Friday, July 15, 2011

Deck Design Do's and Don't's: Part 2

For Part 2 (click here for Part 1) of Deck Design Do's and Don't's, I want to address guard post attachments.  Based on research at Virginia Tech, we now know that typical attachments used in deck construction do not meet code required design loads.  One such instance can be seen in the picture below. 

The 4x4 post has been notched and nailed to the exterior rimboard of the deck.  As you can see, the nails in the thin portion of the member have created a split in the wood along the grain.  Similar notched and un-notched connections with bolts also fail to meet the code design loads.  

Use of hold-down anchor brackets, as shown in the picture below, are required to be installed at guard posts to meet the design loads.  The primary method of failure for typical bolted connections stems from the rotation created in the rimboard.  The rimboard attachment to the joists must support that rotation.  Hold-down anchors provide a means of transferring the load out of the rimboard and into the floor system.  

Photo Courtesy of Simpson Strong-tie.
For more information on deck design, including links to deck design guides, you can look at my previous post here.  For more information about guard post connections you can look here for details and here for design.   

Wednesday, July 6, 2011

2010 Wood Handbook

The Forest Products Laboratory (FPL) has recently released the printed edition of the 2010 Wood Handbook: Wood as an Engineering Material.  While you can download the entire book from the FPL website (see below), I encourage anyone serious about wood design to buy the printed edition as a desk reference.  At a cost of $60, this may be one of the least expensive engineering reference books you will find. 

If you are looking for a textbook on wood design, such as how to design beams, etc., this is not the book for you.  (I would recommend Design of Wood Structures by Breyer, Fridley,  This book focuses on the physical and mechanical properties of wood and wood composites and provides information on wood preservation, fastening, finishing, and adhesives.  

This is taken from the FPL website:

The Wood Handbook is one of the most widely used documents in the wood literature. The 2010 edition is the first update of the 21st century and includes several new chapters. The original handbook was first published in 1935 by the USDA Forest Products Laboratory (FPL).
The Forest Products Society (FPS) is pleased to cooperate with the FPL to present this newly updated edition in hard copy. This 2010 edition is your one-stop source for information on wood as an engineering material and offers content such as:

• Properties of wood and wood-based products
• Design information for architects and engineers
• Wood and non-wood composites
• Wood-moisture relationships and wood durability NEW CONTENT on:
• Wood as an environmentally responsible, sustainable building material
• Heat-treating and sterilization procedures for wood infected by invasive insect species
• A special COLOR chapter on low-magnification micrographs of cross sections of commercial wood species

You can order your hard copy of the 2010 Wood Handbook here or you can download content or sample the material that is in the book here.