• Structural Engineering and Mechanics
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• v.30 no.6
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• pp.733-761
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• 2008

The failure of reinforced concrete structures in recent earthquakes caused concern about the performance of beam column joints. Confinement of joint is one of the ways to improve the performance of beam column joints during earthquakes. This paper describes an experimental study of exterior beam-column joints with two non-conventional reinforcement arrangements. One exterior beam-column joint of a six story building in seismic zone III of India was designed for earthquake loading. The transverse reinforcement of the joint assemblages were detailed as per IS 13920:1993 and IS 456:2000 respectively. The proposed nonconventional reinforcement was provided in the form of diagonal reinforcement on the faces of the joint, as a replacement of stirrups in the joint region for joints detailed as per IS 13920 and as additional reinforcement for joints detailed as per IS 456. These newly proposed detailing have the basic advantage of reducing the reinforcement congestion at the joint region. In order to study and compare the performance of joint with different detailing, four types of one-third scale specimens were cast (two numbers in each type). The main objective of the present study is to investigate the effectiveness of the proposed reinforcement detailing. All the specimens were tested under reverse cyclic loading, with appropriate axial load. From the test results, it was found that the beam-column joint having confining reinforcement as per IS: 456 with nonconventional detailing performed well. Test results indicate that the non-conventionally detailed specimens, Type 2 and Type 4 have an improvement in average ductility of 16% and 119% than their conventionally detailed counter parts (Type1 and Type 3). Further, the joint shear capacity of the Type 2 and Type 4 specimens are improved by 8.4% and 15.6% than the corresponding specimens of Type 1 and Type 3 respectively. The present study proposes a closed form expression to compute the yield and ultimate load of the system. This is accomplished using the theory of statics and the failure pattern observed during testing. Good correlation is found between the theoretical and experimental results.

• Journal of the Korea Institute of Building Construction
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• v.8 no.1
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• pp.83-90
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• 2008

The reinforcing steel process is composed of the development of placing drawing, cutting and bending, and the placement and fabrication of the reinforcement, and is participated in by reinforcement detailer, the fabricator and placer. Because the reinforcing steel process-from estimating and rebar detailing, to production, material tracking, billing, and general accounting-is conducted by many participant, reinforcement details based on building code and reinforcing bar detailing standards are essential. The process, however, holds some problems. Building code has been revised recently, and the utilization of placing drawings was proved to be low, and the reinforcement estimating in early stage of the process is below what is required for placement. Therefore, in this study, a survey was conducted to the reinforcement detailer, the fabricator and placer of domestic construction industry. According to the analysis of the survey, the reinforcement details on site was not standardized. The improvement in reinforcing steel detailing standards was sought by analyzing the results of the survey including reinforcement constructability.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1215-1222
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• 2005

The object of this thesis is an study on detailing for concrete reinforcement and analytical study for seismic behavior of underground reinforced concrete box structures using the established seismic analytical method. Using the established seismic analytical method that has been presented in various documents seismic behavior of buried reinforce concrete box structures is compared. From the comparsion, it is shown that feasibility and detailing detailng for concrete reinforcement and seismic method for seismic analysis of buried reinforced concrete box structures.

• Land and Housing Review
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• v.6 no.1
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• pp.11-19
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• 2015

This paper presents experimental results on detailing of boundary element transverse reinforcement, proposed to alleviate placement detailing of special shear wall experiencing difficulty in construction at the sites due to recently reinforced seismic regulations, according to the type and placement interval of transverse reinforcement. As a result of experiment, crack and destruction aspects of SSWR series specimen that employed the proposed detailing of transverse reinforcement showed similar trend as SSW series specimen that used closed hoop. Predicted maximum strength values were exceeded. Also as a result of comparing energy dissipation ability, SSWR2 specimen that follows alleviated placement detailing was found to have similar seismic performance as special shear wall SSW2 specimen based on the existing design standard. As it satisfies the deformation angle condition of 1.5% provided in the design standard, SSWR2 can be used as the main lateral force resistance element in structures.

