• Structural Engineering and Mechanics
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• 제71권2호
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• pp.131-138
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• 2019

It is necessary to predict subway induced vibration if a new subway is to be built. To obtain the vibration response reliably, a three-dimensional (3D) FEM model, consisting of the tunnel, the soil, the subway load and the building above, is established in MIDAS GTS NX. For this study, it is a six-story frame structure built above line 3 of Guangzhou metro. The entire modeling process is described in detail, including the simplification of the carriage load and the determination of model parameters. Vibration measurements have been performed on the site of the building and the model is verified with the collected data. The predicted and measured vibration response are used together to assess vibration level due to the subway traffic in the building. The No.1 building can meet work and residence comfort requirement. This study demonstrates the applicability of the numerical train-tunnel-soil-structure model for the serviceability assessment of subway induced vibration and aims to provide practical references for engineering applications.

• Advances in concrete construction
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• 제17권4호
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• pp.221-232
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• 2024

As a supplemental energy dissipation device, friction dampers are widely employed to augment the behaviour of buildings under seismic forces. In the current work, a methodology for the design of the friction damping system of RC frame buildings is offered using performance-based plastic design (PBPD) method. Here 2% of maximum interstorey drift ratio for life safety (LS) level is taken into account as a target drift to estimate the design base shear. In this approach, the distribution of friction damper is determined based on the hysteretic energy demand of that storey. Two frames, five storey three bay (5S3B) and eight storey three bay (8S3B) RC frame building with and without friction damping systems are also taken up for the investigation. The suggested design approach is validated by the nonlinear time history analysis (NLTHA) procedure. Inter story drift ratio (ISDR) and storey displacement, which are the more closely related to structural damage during seismic excitation are evaluated. The results show that the friction damping system on a retrofitted RC frame building performs effectively under seismic excitations and that storey displacement and ISDR are within the limit at moderate and high seismic intensities.

• Structural Engineering and Mechanics
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• 제55권6호
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• pp.1121-1137
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• 2015

High powered computers and engineering computer systems allow designers to routinely simulate complex physical phenomena. The presented work deals with the analysis of two finite element method optimization techniques (First Order Method-FOM and Subproblem Approximation Method-SAM) implemented in the individual Design Optimization module in the Ansys software to analyze the behavior of real problems. A design optimization is a difficult mathematical process, intended to find the minimum or maximum of an objective function, which is mostly based on iterative procedure. Using optimization techniques in engineering designs requires detailed knowledge of the analyzed problem but also an ability to select the appropriate optimization method. The methods embedded in advanced computer software are based on different optimization techniques and their efficiency is significantly influenced by the specific character of a problem. The efficiency, robustness and accuracy of the methods are studied through strictly convex two-dimensional optimization problem, which is represented by volume minimization of two bars' plane frame structure subjected to maximal vertical displacement limit. Advantages and disadvantages of the methods are described and some practical tips provided which could be beneficial in any efficient engineering design by using an optimization method.

• 한국안전학회지
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• 제25권1호
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• pp.57-61
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• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.

• 한국건설관리학회논문집
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• 제23권6호
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• pp.3-14
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• 2022

현장에서 발생하는 정량적인 공사 인원과 기간의 분석은 새로운 적정 인원의 기준을 제시할 수 있다. 본 연구는 업무효율 지표들 중 가장 중요한 요소인 업무절차의 수행시간을 예측하는 대기행렬 모형을 제시한다. 아파트 골조공사 작업 사이클은 같은 공정이 반복되는 특성을 가진다. 본 연구는 이러한 특성을 바탕으로 지연된 골조공사 기준층 사이클을 대기행렬 모형을 활용하고 그것을 분석하였다. 그리고 인원수와 공사 기간을 조정한 후 모형의 성능을 분석하였다. 본 연구는 대기행렬의 성능 분석을 실시하여 공정의 물량에 따른 인적자원관리 의사결정을 지원하고자 한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.156-159
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• 2008

This paper introduces a remained tensile force estimation method using SI technique based on evolutionary algorithm for externally prestressed tendon. This paper applies the differential evolutionary scheme to SI technique. A virtual model test using ABAQUS 3 dimensional frame model has been made for this work The virtual model is added to the tensile force(28.5kN). Two set of frequencies are extracted respectively from the virtual test and the self-coding FEM 2 dimension model. The estimating tendon tension for the FEM model is 28.31kN. It is that the error in the tendon tension is 1% through the differential evolutionary algorithm. The errors between virtual model and the self-coding FEM model are assumed as the model error.

• 한국안전학회지
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• 제30권2호
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• pp.27-34
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• 2015

Nowadays, remodeling cases for some apartment like Hyundai through the support of government are reported. Conventionally, balcony and aisle are extended for additional private area or balcony which is supported by new frame is extended. In extension work at site, dowel bar is conventionally inserted in old concrete slab for connection with old and new slab, however, an examination for structural safety is rarely performed prior to construction, if ever, vertical load is only considered for structural analysis. When conventionally connected structures are exposed to earthquake, the old and new structures have individual earthquake behavior with different mode, which may lead the elimination of resistance to earthquake in new structures. As of this reason, new detailing connection system which can have light weight and sufficient ductility performance is developed for application to domestic extension works. Additionally, user manual and specification are also developed for fertilization of application for the developed technology.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.35-36
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• 2011

Recently, an irregular-shaped super tall building has been increased, aiming toward landmarks of cityscape. However, the complex floor plan derived from an irregular shape requires considerable resources including time, cost, and effort to meet complex structural framework. Based on the motivation, the study proposes a table-form system that is variable slab form appropriate to an irregular shaped floor through improving limitations of an existing table-form system. The variable table-form is expected to reduce construction resources and improve constructability on an irregular floor plan of super tall buildings as well.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.531-534
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• 2006

A multi-scale (macro-micro) finite element framework for analysis of polycrystalline solids is suggested. The proposed frame work is strongly-coupled in a sense that the two scale calculation is performed at the same time. The issue of averaging micro-scale material stress and stiffness is addressed and a strategy is proposed. The proposed framework is implemented and applied to two examples having different geometries and loading modes. It is concluded that the proposed multi-scale framework can be used for more detailed and accurate analysis compared with the single-scale finite element analysis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 가을 학술발표회 논문집
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• pp.239-246
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• 1997

The general formulation of free vibration and stability analysis of unsymmetric thin-walled space frames and beam-columns is presented. The kinetic and total potential energy is derived by applying the extended virtual work principle, introducing displacement parameters defined at the arbitrarily chosen axis and including second order terms of finite semitangential rotations. In formulating the finite element procedure, cubic Hermitian polynomials are utilized as shape functions of the two node space frame element. Mass, elastic stiffness, and geometric stiffness matrices for the unsymmetric thin-walled section are evaluated. In order to illustrate the accuracy and practical usefulness of this formulation, finite element solutions for the free vibration and stability problems of thin-walled beam-columns and space frames are presented and compared with available solutions.