By Youssaira Belmokadem and James Rashford
Established in the mid-1800s, the still-booming metropolis of Houston, Texas is now the fourth largest American city with a population of approximately 7 million people. The region’s tremendous growth began to take a toll on its roadways, including the critical North-South State Highway 288 (SH 288) transportation corridor.
SH 288 traverses Harris and Brazoria counties between Houston and Freeport and provides a vital hurricane evacuation route for the community. It is also a freight and commercial trucking route and connects directly to the Texas Medical Center, which is the largest medical complex in the world.
With worsening congestion resulting in safety issues, the community needed a solution. The SH 288 Toll Lanes project delivered, expanding roadway capacity with four toll lanes within the existing SH 288 median, and preparing the city for serious growth.
Working with myriad partners on a $850 million mega project
This $850 million Design-Build-Finance-Operate-Maintain (DBFOM) project encompassed a 10.3-mile segment of SH 288 from US 59 to the Harris County line. Stantec served as the engineer of record and led the design for the project, which was developed through a public-private partnership P3 between the Texas Department of Transportation (TxDOT) and the Blueridge Transportation Group and built by Almeda-Genoa Constructors. The project was awarded to the team in February 2015 and design was substantially completed in June 2017.
Careful coordination with the contractor, stakeholders, and adjacent projects is critical to the success of a large project. During the design phase, Stantec’s key team members co-located on site with the contractor to ensure open and constant communication between all parties, which in-turn allowed the work to progress faster than a usual design-bid-build project.
By maintaining an open dialogue, we could quickly address issues and changes to the design as needed. Once the design was complete, Stantec maintained an on-site construction support services (CSS) team with structures and roadway engineers to allow for seamless coordination around construction obstacles.
Deploying the design resources for an accelerated timeline
The project was designed in just under 13 months, and construction began nine months after the Notice to Proceed for detailed design. To meet this challenging schedule, the design team completed preliminary grading, drainage, and bridge substructure designs several months prior to the construction start.
In fact, the design team completed a total of 8,354 design drawings, 380 submittals and nearly 120 design packages in 12 months leveraging more than 150 Stantec design professionals and support staff from 15 offices in the U.S. and Canada, along with 10 subconsultants.
The aggressive schedule required constant collaboration between the multiple design teams to achieve conformity and standardized designs that met the contractor’s dual needs for economy and construction speed.
The project included 40 new bridges with eight connector ramps to and from Beltway-8 and eight connector ramps to and from IH-610. The new infrastructure also features two direct connectors to Holcombe Boulevard near the Texas Medical Center, improving commute times for healthcare workers and supporting emergency medical response. The project also included the modification of 13 bridges for a total of 1.8 million square feet of bridge deck along the corridor.
Bridge construction was accelerated by using as many precast elements as possible, and because elements could be mass-produced off-site, schedules became more flexible. One innovative component of Accelerated Bridge Construction used on the project is precast caps with voids. The voids were used to reduce dead load for lifting operations to accommodate the contractor’s request for a 200-ton weight limit to ease installation and make use of available equipment.
Designers were challenged to come up with a precast cap to single-column connection in order to preserve the bent configuration required by aesthetics. TxDOT already has standards for multicolumn bents with precast caps, but this project required the use of a single column bent type. The precast details for the bent caps (i.e., connections, grout pockets, lifting weight, etc.) had to be carefully considered to be both durable and constructible. Once the column was ready for the precast cap, installation could be completed in a matter of hours.
The use of precast caps also eased congestion by reducing the duration of lane closures.
Engineering solutions to make a mega project work
Simplicity and streamlining quickly became key and consistency in detailing was crucial. Beyond creating a “go-by” set of plans for the bridge design teams, Stantec created a dedicated bridge review team that cross-checked the bridge plans against each other in an effort to maintain a consistent design and construction approach, helping simplify both TxDOT’s reviews and the contractor’s construction.
One year into construction, Hurricane Harvey made landfall in the Houston Metropolitan area. The city suffered catastrophic flooding with an estimated $125 billion in damage, but the SH 288 project still needed to be completed. To assess the storm’s impact, Stantec quickly mobilized crews to inspect existing and newly constructed elements. Thankfully, the project impacts were minimal.
Improving the motorist experience
To improve safety, the team added 72 new high-mast illumination poles and relocated 16 existing high-mast poles to increase visibility for motorists while also upgrading all the lighting to LED to reduce maintenance and operating cost. Other safety enhancements include the resurfacing of 77,000 linear feet of the corridor to improve driving conditions and barrier upgrades throughout the highway.
The new Southmore Bridge over SH 288 incorporated two pedestrian bridges to improve pedestrian access to Texas Southern University.
A modern roadway for Houston commuters
Overcoming an accelerated timeline and obstacles like a hurricane was no small feat for the project team, but in November 2020, the SH288 Toll Lanes project opened for public use, serving approximately 190,000 vehicles daily.
Youssaira Belmokadem, PE is a Bridge Engineer and Deputy CSS Structural Manager. James Rashford, PE is the Deputy Design Manager for the SH 288 Toll Lanes Project.