High-strength concrete and steel interaction in RC members

Abstract

A test examining the structural behaviour of beams, slender columns and portal frames subjected to short-term loading is presented. Concrete cube strengths used were 80–100 MPa. The two reinforcement ratios of beams ( ρ≈0.5% and ρ≈1.5%), two slenderness ratio of columns ( l/ h≈12 and l/ h≈22) and three arrangements of reinforcement of frames ( ρ constant) were taken as main parameters of test. Tests proved that fears of low limit deformability of elements cast of high-strength concrete (HSC) are unfounded. In elements that failed by crushing of concrete in the compression zone this occurred at much higher strains than those recorded in tests on specimens. In beams strains attained even 6%. Limit curvatures of cross-sections were distinctly greater than in elements cast of normal concrete and full redistribution of internal forces took place in frames. Bond between reinforcement and concrete was retained even at very large strains, exceeding 40 ‰. Analytical non-linear model was used to obtain deformation capacity of beams and columns.