Diaphragm Transfer Loads  

Hi there,

I have a nominally ductile shear wall building with a transfer diaphragm at podium level. The podium is tied to very long perimeter retaining walls and is laterally very stiff relative to the walls that run full height of the building.

Due to issues that I won’t get into, we cannot provide a seismic gap between the walls and the podium and therefore there is a large kick-back shear within the walls.

I am looking at the diaphragm transfer forces based on pESA methods and finding out that they are incredibly large. 

I am thinking about factoring these transfer forces down, such that diaphragm to wall connection only has adequate capacity to transfer the loads required to achieve the flexural over strength of the wall under pESA loading. In other words, I want to design the connections just strong enough to only transfer force required to yield the wall in flexure.

Do you see any misgivings with the proposed methodology from a seismic design perspective? I’ve attached a rough sketch hopefully describing what I am proposing above.

Kind regards,

Poornaka