Stress Calculation and Analysis of Super-long Concrete Structures Considering Shrinkage and Creep
Concrete structures may undergo shrinkage due to variations in external environmental temperature and the drying shrinkage during the concrete hydration process.When concrete contracts while being constrained,tensile stress emerges.For super-long structures,if the accumulated tensile stress is overly large,macroscopic cracks are prone to occur,resulting in engineering quality issues.This article expounds on the crack formation causes of super-long concrete structures and the commonly employed control measures at present.It investigates the current calculation methods for shrinkage stress in concrete structures and analyzes the calculation approaches for concrete drying shrinkage and creep.In conjunction with a case of a super-long concrete structure in the Qingdao region,finite element calculations of the floor slab shrinkage stress were conducted using YJK and Midas software.The stresses under uniform temperature drop,temperature differences at different concrete ages,and drying shrinkage creep is calculated respectively.Simulations considering different construction seasons are carried out for the structural shrinkage stress and concrete creep effect.The calculation results indicate that the relaxation coefficients for environmental temperature differences and drying shrinkage differ.The relaxation coefficient of the drying shrinkage effect ranges from 0.35 to 0.45,yet the relaxation coefficient of the environmental temperature difference is related to the duration of the concrete age when the maximum environmental temperature difference occurs.Based on the analysis and calculation results,this paper presents the calculation formula for the equivalent temperature difference of concrete structures considering environmental temperature,drying shrinkage,and creep,with the aim of offering references for the analysis of concrete shrinkage stress in practical engineering.
Super-long concrete structuresdry shrinkage and creeprelaxation coefficientdry shrinkage equivalent temperature differenceequivalent temperature difference
万方数据
维普
