Experimenttal Study On Creep And Shrinkage Of Concrete For Nonuniform Thin-walled Hollow Pier

In the western loess gully region of Henan province , the high-pier continuous girder bridge is the more economical type. The shrinkage and creep are the inherent time-dependent characteristics of concrete material. When the vertical displacement of adjacent high-rise pier of thin-wall and hollow section top has larger difference , continuous beams would have given rise to internal forces. It is important to accurately estimate and predicate the effect on high-rise pier of thin-wall and hollow section which arise from shrinkage and creep for design and construction control. Due to the requirements of the construction process, the use of ready-mixed concrete at the scene is necessary. However, owing to the larger liquidity, the larger ratio of cement and fine aggregate in mixing proportion and the smaller ratio of coarse aggregate, merchandise concrete has larger shrinkage and emerges cracks easily.Through the forgoing research work,the major findings are as follows:(1)Based on the past research findings, this paper explains detailedly the mechanism of concrete shrinkage and creep, the effect factors, the calculation theories and methods. On the solid theoretical foundation, the author do the work of the selection of the prediction model of concrete shrinkage and creep.(2)Comparison research indicates the GL 2000 model performs best for predicting shrinkage and creep, among the four neoteric prediction models. So the GL2000 model and the improved fomula which considering the 1986 model are firstly recommended in case of lack of test data and the foreign models have to be chosen.(3)With Xizhangcun Bridge for engineering background, study batching technology of low-shrinkage and low-creep for concrete. The result has been applied to practical engineering. This paper designs an experiment of shrinkage of C40 concrete, calculats the shrinkage and creep coefficient in accordance with the conditions at the scene and the calculation result fit well with the measured result.(4)Through theoretical calculation, obtain the stress which caused by the shrinkage of concrete and influence coefficients computation of the impact on shrinkage and creep of concrete which caused by reinforced. We can take into the parameters to consider the effect of the reinforced with the finite element method.(5) With Xizhangcun Bridge for engineering background, this paper establishs the MIDAS module of construction supervision, does the simulation and analysis with actual parameters of the construction processes. The result is directly applied to the monitoring of the construction of the high-pier, and provids the data for the design and construction of high-rise pier of thin-wall and hollow section with the same type in this region.