不確定事象と計画修正機能を有する施工モデルの表現方法

施工シミュレーションモデルに関する研究

抄録

 1.Introduction

 In the construction process, as there are many uncertain events, such as weather, ground condition, and work productivity, construction works could rarely progress according to the plan which has been made before the construction.

 In this paper, the author proposed the methodologies of modeling uncertain events and a plan modification function in the construction process model and developed a proto-type system, then the author clarified that the validity of methodologies by applying them through the implementation to a case study.

 2. Uncertain Events and Plan Modification

 To simulate uncertain events at a construction site, we usually investigate only the influences on the completion period and the productivity of activities. However, in an actual construction project, when the delay has occurred, it would be made up by modifying the plan so that the delay would rarely last till the completion time.

 3. Modeling Uncertain Events

 The uncertainty of weather has specific seasonal trends, so the weather should be considered as time serial data. The uncertain weather is modeled by the event “SiteWeather” with the attributes such as the rainfall and wind speed. The uncertain weather is modeled using the past twenty-three-year weather records published by the Meteorological Agency, Japan.

 The uncertainties regarding activities, resources, and spaces are represented as the uncertain attribute values, such as duration and workforce, which are generated using probabilistic random values.

 4. Modeling for Plan Modification

 In the case that any delays and defects are recognized in the construction process, the initial construction plan should be modified to recover them. The plan node modifies the plan by changing the activity sequences or activity contents such as work methods and input resources.

 The alternative processes to be applied are modeled into a plan node frame in a construction process model. As the construction process model includes multiple alternatives, it is possible to make up for the delay by selecting the suitable alternative. Thus, using the alternative, the project with uncertain events can be completed within the mandatory period in simulation.

 5. A Case Study of Simulation

 A building used in a case study of simulation is an eight-storied apartment house with a floor area of about eight thousand square meters, which has been built using pre-cast concrete components.

 The following three factors in simulation that affect the construction progress are: (1) uncertain duration of each activity, (2) uncertain weather, and (3) plan modification. The author investigated the four cases of simulations to clarify the properties of these uncertain events and the effects of plan modifications to be adopted for the delay.

 The results of simulation case studies showed that construction period simulated using the average duration of each activity turned out to be shorter than the period obtained by simulation using uncertain events. Even if there are many uncertain events in the construction process, it is not so difficult to ensure the mandatory construction period by monitoring the difference between the target time and the actual time of each work and by adopting the suitable alternatives in later construction process.

 6. Conclusion

 Through a case study, author analyzed the impacts of uncertain events on the construction progress and clarified the effects of the plan modification function. The author confirmed that the methodologies which are proposed for modeling methods should be competent to make robust the planning of construction project which has many uncertain events.