In Step 5 under minimum and maximum moments we calculate critical stresses that occur at soffit of precast prestressed element. The stress conditions are (P_inf ? M_min/_b) < P_ct
(?P_inf-M/Z_b-M_b/Z_b) > or equal to p_th.

The prestressing steel, sheathing and anchorages should be stored at site in such in such a way as to provide m with adequate corrosion protection and after stressing steel in sheath, it should be provided with permanent protection as soon as possible preferably within one week and while providing protection by pressure grouting of cement, care should be taken that neighboring cables are penetrated by grout.

For spans less than 35m, SSB are cheapest type of construction and as span increases, cost of simply supported beams increases rapidly and it is prohibitively costly for spans exceeding 60m.

The modular ratio of precast prestressed unit varies in range of 1.1 to 1.5 however this value could be larger if light weight concrete with a modulus in range of 5 to 12kn/mm² is used in conjunction with precast units made of normal weight aggregates.

It may become necessary to determine section modulus of precast prestressed section for a composite slab of given depth and eir case, formulae relating section moduli of precast prestressed and composite section loading on member, permissible stresses in concrete and loss ratio may be developed by considering various stages of loading.

Effective bending between two parts of a composite beam may be developed by providing castellation in precast unit or by roughening contact surface of precast unit before placing insitu concrete or by projecting reinforcements from precast unit which serve as ahead connectors.

The efficient utilization of material in a composite member in a composite section in which low and medium strength concentration of insitu construction resists compressive forces while high strength prestressed units resist tensile forces.

In a composite construction precast prestressed members are used in conjunction with concrete cast in situ so that members behave as monolithic unit under service loads and stirrups produced from prestressed unit into added concrete or by castellation on surface of prestressed unit adjoining concrete which in cast in situ.

Precast double tees have been used in partially structures, bridge decks are cast in situ slab, it has long term durability and gives aestic flexibility, fire resistance and low maintenance and resists gravity seismic and using loads.

In many cases precast prestressed units serve as supports and dispense with form work for placement of insitu concrete and composite members are ideally suited for constructing bridge decks without disruption of normal traffic.