Hilton Overhead Walkway
Hilton Overhead Walkway
In 2014, the Hilton Hotel at Neches and East 4th Streets in downtown Austin was facing increased competition from newer properties. The Fairmont Hotel was in the planning phase with walkway plans over Waller Creek for a direct connection to the Austin Convention Center. In response, as part of a two-year modernization project, the design team of Gensler and Walter P Moore were tasked with creating a functional work of art that would serve as the “gateway to Austin” for those arriving in downtown via rail. This $7.5 million overhead walkway provides a seamless and safer alternative for guests to move from the convention center to the Hilton versus crossing at street level over light rail tracks.
Envisioned as a lattice of slender pipes, the walkway is fully open to the air with a perforated metal panel roof for shade and no additional cladding. The fully exposed structure seemingly floats above the earth below. Gensler expected that the bridge would need to be supported from the roof structure above by cables or rods and that an edge beam would be required to support the handrail and tie the walkway beams together.
However, our team was able to cantilever horizontal pipes off the vertical pipes to support both the walkway and its handrail, eliminating the need for an edge beam and structural hangers. This achieved the architect’s original vision of a floating walkway with the appearance of no separation between earth and sky. Walter P Moore’s innovative design allows the bridge to function as a piece of art, winning approval from Austin City Council, which has historically been averse to sky bridges.
The first challenge our team encountered was integrating the bridge into the existing Hilton Austin Hotel structure. As an integral member of the hotel’s original construction team in 2004, we were familiar with and had access to accurate drawings of the hotel. Therefore, we were confident that we could use the hotel structure to support the gravity loads on a single existing corner column. We then used the adequate capacity of the sixth floor’s framework to transfer the lateral loads of the walkway.
Another challenge our team faced was connecting the bridge to the convention center above one of its main entrances. The structural steel in this area was inadequate to support the additional load of the walkway. To provide the needed capacity, we designed a pair of cast-in-place concrete columns installed on each side of the entry, with the westernmost column acting like a wall to carry the east/west lateral loads of the walkway. The existing foundations also lacked capacity to bear the load of the walkway, so the team designed drilled piers from which new foundations were cantilevered to support the new columns.
The final challenge faced by the team was the CapMetro Light Rail, which could only be shut down over a single weekend — about 52 hours — for construction. The entire bridge was pre-assembled on a leased parking lot a block from the site prior to the weekend closure. The assembled bridge was then lifted onto a truck early on a Saturday morning and driven down 4th street. A crane hoisted the bridge into place by Saturday afternoon. Connections to the Hilton and the Convention Center were complete by late in the day Sunday. The crane and other lifting accessories were removed from the site, and the light rail station reopened in time for the Monday morning commute.