• Steel and Composite Structures
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• 제36권5호
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• pp.569-586
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• 2020

The behavior of composite steel-concrete beams depends on the transmission of forces between two parts: the concrete slab and the steel I-beam. The shear connector is responsible for the interaction between these two parts. Recently, an alternative shear connector, called Truss Type connector, has been developed; it aligns efficient structural behavior, fast construction and implementation, and low cost when compared to conventional connectors applied in composite structures. However, there is still a lack of full understanding of the mechanical behavior of the Truss Type connector, due to its novelty. Thus, this study aims to analyze the influence of variation of geometric and physical parameters on the shear resistance of the Truss Type connector. In order to investigate those parameters, a non-linear finite element model, able to simulate push-out tests of Truss Type connectors, was specifically developed and validated with experimental results. A thorough parametric study, varying the height, the angle between rods, the diameter, and the concrete strength, was conducted to evaluate the shear resistance of the Truss Type connector. In addition, an equation to predict the resistance of the original Truss Type shear connector was proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.557-561
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• 2008

Shape memory alloys (SMA) have interesting features which are the superelastic effect (SE), shape memory effect (SME), two-way SME (TWSME), and so on. These are utilized in actuation factor. The thermo-mechanical constitutive equations of SMA proposed by Lagoudas et al. were employed in the present study for simulating SMA truss structures. The constitutive equation includes the necessary internal variables to account for the material transformations and is utilized in the non-linear finite element procedure of three dimensional truss structures that composed SMA bar (wholly or partially). In this study, we observed which element should be actuated to get a desired shape (actuation shape) from computational analysis. To reach this goal, we apply SMA constitutive equation to non-linear finite element formulation. And then, we simulate two-way shape memory effect as well as superelastic effect of various three dimensional truss using SMA.

• 한국구조물진단유지관리공학회 논문집
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• 제14권1호
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• pp.175-181
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• 2010

평형트러스모델, Mohr적합트러스모델, 그리고 연성트러스모델은 회전각에 기초하기 때문에 회전각모델이라 불리 운다. 이러한 회전각모델들은 콘크리트기여도를 예측할 수 없는 단점이 있다. 콘크리트 기여 성분을 계산할 수 있는 MCFT(Modified Compression Field Theory)나 RA-STM(Rotating Angle-Softening Truss Model) 같은 최근 트러스모델(Modern Truss Model, MTM)은 균열이 발생한 철근콘크리트요소를 연속체 재료로 취급한다. 또한 MTM은 평형조건과 적합조건 그리고 2축 상태에서 콘크리트의 연성 응력-변형률 관계를 이용하여 비선형해석을 수행하고 있다. 본 연구는 전단응력-변형률의 전체 이력 상태를 모두 계산하지 않고, 철근항복과 스트럿 압괴(crushing failure) 파괴기준을 이용하여 해를 찾는 방법으로 수렴속도를 개선한 것이다. 이 알고리즘을 이용하여 Hsu가 실험한 9개의 전단응력-변형률 자료를 분석하였다.

• Structural Engineering and Mechanics
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• 제39권2호
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• pp.187-206
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• 2011

This paper uses dynamic computer simulation techniques to develop and apply a multi-criteria procedure using non-destructive vibration-based parameters for damage assessment in truss bridges. In addition to changes in natural frequencies, this procedure incorporates two parameters, namely the modal flexibility and the modal strain energy. Using the numerically simulated modal data obtained through finite element analysis of the healthy and damaged bridge models, algorithms based on modal flexibility and modal strain energy changes before and after damage are obtained and used as the indices for the assessment of structural health state. The application of the two proposed parameters to truss-type structures is limited in the literature. The proposed multi-criteria based damage assessment procedure is therefore developed and applied to truss bridges. The application of the approach is demonstrated through numerical simulation studies of a single-span simply supported truss bridge with eight damage scenarios corresponding to different types of deck and truss damage. Results show that the proposed multi-criteria method is effective in damage assessment in this type of bridge superstructure.

