Detail A

Load Path

• Load path is from bottom to top and then back to bottom - not efficient.
• Overturning forces are transferred to posts through edge nailing and travel upward through compression until finding a point of restraint at the top of the building.
• The whole system is restrained at the upper most top plate by a large steel bearing plate.
• Bearing plate transfers the cumulative load to the nut and then the rod.
• The free body-diagram shows that top floor tension force is a result of all of the lower floors transferring the cumulative uplift load upward to the top floor before coming back down. In order for this to happen, the posts in the lower floors must carry that force up in compression. Therefore, posts in the top floor must resist the uplift force from bottom floor. (See Detail A below)

Note:
F₁, F₂ and F₃ are inter-story uplift forces.
T₁, T₂ and T₃ are rod tension loads.
C₁, C₂ and C₃ are the post compression loads due to uplift forces.
Example does not include gravity loads.

Axial Load Diagram of Posts
on Uplift Side of Wall

Load Path

• Overturning loads are transferred to posts through boundary nailing and travel upward through the floor system until finding a point of restraint at each story.
• Floor system or roof top plates resist the post uplift from each floor below. The posts are engaged in compression because of uplift from the inter-story load.
• Floor system or roof top plates are held down by the bearing plate on the sole plate or roof top plates. The bearing plates resist inter-story uplift load at each floor.
• Bearing plates transfer the incremental load to the nut and then the rod.
• The free-body diagram shows that posts on top floor resist the uplift force from the top floor only.

Note:
F₁, F₂ and F₃ are inter-story uplift forces.
T₁, T₂ and T₃ are rod tension loads.
C₁, C₂ and C₃ are the post compression loads due to uplift forces.
Example does not include gravity loads.

Axial Load Diagram of Posts
on Uplift Side of Wall