• Steel and Composite Structures
• /
• 제23권2호
• /
• pp.173-186
• /
• 2017

Conceptual configuration and seismic performance of high-rise steel frame-brace structure are studied. First, the topology optimization problem of minimum volume based on truss-like material model under earthquake action is presented, which is solved by full-stress method. Further, conceptual configurations of 20-storey and 40-storey steel frame-brace structure are formed. Next, the 40-storeystructure model is developed in Opensees. Two common configurations are utilized for comparison. Last, seismic performance of 40-storey structure is derived using nonlinear static analysis and nonlinear dynamic analysis. Results indicate that structural lateral stiffness and maximum roof displacement can be improved using brace. Meanwhile seismic damage can also be decreased. Moreover, frame-brace structure using topology optimization is most favorable to enhance lateral stiffness and mitigate seismic damage. Thus, topology optimization is an available way to form initial conceptual configuration in high-rise steel frame-brace structure.

• Earthquakes and Structures
• /
• 제15권4호
• /
• pp.443-452
• /
• 2018

In this paper the new intensity measures (IMs) for probabilistic seismic analysis of RC high-rise buildings with core wall structural system are proposed. The existing IMs are analysed and the new optimal ones are presented. The newly proposed IMs are based on the existing ones which: 1) comprise a wider range of frequency velocity spectrum content and 2) are defined as the integral along the velocity spectrum. In analysis characteristics of optimal IMs such as: efficiency, practicality, proficiency and sufficiency are considered. As prototype buildings, RC high-rise buildings with core wall structural system and with characteristic heights: 20-storey, 30-storey and 40-storey, are selected. The non-linear 3D models of the prototype buildings are constructed. 720 non-linear time-history analyses are conducted for 60 ground motion records with a wide range of magnitudes, distances to source and various soil types. Statistical processing of results and detailed regression analysis are performed and appropriate demand models which relate IMs to demand measures (DMs), are obtained. The conducted analysis has shown that the newly proposed IMs can efficiently predict the DMs with minimum dispersion and satisfactory practicality as compared to the other commonly used IMs (e.g., PGA and $S_a(T_1)$). The newly proposed IMs overcome difficulties in calculating of integral along the velocity spectrum and present adequate replacement for IMs which comprise a wider range of frequency velocity spectrum content.

• Structural Engineering and Mechanics
• /
• 제36권4호
• /
• pp.513-527
• /
• 2010

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete, which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

• Structural Engineering and Mechanics
• /
• 제62권4호
• /
• pp.465-475
• /
• 2017

Photovoltaic (PV) panels are used in high-rise buildings to convert solar energy to electricity. Due to the considerable energy consumption of high-rise buildings, applying PV technology is of great significance to energy saving. In the application of PV panels, one of the most important construction issues is the connection of the PV panel with the main structures. One major difficulty of the connection design is that the PV panel connection consists of two separate components with coupling and indeterminate dimension. In this paper, the gap element is employed in these two separated but coupled components, i.e., hook and catch. Topology optimization is applied to optimize and design the cross-section of the PV panel connection. Pareto optimization is conducted to operate the optimization subject to multiple load scenarios. The initial design for the topology optimization is determined by the common design specified by the Technical Code for Glass Curtain Wall Engineering (JGJ 102-2003). Gravity and wind load scenarios are considered for the optimization and numerical analysis. Post analysis is conducted for the optimal design obtained by the topology optimization due to the manufactory requirements. Generally, compared with the conventional design, the optimized connector reduces material use with improved structural characteristics.

• Structural Engineering and Mechanics
• /
• 제86권4호
• /
• pp.573-587
• /
• 2023

A conventional tuned mass damper (TMD) provides a passive control option to suppress the structures' wind- or earthquake-induced vibrations. However, excessive displacements of the TMD raise concerns in the practical implementation. Therefore, this study proposes a novel TMD designed for and deployed on a high-rise sightseeing tower. The device consists of an integrated two-way slide rail mount and an eddy current damper (ECD) with a stroke control mechanism. This stroke control mechanism allows the damping coefficient to automatically increase when the stroke reaches a predetermined value, preventing excessive damper displacements during large earthquakes. The corresponding two-stage damping parameters are designed with a variable-thickness copper plate to enable the TMD stroke within a specified range. Thus, this study discusses the detailed design schemes of the device components in TMD. The designed two-stage damping parameters are also numerically verified, and the structural responses with/without the TMD are compared. As seen in the results, the proposed TMD yields effective control authority to limit the acceleration response within a comfort level. In addition, this TMD resolves the spatial availability for the damper movement in high-rise buildings by the controllable damping mechanism.

• 한국터널지하공간학회 논문집
• /
• 제20권1호
• /
• pp.23-38
• /
• 2018

현재까지 대부분의 내진해석 연구는 지상과 지하구조물을 개별적으로 분석하는 데 제한되어왔기 때문에 그 상호거동이 효과적으로 분석되지 못했다. 따라서 본 연구에서는 기반암과 표층으로 이루어진 지반에 건물과 인접지하구조물이 설치되는 복합지하시설물을 대상으로 지반과 구조물을 동시에 고려한 동적해석(SSI)을 수행하였다. 내진안정성이 층간변위비와 구조부재의 휨응력에 근거하여 분석되었다. 그 결과, 초고층건물이 저층건물보다 인접지하구조물의 영향을 더 많이 받지만, 지상구조물은 내진안정성이 양호한 것으로 나타났다. 반면, 건물의 지하부와 인접지하구조물에서 발생한 휨인장응력이 허용값을 초과하여 지상부보다는 지하구조물이 더 취약할 수 있다고 나타났다. 따라서 대도시에서의 건물은 주변에 다양한 구조물이 존재하기 때문에 내진해석 시 지상 및 지하구조물을 동시에 고려해야 상호거동을 정확히 예측할 수 있다고 판단된다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
• /
• pp.173-177
• /
• 2006

