Presentation on theme: "1. By Dr. Attaullah Shah Swedish College of Engineering and Technology Wah Cantt. CE-407 Lec-02 Structural Engineering."— Presentation transcript:
By Dr. Attaullah Shah Swedish College of Engineering and Technology Wah Cantt. CE-407 Lec-02 Structural Engineering
The net stress in the prestressed section The resultant stress due to the combined effect of applied loads and pre- stress force is given as: At the ends of the beam where there is no moment the MC/I =0, the stress becomes
The kern of a section is the region in which a compressive point load may be applied without producing any tensile stress on the cross section.
Shapes of pre-stressed sections: −Rectangular shape: Simple and easy to pour −I-Section and T-section: Economical −Channels and Boxes
Prestress losses −The initial prestress becomes smaller with time due to following reasons: A lump sum value has been recommended by ACI Code