Existing School Buildings Research Articles

Seismic retroftting of RC columns with RC jackets and wing walls with different structural details

An original reinforced concrete (RC) column and four strengthened specimens, two with RC jackets and two with wing walls, were tested in this study. The original column specimen was designed to comply with older (pre-1999) design standards so that the usual detailing deficiencies in existing school buildings in Taiwan could be simulated. Two different structural details were chosen to fabricate the full-scale specimens for each retrofitting technique. The study confirmed that either RC jacketing or the installation of wing walls with two different structural details can effectively improve the stiffness and strength of an existing column. RC jacketing shows a better improvement in energy dissipation and ductility when compared to the columns with wing walls installed. This is because the two RC jacketed columns experienced a flexural failure, while a shear failure was found in the two columns with the wing walls installed, and thus led to a drastic decrease of the maximum lateral strengths and ductility. Since many factors may affect the installation of a post-installed anchor, it is better to use standard hooks to replace post-installed anchors in some specific points when using RC jacketing or installing wing walls.

CFTブレースにより耐震補強を施した実在建物の耐震性能改善効果に関する解析的研究

An analytical study was conducted to the existing school building retrofitted by concrete-filled steel tubular (CFT) braces which were only acting under compression. The analytical object was three-story RC building constructed in 1963. The one-span portion cut from this building was already tested statically under horizontal force. In this study, the analytical model was developed to trace the load versus deformation relation obtained by the test. From the comparison between test and analysis, the analytical behavior showed good agreement with the test result. After that, the seismic performances of whole model of the building were investigated by comparing between the behaviors of the non-retrofitted model and the retrofitted model.

Improvement of the Sustainability of Existing School Buildings According to the Leadership in Energy and Environmental Design (LEED)® Protocol: A Case Study in Italy

School-age students spend much of their time in school buildings. The sustainability of these buildings should be a priority as better comfort with a high indoor air quality contributes to an improvement in the conditions for learning. Although new school buildings are often built with high standards of sustainability and energy efficiency, the existing school building stock is generally characterised by very poor quality. The energy retrofit of existing school buildings in recent years is part of the policies of the European Union and, consequently, of the Member States. However, rarely do these measures consider aspects other than energy. This paper proposes and discusses a feasibility study which provides a considerable improvement in the environmental quality of 14 school buildings located in northern Italy: the objective is to ensure the requirements for Leadership in Energy and Environmental Design (LEED)® certification. The analysis considers both the technical and economic aspects. The study shows that there is a technical feasibility: the credits are between 42 and 54, moreover the major cost (the cost of building envelope and heating systems retrofit is 82.9% of the total cost) is due to the improvement of energy efficiency. The improvement of sustainability is therefore a reasonable strategy even if the application of the LEED Protocol in the Italian context involves some critical issues that are discussed in the paper.

Potential and limits to improve energy efficiency in space heating in existing school buildings in northern Italy

Improving the energy performance of public buildings is important for the promotion of a culture of energy efficiency among the local population. Indeed the European Union has developed strategies particularly for this sector using specific legislation and has targeted projects for economic support.In this paper we present a energy audit campaign conducted on 49 school building complexes located in the Lombardy region of Italy to collect data concerning their actual energy consumption for space heating, occupant behaviour and the technical characteristics of the buildings. On the basis of these data, different energy retrofit scenarios were studied with different performance and cost-effectiveness targets. The results show that it is not always convenient to improve excessively energy performance for heating.

In situ experiment on retrofit of school buildings by adding sandwich columns to partition brick walls

SUMMARYMany significantly strong earthquakes have occurred over the years in Taiwan, which have caused tremendous damage to primary and middle school buildings; the 921 Chi‐Chi earthquake was particularly devastating. According to statistics, 786 schools (1,958 classrooms) were damaged on September 21, 1999 during this earthquake event. The devastation showed that a lack of seismic performance is a common problem for existing school buildings in Taiwan. Therefore, the retrofit of existing school buildings has become an urgent issue in the prevention of possible damage in the future. The retrofit technique of adding sandwich columns to partition brick walls is proposed in this paper, and the feasibility of the proposed method was verified by in situ pushover tests of two real school buildings, one without and one with retrofit. The experimental and analytical results show that the sandwich column itself contributes significantly to the seismic capacity of the examined school building. Moreover, the analytical results yielded conservative capacity curves when compared with the experimental results. Copyright © 2013 John Wiley & Sons, Ltd.

