Wind-Loading Effects on Roof-to-Wall Connections of Timber Residential Buildings: Fid-Bau Portal

Wind-Loading Effects on Roof-to-Wall Connections of Timber Residential Buildings

Chowdhury, Arindam Gan / Canino, Iván / Mirmiran, Amir / Suksawang, Nakin / Baheru, Thomas

Abstract

Extensive damage to residential wood-frame buildings caused by failures of roof-to-wall connections during extreme wind events underscores the need to improve their performance. Most of these connections use mechanical connectors, e.g., metal clips and straps (sometimes referred to as hurricane clips and hurricane straps). The allowable capacity of these connectors is based on results of unidirectional component tests that do not simulate multiaxial aerodynamic loading effects induced by high wind events. The objective of this research was to facilitate a better understanding of these loading effects on roof-to-wall connections of a typical low-rise gable roof residential structure subjected to combined impacts of wind and a potential breach of the building envelope. Large-scale experiments on a heavily instrumented building model generated multiaxial aerodynamic loading data on roof-to-wall connections for various wind angles of attack and internal pressure conditions. The results showed the severity of increased loading on connections in certain configurations of wall openings that could occur from the breach of the building envelope in windstorms. It was also shown that lateral components of the wind load acting simultaneously with the uplift may be significant, depending on wind angles of attack and internal pressure conditions. Aerodynamic test data were used to perform component-level triaxial-load testing on hurricane clips to determine their load capacities and compare results to those obtained using the traditional approach of uniaxial-load testing. Component level test results showed that current uniaxial testing methods tend to overestimate the actual load capacities of metal connectors. Neglecting triaxial loading effects in testing of connectors and in the design of connections could potentially cause the type of failures frequently documented in hurricane damage reconnaissance reports.