RC 구조에 있어 TOP-DOWN 공법선정시 시공 효율성 제고를 위한 최적공법 선정에 관한 연구

심재규 ( Jae Gyoo Shim ),김원필 ( Won Pill Kim ) 한국지역사회발전학회(구 한국지역사회개발학회) 2012 地域社會開發硏究 Vol.37 No.2

본 연구는 최근 도심지 대심도 건축공사가 활발히 진해되면서 TOP-DOWN 공법이 확대·적용 되어가는 과정에서 나타나는 문제점들에 대해 최근 TOP-DOWN 공법 적용현장 등을 중심으로 적용시점과 적용요인에 대한 사례분석을 현장 방문과 현장 소장과의 구두 통화를 통하여 분석하고 향후에 TOP-DOWN 적용 현장에서 최적이 공법을 적용하고 아울러 시공의 효율성을 제고시키기 위한 방법들을 제시하는데 있다. 본 연구결과, 현재 약 19가지 TOP-DOWN 방식들이 개발·적용되고 있는데 초기 설계단계나 단순 영업에 의한 공법 적용은 발주처나 시공사들에 대해 경제성과 시공성 등에 손실을 초래하고 있음이 밝혀졌다. 따라서 중요한 사항은 공법의 적용이 설계단계에서 보다는 현장에서 발주처나 시공사가 지반상태, 흙막이 벽체공사, 골조구조, 경제성, 공기단축, 시공성, 안전성, 작업환경 등의 현장여건 적용요인들을 규정하고 우선순위를 고려하여 종합적으로 분석·적용이 필요한 것으로 분석되었다. 또한 R.C. 구조에 있어서 TOP-DOWN 공법 확대 적용을 위하여 관련 공정과의 연계를 통한 공사원가 절감, 시공성 개선, 제도적 보완 등에 지속적인 연구가 필요하다. This study intended to propose optimum Top-down method and efficient building construction method through site visits and interview with project manager for the analysis of top-down application in brisk urban building construction. Among 19 top-down methods, the analysis indicated that from the aspect of building construction and economy, technological application by initial design phase and simple business did impact on building construction firms. Therefore, the study contended that the application of top-down should be made based on the specified priorities of ground condition, structure, economy, shortening of project progress, building construction, safety, and working site condition in the important construction phase, rather than design phase. In conclusion, for the wide application of Top-down in R.C structure, it is necessary to do continuous research on cost down of construction costs, improvement of building construction, and implementation of system in relation with working schedule.

국내 도심지 굴착공사에 적용된 Top-Down 공법의 시공사례 연구

정지승(Jeeseung Chung),박석기(Sukki Park) 한국지반환경공학회 2017 한국지반환경공학회논문집 Vol.18 No.2

국내 건축물 시공을 위한 지하 굴착은 안정성, 경제성 및 굴착 주변 여건 등을 고려하여 재래식 버팀대 공법(Strut, Ground Anchor)에서 점차 Top-Down 공법을 개량한 내부 영구 지지체 공법으로 변화하고 있다. 본 연구에서는 국내에서 범용적으로 사용되고 Top-Down 공법, New Top-Down 공법, S.P.S 공법, S.T.D 공법 및 B.R.D 공법 등 내부 영구 지지체 공법 현장을 선정하여 재래식 버팀대 공법과 공사비 및 공기를 비교・분석하였다. 또한 공사 중 흙막이 벽체의 계측 자료를 분석하여 흙막이 벽체의 안정성을 확인하였다. 그 결과 깊은 굴착 및 기반암층이 지표면으로부터 가까운 경우 영구 지지체 공법이 재래식 버팀대 공법보다 경제성과 시공성이 우수함을 알 수 있었다. Underground excavation for building construction in Korea is changing from conventional support method (Strut, Ground anchor) to inside permanent support method by stability, economic, circumstances around excavation and etc. This study was selected the sites of Top-down, New Top-down, S.P.S, S.T.D and B.R.D in general use. This study was compared and analyzed a construction cost and period between aforementioned methods and conventional support method. Also, this study was confirmed the stability of temporary retaining wall by analysis for measurement data under construction. As a result, this study can grasp that most improved permanent support method is excellent in economic and constructability than conventional support method in case of deep excavation and rapid appearance of bedrock.

슬러리 월의 자립도와 소단을 이용한 탑다운 공법에 관한 연구

박상준(Park, Sang-Joon),소광호(Sho, Kwang-Ho) 대한건축학회 2013 大韓建築學會論文集 : 構造系 Vol.29 No.6

Top-down method is a type of downward construction method that slab, girders and beams are connected to slurry wall by sequentially alternating ground excavation and structure construction after the construction of cast-in-place pile. Top-down method was introduced in Korea in the middle of 1980s. Since early 2000s, about 20 top-down methods have been developed. However, the selection of top-down method adequate to apply at construction site is difficult because almost developed top-down methods excepting reinforced concrete top-down method have been patented. Also, top-down method is often avoided due to high cost, poor work conditions and low work efficiency compared with open-cut method and bottom-up method. This paper proposes a top-down method applied with the independence of slurry wall and berm. In the case study targeted for an actual construction project, the proposed method is compared with existing top-down construction method in terms of economic feasibility and work efficiency. The proposed construction method results in better quality management in PRD work, steel frame work and excavation, increased economic feasibility and reduced construction period.

