Audubon Hollow is a private enclave of 22 luxurious garden homes in a pocket of urban forest in one of the most exclusive areas of Houston, TX. Big R Bridge recently designed and supplied a buried arch bridge across the wooded hollow leading up to the development’s gates.
The solution, featuring our Super•Cor Arch and Vist-A-Wall headwalls, was notable for two main reasons:
- It was undoubtedly our most sustainable project to date, using a high degree of recycled materials, including backfill, and also won an award from the National Corrugated Steel Pipe Association.
- It used a two-stage construction method which allowed one lane to remain open for access during construction in the tight urban site.
That’s a lot of recycled content
Our Super•Cor Structural Steel Plate utilizes 75% recycled steel – the world’s most recycled material. And our Vist-A-Wall MSE Structural Wall System uses almost 100% recycled content in its steel components. Add to this, the use of 100% recycled (crushed) concrete as an engineered backfill material for the structure, and the entire project comes in at about 90% recycled content.
Two-stage construction keeps traffic running
The development site was previously an old estate home with a small driveway and culvert across the hollow, which was prone to flooding. To maintain construction traffic while the new crossing was being built, a two-stage method was used – Super•Cor and Vist-A-Walls being naturals for this. One lane of the crossing is built at a time, with the mid-way retaining wall remaining inside the completed structure.
Simplified foundation saved costs
Due to the snug location between existing buildings and the nature of the soft foundation soils, it was a major benefit to utlize a bridge system that could work with a shallow spread foundation. The more generous settlement allowance of Super•Cor was favourable in this regard, versus the deep foundation systems needed for traditional precast span bridges.
We worked directly with the owner/contractor to help them guide the geotechnical engineer on Super•Cor’s substructure designs and settlement tolerances. We also recommended experienced subcontractors for the project. This, along with quick delivery of all components, helped to expedite the project on a compressed timeline.
Sustainable shipping, too
With the exception of the backfill, the entire structure, including the headwall system was shipped on a single truck. Any other type of structure would have required multiple trucks, resulting in additional pollution, energy use, unloading time, and other inefficiencies.
The finished crossing, with two lanes, two sidewalks and architectural rail treatments, makes a handsome entry to the development. Even the uniform color and gradation of the recycled concrete in the headwalls was exactly what the architect was hoping for.
Project follow-ups indicate that the owner is looking forward to capitalizing on similar cost savings on future projects and has already referred us to other developers in the Houston area.