Wind Uplift Resistance of Roof Edge Components

Abstract

A roof is a critical envelope of a building. It provides protection for the building interior against various weather elements, such as snow, rain and wind. Roofs are normally composed of several components such as insulation, barriers and water proofing membrane. A roof edge is the perimetric part of a roof that serves as termination for roof components. In generic terms, a roof edge system is composed of a parapet with metal components, such as coping and cleat/clip. The edge system is typically subjected to negative pressure (suction) due to wind flow over the roof. Therefore, a roof edge is the front-line of defence against wind action. To develop testing standards and design guidelines for roof edges, a project referred as REST (Roof Edge Systems and Technologies) has been initiated in cooperation with the NSERC (Natural Sciences and Engineering Research Council). For the REST project, this thesis contributes in two folds: wind design procedure and the development of an experimental method for testing roof edge components. The present thesis analyzes the wind load calculation procedures as per the National Building Code of Canada (NBCC) and American Society of Civil Engineers (ASCE). This has been achieved by taking side-by-side cities along Canada-USA border; wind load calculations were performed to demonstrate the differences and similarities between the NBCC and ASCE. As a part of the current contribution, the existing version of the online Wind-RCI Calculator was updated from NBCC2005 to NBCC2010 provisions. Towards the experimental contribution, the current study presents a new experimental method for testing and evaluating wind uplift resistance of roof edge systems by simulating wind loads in a lab environment on full-scale mock-ups. The test apparatus had a gust simulator device to mimic wind gusting (dynamic loading). This research investigates three widely used edge systems in North America: Continuous Cleat Configuration (CCC), Discontinuous Cleat Configuration (DCC) and Anchor Clip Configuration (ACC). Preliminary data show that CCC edge system has higher resistance in comparison to DCC and ACC edge systems. The experiments also revealed the need for experimental setup enhancement. Additional investigations by using the enhanced experimental setup were performed on both CCC and DCC edge systems.