Environmental quality and energy efficiency: sustainable school buildings design strategies

The design and construction qualities of buildings play a key role in limiting energy consumption, while ensuring proper comfort conditions. The existing school buildings stock is mainly characterized by a low level of architectural quality and of performance leading to a high consumption of energy and to an indoor microclimate below comfort level. School buildings play a dual role: on one hand, they have to ensure adequate technical and morphological standards to all spaces used by the students, and on the other, they have to effectively communicate the criteria of sustainable design that have been used for their construction. This paper proposes some innovative case studies projects, highlighting criteria, and strategies adopted in the design for spaces dedicated to children. The aim is to promote sustainable design and construction strategies that combine high levels of energy effi ciency, performance standards, and environmental indoor quality, including innovative strategies to integrate the building and its related systems. Best practices can also effectively encourage experimentations and contribute to formulate sustainable construction strategies that should be widely adopted.

地域利用のために整備されたコミュニティ・スクールの部屋や場所の利用実態

This paper aims to verify the actual condition on the use of the rooms or spaces in “Community Schools” (CSs) in Japan which have been developed spatially in order to activate the community support to children's learning in a school, and to encourage the communitybased development with a school. Based on the analyses on nationwide trends regarding CSs, six samples were selected and analyzed in terms of the relations between the developed rooms or spaces and actual use condition of them by communities. It can be found that there are some gaps between the spatial policy at the stage of planning and the actual use in six samples respectively. In order to resolve these problems, it can be suggested that the trial to use in an existing school building according to an assumed programs before renovation can become an effective measure as well as to fully comprehend the characteristics of spaces that are needed to realize the goals of CSs.

조적조 비내력벽을 가진 기존 학교 구조물의 내진 성능평가

In Korea, most existing school buildings have been constructed with moment frames with un-reinforced infill walls designed only considering gravity loads. Thus, the buildings may not perform satisfactorily during earthquakes expected in Korea. In exterior frames of the building, un-reinforced masonry infill walls with window openings are commonly placed, which may alter the structural behavior of adjacent columns due to the interaction between the wall and column. The objective of this study is to evaluate the seismic performance of existing school buildings according to the procedure specified in ATC 63. Analytical models are proposed to simulate the structural behavior of columns, infill walls and their interaction. The accuracy of the proposed model is verified by comparing the analytical results with the experimental test results for one bay frames with and without infill walls with openings. For seismic performance evaluation, three story buildings are considered as model frames located at sites having different soil conditions (<TEX>$S_A$</TEX>, <TEX>$S_B$</TEX>, <TEX>$S_C$</TEX>, <TEX>$S_D$</TEX>, <TEX>$S_E$</TEX>) in Korea. It is observed that columns behaves as a short columns governed by shear due to infill masonry walls with openings. The collapse probabilities of the frames under maximum considered earthquake ranges from 62.9 to 99.5 %, which far exceed the allowable value specified in ATC 63.

Seismic-Isolation Retrofits of School Buildings: Practice in China after Recent Devastating Earthquakes

AbstractRecent large earthquakes in China (e.g., Wenchuan earthquake and Yushu earthquake) resulted in enormous damage to school buildings and took many students’ lives. Recognizing the seismic vulnerability of existing school buildings, the Chinese government started a nationwide mission in 2009, aiming at increasing the seismic capacity of school buildings through inspection and retrofit activities. This paper presents the experiences of the authors in the retrofits of school buildings in which seismic isolation by using rubber and/or sliding bearings was adopted as a new and efficient retrofit technique, as compared with conventional ones. The retrofitted school buildings include masonry buildings, RC frame buildings, and a mixture of both. Design methods and the corresponding requirements in the modified seismic design code are presented, and typical construction procedures of the seismic retrofit are summarized from an engineer’s point of view. Procedures regarding the contract and review of the retr...

