# 8.2 Refining Scissor Truss Designs (B01, B01A, B01B)

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## Description

This module demonstrates how upgrading bottom chord material from 2x4 to 2x6 can address plating issues for truss designs with a partial ceiling vault.

## Objectives

* Demonstrate how changing bottom chord material can improve joint geometry and plating performance.

## Additional Resources

* Training Plan 3 accessible from Choose/Create Project > OPEN SAMPLE

## Learning Activity

Watch video and follow along within the Paragon Design App.

{% embed url="<https://youtu.be/tanNGv8SOAY>" %}

<details>

<summary>Video Transcript:</summary>

In this next video we will take a look at refining our scissor trusses.

From our component list, let's click on B01 to see where we need to make changes. First let's click analyze, and we'll take a look at any areas that are over capacity. After running the analyze tool, we can view the analysis history. From the options menu let's select the Analysis and History icon. We see here we have a plate pair that's exceeding capacity, and looks like we have another plate pair that's exceeding capacity as well. So, let's look at plate pair 11. It's exceeding capacity at over 128%. If we expand this, the analysis provides us details on the truss and capacity issues. The plate size should be good, but I'd feel better if we increased the bottom chord to 2x6 to increase contact area. Select the bottom chords by control clicking, then right click and select edit lumber, then we will change the dimensions to a 2x6. Next, we need to re-analyze the truss. So, click on analyze, and let's see how changing the bottom chord to a 2x6 goes.

All right. We are looking a lot better. We do see that plate pair 11B, here at the bearing is at a hundred percent. So, if you are okay with that, we leave it, otherwise you could upsize the plate. But, for the sake of this demonstration, we are going to leave it as is. And that's going to do it for B01 truss edits.

Let's go back over to our list of trusses, and we are going to take a look at B01A. Click to open B01A. We can apply the same changes here that we applied to the B01 truss. So, let's select the bottom chord, right click and select edit lumber, then from the dimensions option, we will select 2x6. Let's re-analyze this to see if the updated size of the bottom chord satisfies this truss. Everything looks good here with the bottom chord changes.

We have another truss here to look at that is similar to the last two we just modified. So, let's select B01B. Here we will make the same adjustments to the bottom chord material. Select both bottom chords by Holding down control. Then, right click and select edit lumber once more, and we will select 2x6 from the options. We need to re-analyze this truss to make sure these edits pass the checks. That looks like it solved the capacity issues we had here as well.

And there we have it, that's going to do it for the B01 trusses.

Thanks for watching!

</details>


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