Closing the Gap: What It Takes to Complete a Regional Connection

On a map, the missing piece of Corporate Drive in Lewisville, Texas looks simple: connect one end of the roadway to the other.

But on the ground, that line crosses both the fork of a river and a complex floodplain, presenting challenges that extend far beyond the roadway itself.

Once complete, the 3.75-mile project will provide the final missing piece of a larger east-west corridor across North Texas. What began as a question of how to close the gap has grown into a project shaped by the river it crosses, the communities it connects and the expertise required along the way.

A Connection Shaped By The River

For David Smith, PE, Halff project manager for the Corporate Drive project, getting there has been more than a decade in the making. Halff’s work on Corporate Drive began in 2015, when the City of Lewisville selected Halff to explore what the future connection could look like.

The setting shaped those early conversations. The alignment crosses the Elm Fork of the Trinity River near natural areas and Railroad Park, an athletic complex Halff previously helped design. The team had to consider how the roadway would affect pedestrians, residents, drivers and the surrounding natural environment, including aquatic resources. Working with City staff, the team explored single and split bridge configurations, opportunities to preserve trees, bicycle and pedestrian connections, landscaping and other aesthetic elements.

Early conceptual renderings of Corporate Drive extension illustrate two design alternatives explored by Halff and the City of Lewisville: the “Emergence” single-bridge concept (left) and the “Fire Walk” split bridge concept (right).

When the project advanced into preliminary and final design in 2017, it was time to incorporate those ideas into the realities of the site.

One of the biggest considerations was water.

The roughly 2,000-foot main bridge crosses more than the Elm Fork itself. The surrounding floodplain extends well beyond the river channel, meaning the structure also had to account for how water moves throughout a much larger area.

That movement is particularly complex around the crossing. Swales, embankments and areas of split flow make it difficult to understand the floodplain by looking at the river channel alone. To address that, Halff’s water resources team developed hydraulic modeling that combined one-and two-dimensional approaches to establish a clearer picture of how water moves through the area.

In 2015, a major rainfall event caused Lake Lewisville to overtop the dam spillway upstream of Corporate Drive. The resulting flooding along the Elm Fork presented the same type of conditions Halff’s water resources team had been modeling.

As floodwaters spread through the area, the City captured aerial photographs and videos documenting the extent of the flooding. The team later compared its hydraulic modeling with those observations and found that the predicted flood extents aligned with what had occurred. The event validated the team’s modeling against real-world conditions, providing additional confidence in the model used to inform the design.

The modeling was critical to understanding the existing flow patterns and to determine the appropriate bridge size and location.

Ultimately, the design is projected to cause no rise in the 100-year water surface elevation of the Elm Fork Trinity River.

For Samantha Dorrell, PE, Halff’s lead structural engineer on the project, the challenge wasn’t necessarily the complexity of the bridge’s structural design. It was the length required to cross the floodplain.

The team also considered how the structure would appear from the river below. Near the riverbanks, the bridge columns increase in size closer to the ground to maintain a uniform appearance while meeting structural slenderness requirements. That detail also provides a nice visual effect for kayakers traveling beneath the bridge.

“Bridges are some of the most expensive elements on roadway jobs when they’re required, so generally teams try to limit their length as much as possible. For this project, the bridge’s structural design was straightforward, but the length makes it unique, especially for a City project.” – Samantha Dorrell, PE

Beyond The Bridge

The bridge also shows how quickly one engineering question can become a multidisciplinary one.

In addition to the roadway, a 12-inch potable water line needed to cross the Elm Fork. Rather than create a separate open-cut crossing through the river, Halff’s water/wastewater and structural teams coordinated an integrated solution to carry the line along the underside of the bridge.

A view of the Corporate Drive bridge crossing the Elm Fork of the Trinity River in Lewisville, Texas.

Beyond the clearance required by the hydraulic conditions, the bridge was raised further to preserve room for a future trail underneath, allowing for a potential pedestrian and bicycle connection without crossing the roadway.

Environmental considerations moved alongside those decisions as well. Wetlands and aquatic features within the corridor required coordination and permitting as the roadway and bridge designs developed.

What began as a roadway extension effort ultimately required coordination across a broad range of disciplines. Over the course of design, permitting and construction management, 15 teams across five Halff offices have contributed to Corporate Drive, including public works, transportation, structural, water resources, environmental, utility and other disciplines.

From Concept to Construction

For Halff’s David, Corporate Drive is also part of an extended working relationship with Lewisville. During his 23 years at Halff, David has worked on several projects with the City, giving him a firsthand perspective on the area’s development.

Corporate Drive is a particularly visible piece of the region’s network.

The corridor begins in Flower Mound as Forest Vista Drive before continuing through Lewisville as Corporate Drive. Farther east, it becomes Carrollton Parkway, continues through Castle Hills as Windhaven Parkway, crosses The Colony and ultimately reaches Legacy Drive in Plano.

Map of the proposed Corporate Drive extension (red) and its connection to the surrounding roadway network in Lewisville, Texas.

For Lewisville, a largely built-out community, it also represents one of the city’s last major arterials to be completed. The connection is designed to create a long-needed east-west travel option through the area without requiring drivers to rely on State Highway 121 or Sam Rayburn Tollway for the same movement.

The corridor is also expected to create access to currently undeveloped properties with limited access. Extending Corporate Drive creates another point of entry that positions those properties to support future commercial or industrial development as the surrounding area continues to grow.

For David, the project also carries personal significance.

“My journey with the City of Lewisville began right after graduation as one of my first engineering projects. Having since worked on six other projects around Corporate Drive, it’s been amazing to watch this area grow and evolve over the years. I chose civil engineering because I wanted to build communities and serve the public. It has been an incredible experience partnering with the City to bring these ideas to life and make a real impact on the community.” – David Smith, PE

Bringing the vision closer to reality required the team to address challenges throughout the corridor, including right of way, existing access and construction planning. In one area, a retaining wall was incorporated into the design to accommodate a turn lane while keeping the roadway within available right of way. During construction planning, particular attention and effort ensured that access remained available for existing properties and truck traffic along the corridor.

Halff has remained a strategic partner, guiding Corporate Drive through design, permitting and construction management and providing continuity across each phase.

For a project with so many intersecting pieces, that continuity has been particularly important. A change involving the floodplain could affect structures. A structural decision could affect a utility. A roadway decision could affect right of way or environmental permitting. Keeping those conversations connected became part of moving the larger project forward.

Completing the Corridor

With an expected completion date of 2027, the Corporate Drive extension is designed to improve local east-west mobility and provide access to properties along the corridor, supporting Lewisville’s transportation and future development needs.

From its earliest concepts to current construction, the Corporate Drive project team has balanced the needs of a regional transportation network with the conditions of the surrounding landscape. As the final connection takes shape, the project reflects more than a decade of collaboration between Halff and the City of Lewisville.

Let’s Connect!

Have a project in mind? Discover how Halff’s multidisciplinary expertise can help bring your vision to life.

Reach out to Operations Manager David Smith (dsmith@halff.com) or Structural Project Manager Samantha Dorrell (sdorrell@halff.com).