VRX was a key member of the design/build team responsible for the DART Blue Line Expansion Project, designing three dual track rail bridges. The expansion, beginning at the existing DART Downtown Garland LRT Station, follows the old Missouri-Kansas-Texas Railroad’s right-of-way (ROW). The project continues approximately 4.8 miles eastward to the proposed DART Downtown Rowlett LRT Station site, adjacent to the existing DART Rowlett Park and Ride. The project alignment was designed to achieve a 65 miles per hour operational speed through the majority of the alignment, while maintaining a minimum operating speed of 50 mph through several horizontal curves. Full double-tracking was included to provide 10-minute headways during peak periods and 15- to 20-minute headways during the off-peak periods and weekends.
VRX staff was responsible for the design of the foundations, substructure and superstructure elements for State Highway 66 and Main Street in Rowlett and Garland. The State Highway 66 Structure is a two-span, 190-foot-long bridge carrying two LRT tracks over the existing State Highway 66 on a vertically-curved and horizontally-tangent alignment. Both spans consist of AASHTO Type IV prestressed concrete beams supporting an 8-foot minimum cast-in-place deck with a ballasted rail and service walkways along both sides. Abutments consist of deep abutment caps founded on 48-inch diameter drilled shafts into limestone. The MSE walls terminate in the abutment cap. The pier is located in the median of State Highway 66 and consists of a rectangular cap on twin 48-inch diameter columns founded on 54-inch diameter drilled shafts into limestone. The Main Street structure is a single-span, 95-foot 6-inch-long bridge carrying two LRT tracks over the existing Main Street on a zero-grade profile and horizontally-tangent alignment. The bridge geometrics are governed by the future widening of Main Street and several underground utilities. The Main Street structure consists of AASHTO Type IV prestressed concrete beams.
VRX also produced the construction documents and provided construction support throughout the project. VRX staff were responsible for the design of three ballasted deck, dual-track structures located over Main Street, State Highway 66 and State Highway 78. The aerial structures are multiple-span bridges utilizing AASHTO Type IV beams on concrete caps, columns and drilled shafts.