If you would like to know more about a brand new state-of-the-art seismic retrofit guideline, there are around 30 educational videos and web pages that you will find interesting. Just type ICC 1300 in the search box in the upper right.

The Comparing 2 Options For Retrofitting Floor Connections

 ICC 1300 Vulnerability Based Seismic Assessment and Retrofit of One and Two-Story Dwellings only offers two options for making floor connections to the cripple wall.   The first one is the option we see in all the seismic retrofit guidelines where there is full access to the end joist or blocking and you simply put in a framing anchor such as an L-90.  The other option shown here is when another parallel joist is in the way.

This video will show you how ICC 1300 deals with this problem compared to a system contractors developed.

The method created by contractors uses nails, and the other method recommended by ICC 1300 Vulnerability Based Seismic Assessment and Retrofit of One and Two-Story Dwelling uses a combination of framing anchors and nails.  It is good to know both systems because each one will have its place depending on what you find.  Let’s first start with the one from ICC 1300.

Retrofitting floor connections with steel

It uses a combination of framing anchors and nails.  The video explains how this detail is built and why this detail won’t work.

retrofitting floor connections with nails

This detail is one used by contractors and only uses nails.  It has fewer moving parts and is much easier to install.

Another option is to notch the joist as illustrated below.  It is a code violation to notch a joist like this, but based on my experience, you can’t tell the difference.  If you jump on the floor as hard as you can before and after notching the floor support feels the same.

Retrofitting floor connections with notches.

This webpage is for educational purposes only.

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