기존 학교 건축물의 내진성능평가 및 보강방안 제안

Recently large scale earthquake s are occurred around the world following the damage of buildings. So the interest of preparing for earthquake seismic design and seismic performance has becoming high. School buildings are though used for educational purpose; they are also used as emergency shelter for local residents during earthquake disaster. However, the current seismic design ratio of our country (Korea) is 3.7% and if massive earthquake is occurred it follows a serious damage. In order to overcome this situation, seismic performance evaluation is carried out for existing school building and an accurate and appropriate seismic retrofit is required based on performance evaluation to upgrade the existing school buildings. In this paper, nonlinear static analysis on existing school buildings for ATC-40 and FEMA-356 are carried out using the capacity spectrum method to evaluate seismic performance and to determine the need for retrofitting. In addition, after reinforcement to verify the effect of retrofit enhance the seismic performance is applied the seismic performance evaluation is carried out to verify the effect of seismic retrofit time history analysis using nonlinear dynamic analysis is also performed and nonlinear behavior of earthquake load of seismic retrofit of structures was also investigated.

현장타설 끼움 전단벽 및 철골가새를 활용한 기존 학교 건물의 내진보강

This study proposes a procedure for evaluating the seismic performance and retrofit of a typical reinforced building (R/C) school buildings contructed in the 1980s. The procedure is derived from the Japanese Standard for Evaluation of Seismic Capacity of Existing Reinforced Concrete Buildings and Nonlinear Static Procedure (NSP) specified in Federal Emergency Management Agency (FEMA 356). In this study, the Japanese Standard was applied for evaluating the additionally required seismic performance in the existing school building. Cast-in-place (CIP) reinforced concrete infill walls and steel braces were used to seismically retrofit the existing school building located in the region of Hongsung in Chungnam. In the pushover analysis, i.e NSP, the hinge properties of columns, beams, infill walls and steel braces were carefully calibrated based on the existing experiment results in the available literatures. The predicted seismic performance for the retrofitted building was compared to that for the virgin building. Based on the seismic evaluation with the Japanese Standard and the FEMA 356 criteria, the addition of CIP reinforced concrete infill walls and steel braces have superior constructablility and can improve effectively the seismic performance of the existing school buildings constructed in 1980s.

학교건물에 있어서 비탄성해석 및 비선형 정적해석을 통한 내진성능 평가에 따른 보강 연구

본 연구는 학교 건물의 구조적 성능 평가를 통한 내진보강에 대한 연구이다. 본 연구의 목적은 학교 건물의 구조적 성능평가를 통하여 안전성과 사용성을 고려한 구조보강방안을 비교분석하고 합리적 내진 보강안을 제시하여 보다 지진에 안전한 건축물을 유지하는데 도움 이 되고자 한다. 이 목적을 위해 기존의 학교건물을 연구 대상으로 선정하여 내진성능평가를 실시하고 내진 보강안을 제시하였다. 본 연구의 방법은 기존의 철근콘크리트 학교건물을 대상으로 1차 내진 성능평가와 2차 내진 성능평가를 실시하였다. 위와 같은 방법으로 내진성능평가를 하여 그 결과를 분석하고 내진보강방안을 제시(강재댐퍼, 탄소막대보강재)하였다. 제시된 내진 보강방안을 대상 건축물에 적용하여 내진보강 전, 후의 내진성능평가를 통해 종합적인 결과를 도출 하였다. This study is about earthquake-proof reinforcement through structural function evaluation of an school building. The purpose of this study is to comparatively analyze structure reinforcement measures in consideration of safety and usability through structural function evaluation of school buididng, to offer rational measures for earthquake-proof function and to provide help in maintaining safe structures against earthquake. For this purpose, was selected for this study as an existing school building, earthquake-proof function evaluation was conducted, and measures to reinforce earthquake-proof function was offered. As for the research method, the first and the second earthquake-proof function evaluations were conducted which is an existing reinforced concrete school building. Through the abovementioned methods, earthquake-proof function evaluation were conducted, the results were analyzed and the measure to reinforce earthquake-proof function were offered(Steel damper, Carbon plate stiffeners). The offered measure to reinforce earthquake-proof function was applied to the subject structure, and comprehensive results were derived from earthquake-proof function evaluation regarding before and after earthquake-proof function reinforcement.

