Strengthening and Closing Cracks for Existing Reinforced Concrete Girders Using Externally Post-Tensioned Tendons
محتوى المقالة الرئيسي
الملخص
This research is devoted to study the strengthening technique for the existing reinforced concrete beams using external post-tensioning. An analytical methodology is proposed to predict the value of the effective prestress force for the external tendons required to close cracks in existing beams. The external prestressing force required to close cracks in existing members is only a part from the total strengthening force.
A computer program created by Oukaili (1997) and developed by Alhawwassi (2008) to evaluate curvature and deflection for reinforced concrete beams or internally prestressed concrete beams is modified to evaluate the deflection and the stress of the external tendons for the externally strengthened beams using Matlab 7.0.
The analytical investigation is implemented on three ideal reinforced concrete beam models, each model is considered to be strengthened using three types of external tendon profile (straight, draped and double draped), where each type of tendon profile is analyzed separately. No comparisons were made with analytical or experimental investigations, because no publications for this kind of studies were found.
تفاصيل المقالة
كيفية الاقتباس
تواريخ المنشور
المراجع
• ACI Committee 318, “Building Code requirements for Reinforced Concrete (ACI 318-2008),” American Concrete Institute.
• Alhawwassi I. F., “Short term deflection of Ordinary, partially prestressed and GFRB Bars reinforced Concrete Beams” M.Sc thesis,
Baghdad university, Iraq, 2008.
• Beeby, A. W., “The Prediction of Crack width in Hardened Concrete Cracking” Journal of Structural Engineering, Vol. 57, No. 1, pp 9-17, 1979.
• Chi, M. and Kirestein, A. F. , “Flexural Cracks in reinforced Concrete Beams” ACI Structural journal, Proceeding, Vol. 54, No. 10, pp 865-878, 1958.
• Clark, A. P., “Cracking in reinforced Concrete Flexural members” ACI Structural journal, Proceeding, Vol. 52, No. 8, pp 851-862, 1956.
• Frotch R., “Another Look at Cracking Crack Control in Reinforced Conrete” ACI Structural journal, Vol.96, No. 3, pp437-442, 1999.
• Gergely, P. and lutz, L. A., “Maximum crack width in Reinforced Concrete, Causes, Mechanism, and Control of Cracking Concrete”, SP20, ACI Structural journal, pp87-177, 1968.
• Hong Sung Nam, Han Kyoung Bong, Kim Tae Wan, Beak Kyeong Seok , Park Sun Kye, and Ko Won Jun, “ Estimation of Flexural Crack Width in Reinforced Concrete Members” ,The 3rd ACF international conference –ACF/VCA 2008.
• Kaar , P. H., and Mattock, A. H. ” High Strength Bar as Concrete Reinforcement ’’, Part 4, Control of Cracking, Journal of Portland Cement Association Research and Development Laboratories , Vol. 7, No.1, pp 42-5.
• Korpenko, N. I., Mukhamediev, T.A. and Petrov, A. N., “The Initial and Transformed Stress - Strain Diagrams of Steel and Concrete.
“ Special Publication, Stress-Strain Condition for Reinforced Concrete Construction, Reinforced Concrete Research Center, Moscow, 7 –
, 1986.
• Newmark, N. M., "Numerical Procedure for Computing Deflections, Moments, and Buckling Loads", Transactions, ASCE, 1-8, 1943.
• Oukaili, Nazar K. Ali, “Strength of Partially Prestressed Concrete Elements with Mixed Re-nforcement by Highly Strength Strands and
Steel Bars”, PH.D. Thesis, Moscow Civil Engineering University, Moscow, 1991.
• Oukaili, Nazar K. Ali, “Moment Capacity and Strength of Reinforced Concrete Members Using Stress-Strain Diagrams of Concrete and
Steel”, Journal of King Saud University, Vol. 10, pp. 23-44, 1997.
• Venkateswarlu, B. and Gesund, H., “Cracking and Bond Slip in Concrete Beams” Journal of Structural Engineering, ASCE, Vol. 98, No.
ST11, pp 2663-2885, 1972.
• Cook R.D., "Concept and Application of Finite Element Analysis", Second Edition, John Wiley and Sons, New York, 1981.