Introducing the Joist Hanger Selector Web App

Designing buildings and dealing with construction has always been a satisfying career for me. It is challenging to design a complete structural system, coordinate with the other consultants and create a clear set of construction documents for the contractor. Throughout my career, I’ve occasionally had a few panicked “Uh oh!” moments. I hope I’m not alone in admitting those happen. These typically occur far away from work when something prompts me to think about a project. I might see concrete being placed, then question whether I remembered to change the reinforcing callout on a mat slab I had just designed. I can’t stop thinking about it until I get back in the office to check.

I had an “Uh oh!” moment a few days after I started work at Simpson Strong-Tie. We have a training plan I call Catalog 101 where new engineers meet with each engineer who is an expert for a given product line. After I had met with our experts on holdowns, concrete anchors and engineered wood products, it was on to top-flange hangers (and my “Uh oh!” moment).

Catalog 101

We really do call it Catalog 101

After learning a lot of things I didn’t know about hangers, we moved on to available options for some of our top-flange hangers – sloped, skewed, sloped and skewed, sloped top-flange, and offset top-flange. I learned that some hanger options get full load, some have small reductions and others large reductions. For example, the GLT with an offset top-flange gets 50% of the table load.

GLT/HGLT hanger options section of Wood Construction Connectors Catalog, C-2013

GLT/HGLT hanger options section of Wood Construction Connectors Catalog, C-2013

“Uh oh!”

I had recently designed a project and specified a bunch of GLT hangers with offset top-flanges. I hadn’t noticed there was a reduction for this modification; I just thought it was really cool that Simpson Strong-Tie had a hanger that worked at the end of a beam. Minor panic set in until I could check my calculations. Fortunately, the beams at the framing conditions that required offset hangers had half the load of the typical beams, so the hanger was okay even with the load reduction.

Hanger Option Matrix from Wood Construction Connectors Catalog, C-2013

Hanger Option Matrix from Wood Construction Connectors Catalog, C-2013

The Wood Construction Connectors Catalog has a Hanger Options Matrix that makes it relatively simple to see which options – sloped, skewed, concealed, welded – are available for each hanger. The pages following the options matrix have more detailed information about size restrictions and load reductions associated with each option. It can be somewhat tedious to sift through all of the options and apply the reduction factors, so I always recommend using the Simpson Strong-Tie Connector Selector® software to do the work for you.

Connector Selector

Connector Selector

Connector Selector software allows you to input you geometry and loads and returns a list of connectors that meet those requirements, including any reductions due to modifications. Connector Selector is a desktop application, which needs to be downloaded and installed on your PC. Engineers have indicated they like the functionality of Connector Selector, but wished the input was more intuitive and preferred it as a web application.

Joist Hanger Selector web app

Joist Hanger Selector web app

I’m happy to say we listen, and the new Simpson Strong-Tie Joist Hanger Selector web app is available now. The easy-to-use interface enables users to quickly select the connection details and print out results. You can access the app from any web browser without having to download or install special software. The allowable loads are automatically calculated to reflect reductions associated with modifications – no more “Uh oh!” moments for me (at least with hangers).

Joist Hanger Selector App

The joist hanger selector app makes it easy to pick the right hanger.

Give the new Joist Hanger Selector web app a try and let us know what you think. We always appreciate your feedback!

Minding the Gap in Hangers

Mind The Gap sign

Mind The Gap sign

Have you ever seen this famous sign? You may have seen it while riding the London Underground, to draw attention to the gap between the rail station platform and the train door. The warning phrase is so popular that you may also recognize it from souvenir T-shirts or coffee mugs.

In the connector world, the phrase comes to mind when thinking of the space, or “gap” between the end of the carried member and the face of the carrying member. Industry standards for testing require that a 1/8” gap be present when constructing the test setup (in order to prohibit testing with no gap, where friction between members could contribute significantly), so this is the gap size that is typically permitted for the joist hangers listed in our catalog.

Gaps exceeding 1/8” can affect hanger performance in several ways. A larger gap creates more rotation for the connector to resist by moving the downward force further from the header. Fasteners may also have reduced or no penetration into the carried member due to the gap. Testing confirms that these factors decrease hanger allowable loads for larger gaps.

Hanger installation with gap

Example of field installation with a 1” gap (approx.)

What are my options then if the field conditions create a gap larger than 1/8”? We have performed testing to establish allowable loads for many common joist and truss hangers with gaps up to 3/8” (up to ½” for HTU hangers), as well as testing for possible field remedies and repair scenarios. Our technical bulletin T-HANGERGAPS10 provides this information, along with a design example, and general recommendations and guidelines for preventing gaps. Notes on shim details are also included – shim size, material, and attachment (independent of the hanger fasteners) are key design considerations that must be covered by the engineer or truss designer.

What is your experience dealing with hangers that exceed 1/8” gaps? Let us know in the comments below.

Do 50 Kip Wood Construction Connectors Exist?

The 2009 IBC Section 1604.4 states, “Load effects on structural members and their connections shall be determined by methods of structural analysis that take into account equilibrium, general stability, geometric compatibility and both short and long-term material properties.” This requirement applies to a 200 pound handrail connection as well as a 50,000 pound glulam connection.

Hanger installation at jobsite

50 kips is not a typical beam reaction in wood framed construction, but we’ve received some recent requests to design higher capacity hangers for use in wood podium decks for mixed-use structures. Although post-tensioned concrete is most commonly used for this application, the use of heavy timber for podium decks is driven by the benefits of wood: sustainability, saving construction time and money, architecturally attractive, long-term energy savings, light construction material, and performance in earthquakes.

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