Formalizing Construction Sequencing Constraints for Rapid Generation of Schedule Alternatives

摘要：施工计划人员通常依靠基于CPM（关键路径法）的进度计划来安排和协调项目中多个专业的工作。在一个项目的过程中，规划者经常需要修改活动顺序，以满足不断变化的需求。特别是，规划人员需要协调往往在有限时间内工作的多个行业，以确保达到中间里程碑，并及时安装组件，以最大限度地提高后续工作的工作流程。为了确定各行业工作的适当活动顺序，规划者需要开发和评估不同的排序方案。在制定排序备选方案时，规划者需要确定一项活动对后续活动的物理或技术影响或“作用”。他们还需要确定哪些活动可以或不可以推迟。区分角色和“地位”（即，一项活动是否可能被推迟）反过来又要求规划者理解活动之间制约的理由和灵活性。然而，当前的CPM框架仅使用优先关系（例如，FS、SS等）。此外，现有的进度加速技术，如时间-成本权衡假设活动顺序是固定的，因此不适用于开发排序替代方案。因此，使用基于CPM的时间表识别和开发测序替代方案目前是一个容易出错且耗时的过程。本研究的预期贡献集中在CPM时间表中的约束的合理性和灵活性的形式化，并利用这种形式化的表示来确定活动的角色和状态。这项工作应使施工规划人员能够正确和快速地确定和开发排序方案，这反过来又有助于减少完成已建设施的时间和成本。

Abstract: Construction planners typically rely on CPM (Critical Path Method) based schedules to schedule and coordinate the work of the multiple disciplines on a project. During the course of a project, planners frequently need to modify activity sequences to meet changing demands. In particular, planners need to coordinate multiple trades often working in limited workspaces to ensure that intermediate milestones are met and that components are installed in a timely manner to maximize the workflow of follow-on work. To determine an appropriate sequence of activities for trades to work, planners need to develop and evaluate different sequencing alternatives. When developing sequencing alternatives, planners need to determine the physical or technical impact or "role" an activity has on following activities. They also need to determine which activities may or may not be delayed. Distinguishing the role and "status" (i.e., whether an activity may be delayed) of activities in turn requires planners to understand the rationale and flexibility of constraints between activities. However, the current CPM framework only represents the temporal aspect of constraints using precedence relationships (e.g., FS, SS etc.). In addition, existing schedule acceleration techniques such as time-cost trade-off assume that activity sequences are fixed and hence are not applicable for developing sequencing alternatives. Consequently, identifying and developing sequencing alternatives using CPM-based schedules is currently an error-prone and time-consuming process. The anticipated contributions of this research focus on formalizing the rationale and flexibility of constraints in CPM schedules and on leveraging such a formalized representation to determine the role and status of activities. This work should enable construction planners to identify and develop sequencing alternatives correctly and rapidly, which in turn should help reduce the time and cost to complete constructed facility.