Metal-plate-connected wood trusses with semi-rigid joints were investigated by the matrix method of structural analysis. The element-stiffness matrix and fixed-end forces of an individual member with one or both ends semi-rigid were derived as modifications of the idealized cases. The case of unequal elastic connections at two ends of a...
Probability density functions (normal, lognormal, and three-parameter Weibull) were used to characterize strength data for three different types of metal-plate-connected wood truss joints (web at the bottom chord, tension splice, and heel). Modulus of elasticity (MOE) of the lumber used to fabricate the joints was also characterized. A probability-plot technique,...
The focus of this research is to develop a prototype
expert system for softwood lumber grading. The grading
rules used in the knowledge base of the system are based on
Western Lumber Grading Rules 88 published by the Western
Wood Products Association. The system includes 27 grades
in Dimension, Select/Finish,...
In order to describe long term creep behavior of structural lumber in a natural
environment, a bending test with twenty Douglas-Fir beams subjected to a constant
load was set up in an open shed in the Forest Research Laboratory at Oregon State
University. Deflections of the beams were measured along...
A commercially available, three-dimensional (3-D) finite-element (FE) analysis
program was used to model metal-plate-connected (MPC) joints in wooden trusses.
The model's features included consideration of material properties, teeth-to-grain-to-direction-
of-force orientation, and wood-to-wood contact. Non-linear spring elements,
placed on the wood surface between wood and plate, were used to represent wood-to-teeth...
The objectives of this research were to evaluate the
behavior of actual metal-plate-connected (MPC) tension-splice
and heel wood truss joints under seismic loads from the
Northridge earthquake (tension-splice joints only) and under
loads from a large artificial earthquake (1.0 g's and 0.67
g's maximum horizontal and vertical accelerations,
respectively). A...
"This publication has presented an overview of current research on MPC joints in wood trusses. The literature search was primarily of U.S. sources, with some effort to obtain literature from other parts of the world. An enormous amount of important information has been amassed by studies on testing procedures and...
Five different test methods to determine the parallel-to-grain shear
strength of Douglas-fir structural lumber were compared. Four methods
assessed the shear strength of lumber sections having a full nominal two by
four inch cross-section. These were: three-point bending, four-point bending,
five-point bending, and torsion. The fifth method was the ASTM...
A commercially available, three-dimensional finite-element analysis software was used to model the load-displacement
behavior of metal-plate-connected (MPC) joints in wooden trusses. Model features included consideration
of material properties, teeth-to-grain-to-direction-of-force orientation, wood-to-wood interaction, and gaps between wood
members. To simulate wood-to-plate interaction, the main feature of the model, each tooth of...
The objective of this study was to test a method under development for assigning allowable properties to foreign species graded by American Lumber Standard machine-stress-rated (MSR) rules. The method was tested on dahurian larch (Larix dahurica), a major softwood species that grows in the Russian Far East and could be...
Metal-plate-connected (MPC) trusses have traditionally been designed based on a
tributary load distribution and a simplified truss model. This design method ignores the
load-sharing and composite action in MPC roof truss systems, the semi-rigidity of MPC
joints, and joint eccentricity.
The main objective of this study was to provide a...
The torsion test was evaluated as a method for determining the shear
strength of full-size structural lumber. The evaluation involved an experimental
length study, an experimental depth study, and a finite element study.
The length study consisted of fifty nominal 2x4 specimens, ten specimens
for each length, and ten American...
The objective of this research was to develop a one-third scale model of full-size
(prototype) metal-plate-connected (MPC) wood truss joints using similitude theory. The
prototype metal connector plates in MPC joints were modeled using thin galvanized sheet
metal and short staples. Truss grade wood material was ripped to one-third scale...
The objective of this research is to understand the behavior of metal-plate-
connected (MPC) joints by examining actual MPC truss heel and tension
splice joints subjected to hurricane wind load simulations and impact loads.
A hurricane wind load simulation was applied to MPC heel joints to
determine if a large...
The objective of this research was to evaluate the duration of load factor for
metal-plate-connected (MPC) truss joints subjected to various cyclic loading conditions.
Heel and tension-splice joints from a standard 30-foot span Fink truss constructed from
nominal 2x4 Douglas-fir lumber were tested. A testing frame similar to that developed...
This study evaluated the effects of pretreatment incising of dry lumber and preservative treatment on the shear strength of 1980 pieces of 2 X 4 dimension lumber (nominal 50 mm X 100 mm X 3.6 m long). Three species groups (Douglas-fir, Hem-Fir. and Spruce-Pine-Fir-South) and two commercially produced machine-stress-rated grades...