I-75 (SR 93) from Pasco/Hernando County Line to North of SR 50 (US 98)

This project consisted of widening 9.09 miles along I-75 from the Pasco/Hernando County line to north of SR 50 (Cortez Boulevard) in Hernando County. The proposed improvements called for widening the existing four-lane divided interstate highway to six lanes and resurfacing the existing lanes. This project also included the reconstruction of the I-75/SR 50 (Cortez Boulevard) interchange to include dual left-hand turn lanes from SR 50 to I-75, and the addition of a northbound I-75 to westbound SR 50 flyover ramp and a southbound I-75 to eastbound SR 50 flyover ramp.
The proposed six-lane widening maintained the current vertical clearance at Lockhart; however, at Church, I-75 is in a super elevation and the widening reduced the vertical clearance to slightly above 15 feet. This required the existing bridge to be jacked and the piers, end bents, and approach roadways rebuilt to meet the required vertical clearance at the mainline.
Right-of-way acquisition was required for the proposed roadway improvements, new southbound flyover ramp, stormwater management facilities, and mitigation sites. The required right-of-way acquisition was within a state park, which required 4f coordination.
The interchange reconstruction was designed as a Single Point Urban Interchange (SPUI), which required two new mainline bridges along with the two new flyovers. The mainline bridges each were simple-span steel structures with span lengths of 300 feet. The geometry of the interchange was set such that the two new mainline bridges could be constructed while maintaining traffic on the existing bridges and avoid the need for staged construction. The northbound and southbound flyover bridges have total lengths of 2,440 and 2,800 feet respectively. Both flyover bridges were designed with two continuous steel plate girder units on a horizontal curve with a 588-foot radius and in full superelevation. The geometry of the interchange and alignment of the flyover bridges required maximum span lengths of 374 feet and utilized variable depth steel plate girders. Hammerhead piers were utilized and founded on 24-inch square prestressed concrete piles. The substructure design was complicated by the large loads induced by the long span lengths and presence of poor soils within the project limits. All piers were designed with reduced nominal bearing resistance to account for the poor soil properties.

Other features of the project included drainage, signing, pavement marking, and highway lighting.