Fire endurance of high strength concrete columns

In buildings, re represents one of the most severe environmental conditions, and therefore, should be properly accounted for in the design of high strength concrete (HSC) structural members. The increased use of HSC in buildings has raised concerns regarding the behavior of such concrete in re. In particular spalling at elevated temperatures, as identified in studies by a number of laboratories, is a main concern. In this paper results from an experimental program on the re resistance of HSC columns are presented. The factors that influence the thermal and structural behavior of HSC concrete columns under re conditions are discussed. Data from this study indicate that the type of aggregate, concrete strength, load intensity and detailing and spacing of ties have an influence on the re resistance performance of HSC columns. Further the test results show that tie configuration (bending of ties at 135degrees ties and provision of cross ties) and closer tie spacing has a significantly beneficial effect on the re resistance of HSC columns. The results presented will generate data on the re resistance of HSC columns, and contribute to identifying the factors that influence the behavior of HSC columns.