What are hard steel puffs: features and differences
Strong steel puffs are made of two channels facing the shelves inside. This location of the channel provides a convenient device for tightening shoes.
On top and below, the channels are connected together by steel strips 6 mm thick after 1, 5-2 m in a checkerboard pattern. Reinforced concrete puffs are constructed in the form of preliminary tense bars of rectangular cross section. The tightening prior tension force is taken equal to the expansion from the constant load. High -strength wire or reinforcing beams are used as strained reinforcement. In the first case, puffs are made in advance and reinforced with a high -strength wire pulled to stops.