Recently, the occurrence frequency of earthquake has increased in Korea, and the interests for seismic reinforcement of existing school buildings have been raised. To this end, the seismic performance evaluations for school buildings that did not accomplish the seismic design are required. In particular, this study checks the eigenvalue analysis, pushover curves, maximum base shears, performance points and story drift ratios, and then analyzes the seismic performance characteristics according to bracing configuration of steel frame system reinforcement. Also, this study presents the practical field application methods through the comparison of analysis results for the seismic performance characteristics.

In the case of a school building, even though it is a regular structure in terms of plan shape, if the masonry infill wall acts as a lateral load resisting element, it can be determined as a torsionally irregular building. As a result, the strength and ductility of the structure are reduced, which may cause additional earthquake damage to the structure. Therefore, in this study, a structure similar to a school building with torsional irregularity was selected as an example structure and the damping performance of the PC-BRB was analyzed by adjusting the eccentricity according to the amount of masonry infilled wall. As a result of nonlinear dynamic analysis after seismic reinforcement, the torsional irregularity of each floor was reduced compared to before reinforcement, and the beams and column members of the collapse level satisfied the performance level due to the reduction of shear force and the reinforcement of stiffness. The energy dissipation of PC-BRB was similar in the REC-10 ~ REC-20 analytical models with an eccentricity of 20% or less. REC-25 with an eccentricity of 25% was the largest, and it is judged that it is effective to combine and apply PC-BRB when it has an eccentricity of 25% or more to control the torsional behavior.

Following the social requirement to strengthen field supervision of the asbestos containing materials (ACM) abatement process with regard to asbestos school buildings, this study was conducted to understand the status and characteristics of airborne asbestos that may potentially occur after the ACM abatement process is completed. In the area where a series of asbestos abatement processes were finally completed, comprehensive area air sampling was performed. For sample analysis, Transmission Electron Microscopy (TEM) was used according to The Asbestos Hazard Emergency Response Act (AHERA) method and Phase Contrast Microscopy (PCM) analysis was also performed. Airborne asbestos was detected in 29.5% of the total samples, and the average concentration was 0.0039 ± 0.0123 s/cc (12.3 ± 38.9 s/mm2). 4.5% of the total samples exceeded the AHERA standard (70.0 s/mm2) and the average concentration was 0.0528 ± 0.0256 s/cc (167.2 ± 82.0 s/mm2). Airborne asbestos was no longer detected at the point when AHERA is exceeded after re-cleaning. Most of the detected asbestos was chrysotile (94.4%) and the structure types of asbestos were Matrix (41.4%), Fiber (39.9%), Bundle (10.8%), and Cluster (7.8%). Among the asbestos structures detected through transmission electron microscope analysis, the asbestos structures satisfying PCM-equivalent structures were found to be 6% of the detected asbestos, indicating that there is a limitation of the PCM analysis to check the airborne asbestos in that area. As a result of reviewing the status of airborne asbestos that may potentially occur and the type and dimensions of asbestos structure detected in the area, since the airborne asbestos exposure caused by poor field supervision for the ACM abatement process could not be ruled out, thorough management is necessary. In addition, the result of this study could be used as scientific evidence for establishing and strengthening policies related to ACM abatement, including cases of school buildings.

Steel brace strengthening is the most popular seismic rehabilitation method for school buildings. This is because the design can be conducted by using relatively easy nonlinear pushover analysis and standard modeling in codes. An issue with steel brace strengthening is that the reinforced building should behave elastically to satisfy performance objectives. For this, the size of steel braces should be highly increased, which results in excessive strengthening cost by force concentration on existing members and foundations due to the considerable stiffness and strength of the steel braces. The main reason may be the brittle failure mode of columns, so this study investigated the relationship between the efficiency of steel brace strengthening and column failure modes. The result showed that the efficiency is highly dependent on the shear capacity ratio of columns and structural analysis methods. School buildings reinforced by steel braces do not need to behave elastically when the shear capacity ratio is low, and pushover analysis is used, which means reducing steel material is possible.

