PhD Oral Exam - Abdelhady Hosny, Building Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

As design complexity increases and clients demand faster deliveries, space is becoming a critical constraint affecting construction projects’ progress. Multiple activities involving heavy machinery and labor must be carried out simultaneously. When multiple activities require the same space at the same time, projects are subject to consequences ranging from delays and productivity losses to safety risks. Therefore, it is essential to implement appropriate workspace management practices throughout the duration of a project. Currently, industry practices for managing workspaces are exceedingly limited, whether they are performed manually or with existing 4D commercial software. Previously developed models for workspace management have failed to acquire traction in the market. Three critical gaps were identified: (i) the lack of considering temporal and spatial uncertainties during project planning; (ii) the absence of modelling the propagating effects of 4D clashes on schedule progress; and (iii) not accounting for the unpredictability of decisions made by crews involved in a workspace clash for resolving the clash. Additionally, the recent pandemic outbreak has exacerbated vulnerabilities with the need to implement physical distancing, which has created a new class of clashes – soft operational clashes. Where, opposing typical 4D operational hard clashes, soft clashes are a result of crews’ proximity to each other but do indicate a physical obstruction to continuing the works. Hence, having a physical distance space that behaves differently from typical operational space, and creates soft clashes has triggered the need to introduce physical distance as a new independent workspace and to redefine the clash detection rules implemented in previous works to capture the soft operational clashes.

In an effort to address the gaps cited above, this thesis presents the framework developed and the software tool deployed, adopting open BIM, for a comprehensive workspace management solution. Contributions to the body of knowledge can be summarized as: (i) simulating space as a probabilistic variable; (ii) automatically generating physical distance workspaces; (iii) smart clash detection identifying soft and operational clashes, while eliminating unrealistic and redundant results; (iv) automated clash resolution based on set priorities and heuristic rules; and (v) forecasting schedule variations from crews’ decision for handling unresolved clashes. A software tool was developed as well to handle the computational efforts. The tool utilizes Blender’s graphical user interface (GUI) and benefits from its open-source license and IfcOpenShell add-on that allow it to read Industry Foundation Classes (IFC) formats from any design authoring tool. Additionally, an application using C# language was developed to specify thresholds and view the simulation steps while operational. Using a simplified test model, 60 use cases were created to test the semantic rules and functionality of the method/software. With each test, the tool’s outputs were compared to manual calculations / using geometrical intersection tests (used in typical clash detection software) to verify the accuracy and the soundness of the logic. The tool achieved a 99% accuracy in clash detection and volume estimation. The work was also validated through two case studies. The first case study focused on labor workspaces for a residential project. The solution presented a 3-tier analysis showing 50% more clashes than stochastic simulation without physical distances and categorized the soft and operational clashes. The second case study simulated the refurbishment of an industrial plant during its shutdown. The solution presented 6,930 possibilities for the project completion resulting from the automated resolution and scenario planning of the clashes, recommending an 8% duration increase to achieve a 75% confidence level. The results were presented to industry experts for validating the reliability of the results and the method implemented. They acknowledged the benefits of the research in its current state, highlighting the ability to extend/adapt it to other domains.