We’re very excited to have had the following article published in the November issue of Structure magazine. It goes without saying that we’re super proud of the M+K staff members who co-authored this piece: Bert Coelho, P.E. [Principal + Dir. Business Development], Kevin Quan, P.E. [Sr. Project Engineer], and Micah Milner, P.E. [Project Engineer].
Steel Stud Bearing Walls
An Alternative to Traditional Podium Levels
Developers are always looking for new and innovative ways to make buildings more profitable and financially efficient. Traditionally, a multi-story bearing wall building over one to two levels of steel or concrete, also known as a podium structure, has filled this need by offering high-density residential units at the upper levels and parking or retail spaces at the lowest floors. For multi-story residential buildings, wood construction is generally considered the most cost-efficient form of construction, followed by cold-formed steel (CFS) bearing walls and then heavy steel or concrete framing. Because of this, developers have sought to maximize the number of wood-framed floors over the podium level before switching to more costly materials.
Wood bearing wall systems are limited to either 4-stories using Type V-A construction or 5-stories using Type III-A construction. Both types of construction can be supported on grade or a podium structure. Podium structures have been covered extensively in previous articles by STRUCTURE magazine. They are proven methods of meeting not only financial requirements but zoning and regulatory obligations as well. This article focuses on an alternate hybrid system that maximizes the number of stacking levels of residential units by introducing multiple levels of CFS bearing walls to support the wood-framed levels before transitioning to the transfer level or foundation.
The Challenge
Recently, some developers have opted to add additional residential units below the Type V-A and III-A constructed units. This means the stacking residential units from above are carried down below the podium level by minimizing or removing the retail and parking areas altogether. This change increases unit density, thus maximizing more profitable areas by limiting the less profitable retail and parking areas.
The challenge with incorporating stacking units from above with a typical steel or concrete podium superstructure is the interference of regularly spaced columns with residential unit layouts. While the podium column scheme lends itself well to open spaces required for retail and parking, the standard grid pattern presents architectural challenges at residential levels in accommodating columns within the unit layouts. Additionally, non-stacking loads from the residential bearing wall system above inevitably require deep steel or concrete beams or heavily reinforced concrete slabs and may even require drop panels. The ideal column grid may also disrupt stacked window layouts along the exterior of the building below the podium level.
Architecture is not the only discipline to face challenges with this system. Plumbing, electrical, and HVAC systems are typically accommodated by having stacking mechanical penetrations for the full height of the building. In a wood-framed building, these are commonly located within the wall stud cavity. Therefore, stacked penetrations running down through the steel or concrete podium structure invariably conflict with beam and column locations that directly support the walls above.
To resolve these issues, architects frequently need to create new unit types and floor layouts to work around the traditional podium structural elements. Unfortunately, the new layouts can create spaces that may be inefficient or undesirable to developers or prospective tenants. Continue reading “M+K Article Published in Structure Magazine”
