• Journal of Korean Association for Spatial Structures
• /
• v.17 no.4
• /
• pp.115-122
• /
• 2017

In this study, performance based seismic design was performed on the shear wall structural system and the beam-column system as a variable general rebar and seismic rebar, and comparing the capacity of the two models of each system. From nonlinear analyses, the capacity of the shear wall structural system applying seismic rebar has shown a stable behavior after the maximum strength, but there is little difference. Furthermore, both models showed similar capacity between story drift and story shear force and capacity of members. These results are attributed to the fact that the seismic rebar, which is highly ductile under the seismic load applied to the target structure, does not render sufficient capacity.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.1
• /
• pp.109-116
• /
• 2008

In order to test the adhesive capacity of carbon fiber sheet, a static loading method for bending-behavior-type beam specimens, cut in half was developed and test was conducted with compressive strength of concrete set as the test parameter. The tests were performed to prescribe adhesive shear strength based upon the result of shear failure as well as verification of testing method. First of all, the test method proved to be reliable in determining the adhesive shear strength. The test result also exhibited two types of variations in adhesive shear strength. Among two types of variations, average and minimum values for adhesive shear strength, relatively stable results, 3.41MPa and 2.11MPa, respectively. Particularity in the adhesive shear strength with respect to compressive shear strength was not found.

• Journal of Korean Association for Spatial Structures
• /
• v.15 no.2
• /
• pp.61-68
• /
• 2015

The performance enhancement of various structural building systems from natural hazards has become an inctreasingly important issue in engineering field. In this paper, visco-elastic(VE) CST30 damping systems were tested under cyclic loadings to evaluate their performance in terms of ductility and energy dissipation. Main test variables are relative shear stiffness, rate of loading frequency, and thickness of specimens to evaluate the seismic capacity based on the performance criteria. This experiment was performed using a total of 12 specimens, subjected to cyclic loadings up to a shear deformation of 500%. All the CST30 dampers provided a ductile and stable hysterestic behavior when subjected to the demands of large shear stiffness and different loading frequencies. The test results showed that the CST30 dampers are an effective damping systems to enhance the buildings performance for remodeling and retrofit of buildings.

• Structural Engineering and Mechanics
• /
• v.60 no.2
• /
• pp.251-269
• /
• 2016

In common structural systems, there are some limitations to provide adequate lateral stiffness, high ductility, and architectural openings simultaneously. Consequently, the concept of T-Resisting Frame (TRF) has been introduced to improve the performance of structures. In this study, Configuration of TRF is a Vertical I-shaped Plate Girder (V.P.G) which is placed in the middle of the span and connected to side columns by two Horizontal Plate Girders (H.P.Gs) at each story level. System performance is improved by utilizing rigid connections in link beams (H.P.Gs). Plastic deformation leads to tension field action in H.P.Gs and causes energy dissipation in TRF; therefore, V.P.G. High plastic deformation in web of TRF's members affects the ductility of system. Moreover, in order to prevent shear buckling in web of TRF's members and improve overall performance of the system, appropriate criteria for placement of web stiffeners are presented in this study. In addition, an experimental study is conducted by applying cyclic loading and using finite element models. As a result, hysteresis curves indicate adequate lateral stiffness, stable hysteretic behavior, and high ductility factor of 6.73.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.1
• /
• pp.33-42
• /
• 2008

Buckling-Restrained Braces (BRB) has been developed to inhibit buckling and exhibit stable behavior underboth tensile and compresive cycles. In this study, an experime nt has been conducted by using the strength of its members and loading protocols as parameters to evaluate the structural performance of BRB (without in-filed concrete). Specimens are composed of an inner core and an outer tube with diferent steel strengths. When high-strength steels were used as iner cores, the ductility of BRB decreased, and the requirements (Cumulative Plastic Ductility) of the AISC Seismic Provisions were not satisfied. however, when high-strength steels were used as inner cores instead of conventional strength stel cores, the maximum capacity increased significantly and displayed similar performance in total energy dissipation.

