Truss Bracing: A Framers Perspective
What is truss bracing? If you have been staying up to date on our blog articles you should have a pretty solid understanding of what truss bracing is and what it does from the perspective of the designer. But if you haven’t, here is a quick recap: Truss bracing is additional, field installed, bracing that is specified by the design software to reinforce specific webs that need extra support to meet the loading and design requirements of the job.
What we are referring to are web braces which are typically displayed as the symbol shown below:
A system of trusses may also require additional “bracing” specified by the EOR (Engineer of Record) such as gable bracing like this:
These details are typically found in the structural plans, and as a framer these are the easiest details to find and install, since they are related to nailing requirements and necessary hardware and clips that should be installed in order to satisfy shear transfer and drag loads. These are also the easiest pieces of reference for the building inspector to identify.
Bright, shiny clips and straps have a way of standing out against wood on a job site. Much more so than additional wood on top of the many directions of webs in a truss system like this:
These pesky braces tend to be the most misunderstood and overlooked part of installing a truss system when it comes to completing a job, especially if the crew doing the work and the building inspector don’t know what they are looking for. When the trusses are delivered they leave behind a packet of paper that can be hundreds of pages with a layout on top. The layout is often peeled off and used for proper placement of the various trusses, but the rest of the packet showing the truss profiles and required web bracing is tossed aside and possibly not looked at again.
After all, who wants to shuffle through a couple hundred pages of paper looking for a few bracing symbols when you are trying to complete a job? Most of the time not every truss requires web bracing. One method I use is to spend the time sorting through the packet provided for the truss package in the comfort of my office and highlighting the truss bracing on every truss that needs web bracing. I also highlight the trusses on the layout that bracing must be applied to.
Only the highlighted layout and the truss profiles that require bracing are copied and sent to the job foreman as a supplemental packet to the entire bundle that is delivered to the job. This way my foreman has streamlined information that I have called specific attention to. With work on tract subdivision work I only have to do this once to make a master copy, I keep it in a binder along with other important information I want the foreman to be aware of and send it every time we build that plan and elevation. I understand how critical the truss bracing is and by doing this I have found that it actually get applied in the field!!!
Now as a framer, there tends to be a bias that once the truss design is complete and the truss calc package makes it to your hands it is set in stone, unless there is an error or repair necessary. However I like to review the truss calcs and work with the truss designer to eliminate as much bracing as possible to minimize missing bracing in the field.
Many times flipping a web or upgrading the web lumber can eliminate many of the braces that are specified through system default design without the designer spending much time on it. Revisions can be resubmitted to the EOR or city so everyone has the correct information. Often times just being able to provide a copy of the revised truss to the inspector on the job is enough.
Many times when bidding on a job, the approved truss supplier has not completed the truss design yet, so it is difficult to bid out truss bracing when I have no idea how many/what type are required. So paying attention to the total footage of lumber needed to complete the roof is very critical to being in budget. If the truss design is calling for hundreds of feet of bracing more than I have budgeted, you better believe the designers are going to be spending some time on the phone.
At the end of the day, primary goal in every design is to provide cost conscious solution to the customer, while providing a “framer friendly” solution to the end-user.
What are some of the ways you ensure your team understands and installs bracing correctly?