• Earthquakes and Structures
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• 제3권1호
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• pp.37-57
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• 2012

The behavior of beam-column joints in moment resisting frame structures is susceptible to damage caused by seismic effects due to poor performance of the joints. A good number of researches were carried out to understand the complex mechanism of RC joints considered in current seismic design codes. The traditional construction detailing of transverse reinforcement has resulted in serious joint failures during earthquakes. This paper introduces a new design philosophy involving the use of additional diagonal bars within the joint particularly suitable for low to medium seismic effects in earthquake zones. In this study, ten full-scale interior beam-column specimens were constructed with various additional reinforcement details and configurations. The results of the experiment showed that adding additional bars is a promising approach in reinforced concrete structures where earthquakes are eminent. In terms of overall cracking observation during the test, the specimens with additional bars (diagonal and straight) compared with the ones without them showed fewer cracks in the column. Furthermore, concrete confinement is certainly an important design measure as recommended by most international codes.

• Steel and Composite Structures
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• 제23권1호
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• pp.17-29
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• 2017

The seismic performance of steel beam to concrete-encased composite column with unsymmetrical steel section joints is investigated and reported within this paper. Experimental and analytical evaluation were conducted on a total of 8 specimens with T-shaped and L-shaped steel section under lateral cyclic loading and axial compression. The test parameters included concrete strength, stirrup ratio and axial compression ratio. The response of the specimens was presented in terms of their hysterisis loop behavior, stress distribution, joint shear strength, and performance degradation. The experiment indicated good structural behavior and good seismic performance. In addition, a three-dimensional nonlinear finite-element analysis simulating was conducted to simulate their seismic behaviors. The finite-element analysis incorporated both bond-slip relationship and crack interface interaction between steel and concrete. The results were also compared with the test data, and the analytical prediction of joint shear strength was satisfactory for both joints with T-shaped and L-shaped steel section columns. The steel beam to concrete-encased composite column with unsymmetrical steel section joints can develop stable hysteretic response and large energy absorption capacity by providing enough stirrups and decreased spacing of transverse ties in column.

• Structural Engineering and Mechanics
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• 제86권3호
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• pp.417-430
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• 2023

As the key part in the reinforced concrete column-steel beam (RCS) frame, the beam-column joints are usually subjected the axial force, shear force and bending moment under seismic actions. With the aim to study the seismic behavior of RCS joints with and without RC slab, the quasi-static cyclic tests results, including hysteretic curves, slab crack development, failure mode, strain distributions, etc. were discussed in detail. It is shown that the composite action between steel beam and RC slab can significantly enhance the initial stiffness and loading capacity, but lead to a changing of the failure mode from beam flexural failure to the joint shear failure. Based on the analysis of shear failure mechanism, the calculation formula accounting for the influence of RC slab was proposed to estimate shear strength of RCS joint. In addition, the finite element model (FEM) was developed by ABAQUS and a series of parametric analysis model with RC slab was conducted to investigate the influence of the face plates thickness, slab reinforcement diameter, beam web strength and inner concrete strength on the shear strength of joints. Finally, the proposed formula in this paper is verified by the experiment and FEM parametric analysis results.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.393-394
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• 2023

This paper provides an overview of seismic design considerations for vertical construction joints of a slurry walls used as a permanent basement walls.

• 콘크리트학회논문집
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• 제18권6호
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• pp.729-736
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• 2006

적절한 내진상세로 설계되지 않은 철근콘크리트 구조물은 보-기둥 접합부내에서 취약한 전단파괴에 노출되고 큰 변형이 일어나, 구조적인 붕괴가 일어날 수 있다. 본 연구는 CFRP로 보강한 철근콘크리트 외부 보-기둥 접합부를 반복 횡력을 적용하여 보강된 보-기둥 접합부의 내진성능을 알아보았다. 보-기둥 접합부의 구조적 성능을 향상시키기 위해 CFRP의 부착 위치나 두께를 달리하여 효과적인 보강방법을 관찰하고자 하였다. 비내진상세로 배근된 실험체 1개와 내진상세로 배근된 실험체 1개 그리고 비내진상세를 가진 실험체를 CFRP로 보강한 실험체 6개, 총 8개의 보-기둥 접합부 실험체에 반복횡력을 가하여 내진보강의 효과를 조사하였다. 반복 횡력을 적용하였다. 본 연구에서는 비내진상세를 가진 콘크리트 보-기둥 접합부에 대한 CFRP의 보강방법은 구조물의 강도와 연성을 증가시켜 구조물의 내진성능을 향상시키는데 효과적임을 보여 주었다.