From the viewpoint of coastal hydrodynamics, one of the most important effects of global warming is a sea-level rise in coastal areas. In the present study, impacts on port facilities against sea-level rise were investigated. The sea-level rise causes the increase of the water depth, and it generates variations on the wave height, buoyancy, tidal system and nearshore current system and so on. The increase of water depth gives rise to the decrease of crown height of the structure and it causes increase of wave overtopping quantity. It may flood the port zone and its facilities, and may decrease harbor tranquility. It also leads to difficulties on navigation, mooring and loading/unloading at the port. Increase in water depth also causes increase of wave height in surf zone. This high wave makes structures unstable and may cause them to collapse during storm. In addition, increase in buoyant force due to sea-level rise also makes the gravity type structures unstable. Consequently, theses variations due to sea-level rise will cause functional deterioration of port facilities. In order to protect port facilities from the functional deterioration, reinforcement plan is required such as raising the crown height and increase in block weight and so on. Hence proper estimation method for the protection cost is necessary in order to protect port facilities efficiently. Moreover response strategies and integrated coastal zone management plan is required to maintain the function of port facilities. A simple estimation of cost for breakwaters in Korea was performed in the present study.

• 화약ㆍ발파
• /
• 제29권2호
• /
• pp.1-12
• /
• 2011

외부폭발, 화재, 충돌, 지진, 태풍과 같은 비정상 하중에 의한 고층빌딩의 연쇄붕괴(progressive collapse) 해석에 관련된 많은 연구가 진행되고 있다. 특히 그러나 실규모의 고층건물을 대상으로 한 손상 및 붕괴에 실험은 현실상 불가능한 실정이다. 본 연구에서는 구조물 발파해체분야에서 적용되는 ELS 소프트웨어를 이용하여 외부폭발에 의한 고층 RC 구조물의 국부손상 및 연쇄붕괴시뮬레이션을 수행하였다. 현관으로부터 1m, 2m, 5m, 10m, 15m 이격되어 폭약 1,500kg이 폭발한 것을 가정하여, 이격거리에 따른 국부손상과 이에 따른 연쇄붕괴현상을 파악하였다. 특히 기폭시나리오에 따라 구조물 지지부재의 일부를 제거하여 구조물의 붕괴를 유도하는 발파해체기법을 국부손상-연쇄붕괴 전이과정 연구에 적용하였다.

• 한국전산구조공학회논문집
• /
• 제15권2호
• /
• pp.351-365
• /
• 2002

현재 국내에서는 벽체와 바닥판으로만 구성된 벽식 구조형식의 아파트 건물이 많이 사용되고 있다. 또한 청력에 대한 저항이 뛰어나기 때문에 전단벽 코어를 갖는 입체골조구조물이 고층 빌딩의 구조시스템으로 자주 이용된다. 기능적인 이유로 인해 이러한 구조물들의 전단벽에는 하나 또는 여러 개의 개구부가 발생하게 된다. 개구부가 있는 전단벽을 정확하게 해석하기 위해서는 여러 개의 유한요소를 사용하여 구조물을 세분모형화하는 것이 필요하다. 그러나, 전체 구조물을 유한요소로 세분하여 모형화하는 것은 막대한 해석시간과 컴퓨터 메모리를 소요하게 된다. 개구부의 수, 크기, 위치에 상관없이 적용할 수 있는 효율적인 해석기법이 본 논문에서 제안되었다. 제안된 해석기법에서는 슈퍼요소와 부분구조, 행렬응축, 가상보 등을 이용하였고 제안된 해석기법의 효율성을 검증하기 위해 벽식구조물과 전단벽 코어를 갖는 입체골조구조물의 3차원 해석이 수행되었다. 예제구조물의 해석을 통해 제안된 해석기법이 해석시간과 컴퓨터메모리를 크게 감소시키고, 정확한 해석결과를 얻을 수 있음이 확인되었다.

• Earthquakes and Structures
• /
• 제16권4호
• /
• pp.469-485
• /
• 2019

A numerical investigation regarding local (${\mu}_L$) and story (${\mu}_S$) ductility demand evaluation of steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF), is conducted in this study. The interior connections are modeled, firstly as perfectly pinned (PP), and then as semi-rigid (SR). Three models used in the SAC steel project, representing steel buildings of low-, mid-, and high-rise, are considered. The story ductility reduction factor ($R_{{\mu}S}$) as well as the ratio ($Q_{GL}$) of $R_{{\mu}S}$ to ${\mu}_L$ are calculated. ${\mu}_L$ and ${\mu}_S$, and consequently structural damage, at the PMRF are significant reduced when the usually neglected effect of SR connections is considered; average reductions larger than 40% are observed implying that the behavior of the models with SR connections is superior and that the ductility detailing of the PMRF doesn't need to be so stringent when SR connections are considered. $R_{{\mu}S}$ is approximately constant through height for low-rise buildings, but for the others it tends to increase with the story number contradicting the same proportion reduction assumed in the Equivalent Static Lateral Method (ESLM). It is implicitly assumed in IBC Code that the overall ductility reduction factor for ductile moment resisting frames is about 4; the results of this study show that this value is non-conservative for low-rise buildings but conservative for mid- and high-rise buildings implying that the ESLM fails evaluating the inelastic interstory demands. If local ductility capacity is stated as the basis for design, a value of 0.4 for $Q_{GL}$ seems to be reasonable for low- and medium-rise buildings.