Best Bridge - Structural
SH249 – SH99 Interchange
Description
This SH249-SH99 Flyover Project included the first precast/post-tensioned Curved U beams produced in the State of Texas.
Project Timeline
Geographically, the SH249-SH99 project is located in Tomball TX, just outside of Houston, and had a two-year duration from 2020 to 2022. The project scope included two flyover connectors at the SH249-SH99 Interchange. In addition to the Curved U96 beams, this project also incorporated other precast/prestressed products such as 33,400 linear feet of U54 girders as well as 54,000 square feet of prestressed deck panels.
Key design features
Although this project included various precast/prestressed products, the innovation, and key design features came from the U96 Curved Girders. Cast on a 903’ radius, these beams were of various lengths and weights up to 103’ in length and over 300K lbs. in weight. Dimensions on these beams were 8’ tall and 11’-3” wide at the top. Drop-in corbels were also cast in a number of these beams in lieu of the use of strong backs during the erection process.
Accomplishments
Shipping the U96 beams proved to be a challenge. Specialty trailers 16’ wide were used that had to be designed to safely haul over 300K lbs. Further, permission was granted to allow for the use of Toll Roads on this project while the loads were not allowed to exceed 35 mph.
Precast concrete components
SH249-SH99 project included using (56) Curved U96 Bridge Beam produced in Eagle Lake, Texas by Valley Prestress. The longest of these beams measured just over 100’ in length, and weighed upwards of 300K lbs.
- Precast Manufacturer: Valley Prestressed Products, Inc. – Eagle Lake, Texas
- Engineer: Costello Inc. – Houston, Texas
- Engineer: LIA Engineering – Houston, Texas
- Engineer: Modieski and Masters – Littleton, Colorado
- Owner: Harris County Toll Road Authority – Harris County, Texas
- Owner: Texas Department of Transportation – Austin, Texas
- General Contractor: Williams Brothers Construction Company – Houston, Texas
