Installation

In Pursuit of a Better Performing Truss

When it comes to getting the right structural building components for a project, cost isn’t everything, but how do you convince the building designer? Communication is key.

Trusses with a Twist

Woodhaven designed and built the roof and floor trusses for the Spruce Street Shul. Woodhaven also supplied the lumber and hardware for the project.

The Turnkey Movement Is Here

  • Inadequate communication can fragment the various trades working on a project and lead to costly mistakes and frustrating delays.
  • GCs are looking to turnkey framing as a way to minimize that fragmentation and reduce waste and the potential for mistakes.
  • The efficiencies of the turnkey approach with componentized framing make it the best solution going forward.

Bracing Options for Webs Revisited

  • The following Technical Q&A has been updated from the version that appeared in the 2006 June/July issue of SBC.  
  • Lateral restraints are installed to reduce the buckling length of the web(s), but must be restrained laterally to prevent the webs to which they are attached from buckling together in the same direction.
  • BCSI-B3, Permanent Restraint/Bracing of Chords and Web Members, provides general industry recommendations and methods for restraining web members against buckling.

Isolated Testing Helps Understanding of Heel Height Load Paths: Downstream Improvements Probable

  • Couple the IRC requirements with energy code requirements that are pushing more buildings to utilize a higher heel, and it is apparent the connection of high heels to walls is a key application issue.
  • The SBC Industry Testing Task Group and the TPI TAC/SBCA E&T Testing Review and Vetting Group has begun to evaluate the needs and priority of testing the performance of assemblies to quantify the effect of heel blocking. 
  • It is clear from the very specific and isolated heel height testing already performed that there is an opportunity to provide revisions to 2009 and 2012 model code blocking requirements to transfer the lateral load resulting from wind and seismic events into braced wall lines.

Connecting Wood Trusses to Braced Wall Panels

  • The 2012 IRC does not provide sufficient details on how to connect wood trusses to braced wall panels.
  • SBCA has developed a couple of details and will continue to develop standard details that provide code-compliant connections between roof/floor trusses and braced wall panels.
  • Component manufacturers can provide framers with specialty or standardized blocking panel products to reduce the time needed to install the blocking between trusses for these connections.

 

Installation & Fastening of Wood Structural Panel Wall Bracing

  • Use of galvanized box nails may result in shear walls with a shear capacity significantly below the nominal unit shear capacities given in SDPWS.
  • Thus, the majority of WSP shear walls have a shear capacity with a high degree of design value variability. This may have unintended consequences that are unknown and unappreciated by the professional engineering and/or building design community.
  • Once SBCA and SBCRI were certain their testing and engineering analysis was consistent and repeatable, they were persistent in bringing all WSP shear wall performance issues to the attention of APA, AWC, ICC-ES and ICC.  

Field Splices

  • Field splices provide a means of connecting two truss sections together creatively at the jobsite, to allow manufacturing, shipping and installation greater flexibility in serving customer needs.
  • A field-spliced truss should be designed as one component so that the proper load transfers at the splice.
  • Correct installation is important to avoid increased deflection of the field-spliced truss and potential long-term serviceability problems.

Embrace the City Slicker in You: Capitalizing on the Growth of Urban Living

If you do a web search for current trends in U.S. urban planning, article after article will discuss similar issues. Urban planners face new challenges as a result of the recent economic downturn, and subsequent sluggish growth. A few examples include: a higher percentage of renters over owners due to foreclosures and defaults; delayed housing purchases by Generation Y; a growing desire for alternative transportation choices and shorter commutes; all coupled with a decreasing availability of urban land.

Parting Shots

In case you ever needed a picture to define the importance of diagonal bracing in the context of lateral restraint (i.e., top chord purlins as well), these photos of long span trusses say it all.