A Study on safety improvement of Underground wall construction to Design for Safety

설계안전성검토를 통한 지하외벽공사의 안전개선 연구

Abstract

Safety-conscious design on site is required for site constructions because of the introduction of the design for safety, but it still leaves much to be desired. This study compared the site where the design was applied and the site where it was not applied. The applied case examined the underground wall construction during frame construction, which corresponds to the skeleton of the building construction. The underground wall construction is quite risky due to the exposure to exterior environments and involvement of various stages, such as scaffolding, formwork, reinforcing work, and concrete casting work. Therefore, the risk factors for each stage were identified and a risk assessment was carried out to select an alternative method to reduce the risk. The risk factors of the selected alternative construction method were also identified and a risk assessment was conducted. The risk assessment weight was calculated by comparing the site where the construction method was applied and the site where it was not, explaining the necessity of the design for safety in reducing the risk. In addition, an actual case where an alternative construction method was used was studied to highlight the necessity for a design for safety.

설계안전성검토 제도 도입으로 현장공사수행 시 안전을 고려한 설계를 도입해야하나 실제 현장에서 설계안전성검토를 적용하여 수행하기에는 아직 미흡한 점이 많다. 본 연구에서는 설계안전성검토를 적용하지 않은 현장과 적용을 한 현장을 비교연구하였다. 적용공종은 건축물공사의 뼈대에 해당되는 골조공사 중 지하외벽공사에 대하여 연구하였다. 지하외벽 공사는 대부분 작업 조건이 외부 환경에 노출되어 작업조건이 열악하고 작업단계도 비계공사, 거푸집공사, 철근공사, 콘크리트타설공사 등을 거쳐야 완성되므로 안전사고 위험요소가 매우 높은 공종이다. 이에 각단계별 위험요소를 도출하고 위험성평가를 실시하여 이를 저감하기 위한 대안공법을 선정하였다. 대안으로 선정된 공법의 위험요소를 도출하고 위험성평가를 실시하여 설계안전성검토 미적용현장과 적용현장을 비교하여 위험성평가 가중치를 산출하고 저감효과를 연구하여 설계안전성검토가 필요한 사유를 설명하였다. 또한, 대안으로 수립된 공법을 실제 적용한 사례를 연구하여설계안전성검토 필요성을 제시하였다.

Fig. 1. Group Interview career

Fig. 2. Risk assessment comparison before and after improvement

Fig. 3. Comparison of work steps before and after improvement

Fig. 4. MDW Reinforcement and formwork installation

Fig. 5. MDW unloading and installation

Fig. 6. MDW support and base anchor installation after MDW assembly

Fig. 7. MDW concrete pouring

Table 1. Risk Evaluation(4x4 Matrix)

Table 2. Project Description (Projcet No. 1)

Table 3. Risk Evaluation(risk by score)

Table 4. Scaffold construction risk assessment table

Table 5. Installation of retaining wall formwork, dismantling risk assessment

Table 6. Rebar installation risk assessment

Table 7. When pouring concrete Risk assessment

Table 8. Project Description (Projcet No. 2)

Table 9. Evaluation for Alternatives

Table 10. Risk assessment during MDW member entry and installation

Table 11. Risk Assessment of MDW Plate Reinforcement

Table 12. Risk assessment for MDW concrete pouring

Table 13. Comparison of risk assessment when existing quay exterior wall formwork and MDW improvement