesion. These parameters vary with the relative density, cyclic load, the amplitude of the cyclic load and loading rate. The shear strength increases with the increase of the relative density. The shear strength increases after subjecting to cyclic loading. The amplitude of the cyclic load affects the shear strength of coral gravelly sand, the shear strength increases as the amplitude of the cyclic load increases. The loading rate has insignificantly effect on the shear strength of the coral gravelly sand.

• Steel and Composite Structures
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• v.42 no.4
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• pp.477-487
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• 2022

The shear stiffness of headed-stud shear connectors has no unified definition due to the nonlinear characteristics of its load-slip relationship. A unified framework was firstly adopted to develop a general expression of shear load-slip equation for headed-stud shear connectors varying in a large parameter range based on both force and energy balance. The pre- and post-yield shear stiffness were then determined through bilinear idealization of proposed shear load-slip equation. An updated and carefully selected push-out test database of 157 stud shear connectors, conducting on studs 13~30mm in diameter and on concretes 30~180 MPa in cubic compressive strength, was used for model regression and sensitivity analysis of shear stiffness. An empirical calculation model was also established for the stud shear stiffness. Compared with the previous models through statistical analysis, the proposed model demonstrates a better performance to predict the shear load-slip response and stiffness of the stud shear connectors.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.97-103
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• 2002

This study was carried out to obtain basic information on racking resistance of shear walls and the factors affecting racking resistance of shear walls. Shear walls constructed by larch lumber nominal 50 mm × 100 mm framing and various sheathing materials were tested by applying monotonic and cyclic load functions. Shear walls with various stud spacing such as 305 mm, 406 mm, and 610 mm were tested under both of monotonic and cyclic loads and shear walls with various aspect (height-width) ratios were tested under cyclic load functions. The effect of hold-down connectors in shear walls was also tested under cyclic load functions. Racking resistance of shear walls has very close linear relation with stud spacing and width of shear walls. The ultimate racking strength of shear walls was reached at around or before the displacement of 20 mm. It was proposed in this study that the minimum racking strength and minimum width for shear wall be 500 kgf and 900 mm, respectively. Load-displacement curves obtained by racking tests under monotonic load functions can be represented by three straight line segments. Under cyclic load functions, envelope curves can be divided into three sections that can be represented by straight lines and the third section showed almost constant or decreasing slope.

• Steel and Composite Structures
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• v.36 no.5
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• pp.493-506
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• 2020

The load-slip relationship of the shear connection is an important parameter in design and analysis of composite structures. In this paper, a load-slip curve prediction method of the shear connection based on the artificial neural networks (ANNs) is proposed. The factors which are significantly related to the structural and deformation performance of the connection are selected, and the shear stiffness of shear connections and the transverse coordinate slip value of the load-slip curve are taken as the input parameters of the network. Load values corresponding to the slip values are used as the output parameter. A twolayer hidden layer network with 15 nodes and 10 nodes is designed. The test data of two different forms of shear connections, the stud shear connection and the perforated shear connection with flange heads, are collected from the previous literatures, and the data of six specimens are selected as the two prediction data sets, while the data of other specimens are used to train the neural networks. Two trained networks are used to predict the load-slip curves of their corresponding prediction data sets, and the ratio method is used to study the proximity between the prediction loads and the test loads. Results show that the load-slip curves predicted by the networks agree well with the test curves.

• Steel and Composite Structures
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• v.13 no.5
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• pp.473-487
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• 2012

An experimental study was performed to investigate the seismic performance of steel reinforced concrete (SRC) special-shaped columns. For this purpose, 17 steel reinforced concrete special-shaped column specimens under low-cyclic reversed load were tested, load process and failure patterns of the specimens with different steel reinforcement were observed. The test results showed that the failure patterns of these columns include shear-diagonal compression failure, shear-bond failure, shear-flexure failure and flexural failure. The failure mechanisms and characteristics of SRC special-shaped columns were also analyzed. For different SRC special-shaped columns, based on the failure characteristics and mechanism observed from the test, formulas for calculating ultimate shear capacity in shear-diagonal compression failure and shear-bond failure under horizontal axis and oblique load were derived. The calculated results were compared with the test results. Both the theoretical analysis and the experimental results showed that, the shear capacity of T, L shaped columns under oblique load are larger than that under horizontal axis load, whereas the shear capacity of +-shaped columns under oblique load are less than that under horizontal axis load.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.471-477
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• 1999

A new stress, load and displacement controlled direct shear apparatus has recently been developed at the Hyundai Institute of Construction Technology This direct shear apparatus is capable of testing of rock joint under constant normal stiffness, constant normal stress or constant normal load boundary conditions. This paper describes this direct shear apparatus and illustrates results of shear tests at constant normal stress condition, constant normal load condition and constant normal stiffness condition with dental stones which have a same joint roughness and unconfined compressive strength.

