Based on the deterioration of the existing Johns Pass Bridges substructure conditions and the frequency of ship impact causing damage to the existing fender system, two new mid-level bascule bridges were constructed in conjunction with the widening of the existing 60′ channel width to 100′. The profiles were raised to the maximum extent possible while staying within the existing R/W and maintaining compliance with ADA requirements. The bridge foundations consisted of approximately 200 drilled shafts to depths of up to 120 feet.

H2R Corp provided geotechnical engineering, drilling, design, drilled shaft inspection, cross-hole sonic logging, and materials testing during the construction. Performed SPT borings and rock coring to 150′ below water level, designed 60″ and 36″ diameter drilled shafts that were constructed to approximately 110′ below grade for both the Northbound and Southbound SR699 bridges Madeira Beach and Treasure Island.