If we were to construct a building by slipforming how would we control the operation so that the walls were plumb? Would we have trouble compensating for wind?
The instruments that can be used are levels, transits or optical plumbs. Plots should be taken every few hours and the progress carefully observed. If there is movement of the wall away from vertical in any direction the deck of the slipform can be tilted by adjusting the rate of jacking on opposite sides until sufficient correction has been made. An acceptable tolerance in wall surface is 1 inch in 50 feet, or 2 inches in the whole building without regard to height. Tolerances of only 1/2 inch for a building 400 feet high have been achieved. Wind hasn't been a problem, because slipformed structures are highly stable. One structure was hit by a 100-mile-per-hour wind that stopped construction. If it were necessary to adjust for wind, this could be done by tilting the deck.