Shear wall collector load path

Question

Shear wall collector load path

YC611 (Structural)

(OP)

12 Oct 23 18:15

Hi all,

Long time lurker here and happy to finally decided to join the forum.

I am currently involved in a townhouse alteration in NYC and I have to design the lateral force resisting systems based on the architectural plans. This building is approximately 20'W x 50'L x 40'H (typical residential building). As always, the front and rear facades are more than 50% of window and door openings. So my best options are to utilize the interior shear walls. However, for one of the shear walls, I have a stair opening on the way of the collector. I was wondering if I can still analyze and design it as collector. Please see sketch attached.

My guess is that: lateral force >> diaphragms >> beams 1 and 2 >> beam 3 >> collector >>shear wall.

If it isn't the case, how will the lateral load be transferred to the shear wall in the current setting? Or that it is not working and I will have to find a new shear walls elsewhere.

phamENG (Structural) · Answer 1 · 2023-10-12 18:21:06

You'll need to extend a collector in line with beam 3 to the front and back walls. That'll give you a number of sub diaphragms that will all work together to get the loads to the shear walls.

Take a look at Malone's Analysis of Irregular Shaped Structures Diaphragms. Here's an article he wrote for WoodWorks. In the article, look at Figure 3. Your diaphragm essentially this and its mirror image joined along line 1.

YC611 (Structural) · Answer 2 · 2023-10-12 18:43:59

Thank you! I did read about this literature a while ago and it never crossed my mind of imagining it in mirror views.

Now it is making a lot of senses to me.

phamENG (Structural) · Answer 3 · 2023-10-12 19:17:00

RE: Shear wall collector load path

phamENG (Structural) 12 Oct 23 19:17

No problem. Best of luck to you.

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Shear wall collector load path