비보강 조적조 건축물의 외부보강기법에 따른 내진성능 및 경제성 비교 연구 = A Comparative Study on Seismic Performance and Economics of External Reinforcement Techniques for Unreinforced Masonry Buildings

국문 초록 (Abstract)

최근들어 환경파괴로 인한 자연재해의 강도가 점점 더 강해지면서 지 진에 대한 우려와 피해도 커지고 있는 실정이다. 과거 오래전부터 저층 주거용 건축물의 경우 지진에 취약한 조적조 구조로 되어 있어 적합한 구조적 보강이 필요한 시점이다. 내진 보강 기법으로는 조적벽체 자체의 강도를 증가시켜 내진성능을 향상시키는 방법이나 건축물의 내부 또는 외부에 구조물을 보강하는 방법이 제시되고 있다. 그러나 주거용 건축물 의 내진보강 공법은 거주성을 고려하지 아니할 경우 실제 보강 공사비 외에 공사기간 동안의 이주에 생활상의 큰 불편과 추가적인 비용이 발생 될 수 있다. 따라서 이 연구의 목적은 거주성을 고려한 조적조 건축물의 외부 내진 보강방안과 안전성과 적정성 여부 판단, 그에 따른 공사비 산 출을 통해 경제적이고 현실적인 보강방안을 제시하고자 하는 데에 있다. 보강기법으로는 기존 조적조 건축물에 철골 보-기둥+가새형 보강과 철골 트러스형 모서리 보강 및 RC 전단벽형 모서리 보강, 3가지 방식으 로 보강하여 내진성능을 평가하고 안전성을 분석하였다. 또한 조적조 건 축물 외부보강 방식에 따른 공사비를 산출하여 합리적이고 현실적인 보 강 방안을 제시하고자 하였다. 이에 대한 연구의 프로세스를 살펴보면 다음과 같다. 1장에서는 연구 의 배경 및 목적, 연구 방법을 서술하였으며, 2장은 비보강 조적조 건축 물의 내진보강 향상방법을 기술하였다. 3장에서는 비보강 조적조 건축물의 내진성능 평가방법에 대해 서술하였으며, 4장에서는 비보강 조적조 건축물 해석모델을 선정하여 내진성능을 평가하였다. 5장에서는 비보강 조적조 건축물에 보강기법 3가지 방식을 적용하여 각각에 대한 내진성능 과 공사비를 산출하여 보강기법의 효율성과 적정성을 분석하였다. 6장은 결론으로서 비보강 조적조 건축물의 외부보강 기법의 기초자료를 마련하 였다. 이상의 연구 결과를 요약하면 다음과 같다. (1) 비보강 조적조 건축물의 건축 경과 연수를 10년 이상 20년 미만으로 하였을 때 예비평가 및 상세평가에서 지진저항성능이 현저히 떨어짐을 알 수 있었다. 현재 우리나라의 주택 내진설계 비율을 고려하면 내진 보 강이 시급한 것으로 판단된다. (2) 철골 트러스형 모서리 보강구조의 경우 철골 보-기둥+가새형 보강구 조에 비해 최대 밑면 전단력이 1.51배 정도 높은 것으로 나타났으며, RC 전단벽형 모서리 보강구조의 경우 철골 보-기둥+가새형 보강구조에 비해 최대 밑면 전단력이 1.8배 정도 높은 것으로 나타났다. RC 전단벽형 모 서리 보강구조의 경우 철골 트러스형 모서리 보강구조에 비해 최대 밑면 전단력이 1.19배 정도 높은 것으로 나타났다. (3) 3종류의 보강방식 중 보강 공사비는 철골 보-기둥+가새형 보강구조, 철골 트러스 모서리 보강구조, RC 전단벽 모서리 보강구조의 순서로 높 게 나타났다. 철골 보-기둥+가새형 보강구조에 비하여 철골 트러스 모서 리 보강구조의 공사비가 약 1.69배 높으며, 철골 보-기둥+가새형 보강구 조에 비하여 RC 전단벽 모서리 보강구조의 공사비는 약 2.05배 정도 높 은 것으로 산출되었다.

다국어 초록 (Multilingual Abstract)

