Influence of creep and drying shrinkage of reinforced concrete shear walls on the axial shortening of high-rise buildings

摘要

Prediction of shrinkage and creep is important for evaluating the time-dependent effects on the structural performance of concrete structures. Differential axial shortening of high-rise buildings, caused by shrinkage, creep and elastic deformation, is becoming significant with increasing building height. In this paper, an experimental investigation was carried out to study the time-dependent deformation of a RC shear wall which is widely used in high-rise buildings. The large-scale RC shear wall was under sustained load for about 1 year and the shrinkage and creep strains were monitored. The test results show that the rate of time-dependent strains was shape dependent. This indicates that, with the same volume-surface ratio, the current prediction models, which are based on longitudinal measurements of prismatic or cylindrical specimens, underestimate the shrinkage rate of concrete shear walls. A case study was further conducted to illustrate the effects of vertical components' shape on the differential axial shortening of high-rise buildings. In addition, the test results also show that the influence of seasonal variations of ambient relative humidity on shrinkage and creep is significant. Therefore, the axial shortening prediction of high-rise buildings using mean annual relative humidity may not accord with actual situations.