During the construction , 2 @.@ 2 million cubic yards of earthwork was used , 350 @,@ 000 cubic yards of concrete was mixed on site , and 300 @,@ 000 square feet of retaining walls were built . Additionally , 40 @,@ 000 feet of drilled shafts and 75 @,@ 000 linear feet of drainage pipe were completed . In addition to the construction of 43 permanent bridges , six temporary bridges were built , resulting in 2 @.@ 3 million square feet of bridge deck .