材料耐久性损伤对混凝土构件抗震性能影响

Influence of material durability damage for concrete member on seismic performance

通过试验验证有限元分析合理性,采用非线性分析方法并考虑钢筋锈蚀后黏结滑移性能退化,并从碳化率的角度,研究材料耐久性损伤对钢筋混凝土构件抗震的影响。研究结果表明:混凝土碳化对构件承载力、刚度及延性影响较小,碳化对构件滞回性能的影响主要体现在滞回曲线饱满程度降低,随碳化率的增大耗能能力退化明显,当保护层混凝土完全碳化时,耗能性能约降低28%。钢筋锈蚀对构件滞回性能影响较大,承载力、延性及耗能性能均随锈蚀率的增大而降低;考虑黏结滑移后,构件开裂前滞回性能变化不大,随着荷载增大,考虑黏结滑移要比不考虑黏结滑移时构件刚度及延性退化更为严重,但对承载力及耗能退化影响较小。综合考虑碳化及钢筋锈蚀对钢筋混凝土构件抗震性能的影响,建议在抗震区控制构件碳化深度及钢筋锈蚀,限制保护层混凝土碳化率不大于60%及锈蚀率不大于10%,从而保证结构良好的抗震性能。

For the purpose of understanding the seismic performance of durability damage reinforced concrete member,based on tests and using the nonlinear analysis methods,corroded reinforced bond-slip performance and concrete carbonation rate were considered in this paper.It’s revealed that bearing capacity,stiffness and ductility of concrete members have been less affected by concrete carbonation than dissipation capacity which degraded significantly as concrete carbonation rate increases.When concrete cover was complete carbonized,dissipation capacity declined about28%.Reinforcement corrosion rate of concrete members greatly affects hysteretic behavior,and bearing capacity,ductility and energy dissipation decreased as corrosion rate of reinforcement increases.When considering bond-slip,hysteretic behavior changed slightly before the concrete section cracks,bearing capacity and energy dissipation changed insignificantly,and degenerative changes of stiffness and ductility were more severe than neglecting the bond-slip.Synthesizing the influence of concrete carbonation and reinforcement corrosion on seismic performance of durability damage reinforced concrete member,this paper suggests keeping concrete cover carbonation rate under60%and reinforcement corrosion rate under10%in order to enhance earthquake-resistance capability of building structure in regions prone to earthquake damage.