• Geomechanics and Engineering
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• v.17 no.3
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• pp.253-259
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• 2019

Concrete-to-concrete bedding planes (CCBP) are observed from time to time due to the multistep hardening process of the concrete materials. In this paper, a series of direct/cyclic shear tests are performed on CCBP under static and dynamic normal load conditions to study the frictional behavior effect by the shear velocities, normal impact frequencies, horizontal shear frequencies, normal impact force amplitudes, horizontal shear displacement amplitudes and normal load levels. According to the experimental results, apparent friction coefficient k ($k=F_{Shear}/F_{Normal}$) shows different patterns under static and dynamic load conditions at the stable shear stage. k is nearly constant in direct shear tests under constant normal load conditions (DCNL), while it is cyclically changing with nearly constant peak value and valley value for the direct shear tests under dynamic normal load conditions (DDNL), where k increases with decreasing normal force and decreases with increasing normal force. Shear velocity has little influence on peak values of k for the DCNL tests, but increasing shear velocity leads to increasing valley values of k for DDNL tests. It is also found that, the valley values of k ascend with decreasing impact normal force amplitude in DDNL tests. The changing pattern of k for the cyclic shear tests under constant and dynamic normal load conditions (CCNL and CDNL tests) are similar, but the peak value of k is smaller in CDNL tests than that in CCNL tests. Normal load levels, shear displacement amplitudes, vertical impact frequencies, horizontal shear frequencies and normal impact force amplitudes have little influence on the changing pattern of k for the cyclic shear tests. The tests of this study provide useful data in understanding the frictional behavior of the CCBP under distinct loadings, and these findings are very important for analyzing the stability of the jointed geotechnical structures under complicated in situ stress conditions.

• Earthquakes and Structures
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• v.26 no.6
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• pp.449-461
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• 2024

The vertical reinforcement connection between the precast reinforced concrete shear wall and the cast-in-place reinforced concrete member is vital to the performance of shear walls under seismic loading. This paper investigated the structural behavior of three precast reinforced concrete shear walls, with different levels of connection (i.e., full connection, partial connection, and no connection), subjected to quasi-static lateral loading. The specimens were subjected to a constant vertical load, resulting in an axial load ratio of 0.4. The crack pattern, failure modes, load-displacement relationships, ductility, and energy dissipation characteristics are presented and discussed. The resultant seismic performances of the three tested specimens were compared in terms of skeleton curve, load-bearing capacity, stiffness, ductility, energy dissipation capacity, and viscous damping. The seismic performance of the partially connected shear wall was found to be comparable to that of the fully connected shear wall, exhibiting 1.7% and 3.5% higher yield and peak load capacities, 9.2% higher deformability, and similar variation in stiffness, energy dissipation capacity and viscous damping at increasing load levels. In comparison, the seismic performance of the non-connected shear wall was inferior, exhibiting 12.8% and 16.4% lower loads at the yield and peak load stages, 3.6% lower deformability, and significantly lower energy dissipation capacity at lower displacement and lower viscous damping.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.1
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• pp.93-100
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• 2000

The purpose of this study is to investigate the shear behavior of reinforced concrete beams according to small shear span-depth ratio between a/d=1.5, 2.8, 3.6. In general, shear strength of reinforced concrete beams is dependent on the compressive strength of concrete the longitudinal steel ratio, the shear span-depth ratio and shear reinforcement. The static test was carried out to measure the ultimate load, the initial load of flexural and diagonal cracking, crack patterns, fracture modes. The load versus strain and load versus deflection relations were obtained from the static test. The test results on shear strength were compared with results obtained by the formulas of ACI code 318-95. The shear strength of reinforced concrete beams exceeded those predicted following present ACI code 318-95(11-6).

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.271-276
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• 2010

In this study, the light-frame wood shear walls according to the sheathing materials was carried out to investigate the shear load performance. Most common sheathing materials are the structural OSB and gypsum board used to consist wall of wood-frame house. Seven different type of specimens are composed of several sheathing materials and shear test was taken to evaluate shear performance by KS F 2154. As a result, shear walls(G12.5/G12.5 and G12.5/OSB) show that maximum shear strength and shear rigidity modulus are 7316N/mm${\cdot}$118.25 N/mm and 11129 N/mm${\cdot}$184.66 N/mm respectively. The shear wall using gypsum board 15mm improve maximum shear strength and shear rigidity modulus about 30%. The shear wall using 15mm gypsum board showed intermediate value in one side specimens. Different types of shear walls could be compared with the shear load performance. Also, nailed joint failure aspects are different to sheathing material and installing method.