Built on a 30,000-sq-ft site with zero laydown area, The Austonian project team had to lease an adjacent 5,000-sq-ft staging area during construction and orchestrate material deliveries with precision.

Photo:Thomas Mcconnell

The 850,000-sq-ft, 60-story building, which was completed in an aggressive 28-month time frame, is the tallest building in Austin and the tallest residential building in the western United States.

The Austonian is noteworthy for its adherence to Austin’s corridor setback requirements. To ensure all buildings along the corridor offer views of the historic Texas State Capitol, corridor setback requirements mandate that no structure rise higher than 90 ft at the property line fronting Congress Avenue.

As a result, The Austonian was designed with a 10-story podium that extends to the property line, topped by a tower setback the mandated 60 ft. One level of parking is below grade, which reduced excavation expenses. Level 10 features a green roof and pool deck along with a theater, spa rooms, game rooms, meeting rooms and several guest suites.

The uppermost levels of the building house mechanical/electrical systems and a sloshing tank, engineered to dampen the building’s natural sway.

Construction of a tall, elliptical shape was more complex than building a traditional square or rectangular building. The structural forming system was more complicated, with additional requirements for layout and field engineering of the post-tension concrete decks making up the building’s residential tower. In structural terms, the building is designed much like two 30-story buildings with one stacked atop the other.

The bottom half of the tower is stiffened by its podium base, while the upper half is stiffened by an outrigger floor at level 31. This level’s slabs are thickened, and full-height web members create an ultrastiff floor that acts like a belt, allowing the upper half of the building to develop lateral strength.

Key Players

Submitted by: Benchmark Development Inc.
Developer/owner: Benchmark Development Inc., Austin
General contractor: Balfour Beatty Construction, Dallas
Construction manager: Benchmark Development Inc., Austin
Architect: Ziegler Cooper Architects, Houston
Civil engineer: Axiom Engineers, Austin
Structural engineer: CBM Engineers, Houston
MEP engineer: CHP and Associates, Houston