• Steel and Composite Structures
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• 제38권4호
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• pp.431-445
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• 2021

This paper presents experiments and theoretical analysis on shear behavior of eight concrete-encased square concrete-filled steel tube (CECFST) specimens and three traditional reinforced concrete (RC) specimens. A total of 11 specimens with the test parameters including the shear span-to-depth ratio, steel tube size and studs arrangement were tested to explore the shear performance of CECFST specimens. The failure mode, shear capacity and displacement ductility were thoroughly evaluated. The test results indicated that all the test specimens failed in shear, and the CECFST specimens enhanced by the interior CFST core exhibited higher shear capacity and better ductility performance than that of the RC specimens. When the other parameters were the same, the larger steel tube size, the smaller shear span-to-depth ratio and the existence of studs could lead to the more satisfactory shear behavior. Then, based on the compatible truss-arch model, a set of formulas were developed to analytically predict the shear strength of the CECFST members by considering the compatibility of deformation between the truss part, arch part and the steel tube. Compared with the calculated results based on several current design specifications, the proposed formulas could get more accurate prediction.

• 한국강구조학회 논문집
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• 제27권2호
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• pp.131-142
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• 2015

트러스구조는 대형구조물의 설계 및 시공에 편리하며, 부재의 경량화에 따른 비용의 절검 효과를 얻을 수 있는 구조물로 최근 다양한 형태의 구조물건설에 많이 사용되고 있다. 본 연구에서는 응력, 좌굴 그리고 구조물의 고유진동수 제약조건을 고려한 트러스 구조물의 단면과 형상에 대해 최적설계를 하였다. 최적설계에서 최적화기법으로 HA-SA방법을 제시하였으며, HA-SA방법은 HA 초기메모리에서 최상의 설계를 SA의 초기 설계로 하여 최적화 하는 방법이다. 예제에 사용된 트러스 구조물은 고유진동수 제약조건으로 10-bar, 72-bar, 52-bar 트러스와 응력 및 좌굴응력 제약조건으로 18-bar, 47-bar 트러스를 사용하였다. 그리고 52-bar, 18-bar, 47-bar의 경우는 트러스의 형상을 최적설계 하였다. 예제로부터 다양한 설계 제약조건하에서 여러 연구결과와 HA, SA, GA, HA-SA방법에 의한 결과를 서로 비교하여 HA-SA방법의 적용성을 입증하였다.

• Steel and Composite Structures
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• 제5권1호
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• pp.49-70
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• 2005

This paper reports on finite element analysis techniques that may be applied to the study of circular hollow structural sections and related bearing connection geometries. Specifically, a connection detail involving curved steel saddle bearings and a Structural Tee (ST) connected directly to a large-diameter Hollow Structural Section (HSS) truss chord, near its open end, is considered. The modeling is carried out using experimentally verified techniques. It is determined that the primary mechanism of failure involves a flexural collapse of the HSS chord through plastification of the chord wall into a well-defined yield line mechanism; a limit state for which a shell-based finite element model is well-suited to capture. It is also found that classical metal plasticity material models may be somewhat limited in their applicability to steels in fabricated tubular members.

• 콘크리트학회논문집
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• 제12권6호
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• pp.57-66
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• 2000

The truss analogy for the analysis of beam-columns subjected of shear and flexure is limited by the contribution of transverse and longitudinal steel and diagonal concrete compression struts. However, it should be noted that even though the behavior of reinforced concrete beam-columns after cracking can be modeled with the truss analogy, they are not perfect trusses but still structural elements with a measure of continuity provided by a diagonal tension field. The mere notion of compression field denotes that there should be some tension field coexisting perpendicularly to it. The compression field is assumed to form parallel to the crack plane that forms under combined flexure and shear. Therefore, the concrete tension field may be defined as a mechanism existing across the crack and resisting crack opening. In this paper, the effect of concrete tensile properties on the shear strength and stiffness of reinforced concrete beam-columns is discussed using the Gauss two-point truss model. The theoretical predictions are validated against the experimental observations. Although the agreement is not perfect, the comparison shows the correct trend in degradation as the inelasticity increases.

