Shrinkage Stress Analysis of Concrete Slab in Multi-Story Building Considering Construction Sequence

Title & Authors
Shrinkage Stress Analysis of Concrete Slab in Multi-Story Building Considering Construction Sequence
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Abstract
Shrinkage strains of concrete slab in multi-story building are restrained by structural members such as columns or walls, then can induce cracks due to excessive shrinkage stress over tensile strength of member. In this study, a shrinkage stress analysis method of concrete slab in multi-story building considering not only material properties such as shrinkage, creep and reinforcement effect but also construction sequence is proposed. Tensile stresses of slab due to shrinkage are calculated by converting shrinkage strains into equivalent temperature gradients, creep that can release shrinkage stress can be considered by replacing the modulus of elasticity of concrete, Ec , to the effective secant modulus of elasticity of concrete, E$\small{\_}$eff/ Reinforcements are also considered by modeling them as equivalent beam elements in FEM program. Results of step by step analysis reflecting construction sequence summed up to calculate stresses of the whole building considering that shrinkage stresses of the building come from the difference of shrinkage between i-th floor and (i-1)-th floor, named as effecitive shrinkage, and it can be varied by construction sequence. The results of 10-story example building show that shrinkage stresses of lower floors are greater than those of upper floors, that is, stresses of lower floors(1∼2FI.) exceed modulus of rupture of concrete, but stress ratios of higher floors are in the range of 27.9∼92.8%.
Keywords
equivalent temperature gradient;effecitve secant modulus of elasticity;effective shrinkage;shrinkage analysis;step by step analysis;
Language
Korean
Cited by
1.
터널 덕트슬래브의 종방향 균열에 대한 원인 분석 사례 연구,박성우;박승수;황인백;차철준;

한국구조물진단유지관리공학회 논문집, 2012. vol.16. 5, pp.19-28
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