BASIC STUDY ON THE ESTIMATION OF THE MAN-HOUR RATE FOR OFF-SITE CONSTRUCTION MANAGEMENT

A case study of construction project of collective housing

Abstract

 This study aims to estimate the man-hour rate of construction management that can be performed in off-site.

 In Japan, shortages labor due to a decrease in the working-age population is becoming obvious, so improvement of productivity is pointed out as an issue in the construction industry. Construction management activities are becoming more efficient, but it has remained in the incremental improvement in many cases and not yet to achieve a radical review, called BPR (Business Process Re-engineering).

 There is the idea called shared services that is one idea of the BPR. Shared services are the internal service provider that to perform the specific operational tasks such as an accounting operations and human resource management.

 By applying shared services, it is possible to perform activities intensively and efficiently in specific department that is being performed in separate departments.

 

 Most of the construction management activities are characterized that being performed by each site. For this reason, drastic improvement of activities can be achieved by introducing shared services concept.

 Thus, this study estimated the man-hour rate that can be performed in off-site. In this study, we utilize the activity data that is revealed by the process chart method, which is one of the methods of Industrial Engineering. The data includes the name of 436 activities and the man-hour rate. Though it is not in a statistically significant because of the data from a single site, the data is valuable that records the activities that is performed from before construction to after completion.

 

 There are various factors of constrains in off-site management. In this study, it was classified into physical constraints and operational characteristics of activities.

 Classification of physical constraints were determined by whether the activity contains a task that must be performed in the field or not. And classification of constraints by possibility of standardization were classified activities into highly specialized, specialized, and non-specialized. The activities except for the “highly specialized”, can be standardized.

 

 The result of the classification based on the two constraints, it was found that 216 activities (man-hour rate:28.4%) can be performed in off-site. Because of the man-hour rate accounts for a large proportion, it has been suggested that introducing shared services can contribute to improve the productivity in the construction management activities.