High-rise buildings are equipped with TMD (Tuned Mass Damper), a vibration control device that ensure the stability and usability of the building. In this study, the seismic response control performance was evaluated by selecting the design variables of the TMD based on the installation location of the twisted irregular building. To this end, we selected analysis models of 60, 80, and 100 floors with a twist angle of 1 degree per floor, and performed time history analysis by applying historical seismic loads and resonant harmonic loads. The total mass ratio of TMDs was set to 1.0%, and the distributed installation locations of TMDs were selected through mode analysis. The analysis results showed that the top-floor displacement responses of all analysis models increased, but the maximum story drift ratio decreased. In order to secure the seismic response control performance by distributed installation of TMDs in twisted irregular buildings, it is judged that the mass ratio distribution of TMDs will act as a key variable.
Recently, deep learning that is the most popular and effective class of machine learning algorithms is widely applied to various industrial areas. A number of research on various topics about structural engineering was performed by using artificial neural networks, such as structural design optimization, vibration control and system identification etc. When nonlinear semi-active structural control devices are applied to building structure, a lot of computational effort is required to predict dynamic structural responses of finite element method (FEM) model for development of control algorithm. To solve this problem, an artificial neural network model was developed in this study. Among various deep learning algorithms, a recurrent neural network (RNN) was used to make the time history response prediction model. An RNN can retain state from one iteration to the next by using its own output as input for the next step. An eleven-story building structure with semi-active tuned mass damper (TMD) was used as an example structure. The semi-active TMD was composed of magnetorheological damper. Five historical earthquakes and five artificial ground motions were used as ground excitations for training of an RNN model. Another artificial ground motion that was not used for training was used for verification of the developed RNN model. Parametric studies on various hyper-parameters including number of hidden layers, sequence length, number of LSTM cells, etc. After appropriate training iteration of the RNN model with proper hyper-parameters, the RNN model for prediction of seismic responses of the building structure with semi-active TMD was developed. The developed RNN model can effectively provide very accurate seismic responses compared to the FEM model.
A seismic isolation system is one of the most effective control devices used for mitigating the structural responses due to earthquake loads. This system is generally used as a type of base isolation system for low- and mid-rise building structures. If the base isolation technique is applied to high-rise buildings, a lot of problems may be induced such as the movement of isolation bearings during severe wind loads, the stability problem of bearings under large compression forces. Therefore, a mid-story isolation system was proposed for seismic protection of high-rise buildings. Residence-commerce complex buildings in Korea have vertical irregularity because shear wall type and frame type structures are vertically connected. This problem can be also solved by the mid-story isolation system. An effective analytical method using super elements and substructures was proposed in this study. This method was used to investigate control performance of mid-story isolation system for residence-commerce complex buildings subjected to seismic loads. Based on numerical analyses, it was shown that the mid-story isolation system can effectively reduce seismic responses of residence-commerce complex tall buildings.
Recently, the concept of an outrigger damper system with a damper added to the existing outrigger system has been developed and applied for dynamic response control of high-rise buildings. However, the study on the structural characteristics and design method of Outrigger damper system is in the early stages. In this study, a 50 story high - rise building was designed and an outrigger damper system with viscoelastic damper was applied for wind response control. The time history analysis was performed by using the kaimal spectrum to create an artificial wind load for a total of 1,000 seconds at 0.1 second intervals. Analysis of the top horizontal maximum displacement response and acceleration response shows that outrigger damper systems are up to 28.33% and 49.26% more effective than conventional outrigger systems, respectively. Also, it is confirmed that the increase of damping ratio of dampers is effective for dynamic response control. However, since increasing the damping capacity increases the economic burden, it is necessary to select the appropriate stiffness and damping value of the outrigger damper system.
Large space structures exhibit different natural vibration characteristics depending on the aspect ratio of structures such as half-open angle. In addition, since the actual large space structure is mostly supported by the lower structure, it is expected that the natural vibration characteristics of the upper structure and the entire structure will vary depending on the lower structure. Therefore, in this study, the natural vibration characteristics of the dome structure are analyzed according to the natural frequency ratio by controlling the stiffness of the substructure. As the natural frequency of the substructure increases, the natural frequency of the whole structure increases similarly to the natural frequency of the upper structure. Vertical vibration modes dominate at 30° and 45°, and horizontal vibration modes dominate at 60° and 90°.
An automation of standardized rebar shop drawing is necessary for easy application by improving workability, prompt preparation to field change request and easy revisions of shop drawing. Through investigating problem of current rebar shop drawing, we found that standardization of reinforcing detail, standardization of rebar expression and automation of rebar shop drawing program for the sake of designer is needed. We will investigate disagreement of reinforcing detail between building code and how worker build structure for standardization of reinforcing detail, demands of companies participated in rebar process for standardization of rebar expression and proper algorithm with selectable level of inputting data for automation of rebar shop drawing program for the sake of designer.