In recent years, as environmental degradation has intensified, the frequency and severity of natural disasters have continued to increase, leading to growing concern over earthquakes and their potential damage. Historically, many low-rise residential buildings have been constructed using masonry structures, which are particularly vulnerable to seismic forces. As a result, there is an urgent need to implement appropriate structural reinforcement measures to enhance their seismic performance and ensure the safety of occupants. Seismic retrofitting techniques include methods that enhance seismic performance by increasing the strength of the masonry walls themselves, as well as approaches that reinforce the structure by adding structural elements to the interior or exterior of the building. However, if seismic retrofitting methods for residential buildings do not take habitability into consideration, significant inconvenience and additional costs may arise due to relocation during the construction period, beyond the actual cost of the retrofitting work itself. Therefore, the purpose of this study is to propose an economical and practical seismic retrofitting strategy for masonry buildings by developing exterior retrofitting methods that consider habitability, evaluating their safety and suitability, and estimating the associated construction costs. For the retrofitting methods, three approaches were applied to existing masonry buildings to evaluate seismic performance and analyze structural safety: (1) steel beam–column frame with bracing reinforcement, (2) steel truss–type corner reinforcement, and (3) reinforced concrete (RC) shear wall–type corner reinforcement. In addition, construction costs were estimated according to the different external retrofitting methods for masonry buildings in order to propose rational and realistic reinforcement solutions. The research process for this study is outlined as follows. Chapter 1 describes the background and objectives of the study, as well as the research methodology, while Chapter 2 presents methods for improving the seismic performance of unreinforced masonry buildings. Chapter 3 describes the methods for evaluating the seismic performance of unreinforced masonry buildings, and Chapter 4 evaluates their seismic performance by selecting appropriate analytical models for unreinforced masonry structures. Chapter 5 applies three different retrofitting techniques to unreinforced masonry buildings and analyzes the efficiency and suitability of each method by evaluating their seismic performance and estimating the corresponding construction costs. Chapter 6 presents the conclusions and provides fundamental data for external retrofitting techniques for unreinforced masonry buildings. The research findings are summarized as follows. (1) When the age of unreinforced masonry buildings was assumed to be more than 10 years and less than 20 years, both the preliminary and detailed evaluations indicated a significant reduction in seismic resistance performance. Considering the current proportion of earthquake-resistant housing design in Korea, seismic retrofitting is deemed to be urgently necessary. (2) The steel truss–type corner reinforcement structure exhibited a maximum base shear approximately 1.51 times higher than that of the steel beam–column frame with bracing reinforcement, while the RC shear wall–type corner reinforcement structure showed a maximum base shear approximately 1.8 times higher than that of the steel beam– column frame with bracing reinforcement. In the case of the RC shear wall–type corner reinforcement structure, the maximum base shear was found to be approximately 1.19 times higher than that of the steel truss–type corner reinforcement structure. (3) Among the three retrofitting methods, the construction cost was found to increase in the following order: the steel beam–column frame with bracing reinforcement, the steel truss–type corner reinforcement, and the RC shear wall–type corner reinforcement. Compared with the steel beam–column frame with bracing reinforcement, the construction cost of the steel truss–type corner reinforcement was estimated to be approximately 1.69 times higher, while that of the RC shear wall–type corner reinforcement was estimated to be approximately 2.05 times higher.

목차 (Table of Contents)

• 제 1 장 서 론····································································································1
• 1.1. 연구 배경 및 목적 ··················································································1
• 1.2. 연구 동향 ································································································3
• 1.3. 연구 범위 및 방법 ··················································································5
• 제 2 장 내진성능 향상····················································································7
• 2.1. 내진보강 설계 ··························································································7
• 2.2. 내진성능 보강방법 ··················································································8
• 2.2.1. 보강효과 ·····························································································8
• 2.2.2. 보강기법 ·····························································································9
• 2.2.3. 보강재료 ·····························································································9
• 2.3. 내진성능 보강방법 선정 ········································································9
• 2.4. 비보강 조적조 건축물의 보강 ····························································10
• 2.4.1. 섬유보강재 보강 ············································································10
• 2.4.2. 철골 골조 보강 ··············································································11
• 2.4.3. 코어링 보강 ····················································································12
• 2.4.4. 외부 버팀대 보강 ··········································································13
• 2.4.5. 벽체 덧댐 보강 ··············································································13
• 2.4.6. 강재 스크류 보강 ··········································································14
• 2.4.7. 앵커 타이(anchor tie) 보강 ·························································15
• 2.4.8. 벽체 ․ 슬라브 연결부위 보강 ······················································15
• 2.4.9. 스틸 타이(steel tie)보강 ·······························································16
• 2.5. 조적 벽체의 파괴형태 ·········································································18
• 제 3 장 내진성능 평가··················································································21
• 3.1. 일반사항 ··································································································21
• 3.2. 건축물의 성능수준 ················································································22
• 3.3. 지진위험도 ····························································································24
• 3.3.1. 지진구역, 지진구역계수 및 위험도계수 ····································24
• 3.3.2. 지반증폭계수 ·················································································25
• 3.3.3. 평가지진의 가속도응답스펙트럼 ···············································25
• 3.4. 내진성능 예비평가 ··············································································27
• 3.5. 상세평가 ································································································29
• 3.5.1. 일반사항 ···························································································29
• 3.5.2. 성능수준의 판정 ···········································································30
• 3.5.3. 전단 강도식 ·····················································································33
• 제 4 장 비보강 조적조 건축물 내진성능 평가········································35
• 4.1. 해석모델 선정 ························································································35
• 4.2. 평가방법 ··································································································41
• 4.3. 내진성능 예비평가 ················································································43
• 4.3.1. 기본사항 ···························································································43
• 4.3.2. 층별요구량 산정(평가층의 위치:1층) ·········································44
• 4.3.3. 성능등급의 결정 ·············································································46
• 4.4. 내진성능 상세평가 ················································································46
• 4.4.1. 층간변형각 ·······················································································47
• 4.4.2. 성능수준 판정 ·················································································51
• 4.4.3. pushover ···························································································53
• 4.4.4. 벽체 상세평가 ·················································································55
• 제 5 장 보강구조 내진성능 및 경제성 평가············································59
• 5.1. 해석모델 선정 ························································································59
• 5.2. 평가방법 프로세스 ················································································66
• 5.3. 성능평가 ··································································································69
• 5.3.1. 층간변형각 ·······················································································69
• 5.3.2. 성능수준별 중력하중 저항능력 ···················································77
• 5.3.3. pushover ···························································································79
• 5.3.4. 벽체 상세평가 ·················································································82
• 5.4. 보강 공사비 및 경제성 ······································································82
• 5.5. 소결 ········································································································87
• 제 6 장 결론····································································································91
• 참고문헌···············································································································93
• 부록 ·····················································································································95
• Abstract ··············································································································133