Vulnerability assessment and retrofitting of existing school buildings: a case study of Aceh

PurposeAs the widely held perception is that retrofitting is a complicated process and is expensive, the purpose of this paper is to analyze cost effectiveness of retrofitting existing buildings in order to make them safer against earthquake and also to add child friendly features. This case study focuses on the simple method of retrofitting on rectangular single storey existing school buildings. The school buildings are of different types, based on material, shape and size, number of storeys and their vulnerability to earthquake is different case by case. The paper also outlines the process of vulnerability assessment and approach to retrofitting.Design/methodology/approachThe paper is based on the data collected from a case study carried out in Aceh (Indonesia) as a part of an assessment of vulnerability of newly constructed school facilities and retrofitting them in order to increase their seismic performance.FindingsOne of the key findings of this study is that retrofitting can be achieved through the use of simple methods, tools and equipment and local human resource. This approach not only reduced the vulnerability of school children to earthquake disaster but also contributed to disseminate the message of culture of safety among the neighboring communities. Another major finding is that cost of retrofitting is less compared to the cost of demolition and rebuilding. The retrofitting option further saves the cost as it is time saving and the downtime is less. The retrofitting process and onsite training can also be an effective medium for dissemination of best construction practices in the community. The process also helps the local people to understand the context of risk and raise awareness on disaster risk reduction.Research limitations/implicationsThe findings of this paper are not limited to vulnerability assessment and retrofitting of school building in Aceh. They can be replicated in other parts of Indonesia and countries having similar type of buildings.Practical implicationsThe findings of this paper will be useful for decision makers to replicate similar processes in other types of schools in other areas. The findings will also be useful advocate disaster safer and child friendly schools.Originality/valueThe paper is unique in its findings that retrofitting of school buildings does not only make the schools safer and reduces the risk to children but is also cost effective compared to new construction.

Applicability investigation of code-defined procedures on seismic performance assessment of typical school buildings in Taiwan

Seismic resistance of elementary and high school buildings is of great concern due to high earthquake risk in Taiwan. Existing school buildings are often built of similar configurations, and designed based on previous building codes, which are not in compliance with current codes in seismic performance objective. The use of current code procedures on seismic performance assessment of existing typical school buildings may not be applicable in predicting their structural behavior during earthquakes. This paper describes a full-size two-story, three-bay frame structure test of typical school building design in Taiwan, and examines the performance and failure mechanism of the frame structure with current building codes. Results from loading test show good agreement with the code-defined procedures in identifying soft story, weak story, and failure modes of columns, but show different failure mechanism in beam–column joint region, i.e. strong-column–weak-beam is expected by building code procedures, whereas the test specimen exhibits weak-column–strong-beam behavior. Although the joint shear check following current code procedures gives satisfactory results, i.e. is consistent with the experiment, the check on its own is not a reasonable one. Revisions of current checking procedures for failure mechanism in beam column joint and for joint shear are also proposed in this paper for existing non-ductile reinforced concrete school buildings. The revised procedures incorporate the effects of both weak story and weak-column–strong-beam behavior. After adopting the proposed procedures, the predicted structural behavior and failure modes are consistent with those observed from the full-size frame test.

The effects of humidity and other environmental parameters on the shear strength of brick walls: evaluation of field test data

Following the destructive Bam earthquake of 2003, the Iranian government initiated a vast program of seismic retrofitting for existing school buildings throughout the country. As a result of the school retrofitting program, an extensive amount of field test data is available on the shear strength of brick walls of buildings from different parts of the country having different climates. A large portion of the available data is utilised in this paper to determine the effects of environmental conditions, particularly those of humidity and temperature, on the shear strength of brick walls. The effects of other factors including the type of material and age of the building are also investigated. Results of the statistical analyses highlight the important effects of the location humidity level. A nearly three folds increase in strength was noted for walls constructed of solid brick units in wetter northern parts of the country compared to those constructed in the drier central parts. Another important factor is found to be the absorption rate of bricks used in constructing the wall. On the other hand, the effect of overall environment temperature is found to be minimal. The daily temperature gradient of the location, however, may affect the strength by causing some long-term fatigue. It is recommended that for assessing the vulnerability of unreinforced brick walls, regionalization is considered and an appropriate ‘climate factor’ is adopted.

Out-of-plane seismic behavior and CFRP retrofitting of RC frames infilled with brick walls

Seismic retrofitting of existing school buildings is a significant issue in Taiwan. Compulsory school buildings often have many openings along their corridors. Here, rather than attempting to change existing doors and windows, it seems convenient to retrofit the confined brick walls between classrooms with carbon fiber reinforced plastic (CFRP) to improve their out-of-plane seismic capacities. This study deals with the out-of-plane seismic behavior of reinforced concrete (RC) frames infilled with brick walls. Five full-scale specimens were tested. The test results showed that the contribution of the brick walls to the out-of-plane lateral strength of frames was not straightforward, although the residual strength of frames infilled with brick walls was clear. Retrofitting enhanced the peak lateral strength and residual strength in tested specimens. The proposed analytical model satisfactorily predicted the load–displacement relationship of all specimens.

