To effect a reduction in the labour cost per ton of prestress in prestressed concrete, larger tendons are required. This demand can be satisfied efficiently by the use of multi wire strand, which can be produced with a maximum tensile strength varying from 4 tons to 150 tons. Strand is a flexible structure made of previously cleaned cold drawn wires of the same quality as those now used as prestressing tendons, so that the working stress used for strand is the same proportion of the maximum strength as that now used for small diameter wires. Strand can be produced in any desired length, either clean or covered with a protective coating. It is easily coiled, transported and
handled.
J. L. Bannister