As earthquakes have increased in Korea recently, people are paying attention to the seismic performance of buildings built in the past. Many school buildings in Korea were built based on standard drawings before the seismic design was applied. However, since school buildings are often designated as emergency evacuation facilities in case of disasters such as earthquakes, seismic evaluation and retrofit must be done quickly. This study investigated the failure modes among structural components (beams, columns, and joints), focusing on 1980s standard drawings for school buildings. The effects of column axial force, partial masonry infills, and different material strengths for concrete and rebar were considered for detailed evaluation. As a result, most of the joints were found to be the weakest among structural components. Column axial forces tended to make the joints more vulnerable, and partial masonry infills increased the possibility of joint failure and shear failure in columns.

As earthquakes continue to occur in Korea in recent years, seismic evaluation and retrofit of existing school buildings have been carried out. Many domestic school buildings were built using or referring to standard drawings. Therefore, if the overall structural characteristics of a school building can be known first based on standard drawings, it can be provided as valuable data for detailed seismic evaluation. For this reason, this study investigated the weak structural components and failure modes by comparing the strength of beams, columns, and joints constituting standard school buildings constructed in the 1980s. The evaluation was performed for different types of standard drawings and different material strengths. The results showed that the joint was mainly the weakest due to the eccentricity, and the failure modes were partially changed depending on the material strength.

Response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills in ‘Manual for Seismic Performance Evaluation and Retrofit of School Facilities’ published in 2018 were investigated in the preceding study. However, since previous studies are based on 2D frame analysis and limited analysis conditions, additional verification needs to be performed to further apply various conditions including orthogonal effect of seismic load. Therefore, this study is to select appropriate response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills by 3D frame analysis. The results are as follows. An appropriate response modification factor for non-seismic RC moment frames with partial masonry infills is proposed as 2.5 for all cases if the period is longer than 0.6 seconds. Also if the period is less than 0.4 seconds and the ratio of shear-controlled columns is less than 30%, 2.5 is chosen too. However, if the period is less than 0.4 seconds and the ratio of shear-controlled columns is higher than 30%, the response modification factor shall be reduced to 2.0. If the period is between 0.4 and 0.6 seconds, then linearly interpolates the response correction factor.

Most school buildings consist of reinforced concrete (RC) moment frames with masonry infills. The longitudinal direction frames of those school buildings are relatively weak due to the short-column effects caused by the partial masonry infills and need to be evaluated carefully. In ‘Manual for Seismic Performance Evaluation and Retrofit of School Facilities’ published in 2018, response modification factor of 2.5 is applied to non-seismic RC moment frames with partial masonry infills, but sufficient verification of the factor has not been reported yet. Therefore, this study conducted seismic performance evaluation of planar RC moment frames with partial masonry infills in accordance with both linear analysis and nonlinear static analysis procedures presented in the manual. The evaluation results from the different procedures are compared in terms of assessed performance levels and number of members not meeting target performance objectives. Finally, appropriate response modification factors are proposed with respect to a shear-controlled column ratio.

We investigated the distribution of asbestos in Seoul for 16 school buildings built before and after 1990, includingkindergartens, elementary schools, middle schools and high schools. The risk assessment standards of AHERA,HSE and ASTM were reviewed and a comparative analysis of assessment standards was conducted in schoolbuildings. For the risk assessment of 16 schools, 170 samples were selected, each of which was assessed usingstandards of AHERA, HSE and ASTM. The school buildings included the ACM (asbestos containing materials)ranged 3-4% of chrysotile and 1-3% of amosite in classroom ceilings and has 7-8% chrysotile in partitions of studenttoilets. The airborne concentrations of fiber materials were ranged with 0.002-0.022 fiber/cc in school buildingsby PCM. In this study, a simplified rating scale was used three categories of Good, Damaged and SignificantlyDamaged. In the result of comparative analysis for the risk assessment criteria, it was found that 113 samples, 132samples and 82 samples were classified as Good when assessed by AHERA, HSE and ASTM, respectively; and46 samples, 29 samples and 53 samples as Damaged, respectively; and 12 samples, 8 samples and 34 samples asSignificantly Damaged, respectively. From the distribution of asbestos and the comparative analysis for the riskassessment criteria, the management plan and new risk assessment were made based on the Korea backgroundshould be established to control asbestos exposure to students from damaged ACM and will be revealed that theassessment for the current condition and potential for disturbance on asbestos in school buildings.

