Title: Five Years’ Monitoring of the Behavior of HPC Structural Columns

Author(s): Buquan Miao and Pierre-Claude Aitcin

Publication: Symposium Paper

Volume: 167

Issue:

Appears on pages(s): 193-210

Keywords: Axial loads; columns (supports); creep tests; high-performance concretes; shrinkage; stresses; temperature; thermal expansion.

DOI: 10.14359/6287

Date: 3/1/1997

Abstract:
High performance concretes (HPC) are increasingly used in high-rise building columns. Some creep and shrinkage data of HPC has been published based on laboratory tests. Very few long term field results are available. During the construction of the new library of Concordia University (Montreal, Canada) in 1990, two pairs of circular 850 mm diameter reinforced, concrete columns made of lOO-MPa silica fume concrete and of 80.MPa non silica fume concrete were instrumented with vibrating wire extensometers. One column (called active column) of each pair was part of the structure; the other (called mockup column) was never loaded and used for shrinkage and thermal strain measurements. Strains and temperatures at different locations in concrete and in reinforcing bars as well as load in concrete were recorded for about 5 years. Data obtained on these HPC columns is presented in this paper. Creep, shrinkage, thermal expansion coefficient of the two field concretes are discussed. Stresses in concrete and in reinforcing bars are analyzed. Axial loads in active columns are calculated from experimental data and compared with the specified loads used in the structural design.