• Wind and Structures
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• 제7권6호
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• pp.393-404
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• 2004

The design of truss type sign support structures is based on the guidelines provided by the American Association of State Highway and Transportation Officials Standard Specifications for Highway Signs, Luminaries and Traffic Signals and the American Institute of Steel Construction Design Specifications. Using these specifications, the column design strength is normally determined using the effective length approach. This approach does not always accurately address all issues associated with frame stability, including the actual end conditions of the individual members, variations of the loads in the members, and the resulting sidesway buckling for truss type sign support structures. This paper provides insight into the problems with the simplified design approach for determining the effective lengths and discusses different approaches for overcoming these simplifications. A system buckling approach, also known as a rational buckling analysis, is used in this study to determine improved predictions for design strength of truss type sign support structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.367-370
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• 2005

This study is to propose a truss model which is able to reasonably predict the shear strength of reinforced concrete (RC) members with high-strength materials. The shear strengths of 107 RC test beams with high-strength steel bars reported in the technical literatures were compared to those obtained from proposed model, TATM, and existing truss models. The shear strength of reinforced concrete beams obtained from test was better predicted by TATM than other truss models. Also, the theoretical results by TATM were almost constant regardless of yield strengths and steel ratios of tension and shear reinforcements.

• Structural Engineering and Mechanics
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• 제55권4호
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• pp.801-813
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• 2015

Flexural stiffness of bridge spans has become even more important parameter since Eurocode 1 introduced for railway bridges the serviceability limit state of resonance. For simply supported bridge spans it relies, in general, on accurate assessment of span moment of inertia that governs span flexural stiffness. The paper presents three methods of estimation of the equivalent moment of inertia for such spans: experimental, analytical and numerical. Test loading of the twin truss bridge spans and test results are presented. Recorded displacements and the method of least squares are used to find an "experimental" moment of inertia. Then it is computed according to the analytical method that accounts for joint action of truss girders and composite deck as well as limited span shear stiffness provided by diagonal bracing. Finally a 3D model of finite element method is created to assess the moment of inertia. Discussion of results is given. The comparative analysis proves efficiency of the analytical method.

• Smart Structures and Systems
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• 제22권6호
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• pp.699-709
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• 2018

With increasing traffic volumes and rising vehicle traffic, especially in cities, the number of pedestrian bridges has also increased significantly. Like all other structures, pedestrian bridges also suffer damage. In order to increase the safety of pedestrians, it is necessary to identify existing damage and to repair them to ensure the safety of the bridge structures. Owing to the shortcomings of local methods in identifying damage and in order to enhance the reliability of detection and identification of structural faults, signal methods have seen significant development in recent years. In this research, a new methodology, based on cone-shaped kernel distribution with a new damage index, has been used for damage detection in pedestrian truss bridges. To evaluate the proposed method, the numerical models of the Warren Type steel truss and the Arregar steel footbridge were used. Based on the results, the proposed method and damage index identified the damage and determined its location with a high degree of precision. Given the ease of use, the proposed method can be used to identify faults in pedestrian bridges.

• Structural Engineering and Mechanics
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• 제29권1호
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• pp.37-53
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• 2008

Plane steel portal frames, with pitched roof, exposed to fire, are examined. First, a determinate frame is analysed by hand. For flexible columns and shallow roof, snap-through occurs before plastic hinges mechanism is formed. An indeterminate frame with shorter columns and taller roof is also analysed by hand. Then, the same frame is simulated by a truss and a nonlinear static analysis is performed by use of a short computer program. The results of computer analysis by use of truss model are compared with those of analysis by hand and a satisfactory approximation between them is observed.

• Advances in concrete construction
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• 제11권1호
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• pp.33-43
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• 2021

A new type of composite insulated concrete sandwich wall (ICS-wall), which is composed of a triangle truss steel wire network, an insulating layer, and internal and external concrete layers, is proposed. To study the mechanical properties of this new ICS-wall, tensile, compression, and shearing tests were performed on 22 specimens and tensile strength and corrosion resistance tests on 6 triangle truss joints. The variables in these tests mainly include the insulating plate material, the thickness of the insulating plate, the vertical distance of the triangle truss framework, the triangle truss layout, and the connecting mode between the triangle truss and wall and the material of the triangle truss. Moreover, the failure mode, mechanical properties, and bearing capacity of the wall under tensile, shearing, and compression conditions were analyzed. Research results demonstrate that the concrete and insulating layer of the ICS-wall are pulling out, which is the main failure mode under tensile conditions. The ICS-wall, which uses a graphite polystyrene plate as the insulating layer, shows better tensile properties than the wall with an ordinary polystyrene plate. The tensile strength and bearing capacity of the wall can be improved effectively by strengthening the triangle truss connection and shortening the vertical distances of the triangle truss. The compression capacity of the wall is mainly determined by the compression capacity of concrete, and the bonding strength between the wall and the insulating plate is the main influencing factor of the shearing capacity of the wall. According to the tensile strength and corrosion resistance tests of Austenitic stainless steel, the bearing capacity of the triangle truss does not decrease after corrosion, indicating good corrosion resistance.