Thesis (M.Sc.) - Cairo University - Faculty Of Engineering - Department Of Civil Engineering

The program has investigated serviceability of partially prestressed concrete beams with different cross sectionsThe main objective of the study was to examine the various flexural limit states behaviour in terms of deflection prior to and after cracking , cracking behaviour , and modes of failureThe program consisted of experimental and analytical phasesThe experimental program includes testing of five 38 - m - long partially prestressed concrete beams , four beams prestressed by two 1524mm diameter strand in addition to two 8mm diameter deformed bar and one beam prestressed by two 1524mm diameter strand onlyThe variables in the experimental program were the partial prestressing ratio , section shape and the concrete gradeThe analytical phase included a rational analysis using the strain compatibility approach to describe the behaviour of the beams in terms of strain distribution , cracking and ultimate carrying capacity of the beams as well as calculation of the deflection and the crack width of the beamsAnalytical results for predicting beams deflection has been compared to the experimental resultsCrack width calculations for partially prestressed members have been related either to a fictitious tensile stress in the concrete or to the stress in the reinforcementControl of the crack width using the fictitious tensile stress approach is achieved by limiting the fictitious tensile stress at the extreme tensile fibre of the concrete memberTwo detailed methods to calculate the crack width according to the stress in reinforcement approach has been used and compared to the observed crack width results

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