• Journal of the Korea Institute of Building Construction
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• v.6 no.2 s.20
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• pp.81-89
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• 2006

A down construction method is frequently used in these days to reduce popular discontent and to assure sufficient working space at early stage in downtown area. There are two main problems in the existing down construction method. One is a confliction between frame works and excavation works, and the other is a cold joint in retaining wall which is unavoidable due to a sequence of concrete placement and induces a water leakage. Therefore, a new method is needed to overcome these problems. The CWS (buried wale Continuous Wall System) method was developed by authors. By replacing RC perimeter beam with embedded steel wale, the steel frame works of substructure can be simplified and the water leakage can be prevented using continuous retaining wall. Consequently, the improved qualify and reduction of construction period can be obtained from CWS method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.1-4
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• 2006

A down construction method is frequently used in these days to reduce popular discontent and to assure sufficient working space at early stage in downtown area. There are two main problems in the existing down construction method. One is a confliction between frame works and excavation works, and the other is a cold joint in retaining wall which is unavoidable due to a sequence of concrete placement and induces a water leakage. Therefore, a new method is needed to overcome these problems. The CWS (buried wale Continuous Wall System) method was developed by authors. By replacing RC perimeter beam with embedded steel wale, the steel frame works of substructure can be simplified and the water leakage can be prevented using continuous retaining wall. Consequently, the improved duality and reduction of construction period can be obtained from CWS method.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.283-291
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• 2004

Recently, the construction of underwater structures has been gradually increased, but underwater concrete got some problems of quality deterioration and water contamination around cast-in-situ of construction. In addition, massive underwater structures such as LNG tank, underwater concrete structures of large and continuous high- strength subterranean wall under water are being demanded lower heat of hydration. In this paper, the mechanical properties of high-strength antiwashout underwater concrete (HAWC) containing with two kinds of mineral admixtures respectively were investigated. On the basis of these results, the pH value and suspended solids of HAWC manufactured in the mock-up test were 10.0$\Box$11.0 and 51 mg/${\iota}$ at 30 minutes later, respectively, initial and final setting time were about 30,37 hours, and the slump flow was 530$\pm$20Tm. In the placement at a speed of $27 m^3/hr$, there was no large difference in flowing velocity with or without reinforcing bar, and flowing slope was maintained at horizontal level. Compressive strength and elastic modulus of the cored specimen somewhat decreased as flowing distance was far; however, those of central area showed the highest value.