Schedule Quality Assessment for nD Models using Industry Foundation Classes

Schedule assessment models were created to ensure the proper development of a schedule. The checks can be categorized into scheduling-related and constructability reviews. Most of the existing automated models are targeted towards two-dimensional schedules, and not nth-dimensional, despite the emergence of building information modelling in the construction industry. The type, method and relations between stored temporal information for activities in nth-dimensional models differ than the typical two-dimensional schedules. Accordingly, this paper presents the adaptation of the existing schedule quality assessment criteria to evaluate nth-dimensional models, utilizing building information modelling and Industry Foundation Classes (IFC). The paper starts with a comprehensive review of previous assessment models, identifying the major checks performed, detailing out the needed activity information and evaluation techniques. The checks are then categorized as quantifiable and qualitative, to differentiate between the measures that can be fully automated and others which would require expert intervention. Afterwards, the paper presents the methodology for attaining the inputs required for the quantitative measures in nD models. The methodology revolves around using IFC, as a standard data model for storing building and construction data. Accordingly, a technological review was conducted of the existing nD modelling software, to view the capabilities and limitations that could affect the development of a schedule assessment model. Initial Algorithms were developed to measure the wellness of schedule properties such as activity duration, criticality levels and accuracy of relationships. These developed algorithms were then verified by testing them versus different schedules with known errors.