• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.252-255
• /
• 2004

The measured longitudinal reinforcement tensions in the shear-critical RC beams were significantly higher than the calculated values by the beam theory. This may be attributed to the reduction of the internal-moment arm length by the development of the arch action. In this paper, the measured longitudinal reinforcement tensions in the test performed by $Kim^4$ were compared with those predicted by the various truss model.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.1
• /
• pp.77-92
• /
• 2003

A set of standard triaxial testing was performed to identify underlying physical processes and inherent limitations in the determination of critical state parameters in sandy soils. The experimental test results showed that the critical state friction angle for a given soil is constant regardless of drainage condition while the critical state line on the e-log p'space is significantly affected by drainage condition mainly because of insufficient strain attained in standard triaxial tests and strain localization effects in udrained tests. It appeared that the best method to determine critical state parameters in laboratory testing is to use homogeneous loose specimens under drained shear condition. In addition, a reference state parameter was suggested to design tests that will avoid dilatancy or strain localization effects in drained tests.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5566-5571
• /
• 2012

Block shear failure is one of limit states, and demands great caution in designing the tension member or connection joint of steel structures. From many studies and design specification, it is shown that the effect of the bolted connection type on the block shear failure was not considered. In order to investigate the effect of the bolted connection type(bearing type connection and slip critical connection) on the mode/strength of the block shear failure, tensile experiment is conducted in this study. Differences about the failure mode according to the design specification, bearing type connection, and slip critical connection are proposed from the analysis of test results. The variation of the block shear failure strength due to the frictional force in the slip critical connection is also investigated.

• Structural Engineering and Mechanics
• /
• v.14 no.3
• /
• pp.365-380
• /
• 2002

Following a series of experiments on isolated low-rise RC shear walls with openings, a theoretical study on the backbone curve of a perforated shear wall shows that there are some important observations from experimental results that make clear a semi-empirical formula of the backbone curve of a perforated wall. Critical shear zones can be depicted from the configuration of shear walls with openings. Different factors, including the size and location of shear wall openings, the wall's height/width ratio, horizontal and vertical steel bar ratios, and location and amount of diagonal steel bars are involved in the derivation of the backbone curve. Bending and shear effects are also considered in the paper. In addition, a comparison of load and displacement for solid and perforated shear walls is discussed. Generally, the comparison between experimental curves and computed backbone curves is favorable.

• Steel and Composite Structures
• /
• v.20 no.1
• /
• pp.185-203
• /
• 2016

Shear connectors are key components to ensure the efficient composite action and satisfactory transfer of shear forces at the steel-concrete interface in composite beams. Under hazardous circumstances, such as fire in a building, the performance of a composite beam significantly relies on the performance of shear connectors. Studies on the behavior of shear connectors subjected to elevated temperatures performed in the last decade are reviewed in this paper. The experimental testing of push-out specimens, the design approaches provided by researchers and different codes, the major failure modes, and the finite element modeling of shear connectors are highlighted. The critical research review showed that the strength of a shear connector decreases proportionally with the increase in temperature. Compared with the volume of work published on shear connectors at ambient temperatures, a few studies on the behavior of shear connectors under fire have been conducted. Several areas where additional research is needed are also identified in this paper.

