A study on the performance of GI roof on wood purlins subjected to extreme wind loads

• Main Author: Lim, Sam Jovinson D.
• Format: text
• Language: English
• Published: Animo Repository 2015
• Subjects: Roofs—Aerodynamics; Civil Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6822
• Institution: De La Salle University

The Philippines is known to be within the "typhoon alley" or "typhoon Gateway". These typhoons are known as the main cause of the failures of the roofs of residential houses. Vulnerability of these structures is often the result of insufficient connection strength. Furthermore, in-situ connection strength are found to be lower compared to the resistance determined in numerical models. Therefore probability of roof failure of installed roofs is higher compared to the value estimated in the design calculations In light of the problem posed, there is therefore a need to ascertain the integrity of wind-sensitive structural elements of low-cost houses due to changes in the extreme wind speeds in the Philippines. One can find several strategies to this end such as (a) strengthen the structure by retrofitting or (b) modify or suggest a design standard to resist higher loads In this study, we take the latter strategy in solving the problem. By first assessing the strength of the roof fixtures via laboratory tests and comparing them with the theoretical models. There would be two types of tests conducted for the laboratory resistances, one would be the determination of withdrawal capacity of a single nail, while the other would be the withdrawal capacity of a roof panel. Tests would be done using the Universal Testing Machine (UTM) and using sand loading as dead weight for roof panels; the resistance capacity would be taken as the maximum load read until failure is observed. iii The analysis of wind loads to be used as the required wind loads to be resisted by the roof panels were acquired from three meteorological gathering devices, namely: PAGASA, Project NOAH and a self-installed instrument. The wind speeds gathered were analyzed using Generalized Extreme Value Theory to generate 50-yr return periods. Lastly, a design chart was showing the suggested set-up for purlin to G.I. roof connection, taking into account the specific gravity, nail embedment depth, nail size and nail spacing.