• 한국구조물진단유지관리공학회 논문집
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• 제16권3호
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• pp.92-98
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• 2012

본 연구는 터널의 유지, 보수, 보강에 필요한 가설공사용 스페이스 트러스 프레임 구조물을 소개한다. 기존 가설공사 시공방식과 장비들의 현황 및 문제점을 분석하고, 터널 설계의 핵심 구성요소를 파악함으로써, 제안된 새로운 가설 시공기술 시스템을 개발하는 과정을 순차적으로 설명한다. 그리고 개발된 가설 시스템을 발주처, 시공사, 터널 이용자 관점에서 사용성 및 경제성을 분석하고, 구조적인 안전성 검토와 최적단면 산정 평가를 상용 유한요소 해석프로그램인 ABAQUS 6.5로 구현하여 본 가설 시스템의 현장적용 기반을 구축한다.

• Steel and Composite Structures
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• 제32권2호
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• pp.189-198
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• 2019

This paper aims to study the mechanical performance of three-tower four-span suspension bridges with steel truss girders, including the static and dynamic characteristics of the bridge system, and more importantly, the influence of structural parameters including the side-main span ratio, sag-to-span ratio and the girder stiffness on key mechanical indices. For this purpose, the Oujiang River North Estuary Bridge which is a three-tower four-span suspension bridge with two main spans of 800m under construction in China is taken as an example in this study. This will be the first three-tower suspension bridge with steel truss girders in the world. The mechanical performance study and parametric analysis are conducted based on a validated three-dimensional spatial truss finite element model established for the Oujiang River North Estuary Bridge using MIDAS Civil. It is found that a relatively small side-main span ratio seems to be quite appropriate from the perspective of mechanical performance. And decreasing the sag-to-span ratio is an effective way to reduce the horizontal force subjected to the midtower and improve the antiskid safety of the main cable, while the vertical stiffness of the bridge will be reduced. However, the girder stiffness is shown to be of minimal significance on the mechanical performance. The findings from this paper can be used for design of three-tower suspension bridges with steel truss girders.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.204-209
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• 2000

This paper suggests that post-tensioned and dome-shaped space truss formed by post-tersionong is easy to fabricate in construction process. In particular, a laboratory model is used to show how a flat space truss system can be transformed into a dome-shaped space truss by means of post-tensioning. There are some diserpancy in vertical displacement of the dxperiment and theoretical analysis for space truss. Nonlinear analysis is used to predict the final shape shape of the space truss, the experiments tndicates that this construction method can offer economy over traditional methods. In addition, the analysis indicates that when all the sxisting mechanisms are controlled, the nonlinear finite element method is more reliable way to predict the shape of the dome-shaped space truss than the linear analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.863-866
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• 2002

In this study, we tried to grasp the characteristic of vibration power flow for the truss core type sandwich plate structure. As the result of the finite element analysis, this paper shows that the vibration power flow characteristic of truss core type sandwich plate structure is understood and the vibration power flow of upper plate according to the mode shape of structure is various. Also it presents the vibration power flow is affected by reinforced structure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1317-1323
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• 2009

A finite element analysis was performed for new earth retention system that is a kind of truss tower with non-supported excavation. A 2D finite element model was adopted in this study to investigate the behavior of the earth retention system. Just because this non-supported truss tower system is too complex to model in 2D plain-strain condition to itself, so have to simplify it by the conception of equivalent rigidity. The horizontal displacement of the wall and lateral earth pressure distribution on the wall were computed. And it is compared with NAVFAC design manual.

• 한국공간구조학회논문집
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• 제3권1호
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• pp.77-85
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• 2003

This paper presents a truss model that can predict the shear behavior of reinforced concrete (RC) beams subjected to the combined actions of shear and flexure. Unlike other truss models, the proposed truss model, TATM, takes into account the effect of the flexural moment on the shear strength of RC beams with different shear span-to-depth ratios. To check the successfulness of the proposed model experimentally obtained stress shear strain curves were compared to the predicted ones using the proposed truss model. Furthermore, the shear strengths of 170 RC test beams with variable shear span-to-depth ratios were compared to the shear strengths as given by the truss model reported in this paper.