For simplifying the analytical procedure of unbonded prestressed beams, an analytical model of concrete beams prestressed with external or internal unbonded tendons was proposed by using a general purpose finite element program.

Take the advantage of the pipe bed height,the technique introduced in this paper is to reinforce the wide-flat beam by out no-conhesion prestressing and laminated slAbs;and to reinforce the precasting hollow slab by using no-conhesion prestressed laminated slAbs.

Effects of corrosion of the unbonded tendons on the mechanical behavior of the tendons and bearing capability of the structure are discussed.

The embedment of unbonded tendons,the calculation of elongation value,the key points in construction of swimming anchor angle tension and so on are introduced,providing a reference for relevant construction.

Characteristics and applications of equivalent loads in unbonded prestressed tendons;