Shear Wall Success

By Frank Salzano and Greg Smith, Contributing Writers
Created: January 16, 2013

CECO Concrete Construction’s approach to planning and placing vertical concrete projects helped the company achieve a successful placement and a satisfied client at its recent work on shear walls at a multi-family project adjacent to Safeco Field in...

CECO Concrete Construction

CECO crews spaced air-powered external vibrators about 6 feet apart and at lifts of 3 to 4 feet. These are moved during the pour to follow the placement lifts and rate.
CECO crews spaced air-powered external vibrators about 6 feet apart and at lifts of 3 to 4 feet. These are moved during the pour to follow the placement lifts and rate.
CECO Concrete Construction

As the photos demonstrate, there are heavily reinforced areas within the shear walls. The beam in the center of the photos has 32 #11 bars, 21 feet long, installed in an “X” pattern across the...
As the photos demonstrate, there are heavily reinforced areas within the shear walls. The beam in the center of the photos has 32 #11 bars, 21 feet long, installed in an “X” pattern across the opening and fully developed into the boundary elements. The design in this location and at the typical boundary elements effectively eliminated the use of internal vibration in much of the walls.

We used air-powered external vibrators. Crews were able to adjust the consolidation force by controlling the air valve. Higher force should be used for deeper and thicker walls with more reinforcing and embeds. Additionally, with external vibration, vibrator men are not required to be on top of the wall — access is from the ground up with a ladder or scaffolding.

Since the project included a performance-based concrete specification, as opposed to a prescriptive specification, we had input into the best concrete mix design for the project. Based on specified compressive strengths of 5,000 and 8,000 psi, exposure classes of F0, S0, P0, C0, and expected SF2.0 finish, our budget and schedule were built around a high slump (8-inch +/-1) pea gravel mix. We choose not to use a self-consolidating concrete (SCC) as it would have increased our material and labor costs since SCC mixes require watertight forms.

This well-coordinated combination of psychology and science produced the desired result and provided for a successful finished product that all project participants are proud to call theirs.

Frank Salzano is Manager, Frame Development and Greg Smith is Regional Frame Manager with Ceco Concrete Construction, LLC. Visit Ceco Concrete Construction online at www.cecoconcrete.com.