A STUDY ON FLEXURAL BEHAVIOR OF PRESTRESSED CONCRETE SIMPLE BEAMS WITH EXTERNAL TENDONS UNDER STATIC LOADS | ||||
| JES. Journal of Engineering Sciences | ||||
| Article 2, Volume 35, No 4, July and August 2007, Page 869-889 PDF (813.88 K) | ||||
| Document Type: Research Paper | ||||
| DOI: 10.21608/jesaun.2007.114321 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Khairy Hassan Abdelkareem* | ||||
| Civil Engineering Department, Faculty of Engineering, Assiut University, Assiut, EGYPT | ||||
| Abstract | ||||
| Using a verified finite element algorithm, non-linear analysis of externally prestressed concrete beams was carried out to investigate the flexural behavior of such beams under static loads. The behavior of such beams is represented by; change of tendon’s eccentricity, load deflection diagram, the relations of load and stress in external tendons, effective depth of beam, and bond strain reduction factor. The parameters affecting the behavior of such beams include: span to depth ratio, distance between loads to span ratio, distance between deviators to span ratio, the ratio of prestressing index and reinforcement index strength and tensile and compressive reinforcement ratios. The strain variation in an external tendon was investigated on the basis of the deformation compatibility of beam. The proposed method for the numerical analysis can satisfactorily predict the behavior of externally prestressed concrete beams up to the ultimate loading stage. The stress increase in an external tendon depends mainly on the overall deformation of beam. The behavior of externally prestressed concrete beams is different than that of bonded prestressed beams due to the second order effect of tendon’s eccentricity. This point is clearly investigated in the current study. From the obtained results, a model was proposed to estimate both of the bond strain reduction factor ( R ) and effective depth reduction factor (K) considering the effect of the parameters affecting the behavior of such beams. Based on numerical analyses, a model was proposed to calculate the flexural strength of externally prestressed concrete beams considering the parameters of the study. | ||||
| Keywords | ||||
| Externally prestressed beam; external tendon; deviators; flexural strength; bond strain reduction factor; effective depth | ||||
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