الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
The specific objectives of the research plan are investigate the behavior of tension lap splice in reinforced concrete beams and its influencing factors an experimental program has been conducted.
The program includes construction and testing of fifteen full-scale simply supported beam with cantilever reinforcing specimens with different configurations under two point load.The test results as observed by visual inspection and by instrumentation are presented in different forms such as crack patterns, load-deflection curves, deformations and strains at critical specimen locations, and summary of major events.
Themain objective of the test program is to the essential need for further research to study the effect using Self compacting ( SCC ) on the bond behavior of tension Lap – spliced reinforcing steel . It designed to study the bond behavior of tension lap spliced for SCC cantilever beam specimens. The concrete compressive strength, splice length ,concrete cover , the effect of confining steel and level of confinement are the main variables considered in this study.Studying the behavior of tension lap spliced in both shear and flexural failure for SCC cantilever beam specimens. Developing an analytical formulation for prediction of the bond stress of tension lap splice cantilever beam.The results and observations of the testedbeam specimens are reported gives a brief description of different test indicators ascrack patterns,load deflection response,load-Steel Strain Curve,load –crack width response,stress profile along splice length and mean bond stress at splice.The recorded results are analyzedin this section. These results include load-deflection relationship, ultimate load, ductility and strength reference and bond stress at lap splice.
The experimental test results of ultimate bond strength and the predicted ultimate bond strength obtained using equations,Several researchers have attempted to formulate equations that represent the bond between the reinforcing bars and the concrete.
5.2 Conclusions
Based on the experimental and analytical results of 15 beams with cantilever specimens constructed from NCC and SCC with different lap splice configurations.The following conclusions can be drawn:
1 Increasing Splice length from (25%to 100%Ld) significantly improve the ductility, energy absorption and the structural behavior at failure (such as mode of failure), When comparing the splice length(25% and 50%Ld) with reference beam we find that the ductility decreased by 43% and 23% respectively, and the energy absorption decreased by 50% and 33% respectively. Splice length (100%Ld) have more ductility and energy absorption than R.B by 31% and 10% respectively. But it had a negative effect on the beam capacity to be lower than the reference beam by 12%, Finally, the measured steel stress and the bond stressfor splice length (25%Ld) increase by 69% according by splice length (100%Ld).
2 Increasing stirrups intensity at splice zone from (ø10@200) to (ø10@100) mm decreases the shear cracks at the ends of splice and raise the capacity of specimens by 22% and make the failure more ductile, In order to the ductility and energy absorption increased by 45% and 63% respectively.Increasing stirrups intensity increases the ultimate bond stress by 14%.
3 Increasing concrete compressive strength from (35 to 65) Mpa raises the beam capacity and have more positive effect on the bond strength of reinforcing bar. As well as the load deflection stiffness increased up to the ultimate load Also the energy absorption by about 26%.
4 SCC raises the capacity of specimens higher than NCC specimens by41% and 8% for splice length (25%Ld and50%Ld) respectively.No significant difference in ductility but the energy absorption higher by13% for (25%Ld) and by 31% for (50%Ld).The bond strength have a significant improvement in SCC specimens in splice length 25%Ld increased by 12% and in splice length (50%Ld) increased by 10%.
5 The analytical results show a good agreement between results of measured bond stress and predicted equations especially in short splice length (25%Ld= 18.5ø) which the experimental results match well with prediction equations especially the (O.J.B model) eq.
5.3 Recommendations for Future Research
1- Study the splice length (1.3Ld) and compared it with the reference beam and beam have splice length equal (100%Ld).
2- ( factor –η );(in the current formulae of lap lengthin ECP203-2007) need to more study or need to be reworked in ECP203-2007 specially in SCC.
3- ACI code has a considerable safety factor and ECP is conservative in calculating lap length.
4- In this study only some parameters are taken in to account in studying the behavior of splice at cantilever ( at negative moment). Other parameters must be studied also such as number of splice, different lap length and different concrete mix proportions.