최근 문화유산에 대한 관심이 고조 되면서 노후화된 건조물문화재의 보존에 대한 중요성이 대두되고 있다. 건조물문화재의 대부분이 목재를 주재료로 사용하였으며, 이들 건조물문화재의 노후화에 따른 부식 및 손상에 대한 보존수리는 부재자체의 문화재적 가치를 고려하여 원형유지를 기본원칙으로 한다. 이에 따라, 합성수지를 이용한 보존처리방법이 부각되고 있다. 이에 본 논문은 합성수지로 보강한 원형단면 목재의 압축보강 성능에 관한 실험적 연구로서 합성수지의 보강단면적비율, 단면의 보강방향, 보강길이, 합성수지강도를 변수로 하여 총 14개의 시험체를 제작하여 실험하였다. 실험결과 합성수지를 이용하여 적절하게 보강할 경우 신재이상의 보강효과가 있는 것으로 나타났으며 문화재의 보수 및 보강에서 가장 중요한 오센티시티(authenticity)를 확보할 수 있을 것이다.
The Crime Prevention Net(CPN) means an integrated model for crime prevention that forms the structure like a close meshed net by making use of the various crime prevention strategies and by collaborate participation of multi-groups. This CPN Model includes three realms, namely the realm of criminal-tendency deterrence, the realm of the criminal opportunity reduction and the realm of recidivists management. The strategies in criminal-tendency deterrence realm are the treatments for individuals with biological or psychological predisposition to crime, the interventions in the process of individual's socialization and the developments of the overall social structure and surroundings. The criminal opportunity reduction strategy is situational crime prevention strategy, such as CPTED, teaching techniques to avoid being a victim of crime, formal surveillance by policemen's patrol and so on. The recidivists management strategies are the management of information of recidivists, parolees and offenders who are under the probation. The CPN is constructed by the obligatory participants and the various strategies and the police play a central role in the CPN : searching and analyzing on the criminal environment in the community, finding accurately the capable resources in the community, selecting participants which forms CPN, designing CPN suitable to the community, coordinating the function of participants, educating the strategies of crime prevention to the participants.
최근 FRP(fibre-reinfored plastic)를 이용하여 기존 RC구조물을 보수보강하는 방법이 각광받고 있다. CFRP plate나 sheet의 형태로 외부에 부착하는 방법이 FRP보강의 주류를 이루어 왔으나, 판단부에서 발생되는 응력집중으로 부착판이 박락하여 조기 파괴되는 경우가 많은 연구를 통해서 밝혀졌다. 따라서 기존 콘크리트구조물에 홈을 형성하여 FRP막대의 형태로 외부에 매립함으로써 이러한 조기파괴의 개선하려는 공법이 개발되었다. 본 실험은 이러한 매립형공법의 보강효율을 조사하고, 각국에서 제시하고 있는 기존 휨 이론에 대한 적용여부를 검토함에 그 목적이 있다.
난 시장이 확대되고 있지만 일반대중이 선호하고 있는 동양계 심비디움 난은 대부분 수입 또는 산채에 의존하여 고가로 판매되고 있고, 서양계 심비디움은 외국 품종에 대한 로열티 지불 등의 문제가 대두되고 있다. 본 연구에서는 관상가치가 있고 대량증식이 가능하여 외국산 품종을 대체할 수 있는 소형 심비디움 난을 육성하고자 하였다. 동양계 및 서양계 심 비디움의 교배종인 "동양"의 바이러스 무병주를 생장점배양에 의해 기내에서 대량증식을 하던 중, 잎무늬 돌연변
건조물문화재의 부식 및 노후화에 대한 보존수리는 원형유지를 기본원칙으로 하며, 수리로 인해 인위적인 훼손을 가하는 과오를 범해서도 안 된다. 따라서 합성수지를 이용한 보존처리방법이 부각되어지고 있다. 본 연구의 목적은 합성수지로 보강한 사각단면 목재의 휨 성능에 관한 연구로서 합성수지의 보강길이, 보강면적비율, 합성수지 재료강도, 보강위치를 변수로 하여 총 11개의 시험체를 제작하여 실험하였다. 이 연구의 결과는 목재의 휨 보강재로 합성수지의 보강효과가 있는 것으로 나타났으며, 사용 가능성을 확인할 수 있었다.
용수는 인간의 생존과 산업생산에 있어서 필수적인 투입요소이다. 용수공급을 위해서는 많은 비용이 소요되지만 경제적 편익도 발생하며, 이에 대한 정보는 용수공급사업의 평가에서 중요하게 활용된다. 이에 본 연구에서는 서울시 가정용수 공급으로 인해 발생하는 경제적 편익을 추정하고자 한다. 특히 2001년부터 2004년까지의 기간을 대상으로 하여, 서울시 11개 수도사업소별로 연도별 소비자 잉여 및 경제적 가치를 추정한다. 소비자 잉여의 계산 과정에서 필요한 가