• Architectural research
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• 제15권1호
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• pp.25-33
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• 2013

The amount of construction waste increased to 176,447 ton/day in 2008 from 28,400 ton/day in 2000, a 6-fold increase in just 10 years. Such dramatic increase in the waste of concrete, asphalt concrete, wood and metals was due to demolition of old buildings as well as a great number of building redevelopment projects and hurried city industrialization. Many buildings targeted for demolition today were built in line with the government policy to provide affordable housing to citizens in the shortest time possible and consequently, said buildings underwent rapid deterioration and required periodic repairs and reconstruction. Based on the above, we predict that construction waste will continue to increase for the foreseeable future. In particular, due to limited availability of suitable space to construct apartments and residential buildings in the city, old buildings are being torn down to make space for new development, further increasing construction waste. In light of that, efforts to recycle as well as reduce generated waste are urgently required.

• Earthquakes and Structures
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• 제8권3호
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• pp.511-539
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• 2015

The main objective of this study is to analytically investigate the effectiveness of different strengthening solutions in upgrading the seismic performance of existing reinforced concrete (RC) buildings in Nepal. For this, four building models with different structural configurations and detailing were considered. Three possible rehabilitation solutions were studied, namely: (a) RC shear wall, (b) steel bracing, and (c) RC jacketing for all of the studied buildings. A numerical analysis was conducted with adaptive pushover and dynamic time history analysis. Seismic performance enhancement of the studied buildings was evaluated in terms of demand capacity ratio of the RC elements, capacity curve, inter-storey drift, energy dissipation capacity and moment curvature demand of the structures. Finally, the seismic safety assessment was performed based on standard drift limits, showing that retrofitting solutions significantly improved the seismic performance of existing buildings in Nepal.

• Earthquakes and Structures
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• 제20권2호
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• pp.225-238
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• 2021

Supplemental passive dampers are widely employed to improve the structural performance of buildings under seismic excitations. Nevertheless, the added damping could be counter-productive if the axial forces induced by the damper reaction forces are not routed properly in the columns. A few researchers engaged to optimize the width-wise damper arrangement to improve the delivered path of the axial column forces. However, most of these studies are limited under the design-based seismic level and few of them has evaluated the collapse performance of buildings under strong earthquakes. In this paper, the strategic width-wise placement method of viscous dampers is explored regarding the building performance under collapse state. Two realistic steel buildings with different storeys are modelled and compared to explore higher mode effects. Each building is designed with four different damper arrangement scenarios based on a classic damper distribution method. Both a far-fault and a near-fault seismic environment are considered for the buildings. Incremental Dynamic Analysis (IDA) is performed to evaluate the probability of collapse and the plastic mechanism of the retrofitted steel buildings.

• Structural Engineering and Mechanics
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• 제2권1호
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• pp.81-94
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• 1994

It is well recognized that structures designed to resist strong ground motions should be able to withstand substantial inelastic deformations. A simple procedure has been developed in this paper to monitor the dynamic earthquake response (time-history analysis) of both steel and concrete multistorey buildings in the inelastic range. The building is treated as a shear beam model with three degrees of freedom per floor. The entire analysis has been programmed to run on a microcomputer and can output time histories of displacements, velocities, accelerations and member internal forces at any desired location. A record of plastic hinge formation and restoration to elastic state is also provided. Such information can be used in aseismic analysis and design of multistorey buildings so as to control the damage and optimize their performance.

• Smart Structures and Systems
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• 제2권4호
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• pp.305-312
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• 2006

In the case of hospital buildings, where seismic design requirements are very high, existing structuresand especially those attacked by past earthquakes, appear, often, unable to fulfil the necessary safety prerequisites. In this paper, the retrofitting of hospital buildings is investigated, using alternative methods of repair and strengthening. Analysis of an existing hospital building in Patras, Greece, is performed. The load-bearing system is a reinforced concrete system. Two solutions are proposed: strengthening using concrete jackets around column and beam elements and application of viscoelastic dampers for the increase of the stability of the structure. Adequate finite element models are constructed for each case and conclusions are drawn on the efficiency of each rehabilitation method.

