Title: A Rational Theory for the Function of Web Reinforcement

Author(s): G. N. J. Kani

Publication: Journal Proceedings

Volume: 66

Issue: 3

Appears on pages(s): 185-197

Keywords: beams (supports) ; cracking (fracturing); diagonal tension; failures; flexural strength;reinforced concrete; research; shear strength; stirrups; stresses; web reinforcement.

DOI: 10.14359/7354

Date: 3/1/1969

Abstract:
A test program is described which was undertaken to answer the two basic questions: (1) What is the structural function of web reinforcement?, and (2) What is the relationship between the shear force and the requirement for web reinforcement? Eleven series of reinforced concrete beams comprising 44 specimens were tested for this purpose. Three series had web reinforcement consisting of bent-up bars, three had inclined stirrups, and five had vertical stirrups. To provide a rational basis for explaining the structural function of web reinforcement, a discussion of internal forces precedes the test report. Beginning with a study of stress trajectories, the principle of internal arches is developed and leads to th e realization that the purpose of web reinforcement is to produce supports for the internal arches and that no direct relationship exists between the shear force and the requirement for web reinforcement. The prime objective of the test program was to substantiate the validity of this "principle of internal arches."