The two main channel piers were undamaged during the failure of the original bridge and were used to support the second bridge with only minor modifications to the concrete pedestals under the new steel tower legs. The original construction of Pier 5 was one of the most difficult ever attempted, establishing a world record for depth of water in which a caisson had ever been landed. Water depth, along with tidal currents of nine miles per hour at the site, required extreme caution and ingenuity on the part of the engineers and contractors. Thirty concrete anchors, each weighing approximately 600 tons and connected to the caisson with 90 one-inch diameter wire cables, were required to hold the caisson against the current. At times the level of water at one end of the caisson would be seven to eight feet higher than at the other. Holding construction barges alongside the caisson was extremely difficult. Steel cutting edges were attached to the bottom of the caisson. After the caisson was lowered to the bottom of the channel in 135 feet of water, the cutting edges assisted in penetrating through 90 feet of sand, gravel, and boulders where the bottom of the caisson was finally positioned at a depth of 225 feet below mean low tide. Lightweight concrete was used in the roadway deck of the present bridge to lessen the load on the piers. However, the total superstructure weight of the present bridge exceeded the first bridge by approximately 1.6 times per lineal foot. The designers determined that this additional weight would not cause excessive overloading of the foundations. The original anchor blocks were also used in the second bridge, but were modified substantially due to the greater weight of the superstructure. This weight increased the horizontal force in the main cables from the original 28 million pounds to 36 million pounds. In addition, the new cables were spaced 60 feet apart compared to the original 39 feet. The concrete anchorage was modified by removing the sides and blasting to the top of the footing blocks. Then, new anchor bars were installed for the main cables. In addition eight feet of concrete was added on each side, and extending the back of the anchor 20 feet to its full height. The additional width and length, in effect, provided a yolk or "U" configuration around the old concrete core that remained.