조적벽의 전단강도를 고려한 철근콘크리트골조의 비탄성 거동

In this study the inelastic behavior of the existing school buildings with infilled masonry walls is analysed by pushover method. The shear stiffness and strength of masonry wall is calculated from the prior experimets and verified by inelastic analysis. The height of infilled masonry wall affects the structural behavior. The higher the masonry wall height, the higher the initial shear stiffness and strength of masonry wall. As the cracks are developed, the strength of masonry wall is much decreased. The proposed inelastic analysis method shows similar results with the experiments and can be used as inelastic analysis model of reinforced concrete buildings with infilled masonry walls.

Experimental study on retrofit of school buildings by adding sandwich columns to partition brick walls

AbstractThousands of buildings were damaged by the devastating Chi‐Chi earthquake on September 21, 1999. Of all the public buildings, school buildings are the most vulnerable to earthquake damage, and the retrofitting of existing school buildings becomes a stringent issue. In addition to cost effectiveness, the impact of retrofitting methods on the functions of the school buildings needs to be considered. This paper therefore proposes the retrofitting of school buildings by adding sandwich columns onto partition brick walls. The sandwich column is divided into two parts and is added to the two sides of the partition brick wall held with pairs of U‐shaped bars. The retrofit does not require the removal of windows or doors in the longitudinal direction making the proposed method cost effective and minimizes the impact on the function of the school buildings. Five full‐scale specimens without and with retrofitting were designed and fabricated for testing based on the partition brick wall frames of the existing school buildings. The specimens were subjected to cyclic loading in the out‐of‐plane direction through a loading frame so that the columns deformed with double curvatures. The experimental results verified the feasibility of the proposed retrofit method. The data showed that the lateral strength of the retrofitted specimen doubled that which was not and that the residual strength of the retrofitted specimen was just as high as the ultimate strength of the specimen without retrofitting. The analytical results in lateral strength yielded conservative figures compared with experimental measurements. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Seismic Analysis of Existing School Buildings Using Different Egyptian Seismic Provesions

This paper presents a comparative study for seismic analysis of a certain class of existing school buildings which are considered as one of the important and wide spread buildings in Egypt. The study focuses on a comparison between all versions of the Egyptian Code of Practice for loading (ECP-201), versions published in 1993, 2003, and the draft of final version October, 2008], and the Regulations of the Egyptian Society of Earthquake Engineering (ESEE, 1988). Base shear and base moment values are calculated using all of the above mentioned seismic provisions. The controller straining actions of these provisions are then compared with those obtained using response spectrum and time history analyses using real ground excitation of pervious earthquakes (Al-Aqba, 1995, Northridge, 1994, and El-Centro, 1940). All these earthquakes are scaled to be matched with the maximum ground acceleration for the study zone. It has been found that high variation between the base shear and base moment obtained using the ECP versions specified different analysis methods and in comparison with the ESEE and Earthquake analysis. This high variation make the new ECP-201 (October, 2008) will be need to recontemplate.

Use of Pushover Analysis for Predicting Seismic Response of Irregular Buildings: A Case Study

Structural irregularity undermines capability of conventional methods for 2D pushover analysis to closely approximate results from inelastic dynamic analysis. In recent years, different methods have been developed to overcome such limitation and their suitability has been checked with reference either to idealized building models or to geometrically simple tested structures. In this paper, suitability of one such method, proposed by Fajfar et al. [2005], is evaluated considering an existing school building which presents both vertical and plan irregularities. Types of irregularity encompass not only those usually considered by seismic codes but also those deriving from a bad conceptual design and construction inaccuracies, very frequent at the year of construction (1974). It is found that, even under such complex irregularity conditions, this ‘modified’ pushover analysis correlates well results from inelastic dynamic analysis almost up to failure, since, in most cases, its predictions of interstorey drifts and plastic rotations are conservatively close to values from inelastic dynamic analysis. Even failure mechanism, consisting of a floor mechanism at the third level, is correctly predicted, thus demonstrating adequacy of such method for actual framed structures.