Create Roof Trusses with Top Chord Bearings

Video Transcript:

 Welcome! In this video, we’ll walk through creating a top chord bearing roof truss. For this scenario we are going to design a component for a 30 foot wide pole barn. The structure will contain some taller farm equipment so it needs to be vaulted.

Let’s get started!

Open the component creation subpanel and set the truss length to 30 feet. Next we will set both, left and right heel heights to be 3 feet.

Our top chords will both have a 6/12 pitch.  Remember to add a negative value for the right side.

Both will be 15 feet long, so we will use the profile line tools to add both of these lines.

Next we need to add the bottom chords. The bottom chords will have a 5/12 pitch.

And the length will be 14 feet 8 and a half inches long for both. Add both bottom chords to close this profile.

Accept the default settings and click insert.

Let's look at two possible scenarios. For the left side, the bearing will be 1 foot below the bottom of the truss. Commonly referred to as a leg down truss. The other end will have the bearing 1 foot above the bottom of the truss.

First we'll edit the left side. Let's trim the bottom chord to the right side of the end vertical.

Next we will add a reference line 1 foot down from the bottom of the truss.

Then we need to move the bearing to align with the reference line. To do this select the bearing, and in the properties panel under Bearing Reference Line click the Select Existing tool, then click on the new reference line. Press escape.

Next, we simply need to update the end cut of the end vertical, so it extends to the new reference line. Select the end vertical, shift click on the reference line and that will extend the end cut to the top of the bearing.

Move over to the right side and we will adjust this end.

Let’s modify the end vertical member to now be a bearing block. Click the member and from the properties panel under member type select bearing block.

Next we will add a new member. Place the new member to be on the left edge of the bearing block. Change this member to be an end vertical from the member type option.

Now we need to trim up a few items. Let’s start by selecting the bottom chord, then shift click the right side edge of the end vertical. Next we will adjust the end of the W7 web to be cut to the left edge of the end vertical. Select W7, then shift click on the left edge of the end vertical. Now we need to extend the end vertical to the bottom chord. Click the end vertical and then shift click on the top edge of the bottom chord.

We will adjust the bearing block end to be 1 foot up from the bottom of the truss.

Insert a reference line 1 foot up from the bottom of the truss. Trim the bearing block back to the reference line. Click the bearing block and shift click the reference line.

One last item, we need to relocate the bearing. Click the bearing, then in the properties panel under the bearing reference line tool click select existing, then click on the reference line.

Now, we can analyze the truss to ensure all checks pass!

That does it for this video on creating a top chord bearing roof truss with two different scenarios. We hope these two examples will help you when solving problems for your top chord bearing truss projects.

We’ll see you in the next one!