• Computers and Concrete
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• 제21권3호
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• pp.335-344
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• 2018

More and more special-shaped structural systems have been widely used in various industrial and civil buildings in order to satisfy the new structural system and the increasing demand for architectural beauty. With the popularity of the special-shaped structure system, its seismic performance and damage form have also attracted extensive attention. In the current research, an experimental analysis of six groups of (2/3 scale) T-shaped column joints was conducted to investigate the seismic performance of T-shaped column joints. Effects of the beam cross section, transverse stirrup ratio and axial compression ratio on bearing capacity and energy dissipation capacity of column joints were obtained. The crack pattern of T-shaped column joints under low cyclic load was presented and showed a reversed "K" mode. According to the crack configurations, a tensile-shear failure model to determine the shear bearing capacity and crack propagation mechanisms is developed.

• 한국전산구조공학회논문집
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• 제24권2호
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• pp.201-210
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• 2011

이 연구에서는 깊은보-내부기둥 접합부의 내진성능평가를 위한 비선형 유한요소해석 기법을 제시하였다. 사용된 프로그램은 철근콘크리트 구조물의 해석을 위한 RCAHEST이다. 깊은보-내부기둥 접합부의 강도, 연성도 등 거동특성을 파악하기 위한 반복횡하중 실험을 수행하였다. 실험의 변수로는 축력과 횡방향 철근량을 정하였다. 이 연구에서는 깊은보-내부기둥 접합부의 내진성능평가를 위해 제안한 해석기법을 신뢰성 있는 실험결과와 비교하여 그 타당성을 검증하였다.

• Steel and Composite Structures
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• 제37권3호
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• pp.307-321
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• 2020

The slim-floor solution provides an efficient alternative to the classic slab-over-beam configuration due to architectural and structural benefits. Two deficiencies can be identified in the current state-of-art: (i) the technique is limited to nonseismic applications and (ii) the lack of information on moment-resisting slim-floor beam-to-column joints. In the seismic design of framed structures, continuous beam-to-column joints are required for plastic hinges to form at the ends of the beams. The present paper proposes a slim-floor technical solution capable of expanding the current application of slim-floor joints to seismic-resistant composite construction. The proposed solution relies on a moment-resisting connection with a thick end-plate and large-diameter bolts, which are used to fulfill the required strength and stiffness characteristics of continuous connections, while maintaining a reduced height of the configuration. Considering the proposed novel solution and the variety of parameters that could affect the behavior of the joint, experimental and numerical validations are compulsory. Consequently, the current paper presents the experimental and numerical investigation of two slim-floor beam-to-column joint assemblies. The results are discussed in terms of moment-rotation curves, available rotational capacity and failure modes. The study focuses on developing reliable slim-floor beam joints that are applicable to steel building frame structures located in seismic regions.

• Structural Engineering and Mechanics
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• 제46권6호
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• pp.809-825
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• 2013

In the present study, in reinforced concrete structures, beam-column connections are one of the most critical regions in areas with seismic susceptibility. Proper anchorage of reinforcement is vital to enhance the performance of beam-column joints. Congestion of reinforcement and construction difficulties are reported frequently while using conventional reinforcement detailing in beam-column joints of reinforced concrete structures. An effort has been made to study and evaluate the performance of beam-column joints with joint detailing as per ACI-352 (mechanical anchorage), ACI-318 (conventional hooks bent) and IS-456(full anchorage conventional hooks bent) along with confinement as per IS-13920 and without confinement. Apart from finding solutions for these problems, significant improvements in seismic performance, ductility and strength were observed while using mechanical anchorage in combination with X-cross bars for less seismic prone areas and X-cross bar plus hair clip joint reinforcement for higher seismic prone areas. To evaluate the performances of these types of anchorages and joint details, the specimens were assembled into four groups, each group having three specimens have been tested under reversal loading and the results are presented in this paper.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.176-187
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• 2001

Most bridges have expansion joints to accommodate thermal expansion and contraction without inducing large forces in the bridges. To evaluate the effects of earthquake-induced at expansion joints of concrete bridges, the first part of this paper deals with a collinear impact between concrete segments, which have the same cross section but different lengths. Especially, impact force, momentum, strain energy and kinetic energy are formulated in mathematically. These results are then used in the second part of this paper to simulate a realistic yet simple analysis of seismic pounding in concrete bridges. Analysis of seismic pounding in idealized concrete bridges is carried out by using a simple lumped-mass model and rationally determined values of the coefficient of restitution and the duration of impact.