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原文传递 Influence of Temperature on Precast Bridge Girders; Final rept. 1990.10-Apr 92

题名：	Influence of Temperature on Precast Bridge Girders; Final rept. 1990.10-Apr 92
作者：	Yazdani, N.
关键词：	Highway bridges; Girders; Precast concrete; Thermal analysis; Thermal stresses; Temperature distribution; Compressive strength; Thermocouples; Prestressing; Thermal expansion; Temperature effects
摘要：	Precast concrete I-griders are commonly used by the Florida DOT to support short to moderately spanned highway bridges. These girders are subjected to daily and seasonal temperature variation during storage at precast yards. Thermal gradient over the depth of such girders can cause unwanted effects such as cracking, twisting or camber. This study was undertaken to investigate the temperature gradients and strains caused by differential temperature on precast girders. Types II, IV, V and VI AASHTO girders were instrumented with thermocouples and vibrating wire strain gages at a precast yard in two phases. Dataloggers were used to collect and store data over two week periods in summer and winter. Temperature and strain data were normalized with respect to the initial data. Data distributions over the depth and length of precast girders were developed. These distributions were compared with theoretical distributions from a computer program. It was found that the heat of hydration released soon after concrete casting in precast girders was significant during the first 24 hours.
总页数：	136p
报告类型：	科技报告