• 태양에너지
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• 제11권3호
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• pp.37-43
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• 1991

본 고에 있어서는 겨울철 난방으로 인한 난방비 절감과 동시에 무공해이며 쾌적한 교육환경을 조성하고자 자연형태양열시스템의 한 부류인 직접획득형 시스템을 적용한 직접획득형 자연형태양열학교를 설계하고 그 열적성능을 분석하였으며, 이에 따른 경제성 문제도 아울러 검토하였다.

• 교육시설
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• 제13권4호
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• pp.15-23
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• 2006

The purpose of this study is to establish the objective deterioration grades and evaluation criteria of building equipment system of educational facilities available for reasonable maintenance and remodeling of them. For the purpose of it, the actual conditions of building equipment systems of the 148 buildings of 84 middle and high schools in Seoul 20 years after construction are investigated and surveyed through one-on-one interviews and questionnaires. And, deterioration grades of them are estimated by the evaluation criteria which is proposed in this study. As a result of this study, the 10 deterioration grades and the 4 evaluation criteria of the 6 performances of building equipment system, which are heating and cooling, water supply and drainage, hot water supply and electrical power performance, are suggested. And, as a result of the survey, it showed that 24% of the investigated school buildings were estimated C grade which needs partial remodelling, and 51% of the school buildings were estimated D grade which needs extensive remodelling. And, 25% of the school buildings were estimated E grade which needs overall remodelling or alteration of building equipment system.

• 한국공간구조학회논문집
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• 제12권4호
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• pp.91-98
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• 2012

As the occurrence rate of terror and hazard is increasing throughout the world, GSA, DoD, and FEMA are proceeding a study about mitigating the damage of terror. Korea is no more a safe place from the terrorist's threat, so we need to make measures against them. In this study we developed modified RVS System by revising some items to adjust the system to the domestic condition and conducted a risk assessment on several tall buildings in Korea. By using IRVS system which is developed by DHS, we also carried out the risk assessment. Comparing the results between RVS with IRVS, we performed terror risk evaluation of tall buildings. Through risk assessment of several tall buildings, we analyzed key factors of each scenarios and suggested the mean value of each items, so we would like to help the counter-terrorism in the design phase.

• Wind and Structures
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• 제21권3호
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• pp.331-352
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• 2015

A series of wind tunnel tests were conducted on tapered super high-rise buildings with a square cross section by applying synchronous pressure measurement technology. The effects of global strategy of chamfered modification on aerodynamic loads and wind-induced responses were investigated. Moreover, local aerodynamic strategies of opening a ventilation slot in the corner of equipment and refuge floors were carried out. Results show that the global strategy of tapered elevation increased the vortex shedding frequency, but reduced vortex shedding energy, leading to reduction of across-wind aerodynamic loads and responses. Chamfered modification suppressed the across-wind vortex shedding effect on tapered buildings. Opening the ventilation slot further suppressed the strength of vortex shedding and reduced the residual energy related to vortex shedding in aerodynamic loads of chamfered buildings. Finally, the optimized locations of local aerodynamic strategies were suggested.

• 국제초고층학회논문집
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• 제10권4호
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• pp.299-310
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• 2021

External fire spread has the potential to breach vertical compartmentation and violate the fire safety strategy of a building. The traditional design solution to this has been the use of non-combustible materials and spandrel panels but recent audits show that combustible materials are widespread and included in highly complex systems. Furthermore, most jurisdictions no longer require detailing of spandrel panels under many different circumstances. These buildings require rapid investigation using rational scientific methods to be able to adequately classify the fire risk. In this work, we use an extensive experimental campaign of material-scale data to explore the critical parameters driving upward flame spread. Two criteria are outlined using two different approaches. The first evaluates the time to ignition and the time to burnout to assess the ability for a fire to spread, and can be easily determined using traditional means. The second evaluates the preheated flame length as the critical parameter driving flame spread. A wide range of cladding materials are ranked according to these criteria to show their potential propensity to flame spread. From this, designers can use conservative approaches to perform fire risk assessments for buildings with combustible materials or can be used to aid decision-making. Precise estimates of flame spread rates within complex façade systems are not achievable with the current level of knowledge and will require a substantial amount of work to make progress.