Apparent Thermal Coefficient of Expansion of Concrete Building with Restraint

Abstract

The expansion coefficient of a four-story open reinforced concrete parking structure subjected to wide temperature variation was measured in this paper. The structure consists of a waffle-slab floor system with regularly placed columns and measures 52.42 x 71.32 m (172 x 234 ft). An expansion joint was instrumented and monitored for 4.5 years and the joint was instrumented using four vibrating wire displacement transducers with integrated temperature sensors. Transducer measurements were recorded hourly. A description of the instrumentation and monitoring results is presented, which included annual, seasonal, and daily ranges of movement and the corresponding values of the apparent coefficient of thermal expansion (ACTE) of the constructed structure in service. In general, the paper found that values of the annual ACTE were primarily dependent on the degree of restraint and, to a lesser extent, temperature. The measured ACTE ranged from 0.000586 to 0.0793% per 100°C (0.00032 to 0.044% per 100°F), depending on the temperature and imposed structural restraint.