The new Salt Lake City Public Library design combined basic geometric shapes – triangles, rectangles, circles, arcs and spirals – to form a complex structure with atriums, spiral staircases and a rooftop garden. Integrating the building’s architectural expression with the facility’s structural systems was of utmost importance since 90 percent or more of the structural elements are visually exposed.

The $75 million facility more than doubled the capacity of the old library, established a modern new city landmark, and created an active gathering place for science, culture and education.

Structural lightweight concrete was used as a topping on all steel composite deck applications to reduce the dead loads on horizontal framing members, columns, and footings.  The lightweight concrete also reduced the seismic demands and provided a two-hour fire rated floor systems without spray-on fire proofing.

“Structural lightweight concrete also was essential to reduce column loads from the vaulted floor slabs of the main library stacks area.  The loads produced by five levels of vaulted floor slabs, which varied in thickness from 8 inches to 28 inches would have exceeded the capacity of the 24 inch maximum diameter columns required by the architect (f’c = 8000 psi) if normal weight concrete was used.  The reduced weight of the concrete floors also saved significant cost in the mat foundation and lateral force resisting systems for the building.”  -A. Parry Brown, S.E.

PROJECT REQUIREMENTS

      §         4000 psi Structural Lightweight Concrete

§         110 +/- 3 lbs. @ 28-days

§         6% +/- 1.5 Air Entrainment

§         2-Hr. UL Fire Rating