• Computers and Concrete
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• 제23권3호
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• pp.171-188
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• 2019

This study proposed a new and efficient 2D damage-plasticity model within the framework of Isogeometric analysis (IGA) for the geometrically nonlinear damage analysis of concrete. Since concrete exhibits complicated material properties, two internal variables are introduced to measure the hardening/softening behavior of concrete in tension and compression, and an implicit gradient-enhanced formulation is adopted to restore the well-posedness of the boundary value problem. The numerical results calculated by the model is compared with the experimental data of three benchmark problems of plain concrete (three-point and four-point bending single-notched beams and four-point bending double-notched beam) to illustrate the geometrical flexibility, accuracy, and robustness of the proposed approach. In addition, the influence of the characteristic length on the numerical results of each problem is investigated.

• 한국전산구조공학회논문집
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• 제25권1호
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• pp.9-18
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• 2012

정보 모델링이라 일컫는 BIM은 단순히 이미지를 표현할 뿐만 아니라 교량의 전 생애주기에 발생하는 정보를 저장하는 도구로 활용된다. 최근 발주부터 유지관리까지 교량의 전 생애주기 동안에 BIM을 활용하여 건설 생산성을 향상시키려는 시도가 증가하고 있다. 현재 BIM에 대한 이점은 어느 정도 인지하고 있는 상태이지만, BIM구축 및 활용에 대한 정보가 부족한 상태에서 도입하면 오히려 이익보다는 추가적인 업무발생에 의한 손실을 일으키게 되므로 아직까지는 조심스러운 단계이다. 따라서 본 연구에서는 교량에 관한 BIM을 실제로 작성하여 토목분야의 객체를 모델링할 수 있는지를 평가하고 BIM을 적절하게 활용하기 위한 개선점 및 향후 활용방안에 대해 고찰하고자 한다. 연구결과 BIM은 도면과 물량산정에 있어서 일관성, 효율성, 정확성에 기여할 수 있었고 파라메트릭 모델을 활용한 치수 설정으로 모델의 재활용이 가능한 것으로 나타났다. 도입 초기에는 모델작성에 따른 노력이 소모되지만 그 이후에는 작성된 모델을 활용하므로 생산성을 증가시키는데 도움이 될 것으로 판단된다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.235-240
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• 2008

PSC box girder bridges are built through the repetitive manufacturing process of concrete segment. However, during the initial segment manufacturing stage, design change may occur frequently due to design errors and interferences between components, resulting in the extension of segment manufacturing period. This paper aims to verify the manufacturing process of PSC box girder segment by 3D simulation technique. All the components of a segment were modelled and assembled by simulation technique and then, some design errors were found and revised appropriately to optimize the manufacturing process of segment. Consequently, 3D simulation technique would be promising to improve the quality of the segment and to reduce its manufacturing time and cost.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.928-934
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• 2009

Although the evolution and deployment of information technologies will undoubtedly play an important role in the current construction industry, many engineers are still unsure of the economic value of using these technologies. Especially for the planning of a construction project, a collaboration system to utilize the whole resources is a essential tool for the successful outcome. A detailed, authoritative, and readily accessible information model is needed to enable engineers to make cost-effective decisions among established and innovative plan alternatives. Most engineers rely on limited private experiences when they create solutions or design alternatives. Initial planning is crucial for the success of the construction project. Most construction projects are done through collaboration of engineers who have different specialized knowledge. Information technologies can dramatically enhance the performance of the collaboration. For the information delivery, we need a mediator between engineers. Object-based 3-D models are useful for the communication and decision assistance for the intelligent project design. In this paper, basic guidelines for the 3-D design according to different construction processes are suggested. Adequate interoperability of 3-D objects from any CAD system is essential for the collaboration. Basic architectures of geometry models and their information layer were established to enable interoperability for design checks, estimation and simulation. A typical international project for roadway was chosen for the pilot project. 3-D GIS model was created and bridge information models were created considering several requirements for planning and decision making of the project. From the pilot test, the integrated construction project planning using 3-D information models was discussed and several guidelines were suggested.

