How do you move thousands of tons of coal per day from railroad cars into ocean-going ships? You build the largest shiploaders in the world.
Along the Mississippi River, North of New Orleans, stands a new dock, nearly 1500 feet long. Until this month, it was mostly empty, but 12 concrete pedestals projected several feet above the dock. Each pedestal holds 12 steel bars, in a precise pattern, projecting vertically for a couple feet.
Seven-hundred miles away, three steel towers grew to more than the height of four-story buildings. The feet of each tower must be precisely built so that the tower can be lifted and secured on the pedestals in Louisiana. Also, each tower foot contains 12 machined holes that must precisely match the dimensions and patterns of the steel bars on the docks. Moreover, once installed, the tops of the towers must be dead level. But no person may be on the towers as they are set in place. Installation of the towers requires a team of 40 engineers and mechanics and a crane that costs $30,000 per day. How do you ensure that all 144 machined holes will exactly fit the 144 steel bars waiting 700 miles away?
The potential for costly errors is both obvious and unnerving.
3D Imaging Services used laser scanners to measure the dock, the pedestals, and steel bars on the Mississippi River, and we measured the towers while they were still being built in Florida. We identified errors that would have prevented two of the towers from being set in place; the steel company made corrections before the towers were shipped across the Gulf by barge.
In Florida, 3DIS also made specific measurements of the completed towers so that they could be positioned with the tops exactly level even though no one was on the towers until they were secured. Savings to the owner totaled more than $300,000 and more than two weeks of delay on the project site.