PARTICULARITIES AND CAUSES OF GREY DEFECTS IN CONSTRUCTION PROJECT WITH MULTIPLE PRIME CONTRACTS: A CASE STUDY OF BHUMISIRI MANGKHALANUSORN BUILDING KING CHULALONGKORN MEMORIAL HOSPITAL
Abstract:
Bhumisiri Mangkhalanusorn Building King Chulalongkorn Memorial Hospital Project is a mega project with multiple prime contracts. During project close-out period, there were conflicts between the contractors in term of defect liability called grey defects, lead to the delay of the move-in process. This research aims to study the particularities of grey defects and their causes, studying 887 grey defects found in the practical complete commissioning of inpatient wards. The data were collected by accumulating documents, participating as a conference observer and inquiring project personnel. Data analysis were implemented by matrix data analysis and cause and effect diagram. As a result, there are 3 types of grey defects impairment namely disappearance, flaws and location errors. More than half of grey defects are disappearance, following by flaw. Lastly, location errors were found the least. Grey defects can be categorized based on location in 5 types namely doors or windows, ceiling, floor, wall or column and furniture or equipment. The grey defects were found on furniture or equipment the most, following by door or windows, wall or column, ceiling, and floor. Grey defects can be sorted by architectural systems intersection at the incident point in 2 types namely grey defect with architectural system intersection and grey defect without architectural system intersection. According to the analysis of the relationship between impairment types and architectural systems intersection, found that difference of impairment tends to relate to different architectural systems intersection; Majority of grey defects of disappearance occurred at the point where architectural systems intersect each other, on the contrary, the majority of grey defects of the flaw were not. On the other hand, Location error occurred where architectural systems intersect each other only. Referring to cause analysis, the causes of the grey defect are categorized in 8 groups namely effects from others activities, construction worker error, documents error, impairment of audit and control, lack of personnel, construction procedure, lack of site management and design error. After arranged the causes in order, found the difference of impairment is directly related to the root causes of the grey defect. As refer to causes analysis, root causes of grey defects are categorized in 6 types namely documents error, impairment of audit and control, lack of personnel, construction procedure, lack of site management and design error. This research result indicates the importance of project management, construction management, and design since during construction period continuously affecting to project close-out. This study is a beneficial lesson preventing the problems.