• Structural Engineering and Mechanics
• /
• v.81 no.6
• /
• pp.715-728
• /
• 2022

A new type of buckling-restrained braces (BRBs) with a longitudinally profiled steel plate working as the core (LPBRB) is proposed and experimentally investigated. Different from conventional BRBs with a constant thickness core, both stiffness and strength of the longitudinally profiled steel core along its longitudinal direction can change through itself variable thickness, thus the construction of LPBRB saves material and reduces the processing cost. Four full-scale component tests were conducted under quasi-static cyclic loading to evaluate the seismic performance of LPBRB. Three stiffening methods were used to improve the fatigue performance of LPBRBs, which were bolt-assembled T-shaped stiffening ribs, partly-welded stiffening ribs and stiffening segment without rib. The experimental results showed LPBRB specimens displayed stable hysteretic behavior and satisfactory seismic property. There was no instability or rupture until the axial ductility ratio achieved 11.0. Failure modes included the out-of-plane buckling of the stiffening part outside the restraining member and core plate fatigue fracture around the longitudinally profiled segment. The effect of the stiffening methods on the fatigue performance is discussed. The critical buckling load of longitudinally profiled segment is derived using Euler theory. The local bulging behavior of the outer steel tube is analyzed with an equivalent beam model. The design recommendations for LPBRB are presented finally.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.5 no.4
• /
• pp.67-74
• /
• 2001

Structural engineers lately have an interest in the safety for equipments and facility in buildings subjected to earthquake. The stability of cultural assets was not considered for the earthquake induced vibration, while the integrity of structure has been considered through the resistant earthquake design. The purpose of this study aimed to analyze the behavior of isolation device named as \"Isolation table system\" and to evaluate its isolation performance through the experiment study. Isolation table is one of isolation systems to reduce the vibration which was transferred from slab to exhibition table. Experimental result shows that isolation table can reduce the vibration by 80-90% and its behavior is very stable within its maximal stroke.al stroke.

• Nuclear Engineering and Technology
• /
• v.45 no.1
• /
• pp.89-98
• /
• 2013

In recent years steel-concrete composite shear walls have been widely used in enormous high-rise buildings. Due to high strength and ductility, enhanced stiffness, stable cycle characteristics and large energy absorption, such walls can be adopted in the auxiliary building; surrounding the reactor containment structure of nuclear power plants to resist lateral forces induced by heavy winds and severe earthquakes. This paper demonstrates a set of nonlinear numerical studies on I-shaped composite steel-concrete shear walls of the nuclear power plants subjected to reverse cyclic loading. A three-dimensional finite element model is developed using ABAQUS by emphasizing on constitutive material modeling and element type to represent the real physical behavior of complex shear wall structures. The analysis escalates with parametric variation in steel thickness sandwiching the stipulated amount of concrete panels. Modeling details of structural components, contact conditions between steel and concrete, associated boundary conditions and constitutive relationships for the cyclic loading are explained. Later, the load versus displacement curves, peak load and ultimate strength values, hysteretic characteristics and deflection profiles are verified with experimental data. The convergence of the numerical outcomes has been discussed to conclude the remarks.

• Journal of the Korean Society of Safety
• /
• v.25 no.6
• /
• pp.128-136
• /
• 2010

In according with concrete structural design standard, it is common designing flexure reinforcement concrete to induce tension failure. So reinforcing ratio is limited to inducing tension failure. And maximum reinforcing ratio is regulated to protecting concrete compression strength caused by over reinforced building. Minimum reinforcing ratio is also limited in designing standard to protecting brittle failure as extremely using less reinforcing bar. But in minimum reinforcing ratio it is extremely conservative or it is sometimes impossible to induce stable tension-failure because they are depending on yield failure and experienced method and concrete designing standard strength. Therefore the purpose of the present paper is to evaluate the flexural behavior of minimum steel ratio of reinforced concrete of beams and to propose the guide-line of equation of minimum steel ratio by performing static flexural test of 16 beams according to size effect, number of steel, yielding stress of steel, and concrete compressive strength which are presumed effective variables. From experimental results, the equation of minimum steel ratio was newly proposed considered size effect.

• Advances in aircraft and spacecraft science
• /
• v.2 no.3
• /
• pp.345-365
• /
• 2015

This paper focuses on the design, fabrication, testing and analysis of a novel load-bearing element with energy dissipation capability. A single element comprises two von-Mises trusses (VMTs), which are sandwiched between two plates and connected to dashpots that stroke as the VMTs cycle between stable equilibrium states. The elements can be assembled in-plane to form a large plate-like structure or stacked with different properties in each layer for improved load-adaptability. Also introduced in the elements are pre-loaded springs (PLSs) that provide high initial stiffness and allow the element to carry a static load even when the VMTs cannot under harmonic disturbance input. Simulations of the system behavior using the Simscape environment show good overall correlation with test data. Good energy dissipation capability is observed over a frequency range from 0.1 Hz to 2 Hz. The test and simulation results show that a two layer prototype, having one soft VMT layer and one stiff VMT layer, can provide good energy dissipation over a decade of variation in harmonic load amplitude, while retaining the ability to carry static load due to the PLSs. The paper discusses how system design parameter changes affect the static load capability and the hysteresis behavior.