Author : Ghanim Abbas Al-Khafaji, Ali
journal of kerbala university,
Volume 13, Issue 2, Pages 44-62
This paper involves the numerical study of nonlinear behavior of fully prestressed high strength concrete beams. A three dimensional nonlinear finite element model was developed using a computer program (ANSYS V.12).The material and geometrical nonlinearity were adopted in the current analysis.This study investigates the effects of some factors on the flexural behavior of prestressed concrete beams related to the compressive strength of concrete, prestressing reinforcement ratio, prestressing force level, and ratio of shear span to the effective depth. The obtained results showed that the ultimate load capacity are affected slightly with increase the compressive strength of concrete. Increasing of the prestressing reinforcement ratio leads to improvement the overall performance of the prestressed concrete beam , moreover increasing this ratio makes prestressed concrete beam more ductile and has the ability to pass high deflections before reaching failure load. Also increase the level of force of prestressing led to increase the load which causes emergence of the first crack ,but the beam stiffness after cracking and the ultimate load was not remarkably sensitive to the effect of the level of force of prestressing. Finally, it is revealed that the ultimate load capacity of those beams increased greatly with decreasing ratio of shear span to the effective depth .