Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Civil and Environmental Engineering

Supervisor

Dr. Gregory A. Kopp

Abstract

A typical wood frame house roof consists of trusses which are nailed to the top-plates of the wall assembly. These are known as roof-to-wall connections (RTWCs). A load-sharing mechanism is developed between adjacent RTWCs via roof elements such as roof-sheathing, fascia beams, etc., during high wind loads. An experimental setup was developed to observe the load-sharing behavior between seven connections. To mimic the roof bending stiffness in the direction perpendicular to the trusses, two steel beams with representative bending stiffness were connected across the RTWCs in a simple way. Identical ramp and identical fluctuating wind loads were applied to all the connections simultaneously. Two types of beams were used for these loading types. The bending stiffness of the stiffer beams is four times higher than the bending stiffness of the less stiff beams. Individual RTWCs were also subjected to identical ramp and fluctuating wind loads to define the load-displacement behavior of toe-nail connections and to make comparisons with the results found from the RTWCs of the systems. From the tests conducted it was found that individual connections displacement variability for the same applied loads is reduced by the system (i.e., beams) due to load-sharing between the connections through the beams. Load-sharing is greatest during the short duration, damaging peak loads. Load-sharing changes and increases continuously with the permanent displacements during damaging peak loads. Due to higher flexural rigidity of the stiffer beams, load-sharing or load re-distribution is higher between the RTWCs than for the less stiff beams.

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