• 한국구조물진단유지관리공학회 논문집
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• 제4권1호
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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).

• 한국방재학회 논문집
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• 제8권2호
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• pp.51-58
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• 2008

본 연구는 전단철근이 없는 초고강도 섬유보강 콘크리트 프리스트레스 I형거더의 극한전단파괴하중 산정에 대한 이론적 근거를 마련하는데 있다. 9개의 초고강도 섬유보강 콘크리트 거더에 대한 극한 전단하중을 측정하였다. 전단하중을 산정하기 위한 해석식은 두 경계이론을 근거로 유도되었다. 섬유가 부담하는 전단력 산정모델은 섬유가 방향과 길이면에서 균일하게 분포한다는 가정하에서 구성되었다. 본 논문에서 제안한 초고강도 섬유보강 콘크리트 거더에 대한 전단강도식을 기존의 섬유보강 콘크리트 전단강도식과 실험에 의한 전단하중과 비교한 결과 비교적 정확한 산정값을 보여주었다.

• Computers and Concrete
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• 제11권1호
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• pp.21-37
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• 2013

High-performance concrete (HPC) usually has higher paste and lower coarse aggregate volumes than normal concrete. The lower aggregate content of HPC can affect the shear capacity of concrete members due to the formation of smooth fractured surfaces and the subsequent development of weak interface shear transfer. Therefore, an experimental investigation was conducted to study the shear strength and cracking behavior of full-scale reinforced beams made with low-cement-content high-performance concrete (LcHPC) as well as conventional HPC. A total of fourteen flexural reinforced concrete (RC) beams without shear reinforcements were tested under a two-point load until shear failure occurred. The primary design variables included the cement content, the shear span to effective depth ratio (a/d), and the tensile steel ratio (${\rho}_w$). The results indicate that LcHPC beams show comparable behaviors in crack and ultimate shear strength as compared with conventional HPC beams. Overall, the shear strength of LcHPC beams was found to be larger than that of corresponding HPC beams, particularly for an a/d value of 1.5. In addition, the crack and ultimate shear strength increased as a/d decreased or ${\rho}_w$ increased for both LcHPC beams and HPC beams. This investigation established that LcHPC is recommendable for structural concrete applications.

• 대한토목학회논문집
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• 제9권4호
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• pp.63-71
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• 1989

고강도(高強度) 콘크리트 보의 전단균열강도와 극한전단강도를 조사하기 위하여 4개의 Series로 철근콘크리트 보를 실험(實驗)하였다. 모든 보는 전단보강철근(剪斷補強鐵筋)이 없는 단철근 보로 하였으며, 주변수는 콘크리트 강도로써 공시체 압축강도를 $247kg/cm^2$(3500 psi)에서 $708kg/cm^2$(10000 psi)까지 변화(變化)시켰다. 각 Series는 콘크리트 강도를 일정(一定)하게 하고서, 보의 전단지간(剪斷支間) 대(對) 유효(有效)깊이의 비(比)(a/d)를 2에서 5까지 변화(變化)시켰다. 실험결과(實險結果)에 따르면, 전단지지력(剪斷支持力)에 대한 콘크리트 강도(強度)의 영향은 보의 a/d에 따라 각기 달랐을 뿐만 아니라 현행(現行) 시방서의 전단설계규정은 철근콘크리트 보의 전단지지력을 산정하는데 일정성이 없음을 보였다. 본 연구에서는 전단지간(剪斷支間) 대 유효(有效)깊이의 비(比)의 변화(變化)에 따른 전단강도(剪斷強度)에 대(對)한 콘크리트 압축강도(壓縮強度)의 영향을 고려하기 위하여 shear failure mode index를 사용한 극한전단강도식(極限剪斷強度式)을 제안(提案)하여 타당성을 검토하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.243-249
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• 1993

The porpose of this study is to suggest an experimental for shear wall of reinforced concrete wall structure. A series of experimental be performed for earned to strength and deformation property of reinforced concrete shear wall. These specimens are three R/C walls among five models which had boundary. As a result, it was found that cyclic experiment is very proper and cyclic time must be increased 3 or 5 times. Monotonic test results was indicated over 15% than other experiment for yielding strength and ultimate strength.