• Steel and Composite Structures
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• 제34권6호
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• pp.853-862
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• 2020

In recent years, due to the many advantages cable-stayed bridges have often constructed in medium and long span. These advantages can be listed as an aesthetically pleasing appearance, economic and easy construction, etc. The main structural elements of cable-stayed bridges are listed as deck, pylon, cables and foundation. Perhaps one of the most vital and expensive of these structural elements is stay-cables. Stay-cables ensure the allowable displacement and distribution of bending moments along the bridge deck with prestressing force. Therefore the optimum design of the stay-cables and prestressing force are very important in achieving the performance expected from the cable-stayed bridges. This paper aims to obtain the stay-cables size and prestressing force optimization of the cable-stayed bridge. For this purpose, single pylon and fan type cable configuration Manavgat Cable-Stayed Bridge was selected as an example. The three dimensional (3D) finite element model (FEM) of the bridge was created with SAP2000. Analysis of the 3D FEM of the bridge was conducted under the different combined effects of the self-weight of the structural element, prestressing force of stay-cable and live load. Stay-cable stress and deck displacement were taken into account as constraints for the optimization problem. To optimize this existing bridge a metaheuristic algorithm named Jaya was used in the optimization process. 3D FEM of the selected bridge was repeatedly analyzed by using Open Applicable Programming Interface (OAPI) properties of SAP2000. To carry out the optimization process the developed program which integrates the Jaya algorithm and the required codes for calling SAP2000 is coded in MATLAB. At the end of the study, the total weight of the stay-cables was reduced more than 40% according to existing stay cables under loads taken into account.

• Structural Engineering and Mechanics
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• 제85권3호
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• pp.337-351
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• 2023

In this paper, the shear behavior of soft filling in rectangular-hollow concrete specimens was simulated using the 2D particle flow code (PFC2D). The laboratory-measured properties were used to calibrate some PFC2D micro-properties for modeling the behavior of geo-materials. The dimensions of prepared and modeled samples were 100 mm×100 mm. Some disc type narrow bands were removed from the central part of the model and different lengths of bridge areas (i.e., the distance between internal tips of two joints) with lengths of 30 mm, 50 mm, and 70 mm were produced. Then, the middle of the rectangular hollow was filled with cement material. Three filling sizes with dimensions of 5 mm×5 mm, 10 mm×5 mm, and 15 mm×5 mm were provided for different modeled samples. The parallel bond model was used to calibrate and re-produce these modeled specimens. Therefore, totally, 9 different types of samples were designed for the shear tests in PFC2D. The shear load was gradually applied to the model under a constant loading condition of 3 MPa (σc/3). The loading was continued till shear failure occur in the modeled concrete specimens. It has been shown that both tensile and shear cracks may occur in the fillings. The shear cracks mainly initiated from the crack (joint) tips and coalesced with another one. The shear displacements and shear strengths were both increased as the filling dimensions increased (for the case of a bridge area with a particular fixed length).

• Smart Structures and Systems
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• 제30권1호
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• pp.35-47
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• 2022

Data-driven engineering is crucial for information delivery between design, fabrication, assembly, and maintenance of prefabricated structures. Design for manufacturing and assembly (DfMA) is a critical methodology for prefabricated bridge structures. In this study, a novel concept of digital engineering model that combined existing knowledge of DfMA with object-oriented parametric modeling technologies was developed. Three-dimensional (3D) geometry models and their data models for each phase of a construction project were defined for information delivery. Digital design models were used for conceptual design, including aesthetic consideration and possible variation during fabrication and assembly. The seismic performance of a bridge pier was evaluated by linking the design parameters to the calculated moment-curvature curves. Control parameters were selected to consider the tolerance control and revision of the digital models. Digitalized fabrication of the prefabricated members was realized using the digital fabrication model with G-code for a concrete printer or a robot. The fabrication error was evaluated and the design digital models were updated. The revised fabrication models were used in the preassembly simulation to guarantee constructability. For the maintenance of the bridge, the as-built information was defined for the prefabricated bridge piers. The results of this process revealed that data-driven information delivery is crucial for lifecycle management of prefabricated bridge piers.

