Date of Award

5-2004

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Habib J. Dagher

Second Committee Member

William G. Davids

Third Committee Member

Eric Landis

Abstract

After the Northridge Earthquake in 1994, the most expensive natural disaster in United States history, more than 25,000 dwellings were rendered uninhabitable. In 1992, approximately 25 percent of insurance losses from Hurricane Andrew were attributed to residential construction that failed to meet code requirements. Given that wood construction represents the vast majority of residential buildings, improving the seismic and high wind survivability of wood frame housing is an important area of research.

A team of researchers at the Advanced Engineered Wood Composites Center at the University of Maine has developed Advanced Oriented Strand Board (AOSB) sheathing that has a fiber reinforced plastic (FRP) layer around the edges of the panel to improves the fastener holding capacity of the sheathing. Previous research at the University of Maine had showed that the strength of AOSB sheathed walls was limited by the strength of framing lumber, the pullout resistance of nails, and the poor performance of overturning restraints. The objective of this research is to engineer a prefabricated structural subcomponent with better fasteners, high strength tie downs, and engineered lumber framing to optimize the performance of AOSB. The result is SuperWall, a high performance prefabricated narrow (4:1 aspect ratio) shear wall.

Single fastener connection tests were performed that establish that collated wood screws had the tensile strength and withdrawal resistance to develop the full capacity of AOSB. Threaded rods glued axially in the tension and compression chords were used as foundation restraints (tie downs). These glued rods used an innovative epoxy confinement system to increase their pull out strength. Two walls were loaded monotonically to failure and a total of seven walls were subject to a simulated earthquake loading using the CUREE cyclic displacement protocol. SuperWall was found to be as strong as a wall with four times the length and held load to greater displacements. Design allowable shear values were calculated according to AC 130, Acceptance Criteria for Prefabricated Wood Shear Panels. A finite element model of the narrow wall was also developed to aid further design of SuperWall.

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