TR151: Geometry-Based Modeling and Simulation of Construction Processes

This research describes a new approach for modeling and simulation of construction processes based on geometric models and techniques. Currently, there is an inadequate support for modeling the spatial aspects of construction operations, evaluation of alternative process plans and visualizing the results directly. Using geometric techniques to generalize and increase applicability of the conceptual process models, this research contributes a process modeling and simulation approach and the geometric techniques to support it.

This process modeling and simulation approach, called GPM, models the conversions in construction processes as sequences of crews acting on geometric work locations. It uses a simple process description: work locations are processed by crews. It describes a crew model that includes a workflow strategy and a production rate function. The workflow strategy specifies in what order crews plan to perform their scope of work. The production rate function specifies at what rate crews can perform work at a specific work location at a specific time instant. A set of crews acting on work locations in a bounded space defines a subsystem. Coupling of a set of subsystems and considering the interactions between subsystems describes the complete process model. GPM uses discrete event simulation on queueing networks to obtain state trajectories for the geometric model and the crews performing work on the project. The system states provide automatic 4D and crew performance visualizations.

In GPM, geometry is not a static representational element, but an integral part of the process model. The geometric model, represented as triangle meshes, is a source for automated extraction of a number of constraints and interactions. The geometric techniques manipulate, reorganize and analyze the geometric model.

GSim is an implementation prototype for GPM. It implements the elements of the modeling and simulation approach, including the geometric techniques. It also provides user interfaces for parameter entry and visualizes the simulation results. Users can utilize 3D models to define subsystems interactively and evaluate alternatives easily by changing parameters and observing the results directly. I tested the research contributions on three construction projects. The research results provide improved modeling and simulation techniques for construction operations and more effective use of geometry for construction practice and research.