Flexural Strength of Prestressed Concrete Beams with Tendon Wrapped by Plastic Sheets

Ta-Heng Wang ； Ran Huang ； Jiang-Jhy Chang

《Journal of Marine Science and Technology》 21卷1期 (2013/02) Pp. 76-81

https://doi.org/10.6119/JMST-011-1226-1

並列摘要

For post-tension prestressed concrete beams, both of tendons laid in metal duct and wrapped by plastic sheets are recognized as unbonded tendon by researchers, and the same equation is used to estimate the flexural strength. But the contacting conditions between tendon and its surrounding concrete are quite different for these two kinds of unbounded tendons. This study compares the flexural strength, crack distribution and crack width of beams with these two kinds of unbonded tendons and bonded tendon. The results reveal that the structural behavior of tendon wrapped by plastic sheets is between bonded tendon and tendon laid in metal duct. A modified equation is proposed to estimate flexural strength of tendon wrapped by plastic sheets. Reducing cost and shortening construction time are the main advantages for this kind of the prestressed beams with tendon wrapped by plastic sheets. After further investigation, it may be an alternative method for the post-tension prestressed concrete structure in the future.

並列關鍵字

unbonded tendon ； prestressed concrete beam ； flexural strength ； crack width.

參考文獻

ACI Committee 318 Structural Building Code, Building Code Requirements for Reinforced Concrete (ACI318M-08) and Commentary, American Concrete Institute, Detroit, Michigan.

Au, F. T. K. and Du, J. S., “Prediction of ultimate stress in unbonded prestressed tendons,” Magazine of Concrete Research, Vol. 56, No. 1, pp. 1-11 (2004).

Baker, A. L. L., “A plastic theory of design for ordinary reinforced and prestressed concrete, including moment redistribution in continuous members,” Magazine of Concrete Research, Vol. 1, No. 2, pp. 57-66 (1949).

Joint ACI-ASCE Committee 423, Recommendations for Concrete Members Prestressed with Unbonded Tendons, American Concrete Institute, Farmington Hills, Michigan, p. 25 (2005).

Mattock, A. H., Yamazaki, J., and Kattula, B. T., “Comparative study of prestressed concrete beams with and without tendons,” Proceeding of American Concrete Institute annual convention, Denver, Colorado, pp. 116-125 (1971).