When VHB’s engineers undertake a design-build (DB) project, they bring our signature passion for finding the right solutions. This starts with developing Alternative Technical Concepts (ATC). On several recent DBs touching critical highways like I-95 in Rhode Island and the Massachusetts Turnpike, our integrated services team and approximately 200 structures specialists have put their heads together in collaboration with our contractor partners to dig into the Base Technical Concept (BTC). Drawing on their creativity, they develop innovative, valuable ATCs that benefit projects and clients from all angles, offering value like cost savings, schedule savings, simpler permitting, reduced environmental impacts, and reduced long-term infrastructure maintenance costs.
RIDOT, Bridge Group 04_R | Contractor Partners: Skanska, McCourt, and Aetna Bridge
In one of VHB’s 15 ATCs for this DB, our team is revitalizing infrastructure at the I-95 and Route 10 interchange by removing the Huntington Viaduct, which would have been replaced under the BTC. VHB realigned the various ramps connecting I-95 and Route 10 into a halo configuration that circulates traffic around the existing footprint of the Huntington Viaduct, a complete reimagination of the interchange that eliminates more than 20, 000 square feet of bridge deck from the BTC, significantly reducing construction and long-term maintenance costs for RIDOT. The geometry of “the halo” enables the ramp bridges to be built offline, reducing impacts to traffic and the Amtrak corridor running through the area. Its geometry also naturally encourages reduced travel speeds and eliminates the existing weave condition on the I-95 southbound collector-distributor road, creating safer driving conditions. VHB has completed several early release for construction packages, allowing construction to commence while final design is ongoing and permits are being secured.
MassDOT, I-495/I-90 Interchange Improvements | Contractor Partners: Barletta Heavy Division, Inc., O&G, and Aetna Bridge
In the BTC design for the interchange improvements, Ramps EN and NE, between I-495 North and I-90 East, crossed over one another. VHB’s ATC redesigned the alignment of both ramps to eliminate the need for three bridges in the BTC: a structure carrying the ramps over one another and two separate structures carrying Ramp EN over I-90 and I-495. As part of our ATC’s streamlined configuration, we shifted the location of Ramp NE to minimize impacts to the adjacent environmentally sensitive Article 97 and archaeological resource areas. We designed these adjustments to meet the design criteria and avoid requiring an updated interchange modification report, seeing that the project schedule was not compromised. The new ramps are currently under construction.
MassDOT, Raynham Route 44 Over 24 Bridge Replacement | Contractor Partners: SPS New England
Due to the high-volume roadways, proximity of wetland resources, and limited width on the existing interchange bridge, MassDOT’s BTC assumed a conventional three-phase construction approach. VHB worked closely with the contractor to develop an ATC to build a portion of the bridge offline and incorporate a lateral superstructure slide. This accelerated bridge construction (ABC) method allowed VHB to eliminate a full phase of construction and the safety concerns associated with a middle work zone that would have been required with the BTC. The first lateral bridge slide in Massachusetts, this approach reduced bridge construction duration by a year and resulted in $3M of savings for MassDOT.
These ATCs are a testament to VHB’s design creativity and commitment to collaboration with our DB contractor partners, with whom we work closely to develop ATCs that are constructible and cost-sensitive.
Learn more about VHB’s alternative delivery services.
