A 32 year old dock that has a rolling ship loader weighing 750 kips suffered severe damage to two of the 70' pre-cast concrete double "T" spans.

Over 70% of the pre-tension cables were either broken or suffered severe sectional loss.  to further complicate the matter, the bottom of the 20" wide x 6'-0" high beams were only inches above the high-tide level.

The remainder of the 10 spans also suffered spalling due to salt water intrusion.

Access to the work site was limited.  We had to contend with tides and weather.

Cut away all damaged concrete (one beam 30', the other beam 20'), dowel in #8 rebars, form and pump 5,000 psi concrete.  After the concrete has cured, install an engineered, custom designed, pre-cured 3/4" thick, 20" wide carbon fiber plates.  Wrap the entire beam with multiple layers of carbon fiber.  After curing, all the carbon fiber was coated with a class V coating for UV protection.

The final design shows that the carbon fiber plates used achieved the following properties:

Mean Tensile = 197,016 psi

Mean Modulus = 19,506,500 psi

Strain to failure = 1.01%

The original design utilized 16 inches of plate width (actual is 17.75").  That means the installed plate has a tensile capacity of 2,364,200 lbs.!