A Study on Flexural Strength with the Spreading of the Negative Steel of Girder into the Adjoining Slab

The study of girder-to-column joints under experiment and numerical analysis was carried out to evaluate change of the flexural capacity of the joints with the 2-layer upper reinforcement of girder within rectangular section and the single-layered upper reinforcement at the girder flange. The distribution of the upper reinforcement of girder within the effective flange width was the variable in the experiment and numerical study. The ultimate strength of the specimen with 2-layer upper reinforcements of girder was larger than that of the single-layered specimen by maximum 17.4%. Based on the results of this experimental study, for the single-layered tension reinforcement it is recommended to provide 15% additional reinforcement at twice slab thickness on each side of the main girder to attain the flexural capacity equal to the 2-layered case.