• Steel and Composite Structures
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• 제42권4호
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• pp.539-552
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• 2022

Concentrically braced frames (CBFs) possess high stiffness and strength against lateral loads; however, they suffer from low energy absorption capacity against seismic loads due to the susceptibility of CBF diagonal elements to bucking under compression loading. To address this problem, in this study, an innovative damper was proposed and investigated experimentally and numerically. The proposed damper comprises main plates and includes a flange plate angled at θ and a trapezius-shaped web plate surrounded by the plate at the top and bottom sections. To investigate the damper behaviour, dampers with θ = 0°, 30°, 45°, 60°, and 90° were evaluated with different flange plate thicknesses of 10, 15, 20, 25 and 30 mm. Dampers with θ = 0° and 90° create rectangular-shaped and I-shaped shear links, respectively. The results indicate that the damper with θ = 30° exhibits better performance in terms of ultimate strength, stiffness, overstrength, and distribution stress over the damper as compared to dampers with other angles. The hysteresis curves of the dampers confirm that the proposed damper acts as a ductile fuse. Furthermore, the web and flange plates contribute to the shear resistance, with the flange carrying approximately 80% and 10% of the shear force for dampers with θ = 30° and 90°, respectively. Moreover, dampers that have a larger flange-plate shear strength than the shear strength of the web exhibit behaviours in linear and nonlinear zones. In addition, the over-strength obtained for the damper was greater than 1.5 (proposed by AISC for shear links). Relevant relationships are determined to predict and design the damper and the elements outside it.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.501-521
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• 2007

This study presents a model to better understand the shear behavior of reinforced concrete walls subjected to lateral load. The scope of the study is limited to squat walls with height to length ratios not exceeding two, deformed in a double-curvature shape. This study is based on limited knowledge of the shear behavior of low-rise shear walls subjected to double-curvature bending. In this study, the wall ultimate strength is defined as the smaller of flexural and shear strengths. The flexural strength is calculated using a strength-of-material analysis, and the shear strength is predicted according to the softened strut-and-tie model. The corresponding lateral deflection of the walls is estimated by superposition of its flexibility sources of bending, shear and slip. The calculated results of the proposed procedure correlate reasonably well with previously reported experimental results.

• 국제강구조저널
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• 제18권4호
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• pp.1139-1152
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• 2018

Many studies on the application of stainless steels as structural materials in buildings and infra-structures have been performed thanks to superior characteristics of corrosion resistance, fire resistance and aesthetic appeal. Experimental investigation to estimate the ultimate strength and fracture mode of the fillet-welded connections of cold-formed austenitic stainless steel (STS304L) with better intergranular corrosion resistance than that of austenitic stainless steel, STS304 commonly used has carried out by authors. Specimens were fabricated to fail by base metal fracture not weld metal fracture with main variables of weld lengths according to loading direction. All specimens showed a block shear fracture mode. In this paper, finite element analysis model was developed to predict the ultimate behaviors of welded connection and its validity was verified through the comparison with test results. Since the block shear behavior of welded connection due to stress triaxiality and shear-lag effects is different from that of bolted connection, stress and strain distributions in the critical path of tensile and shear fracture section were investigated. Test and analysis strengths were compared with those by current design specifications such as AISC, EC3 and existing researcher's proposed equations. In addition, through parametric analysis with extended variables, the conditions of end distance and longitudinal weld length for block shear fracture and tensile fracture were suggested.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.347-358
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• 2018

The main aim of this research was to investigate the shear strength of non-prismatic steel fiber reinforced concrete beams under monotonic loading considering different parameters. Experimental program included tests on fifteen non-prismatic reinforced concrete beams divided into three groups. For the first and the second groups, different parameters were taken into consideration which are: steel fibers content, shear span to minimum depth ratio ($a/d_{min}$) and tapering angle (${\alpha}$). The third group was designed mainly to optimize the geometry of the non-prismatic concrete beams with the same concrete volume while the steel fiber ratio and the shear span were left constant in this group. The presence of steel fibers in concrete led to an increase in the load-carrying capacity in a range of 10.25%-103%. Also, the energy absorption capacity was increased due to the addition of steel fibers in a range of 18.17%-993.18% and the failure mode was changed from brittle to ductile. Tapering angle had a clear effect on the shear strength of test specimens. The increase in tapering angle from ($7^{\circ}$) to ($12^{\circ}$) caused an increase in the ultimate shear capacity for the test specimens. The maximum increase in ultimate load was 45.49%. The addition of steel fibers had a significant impact on the post-cracking behavior of the test specimens. Empirical equation for shear strength prediction at cracking limit state was proposed. The predicted cracking shear strength was in good agreement with the experimental findings.

• 한국강구조학회 논문집
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• 제25권5호
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• pp.463-474
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• 2013

일면전단 오스테나이트계 스테인리스강 및 탄소강에 관한 많은 실험 및 해석적 연구가 수행되어졌고, 수정된 내력평가식이 제안되었다. 본 연구에서는 볼트배열(2행 1열, 2행 2열)과 하중방향 연단거리를 주요변수로 하여 이면전단 볼트접합부 실험체가 제작되었고, 단순인장실험이 실시되었다. 고정변수로는 하중직각방향 연단거리, 볼트직경, 피치, 게이지를 설정하였다. 최대내력과 파단형태와 같은 실험결과와 현행기준식에 의한 예측결과와 비교 검토되었다. 볼트배열에 따른 블록전단내력평가식이 제안되었다.