10.2 Reasons to cause cracking Loading
10.2 Reasons to cause cracking Loading
Shrinkage Temperature heat Uneven deformation of ground base Corrosion of reinforcement Rebar
Shrinkage Corrosion of reinforcement Temperature heat Uneven deformation of ground base Rebar
10.2 Unfavorable effects of concrete cracking Corrosion of reinforcement Leakage Decrease stiffness and increase deflection Insecurity feeling of human being etc
10. 2 Unfavorable effects of concrete cracking Corrosion of reinforcement Leakage Decrease stiffness and increase deflection Insecurity feeling of human being etc
10.3 Acceptable limits in cracking control There are three grades in cracking control The first grade-Cracking is forbidden Osc≤0 The second grade Short term loading oc≤f C,=0.31.0 Long term loading Oc≤0 y-the section modulus plastic coefficient 截面抵抗矩塑性发展系数 The third grade≤[ol +0.20.4mm
10. 3 Acceptable limits in cracking control There are three grades in cracking control The first grade——Cracking is forbidden 0 SC SC ct t f 0 LC 0.3～1.0 ct The second grade Short term loading Long term loading －the section modulus plastic coefficient 截面抵抗矩塑性发展系数 The third grade max 0.2～0.4mm
10.4 Cracking inner force f For uniaxial tension: N,=(1+贷AM=fA 89
10. 4 Cracking inner force For uniaxial tension: 0 ( A ) f f A n N cr A c s t t t , p t f