The seismic performance of school buildings has been a matter of common interest socially and academically. The structural system of the school buildings is representative of the domestic low-rise reinforced concrete moment resisting frames, which apply extensively infills in their masonry walls. The masonry infilled walls are divided into full masonry infill in the transverse direction and partial masonry infill in the longitudinal direction. The masonry infilled walls are usually not included in structural analysis during the design process, but affect significantly the seismic performance because they behave with surrounding frames simultaneously during earthquakes. Many researchers have studied the effect of the masonry infilled walls, but several issues have been missed such as the increase of asymmetry by adding the full masonry infill, the size of the mean strength of the full masonry infill, and short column effect by the partial masonry infill. The issues were analytically investigated and the results showed that they should be checked at least by nonlinear pushover analysis in the seismic performance evaluation process. The results also confirm the weakness of the guideline of Korean Educational Development Institute where the seismic performance is basically assessed without structural analysis.

The core aim of this paper is to empirically scrutinize a strength characteristic and ductility of the beam-column frame of reinforced with steel subjected to the cyclic lateral load. First and foremost, I the author embarks upon making four prototypes vis-à-vis this research. Through this endeavour, the author has analysed cyclic behavior, fracture shape, ductility and energy dissipation of the normal beam-column frame and a beam-column frame of reinforced with steel. In addition, the survey has revealed the exact stress transfer path and the destructive mechanism in order to how much a beam-column frame of reinforced with steel has resistance to earthquake regarding all types of building, as well as school construction. To get the correct data, the author has compared the normal beam-column frame and three types of the beam-column frame of reinforced with steel following these works, the characteristic of cyclic behavior, destructive mechanism, ductility, and Energy dissipation of normal beam-column frame and a beam-column frame of reinforced with steel have been examined clearly.

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 ( ,  ,  ,  ,  ) 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.

Many school buildings are not applied seismic code because of small size structures. But it must be designed to show enough structural performance when subject to earthquake. Especially, most of school buildings are generally used as public shelters when the natural disasters such as flood and earthquake occur. In this study, the seismic risk of the reinforced concrete school building structure was evaluated by using the seismic performance evaluation methods of low-story RC structures developed in Japan and the required seismic performance index. In this paper, the seismic performance of the school building is evaluated by considering this short-column effects, building shape and deterioration.

In this study, the seismic performance of RC school buildings which were not designed according to earthquake-resistance design code were evaluated by using response spectrum and push-over analyses. From the results of analysis, the efficiency of the seismic retrofitting methods RC shear wall, steel frame, RC frame and PC wing wall for existing RC school buildings was evaluated and analysised. The analysis result indicate that the inter-story drift concentrated in the first floor and most plastic hinge forms in the column of the first story. And results of analysis of the efficiency of the seismic retrofitting indicate that inter-story drift significantly reduced and ductile behavior is expected.

Since the school buildings are generally used as public shelters when the natural disasters such as flood and earthquake occur, it must be designed to show enough structural performance when subject to earthquake. Major failure mode of the school buildings observed in past earthquakes were shear failure of column of which length is shortened by infilled masonry blocks. ln this study, the seismic risk of the reinforced concrete school building structure was evaluated by using the seismic performance evaluation methods of low-story RC structures developed in Japan and the required seismic performance index which is obtained according to the KBC2008 seismic hazard map and soil types. ln this paper, the seismic performance of the school building is evaluated by considering this short-column effects, building shape and deterioration.

This study was performed to investigate the characteristics of asbestos distribution in 6 public and 6 school buildings from August to September in 2006. The bulk samples were analysed by PLM(polarized light microscope). Also the airborne samples were analysed PCM(phase contrast microscope) and confirmed by SEM-EDX(scanning electron microscope-energy dispersive using X-ray analysis) method. The 6 public buildings included the ACM(asbestos containing material) ranged 2-7 % of chrysotile in 70 % of samples from ceiling, floor tile, and wall board and has 20 % tremolite in 2 ceiling plaster. The 6 school buildings were identified 1.5 % tremolite in one sample and showed the similar asbestos distribution with the public building. The airborne concentrations of fiber materials were ranged with 0.000-0.017 f/cc in public places and 0.000-0.012 f/cc in school building by PCM. However, the asbestos fibers could not be found by SEM-EDX. In the result of physical assessment of ACM in each buildings, it is considered that there is no chance of a hazardous situation because the ACM is not friable. Its suggested that the asbestos control plan should be established to prevent asbestos exposure to occupants from damaged ACM by repairing and custodial work.

