D. Bapu Rao

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Civil Engineering


The yield-line theory provides a powerful tool for studying the flexural behavior of reinforced concrete slabs at ultimate load. The ductility of steel reinforcement and the plastic properties of concrete material constitute the basis for this theory. Therefore, the application of yield-line theory depends on full plastic behavior in the slab at failure; thus, the slab is assumed to be under reinforced. Yield lines initiate at locations of maximum stress and with increasing load they propagate to a full yield-line pattern; at this stage the slab is divided into-segments and is subjected to its maximum useful load. However, due to strain hardening effect, the resisting capacity of the slab can support a slight increase in load beyond this point. This will follow in large deflections which ultimately results in the instability and collapse of the slab. Being comparatively small, the strain hardening effect is disregarded in yield-line analysis. This adds to the safety against failure. The type of loading and the boundary condition of the slab have an influence on the yield pattern. The yield-line method of analysis can be applied to rectangular as well as non-rectangular slabs; also, it predicts, with good accuracy, the behavior of slabs at failure. Therefore, it provides a realistic estimate of the safety factor against failure; hence this method leads generally to an economical design. These are some of the main advantages of the yield-line theory over the existing classical elastic methods of analysis.

Library of Congress Subject Headings

Reinforced concrete

Concrete slabs

South Dakota State University Theses



Number of Pages



South Dakota State University