The nearly finished David Rubenstein Forum at the University of Chicago features cantilevered boxes that created engineering challenges for the structural and facade systems. The structural system features four columns, a concrete core and two lateral, post-tensioned concrete shear walls.
Under present circumstances, the act of gathering through conferences and summits is a hazy memory. And while many pine for a return to those carefree days untroubled by the airborne transmission of particulates, perhaps the present freeze will allow for a moment of introspection on the role of conference and program centers within urban assemblages.
The David Rubenstein Forum at the University of Chicago, a 97,000-square-foot project nearing completion and designed by Diller Scofidio + Renfro (DS+R), beguiles with an inviting podium and yawning glass curtain walls framed by gleaming zinc panels.
The Chicago metropolitan area is home to vast juxtapositions in living conditions, and nowhere is this juxtaposition more pronounced, arguably, than the University of Chicago campus within the city’s South Side. The ten-story tower is located on the border of the Midway Plaisance Park and is the latest addition to the school’s inexorable southward march.
For DS+R, both the setting and program informed the project’s massing. “The North-South orientation opens the building equally to both the Woodlawn neighborhood and Downtown Chicago, stitching together through view and movement the building’s interior spaces with its community, said DS+R associate principal Sean Gallagher.READ MORE
Post Tensioning in Concrete
Method of prestressing reinforced concrete in which tendons are tensioned after the concrete has attained a specified minimum strength or a specified minimum age.
Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. The materials used to post-tension concrete members are ultra-high-strength steel strands and bars.
Horizontal applications (such as beams, slabs, bridges, and foundations) typically employ strands. Walls, columns, and other vertical applications usually use bars. The steel reinforcing strands are installed in a way that protects them from bonding with the concrete.
Slabs and girder sections are the most common post-tensioned member found in buildings and parking structures.
ACI Concrete Terminology
Shear in Concrete
An internal force tangential to the plane on which it acts.Shear typically denotes a force that acts perpendicular to the length of a beam or a column (often referred to as “beam shear” ) or vertically in a slab. While shear can occur perpendicular to the surface of a wall, walls are most often used to resist shear along their length and are referred to as “shear walls.
” One mechanism that transfers shear from slabs to columns is termed “punching shear.” Such shear can be resisted by the slab-column interface, and additional resistance can be provided by drop panels, shear caps, or reinforcement.