Irving, Texas’ Irving Convention Centre is truly one of a kind.
Designed to garner attention, without being garish or dominating the skyline, this engineering and architectural feat is visible from many points in the surrounding area, yet at the same time minimises its footprint in order to conserve land for other development.
It has earned national recognition in the 2012 Innovative Design in Engineering and Architecture with Structural Steel awards program (IDEAS2), an award which recognises the clever use of steel from both an architectural and structural engineering perspective.
Members of the project team behind the convention centre’s structure and design were presented with awards from the American Institute of Steel Construction (AISC) during a ceremony on June 19.
“Massive overlapping and offset structural elements provide architectural interest,” says Alford ‘Andy’ Johnson, President of the Taos Center for the Arts, Taos, N.M., and a judge in the competition. “Overall appearance is significantly more interesting than the typical convention centre.”
The building’s structure operates on a stacked design whereby conference rooms and the ballroom are placed above the convention centre floor, with the upper floors rotated at 20 degree angles relative to the main grid.
In order to create a 190-foot span above the column-free space, structural engineer Datum Gojer used a set of four trusses, all approximately 40 feet deep.
Three of the trusses, which use a catenary-style bottom cord in straight segments between work points and extend down from the fourth-floor ballroom level to well within the convention space, support the majority of the floor while the fourth, an arch truss, supports the elevated floor plates at the west end.
Such an unconventional truss arrangement, AISC says, not only reduced the required steel tonnage and depth but also reduced the required section sizes, allowing all materials for the buildings to be acquired domestically.
AISC says the building’s configuration, in which upper floors are contained in a copper-clad box structure that is elevated above the exterior terrace level and rotated 20 degrees relative to the main building grid, created long cantilevers at each of the four corners of this ‘copper clad box’.
Beyond that, AISC says, the structure used to support the copper-clad box is exposed and visible within the building at the ballroom level and silhouetted at night when backlit through the copper cladding. Site assembled trusses, which provide both structural support for the roof and backup for the copper cladding, cantilever at all four corners of the box, up to 117 feet.
At the top of the podium level is an exterior terrace which extends the entire length of the building on the southern side, including the two main entrances on the lower-level corners. To achieve the architectural vision of floor to ceiling glass wrapping the corners without visual structural support, engineer Gojer designed two sets of trusses, which were analysed together in order to reduce deflections at the head of the glass and minimise vibrations of the occupied terrace, and which cantilevered as much as 150 feet toward the corner in each direction.
One significant design challenge revolved around maintaining optimum vibration performance in the ballroom and meeting rooms while minimising the weight associated with the elevated box structure. Added to this, the required steel tonnage for the long-span catenary and arch trusses over the floor was directly influenced by the weight of the floor plates.
This was overcome by a type of assembly for the final upper-level floor which used castellated beams at 15 feet in the centre, supporting a lightweight concrete slab. This arrangement minimised steel tonnage while offering a relatively solid floor.
The centre’s environmental credentials, too, are impressive. Made of unfinished copper, the exterior does not require chemical treatments, reducing the volume of chemicals needed to maintain the building. A water treatment system used for the building’s ‘grey’ needs draws upon water from nearby Lake Carolyn, gently re-treating the water after use and placing it back into the lake. Sustainable, locally purchased, non-petroleum-based products were used wherever possible and an emphasis has been placed on recycling and composting to minimise waste.
A Great Example
AISC President Roger E. Ferch says the centre is an excellent example of innovative and clever use of steel products in structure and design.
“The entire Irving Convention Center project team has shown how structural steel can be used to create structures that combine beauty and practicality” Ferch says.
“The result is a convention center that serves its patrons extremely well, while providing an example of what can be achieved when designing and constructing projects with steel”.