Toru SHIGA
Effects of Concrete shrinkage and Creep in long-term deformation and stress of RCˇ¦PC members exposed in the field
Takumi SHIMOMURA
In order to predict the time dependent deformation and stress of reinforced concrete and pre-stressed concrete structures under environment conditions, a constitutive model is required in order to accurately represent creep and other phenomena. Also it is important to propose properly the load environment action of the structure to analyze.
In this study, this results are introduced in the time dependent deformation analysis program of RCˇ¦PC elements which considered the effects of creep and drying shrinkage. Also an outdoor sustained bending load test on PC and RC beam specimens was carried. The effect of the environmental factors in the long term deformation and stress development in concrete members was observed and after this it was reproduced by numerical analysis.
Shrinkage in concrete specimens exposed to the environment was smaller than the shrinkage observed in specimens in a temperature controlled room. It was possible to reproduce the difference of the free shrinkage behavior associated with the differences in the environment based on the hourly analysis that considered the effect of weather, humidity, solar radiation and rain.
In change over time of time-dependent deformation for RCˇ¦PC beams under normal outdoor exposition, depending on the environmental conditions the effect on concrete shrinkage can be measured and proven by experimentation. The experimental results were successfully reproduced by an analysis which considered shrinkage of concrete, creep and restraint due to reinforcement.
Using the environmental effect data obtained from AMeDAS database, we proposed a method for future prediction of the time dependent deformation of concrete structures under outdoor conditions. Weather action modeling was made, considering the weather condition difference depending on the area, it is possible to perform a long-term prediction of the free shrinkage amount of concrete and the time dependent deformation of PC and RC beam members.
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