• Structural Engineering and Mechanics
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• 제81권3호
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• pp.293-303
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• 2022

As infrastructure ages and traffic load increases, serious public concerns have arisen for the well-being of bridges. The current health monitoring practice focuses on large-scale bridges rather than short span bridges. However, it is critical that more attention should be given to these behind-the-scene bridges. The relevant information about the construction methods and as-built properties are most likely missing. Additionally, since the condition of a bridge has unavoidably changed during service, due to weathering and deterioration, the material properties and boundary conditions would also have changed since its construction. Therefore, it is not appropriate to continue using the design values of the bridge parameters when undertaking any analysis to evaluate bridge performance. It is imperative to update the model, using finite element (FE) analysis to reflect the current structural condition. In this study, a FE model is established to simulate a concrete culvert bridge in New South Wales, Australia. That model, however, contains a number of parameter uncertainties that would compromise the accuracy of analytical results. The model is therefore updated with a neural network (NN) optimisation algorithm incorporating Monte Carlo (MC) simulation to minimise the uncertainties in parameters. The modal frequency and strain responses produced by the updated FE model are compared with the frequency and strain values on-site measured by sensors. The outcome indicates that the NN model updating incorporating MC simulation is a feasible and robust optimisation method for updating numerical models so as to minimise the difference between numerical models and their real-world counterparts.

• Structural Engineering and Mechanics
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• 제85권2호
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• pp.163-177
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• 2023

The design of segmental bridges, a structure that typically employs precast prestressed concrete elements and the balanced cantilever construction method for the deck, may demand a highly complex structural analysis for increased precision of the results. This work presents a comprehensive numerical analysis of a 3D finite element model using the software ANSYS, version 21.2, to simulate the constructive deck stages of the New Guaiba Bridge, a structure located in Porto Alegre city, southern Brazil. The materials concrete and steel were considered viscoelastic. The concrete used a Generalized Kelvin model, with subroutines written in FORTRAN and added to the main model through the customization tool UPF (User Programmable Features). The steel prestressing tendons used a Generalized Maxwell model available in ANSYS. The balanced cantilever constructive steps of a span of the New Guaiba Bridge were then numerically simulated to follow the actual constructive sequence of the bridge. A comparison between the results obtained with the numerical model and the actual vertical displacement data monitored during the bridge's construction was carried out, showing a good correlation.

• 한국구조물진단유지관리공학회 논문집
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• 제14권2호
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• pp.97-105
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• 2010

시공단계에 따른 강상판교의 변위를 측정하였고, 이 결과와 비교하기 위하여 3차원 구조해석을 수행하였다. 검증된 모델을 사용하여 대블럭 시공법에 의한 시공단계에 따른 3차원 구조해석을 수행하여 다음과 같은 결론을 얻었다. 1. 설계에 사용된 Grid 해석과 3차원 해석에 의한 결과를 비교하면, Grid 해석의 결과는 곡선교의 변위를 모사하는데 한계가 있었으며, 두 가지 해석방법에 의한 변위의 차이는 약 10~20%정도였다. 2. 가설중에 일어날 수 있는 최대 처짐은 완료된 상태의 처짐에 비하여 1.7배까지 크게 발생하였다. 3. 시공단계 해석 결과, 블록시공법에 의하여 시공되는 교량의 거동은 전체 구조물이 일체로 되어 한 번에 거치되는 교량과는 다른 결과가 도출되며, 중간의 가설과정에서는 설계시 고려된 응답보다 더 큰 결과가 도출되고 있으므로, 설계시 시공단계를 고려한 해석을 통하여 합리적인 구조설계가 이루어져야 한다.