This study investigates the use of carbon fibre reinforced polymer (CFRP) tendons on precast segmental beams (PSBs) to tackle the corrosion problems which are likely to occur at joint locations of PSBs prestressed with steel tendons. Up to date, the use of CFRP tendons was extensively documented for monolithic beams while their application on PSBs has not been reported yet. Three precast segmental T-section beams including two beams with unbonded CFRP and one with steel tendons were built and tested under four-point loads in this study. The test results showed that CFRP tendons can be well used to replace the steel tendons on PSBs. The beams with CFRP tendons demonstrated both high strength and high ductility as compared to the beam with steel tendons. However, the stresses in the unbonded CFRP tendons at ultimate loading conditions of the tested beams were low, ranging from only about 66% to 72% of the nominal breaking tensile strength. The type of joints i.e. dry and epoxied, greatly affects the initial stiffness of the beams but has no effect on the opening of joints at ultimate loading stage. Moreover, a comprehensive examination on four existing code equations to predict the stress in the unbonded tendons showed that the four examined codes predicted well

No abstract

Results of testing twelve hollow core square reinforced concrete columns wrapped with Carbon fibre 33 reinforced polymer (CFRP) are presented. The effect of fibre orientation on the performance of specimens 34 under concentric and eccentric loads was investigated. Twelve specimens were divided into four groups with three 36 specimens each. The specimens in the first reference group were unwrapped, while the specimens in the 37 remaining groups were wrapped with CFRP of different wrap combinations of three fibre orientations.The specimens in each group were tested 39 under three eccentricities: 0 (concentric), 25, and 50 mm up to failure. Test results show that all wrap-40 ping configurations increased both the strength and ductility of hollow core square reinforced concrete 41 columns. However, the increase of compressive strength was marginal. The columns, which were 42 wrapped exclusively with hoop configuration, proved to have the greatest ductility. Axial load-bending 43 moment P-M interaction diagrams of each group were drawn based on the experimental results and 44 compared with theoretical calculations. The following conclusions are drawn:The fibre in the hoop direction can significantly increase the ductility of hollow core square reinforced concrete columns under concentric or eccentric loading. However, the increment of the compressive strength of FRP-confined hollow core columns is marginal.The combination of 45 oriented CFRP layers and one hoop layer was expected to have the largest ductility. However, it did not show any significant increase in deflections of the columns under both concentric and eccentric testing. 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 17The columns, which were wrapped exclusively with hoop configuration, proved to have the 18 greatest ductility. Axial load-bending moment P-M interaction diagrams of each group were 19 drawn based on the experimental results and compared with theoretical calculations. 20

No abstract