Weather-Delay Simulation Model Based on Vertical Weather Profile for High-Rise Building Construction

Abstract

Severe weather can adversely affect the scheduling of construction projects. It is very important to be able to estimate the delay that would result from such severe weather because construction contracts generally differentiate between weather delays that can be anticipated and those that cannot. Only delays caused by abnormal and unforeseeable severe weather are granted a time extension. Normal and foreseeable weather delays in construction contracts are usually estimated as a monthly average of the severe weather days as determined from historical weather data, which are measured at the ground level. In high-rise building construction, however, this approach may be inappropriate because weather conditions generally vary with an increase in altitude and the height of high-rise buildings has become so great that those conditions can actually affect the construction of the upper floors. Therefore, weather delays estimated using this approach could be subject to this error. For such reasons, a simulation model capable of analyzing weather delays with consideration for altitudinal variations in the weather conditions is proposed for high-rise building construction projects. To achieve this goal, the literature addressing the types of weather variables, the threshold criteria causing weather delays, and the duration of weather delays was first reviewed. Then, a weather-generation model using a k-nearest neighbor time-series method and vertical weather profiles was developed to estimate the weather conditions at high altitudes. A simulation model was finally developed by integrating the weather generation model and a construction schedule simulation model by using a discrete event simulation method, and a case study was conducted to validate the results of weather delay estimation and to analyze the degree to which vertical weather variations affect the schedule of building construction projects. The contribution of this study is the proposal of a method based on a vertical weather profile that is capable of reasonably estimating weather delays in high-rise building constructions, and analyzing the pattern of weather delays in building construction projects.