Utilize Masonry Walls to their Full Potential
A Case Study:
This article will step through a review of a multi-story steel and masonry project structural review, and ways to increase efficiency in its structural systems.
Contractor: The masonry stair and elevator shaft walls in the above project are being used by the architect/engineer design team as impact resistant, durable, and fire resistant walls. The walls are also resisting gravity floor and roof loads. Are there other ways the masonry walls can be utilized?
Reviewer: In reviewing the project, it seems masonry is being utilized well. There does seem to be one area of improvement. The masonry walls are tied into the floor and roof framing with beams and diaphragm members connected to the masonry walls. The masonry walls will then participate in, and serve as the primary members in resisting the building lateral loads. However, there are many steel moment frames and steel braced frames also specified. Our initial thought, which was confirmed by a thorough analysis, was that the masonry walls would take a substantial portion of the lateral load and that the contribution of the steel members would be minor due to greater masonry wall stiffness. Our final analysis showed that the masonry walls on the project could have taken the full lateral load with minor changes, which would have allowed for cost savings for all other lateral elements. In other words, all the steel moment frame connections (estimated 108 moment connections) and braced frame members (6 steel braces and 12 gusset frame connections) could have been significantly reduced, or possibly eliminated.
Written by Sam Rubenzer SE, PE – Forse Consulting