Durable, Liquid-tight Tanks

Vertical prestressing of tank walls is an important element of producing a durable, crack-free, liquid-tight storage tank.

Leak and Crack Prevention

Vertical compression of the walls has proven extremely effective in preventing concrete cracking and subsequent deterioration caused by leakage. DYK believes that high strength thread-bars meeting the properties of ASTM A-722 Type 2 provide the best vertical compression in tank core-walls.

The thread-bar is a high strength steel bar of all-thread with a positive screwed-on nut as the anchorage. The nut anchorage eliminates the stress concentrations typically associated with the alternative wedge anchor's razor sharp teeth used to bite into strand tendons.

Optimum Stressing

During field installation, DYK recommends a "ball  and socket" type joint at the end of the nut to allow for construction tolerances. Without this feature, any misalignment can produce bending stresses that increase the tensile stress and overstress the bar.

The thread-bar also eliminates any seating loss by completely tightening down the anchorage nut. By placing a single bar in a rigid PVC pipe, problems associated with multi-strand tendons, such as bunching and friction losses, are also eliminated.