가중치 분석을 통한 도심지 Top-Down 공사에서의 공법요소 선정 모델 개발에 관한 연구

박창욱,문승윤,윤석헌 한국건축시공학회 2008 한국건축시공학회지 Vol.8 No.4

The size of the construction projects become huge and complex, and the depth of excavation for the underground structures become deeper. Also the working area is not enough for loading materials and temporary facilities. This is the most case of recent construction projects in downtown area. Top-down is the most useful method for this kind of construction projects. Top-down construction method consists of supporting method, retaining wall type, foundation type and construction direction such as up-down or up-up. construction managers have to select sub-elements for top-down construction method in planning phase. This study is to suggest the sub-elements selection model for the top-down construction method, and the case study is conducted for evaluating this model.

논문 : Top-Down 공법이 적용된 흙막이벽의 역해석을 이용한 거동분석

홍원표 ( Won Pyo Hong ),강철중 ( Chul Joong Kang ),윤중만 ( Jung Mann Yun ) 대한지질공학회 2012 지질공학 Vol.22 No.1

본 연구에서는 흙막이벽 설계시 널리 사용되고 있는 SUNEX 프로그램을 이용하여 Top-Down 공법이 적용된 지중연 속벽, 주열식 흙막이벽 (CIP벽, SCW벽)의 변형거동을 분석하였다. 해석프로그램에 Rankine의 토압(l857), Terzaghi and Peck의 토압(1967), Tschebotarioff의 토압(1973), 홍원표·윤중만의 토압(1995a)을 적용하여 흙막이벽의 수평변위를 예측하였다. 프로그램 해석결과, 흙막이벽의 수평변위량은 토압의 종류에 따라 큰 차이를 나타내고 있다. 홍원표·윤중만의 토압(I995a)을 적용하여 얻은 흙막이벽의 예측수평변위량이 실측수평변위량과 가장 유사하게 나타났다. 따라서 프로 그램 해석시 홍원표·윤중만의 경험토압(l995a)을 적용하면, Top-Down 공법이 적용된 흙막이벽의 변형거동을 비교적 정확히 예측할 수 있다. Abstract: The behaviors of a diaphragm wall and a contiguous pile wall such as CIP (Case-in-place pile) and SCW (Soil-cement wall), applied to the top-down construction method, were analyzed using the SUNEX program, which is widely used to design earth retaining walls. Four types of earth pressures, as described by Rankine (1857), Terzaghi and Peck (1967), Tchbotarioff (1973), and Hong and Yun (1995a), were applied to the analysis program to predict the lateral displacement of walls, The results show that the displacements of an earth retaining walls vary with the applied earth pressure. The predicted lateral displacement based on Hong & Yun`s (1995a) earth pressure is similar to the measured displacement. Therefore, the actual lateral displacement of an earth retaining wall, as applied to top-down construction method, can be accurately predicted by using an analysis program considering Hong and Yun`s (1995a) earth pressure.

Top-Down 공법이 적용된 건축물의 토압분포 및 바닥 시스템에 따른 구조 안전성

정수진(Jung, Su-Jin),김설기(Kim. Seol-Ki),서수연(Seo, Soo-Yeon) 대한건축학회 2017 大韓建築學會論文集 : 構造系 Vol.33 No.8

In the construction of building, it is necessary to consider the reducement of construction period and the securement of enough work space during the construction. Especially, the importance of those increases during the construction of underground structure requiring the safety of sheeting by excavation work. In this manner, this paper investigates the structural safety of the building constructed by top-down method through analytical approach. Various types of earth pressure distribution were considered in the structural analysis of an example frame at each step of top-down construction. In addition, the variation of stress distribution due to the change of floor system to resist soil pressure in the excavation was evaluated. As an analytical result, the highest member force was found when the soil was medium plastered sand since with highest unit weight. Among three conditions of floor system, the case with both beam and slab was most effective to resist the soil pressure since the soil pressure acting to wale can be uniformly distributed to floor.