본 연구는 전단파괴가 예상되는 기둥 실험체에 부착형 및 구속형 보강재를 적용하여 전단능력 향상과 연성 및 에너지 소산능력을 평가하는데 목적이 있다. 이를 위해 축하중과 횡하중을 동시에 저항하면서 전단파괴가 예상되는 실험체를 제작하였으며, 부착형 및 구속형 보강재를 적용한 실험체의 전단보강 성능을 확인하기 위하여 축하중과 동시에 횡하중을 가력실험을 수행하였다. 실험이 진행되면서 기록된 결과를 토대로 하중-변위 곡선을 작성하여 전단보강을 통한 기둥의 보강효과를 비교·분석하였다. 보통모멘트골조 실험체는 8.00%의 층간변위비에서 하중이 급격히 감소함이 나타났다. 그러나 유리섬유 복합체 보강 실험체는 마지막 8.00%의 층간변위에서도 하중이 크게 줄지 않았으며, 이후 더 큰 층간 변위비에서도 하중을 부담할 수 있음을 보여준다. 이러한 차이는 보통모멘트골조보다 유리섬유 복합체로 보강된 실험체의 내진성능확보능력을 보여 준다.

홍수피해저감효과를 분석하기 위해서는 수리·수문학적 분석을 통한 피해예상지역과 침수심을 분석함과 함께 피해예상지역에 대한 피해액 추정 이 가능해야 한다. 홍수피해액의 추정은 일반적으로 건물의 구조물 및 내용물에 대해서 침수심의 변화에 따라 분석된다. 본 연구에서는 실제 피해 지역의 자료들을 토대로 학교건물에 대한 침수심별 손상함수를 개발하고 적용하였다. 그리고 학교건물에 대한 손상함수의 개발절차, 침수심별 손 상함수의 보완과정을 제시하였고, 그리고 손상함수의 적용결과에 대한 기존 기법과도 비교하여 검증하였다. 본 연구를 통해 손상함수를 개발하는 과정과 개발된 침수심별 손상률 그리고 함수의 적용과정은 향후 피해규모에 따른 홍수피해액 추정을 가능하게 하여 홍수피해저감 대책에 대한 비 용대비 효과분석 수행에 활용될 수 있을 것으로 기대된다.

전 세계적으로 대규모 지진이 빈번히 발생하고 있는 가운데 국내의 경우 특히 사람이 집중되어 있는 학교 건축물에 대한 내진성능 보강이 시급한 것으로 조사되었다. 전국적으로 18,329 동 내진설계대상 학교 건축물 중 내진설계가 적용된 건축물은 약 13%인 2,417동에 불과하다. 본 연구에서는 학교 건축물의 내진보강 활성화를 위해 내진보강에 따른 경제성 분석을 수행하였다. 내진보강에 따른 경제성 분석 방법은 건축물의 내진보강으로 인해 발생하는 경제적 편익(benefit)과 내진보강에 소요되는 비용(cost)을 금액으로 산출하여 실제 투자한 비용 대비 효과가 얼마나 있는지를 평가하였다. 대상으로는 국내 내진설계 적용이전인 2000년 이전과 적용이후인 2000년 이후에 지어진 실제 학교 건축물을 선정하였다. 지진으로 인한 건축물의 총 손실은 건축물 구성요소 손실의 합으로 계산되어 짐으로 건축물을 대표적인 구성요소인 기둥, 보, 슬라브 등 3가지 구조부재와 내부벽, 외벽마감, 외부창호, 천정, 기계전기설비 등 5가지 비구조 부재로 구분하였다. 또한 금액 산출방법에는 건축물의 실제피해(physical damage)를 파악하기 위해 개발한 지진취약도 함수와 손상기준별 초과 확률 값을 사용하여 건축물의 지진 손실(loss)을 평가하였다.