How to avoid creeping concrete and sliding formwork
It should be borne in mind that with large openings in the walls of the structure, a torque arises from the wind load, and the concrete in the upper part of the wall, without having time to gain design strength at this moment, has creep, therefore the upper part of the walls of the structure can be deformed in the direction of torque after the exit. walls from the formwork. To avoid this, the openings in the external walls should be sealed after the walls of the formwork shields exit.
The speed of lifting sliding formwork affects the value of deviations. The higher the speed, the lower the action of the horizontal loads on a certain area of the concrete wall, the less concrete deformation, therefore, is less than the deviation. This is confirmed by the results of observations in the construction of silos at a speed of 8 m/day; At the same time, deviations at an altitude of 40 m were no more than 6 cm.
In another case, when erecting tower Kopov, the speed was 1, 5-2 m/day and deviations reached 10-15 cm at the same height. Along with this, timely geodetic control over the deviation of walls and formwork is of great importance.