역타 공법을 적용한 초고층 건물 기둥축소량의 시공단계해석

고규완,송화철 대한건축학회지회연합회 2024 대한건축학회연합논문집 Vol.26 No.1

초고층 건물에서 수직부재의 장기 변형은 수직부재 간의 부등축소량으로 인하여 구조적 문제와 사용성 문제를 발생시킨다. 그러므로 실제 시공 과정을 포함하는 시공단계해석을 통한 부등축소량 해석이 필요하다. 순타 공법과 달리 역타 공법은 슬래브 설치가 기둥 타설보다 먼저 되는 특징을 가지고 있어 이것을 시공단계해석에 반영할 필요가 있다. 따라서 본 연구에서 역타 공법을 시공단계해석에 반영하여 부등축소량을 해석하는 방법을 제안하고자 한다. Long-term deformation of vertical members in tall buildings can cause structural and serviceability problems by causing differential column shortening between vertical members. Therefore, it is necessary to analyze the differential column shortening through the construction stage analysis assuming the actual construction process. In particular, unlike the general construction process, the top-down method has the characteristic that the slab is installed before the column, so caution is needed in the analysis of the construction stage. In this study, we intend to propose a method for differential column shortening in which the top-down method is applied to the construction stage analysis.

병행순타공법의 현장적용에 관한 연구

소광호(Sho Kwang-Ho),양극영(Yang Keek-Young) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.9

Top-down method is divided into Up-down method which is digging underground from earth level and making underground structure and slab at the same time and Double-up method, advanced technology compared to Up-down, which is making underground structure and ground structure coincidently. Double-up method is making underground and ground structure after excavation, constructing from underground bottom to first floor slab and then from first floor to ground structure simultaneously. Up-down method, one of the Top-down methods, has been studied a lot by the academic world recently. It is broadly used by construction site in urban areas but there are few studies about Double-up method. So this thesis came to the conclusion as followings by applying Double-up method in real construction site. First, Double-up method could reduce construction term over 40%. Second, Core preceding method is effective for Double-up method to reduce construction term. Double-up method costs 8 percent more than conventional method, but the entire construction cost has no big difference in case of considering overheads. If the research and development for the technology to apply Double-up method is completed, Double-up method will be used effectively on the construction site.

지하구조물의 철골철근콘크리트 기둥과 철근콘크리트 보 접합부의 구조성능 평가

주영규(Ju Young-Kyu),천성철(Chun Sung-Chul) 대한건축학회 2003 大韓建築學會論文集 : 構造系 Vol.19 No.2

SRC column-RC beam joint is frequently used for the Top-Down construction of underground structure. Various types of the SRC column-RC beam joint detail have been proposed and implemented for the anchorage of the reinforcing bars. The types can be classified by anchoring methods as follows: (1) passing through type; (2) wing plate type; and (3) H-beam bracket type. Although these types are widely being used in Korea, the structural performance is not clearly understood. For each type of joint, the structural characteristics such as strength, stiffness, energy dissipation capacity, stiffness degradation, and ductility under monotonic and cyclic loads were tested. The test results showed that the passing through type had the best structural performance. By improving the passing through type, the pseudo wide beam type specimens were experimentally investigated for the field application. It uses a number of reinforcing bars that are placed at the edge of the slab not to intersect a steel column without changing its sectional shape. It is concluded that the pseudo wide beam is adequate in the SRC column-RC beam joint not only for its structural capacities but also for its economic merits.

비대칭 단면을 가지는 매입형 합성기둥의 압축-휨 강도 평가에 대한 실무적 접근 방법

김경태,설동현,김종호 대한건축학회 2023 대한건축학회논문집 Vol.39 No.4

In the process of embedding a steel column in an excavated hole during the top-down construction, it often occurs that the geometric centerof the encased column and the center of the steel core is misaligned. In the case of an asymmetric composite section where the steel is notin the center, the compression-bending strength is different due to the effect of eccentricity, but there is not much data that engineers canrefer to. Based on the design formulae for symmetric composite sections provided in the current KSSC Composite Structural Manual, in orderto reflect the effect of asymmetric sections, this paper proposes to add points approximating the P-M interaction diagram and providesformulae for the axial forces and moments of each point. For verification, the error rate was reviewed for 200 cases of sections that dependon the amount of steel, column size, material strength, and eccentricity. As a result of examining the error, it was found that theunconservative error decreased as the eccentricity increased. This tendency can also be confirmed in the P-M interaction curve according tothe eccentricity of the example cross section. 탑다운 시공시 철골기둥을 매설하는 과정에서 합성기둥의 기하학적 중심과 철골 중심이 어긋나는 비대칭 합 성단면으로 시공된 경우, 편심의 영향을 고려하여 압축 휨강도를 다르게 고려해야 한다. 본 논문에서는 한 국강구조학회 합성구조매뉴얼에 제시된 대칭 합성단면의 설계식을 바탕으로 비대칭단면의 영향을 반영하기 위해 P-M 상호 곡선의 근사점을 추가하는 방안을 제안하고 각 축력과 모멘트에 대한 식을 제공한다. 검증 을 위해 편심 0, 50, 100, 150mm 일 때 제안된 방법을 통해 P-M 상호 곡선을 구하고 그 결과를 변형률 적합법과 비교하였다. 그 결과 편심이 커질수록 P-M 상호작용 곡선이 이동하며 두 결과의 값이 유사해지는 것을 확인할 수 있었다. 제안식을 검증하기 위해 실무 예제에 대한 계산 과정을 논문에 기술하였다.