• Computers and Concrete
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• v.33 no.5
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• pp.497-507
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• 2024

In squat reinforced concrete walls, the displacement capacity for lateral deformation is low and the ability to resist the axial load can quickly be lost, generating collapse. This work consists of testing two squat reinforced concrete walls. One of the specimens is built with conventional detailing of reinforced concrete walls, while the second specimen is built applying an alternative design, including stirrups along the diagonal of the wall to improve its ductility. This solution differs from the detailing of beams or coupling elements that suggest building elements equivalent to columns located diagonally in the element. The dimensions of both specimens correspond to a wall with a low aspect ratio (1:1), where the height and length of the specimen are 1.4 m, with a thickness of 120 mm. The alternative wall included stirrups placed diagonally covering approximately 25% of the diagonal strut of the wall with alternative detailing. The walls were tested under a constant axial load of 0.1f'cAg and a cyclic lateral displacement was applied in the upper part of the wall. The results indicate that the lateral strength is almost identical between both specimens. On the other hand, the lateral displacement capacity increased by 25% with the alternative detailing, but it was also able to maintain the 3 complete hysteretic cycles up to a drift of 2.5%, reaching longitudinal reinforcement fracture, while the base specimen only reached the first cycle of 2% with rapid degradation due to failure of the diagonal compression strut. The alternative design also allows 46% more energy dissipation than the conventional design. A model was used to capture the global response, correctly representing the observed behavior. A parametric study with the model, varying the reinforcement amount and aspect ratio, was performed, indicating that the effectiveness of the alternative detailing can double de drift capacity for the case with a low aspect ratio (1.1) and a large longitudinal steel amount (1% in the web, 5% in the boundary), which decreases with lower amounts of longitudinal reinforcement and with the increment of aspect ratio, indicating that the alternative detailing approach is reasonable for walls with an aspect ratio up to 2, especially if the amount of longitudinal reinforcement is high.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.154-159
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• 1993

To develop the detailing methods at the ends of flexural shear walls. which are satisfying the ductility requirement corresponding to R = 3.5 and capable of improving the consturctibility, tests of ten isolated cantilever shear walls were carried out under the load condition comprising the cyclic lateral and constant vertical loads. major test parameters include the way of detailing and arrangement of transverse reinforcement in the boundary elements at the ends of walls, and placement of vertical reinforcement. From tests, comparable ductile behavior in test specimens incorporating the channel type of open hoops, compared with those incorporating the regular type of closed hoops, was observed.

• Structural Engineering and Mechanics
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• v.33 no.2
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• pp.137-158
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• 2009

This paper investigates the behavior of reinforced concrete (RC) circular columns under combined loading including torsion. The main variables considered in this study are the ratio of torsional moment to bending moment (T/M) and the level of detailing for moderate and high seismicity (low and high transverse reinforcement/spiral ratio). This paper presents the results of tests on seven columns subjected to cyclic bending and shear, cyclic torsion, and various levels of combined cyclic bending, shear, and torsion. Columns under combined loading were tested at T/M ratios of 0.2 and 0.4. These columns were reinforced with two spiral reinforcement ratios of 0.73% and 1.32%. Similarly, the columns subjected to pure torsion were tested with two spiral reinforcement ratios of 0.73% and 1.32%. This study examined the significance of proper detailing, and spiral reinforcement ratio and its effect on the torsional resistance under combined loading. The test results demonstrate that both the flexural and torsional capacities are decreased due to the effect of combined loading. Furthermore, they show a significant change in the failure mode and deformation characteristics depending on the spiral reinforcement ratio. The increase in spiral reinforcement ratio also led to significant improvement in strength and ductility.

• Computers and Concrete
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• v.19 no.5
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• pp.589-597
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• 2017

Strut-and-tie modeling method, which evolved on truss-model approach, has generally been preferred for the design of complex reinforced concrete structures and structural elements that have critical shear behavior. Some structural members having disturbed regions require exceptional detailing for all support and loading conditions, such as the beam-column connections, deep beams, short columns or corbels. Considering the general expectation of exhibiting brittle behavior, corbels are somewhat dissimilar to other shear critical structures. In this study, reinforcement layout of a corbel model was determined by the participation of structural optimization and strut-and-tie modeling methods, and an experimental comparison was performed against a conventionally designed model.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.421-426
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• 1998

Current code provisions for the development of positive moment reinforcement is reviewed and criticized in this paper. Both the flexural bond and development length concepts are neccesary to consider anchorage requirement of reinforcement at beam ends. The curent design codes show unconservatism for the detailing of reinforcement at the beam ends. This study proposes a new design formula for the development of positive moment reinforcement.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.589-594
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• 2000

The necessary strength and ductility to avoid structural damage under moderate earthquake can be achieved by properly detailed transverse reinforcement in the plastic hinge zone. However, most structural walls have a higher aspect ratio(M/Vl\ulcorner) without well confined boundary regions. Therefore there is a need for adequate detailing in the plastic hinge zone, particularly boundary regions. In this paper, the fabricated interlocking spirals is introduced as a new seismic detailing for ductile behavior of the structural walls to be able to substitute for existing complicated detailing with ties. This paper also investigates the behavior characteristics of structural walls with interlocking spirals including confinement of the concrete and strength associated with flexure and shear.