Design of an enhanced defect identification system for commercial building construction

Fairfax County of Virginia enforces the Virginia Uniform Statewide Building Code which contains the building regulations that must be complied with when constructing commercial buildings. Current inspection methods consist of inspectors physically searching for building defects with human vision while many defects ranging from structural cracks and loose nuts and bolts to inadequate sealant application and water damage go unnoticed due to varying factors such as limited line of sight and unavailability of safe access equipment. Human vision inspection procedures are also subject to additional deficiencies and complications during inspections of exterior defects as inspectors are often limited to inspect defects from the interior perimeter of the building, consequently compromising their safety and inspection quality. With an annual forecasted growth of 500,000 square feet of new construction each year, an enhanced commercial building inspection system for identifying exterior defects is in need. A stochastic simulation model was developed using distributions derived from time and motion studies to compare the time, safety, and accuracy of three design alternatives to collect, process, and analyze inspection data: (a) human vision inspection system, (b) manual use of automated defect identification system, and (c) aerial-based automated defect identification system. The design alternatives were ranked using a Multi-Attribute Utility Analysis as follows: (1) aerial-based automated defect identification system - 0.664, (2) manual use of automated defect identification system - 0.567, and (2) human vision inspection system - 0.443; the aerial-based automated defect identification system achieved a high utility score based on its improvements in inspection time, safety, and accuracy.