Overview of Course Content
This course offers a buffet of topics often faced by wood design professionals, yet background data and references on the topics are not readily accessible. The first unit on Decay Processes, Design for Durability, and Insects that Attack Wood will address the science of wood decay, insects that attack wood, and design ideas to improve building durability.
In Wood Shrinkage Issues in Construction, we will review published data on the relationship between shrinkage and moisture content (MC), how environmental humidity and temperature dictate the equilibrium moisture content of lumber, and demonstrate through examples how changes in MC can impact dimensional stability in wood framing and connections.
Structural lumber used in North America can be graded visually or by machine (MSR or MEL). In Lumber Grading Methods and Design Values, we will review the methods used to mechanically or visually grade lumber, how allowable stresses are derived from test data, safety factors for lumber, and how the outcomes of grading method affect the manufactured product. Updated lumber design values by the grading agencies will be summarized.
In Design of Built-Up Beams and Columns, we will present for designer consideration an adjustment factor for Emin to account for the reduction in variability of E when multiple plies of dimension lumber are constrained to deflect equally by proper design, detail, and installation. Example problems will demonstrate design efficiencies that can be gained.
In Glulam Beam Design, we will review how to size and specify glulam beams and present design examples for laterally supported and unsupported glulam beams with design checks for bending, shear and deflection (short- and long-term).
In Evaluating Structural Capacity of Fire-Exposed Timber Beams and Columns, a general procedure and rational calculation methodology for determining the residual structural capacity of fire-exposed timber beams and columns will be presented.
In Multiple-Bolt Wood Connection Design, participants will review a model code requirement through the NDS to check “local stresses” in multiple-bolt connections. Design methods offered in the NDS for calculating the additional failure modes for multiple-bolt connections due to “local stresses” will be demonstrated by calculations.
In Wood Truss Design Responsibilities, we will discuss the responsibilities of the Owner, Registered Design Professional or Building Designer, Contractor, Truss Design Engineer or Truss Designer, and Truss Manufacturer when metal-plateconnected wood trusses are utilized in a project. ANSI/TPI 1-2007 defines the various responsibilities for the parties involved in the use of MPC wood trusses. ANSI/TPI 1-2007 is referenced for MPC wood trusses in the 2009/12 IBC.
In Basics of Diaphragm and Shear Wall Design, we will present load path concepts and basic design methodologies for resisting lateral loads due to wind and seismic events. Examples will illustrate design of framing, panels, chords and tie-down anchorage. We will illustrate how to apply appropriate adjustment factors for Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) and discuss sources of design values for diaphragms/shear walls.
Post-frame buildings differ somewhat from typical light-frame wood construction with respect to framing member size and spacing, and often corrugated steel panels are used to sheath the buildings. In Post-Frame Building Design and Diaphragm/ Shear Wall Tests, we present a streamlined design method that follows the procedures used in light-frame wood diaphragms and shear walls. An example problem will be presented showing how to design the diaphragm, shear wall, sidewall posts and post embedment depth.
The unit on Creep of Solid-Sawn Joists, I-Joists, and MPC Floor Trusses will address the literature and recognized standards on methods to evaluate long term deflection of the three member types caused by long-term loads.
In Design Considerations for Preventing Flat Roof Failures from Gravity Loads or Sustained Live Loads, we will discuss the well-known problem area of the collapse of “flat-roofs” due to ponding and snow/ice accumulation. A rational design method for accounting for long-term deflection of MPC parallel-chord roof trusses will be demonstrated.
In Wood Truss Repair Design Techniques, the instructor will review his general approach to repair of roof and floor trusses to include documentation of the damage, data required for the repair, materials for the repairs, typical design values for the selected materials, and specifications for the materials to be used. A sample of two truss repair drawings will be discussed.
In Permanent Truss Bracing Design Basics, procedures for calculating required lateral bracing forces in webs and chords without sheathing (as for piggyback trusses and valley sets) will be presented.
While required by the 2009 IRC, the design of residential decks to resist lateral loads (wind, seismic, and occupant) had not been explored, documented, and published prior to 2009. In Lateral Design of Decks, we will illustrate how to apply the provisions of the ASCE 7 load standard to calculate wind and seismic loads on decks. The ASCE 7 load standard does not give guidance on how to determine lateral loads on decks caused by occupants. In part two of the unit, the results of laboratory tests of full-size decks at Washington State University will be presented. The subject decks were loaded by occupants under a variety of dynamic loading cases. Data and video of the testing will be shown.