STRUCTURAL MODELLING AND VERIFICATION METHODS TO DEVELOP A CABLE ROOF HARNESS RETROFIT SYSTEM

摘要

Load paths in light-frame wood structures have historically been nailed connections between the sheathing and rafters, and toenail connections between the rafters and stud walls. However, these connections have poor resistance to uplifting forces, as occurs in high wind speed events, causing sheathing or roof-to-wall-connection (RTWC) failures. The improvements made to building codes after Hurricane Andrew affected only new construction, and the economic losses caused by roof failures in homes built prior to 1993 from Hurricane Katrina pointed to a need to retrofit older structures. This paper will investigate the design, analysis, and testing of a temporary cable-netting roof harness as an alternative to relatively expensive and invasive retrofitting options. To do this, a non-linear finite element analysis (FEA) is performed to model a typical light-frame wood structure with the roof harness, which is then validated through test results. After, as a comparative study, scaled down versions of the structure with and without the roof harness are created and tested using real wind load until failure at the WindEEE facility. This is done to assess the efficacy of the retrofit system. Corresponding FEA and computational fluid dynamics (CFD) models are then created to simulate the test.