... Fig. 11 .8 has been prestressed to effective stress of 900 N/mm2 by four 10.9 mm diameter stabilized strands of characteristic strength of 1700 N/mm2. The area of steel provided is 288 mm2. ... available, for an initialload of 60%, 70% and 80 % of the breaking load, from the manufacturers of the prestressing steel. Linear interpolation of this loss between 60%and 30% of breaking load is allowed, ... weight of masonry is 21kN/m3. Design the beam for serviceability condition(␥f=1). Solution (clause 29.1, BS 56 28: Part 2) (clause 29.2, BS 56 28: Part 2) Assume Mi is 30% of...