• Earthquakes and Structures
• /
• v.19 no.1
• /
• pp.59-77
• /
• 2020

The code static eccentricity model for elastic torsional design of structures has two critical shortcomings: (1) the negation of the inertial torsional moment at the center of mass (CM), particularly for torsionally-unbalanced (TU) building structures, and (2) the confusion caused by the discrepancy in the definition of the design eccentricity in codes and the resistance eccentricity commonly used by engineers such as in FEMA454. To overcome these shortcomings, using the resistance eccentricity model that can accommodate the inertial torsional moment at the CM, interactive relations between shear and torsion are proposed as follows: (1) elastic responses of structures at instants of peak edge-frame drifts are given as functions of resistance eccentricity, and (2) elastic hysteretic relationships between shear and torsion in forces and deformations are bounded by ellipsoids constructed using two adjacent dominant modes. Comparison of demands estimated using these two interactive relations with those from shake-table tests of two TU building structures (a 1:5-scale five-story reinforced concrete (RC) building model and a 1:12-scale 17-story RC building model) under the service level earthquake (SLE) show that these relations match experimental results of models reasonably well. Concepts proposed in this study enable engineers to not only visualize the overall picture of torsional behavior including the relationship between shear and torsion with the range of forces and deformations, but also pinpoint easily the information about critical responses of structures such as the maximum edge-frame drifts and the corresponding shear force and torsion moment with the eccentricity.

• Steel and Composite Structures
• /
• v.25 no.5
• /
• pp.603-615
• /
• 2017

This experimental research presents the seismic performance of steel reinforced high-strength concrete (SRHC) short columns. Eleven SRHC column specimens were tested under simulated earthquake loading conditions, including six short column specimens and five normal column specimens. The parameters studied included the axial load level, stirrup details and shear span ratio. The failure modes, critical region length, energy dissipation capacity and deformation capacity, stiffness and strength degradation and shear displacement of SRHC short columns were analyzed in detail. The effects of the parameters on seismic performance were discussed. The test results showed that SRHC short columns exhibited shear-flexure failure characteristics. The critical region length of SRHC short columns could be taken as the whole column height, regardless of axial load level. In comparison to SRHC normal columns, SRHC short columns had weaker energy dissipation capacity and deformation capacity, and experienced faster stiffness degradation and strength degradation. The decrease in energy dissipation and deformation capacity due to the decreasing shear span ratio was more serious when the axial load level was higher. However, SRHC short columns confined by multiple stirrups might possess good seismic behavior with enough deformation capacity (ultimate drift ratio ${\geq}2.5%$), even though a relative large axial load ratio (= 0.38) and relative small structural steel ratio (= 3.58%) were used, and were suitable to be used in tall buildings in earthquake regions.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.10
• /
• pp.151-163
• /
• 2006

This paper presents the interrelationship between undrained static and cyclic shear behavior. Laboratory works were performed through the undralned static and cyclic triaxial test using Nak-Dong River sand. And static triaxial test involved the triaxial extension test for comparison with cyclic shear behavior Cyclic triaxial test was performed with a variety of combination conditions of initial static shear stress $(q_{st})$ and cyclic stress $(q_{cy})$. In this result, the stress path of cyclic shear behavior was correspondent with static shear behavior passing the critical stress ratio (CSR) line because of the development of flow deformation. After that, a failure occurred according to failure line (FL) of static shear behavior. The stress path of cyclic shear behavior showed essentially the same with static shear behavior, although it appears a little different in test method.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.275-278
• /
• 2005

This paper presents a model for evaluating the contribution by arch action and frame action to shear resistance in shear-critical reinforced concrete beams without stirrup. The rotating angle softened truss model is employed to calculate the shear deformation of the web and the relative axial displacement of the compression and tension chord by the shear flow are also calculated. From this shear compatibility condition in a beam, the shear contribution by the arch action is numerically decoupled. The transverse strain obtained from the proposed model is selected for shear failure criterion. Using the failure criterion, shear strength of RC slender beams without stirrup is predicted.

• Journal of Advanced Marine Engineering and Technology
• /
• v.18 no.1
• /
• pp.101-113
• /
• 1994

This research has presented and experimental investigation on the characteristics of turbulent wake past a rectanular cylinder, according to various width/height ratio such as B/H=2.0, 2.79, 3.0, and 4.0 in a uniform shear flow. In order to perform this study, a special shear flow generator which produces the uniform shear flow has been designed and manufactured. It is found that the characteristics of the wake in a uniform shear flow are quite different from those of a uniform flow and vary with shear rate. And also, the formation of regular vortex structure is concerned with shear rate.