Interaction Equation Values for Wood Truss Compression Chords Considering the Effects of Partial Composite Action
Abstract
A finite element, planar frame analysis is used in this study to analyze top chord (composite) members of common truss which have two layers fastened by flexible connections. A parametric study was conducted using the computer program LTRUSS (Layered TRUSS) to determine the effects of wood sheathing on the top chord members of wood trusses. This study is directed at determining the appropriateness of the 1986 National Design Specification for Wood Construction equation which allows for beam-columns to incorporate the effects of the attached sheathing and to provide information to allow for a more rational approach to account for the sheathing. Results of this study show that the current design provisions do not adequately account for the reduction of stresses realized in the composite members. The theoretically exact interaction equation for the beam-columns indicates that the loads allowed could sometimes be as great as four times what is currently allowed. Additionally, results show that truss span, connector spacing and stiffness, truss member dimensions, sheathing effective area and modulus of elasticity, and truss pitch all should be included in any equation to adequately represent the actual stiffness gained by the composite member.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1991
- Accession Number
- ADA245258
Entities
People
- Patrick J. Gibbons
Organizations
- University of Texas at Austin