Experimental Research On Fire Resisitence Performance For R. C Columns Under Eccentric Loading With Damages Caused By Service Loads

Since reinforced concrete structures and members are destroyed seriously and even collapse in fire.pecople put more and more attention to the behaviors of reinforced concrete structure and members under elevated temperature. Considerable experimental research and theoretical analysis are in progression, for example, materials strength and elastic modulus of reinforcement and concrete and bond strength between reinforcement and concrete deteriorate significantly. Systematic analysis and conclusions are made; meanwhile other studies in this thesis were included as following:(1) The concrete structural performance and influencal factors under fire were analyzed with material and member;(2) Thermal and mechanical properties of concrete and reinforced bar were reviewed comprehensively, besides, achievements and shortcomings were comprehensively analyzed as well.(3) Five R.C. eccentric compression columns were designed to simulate the developing of cracks at serviceability limit states which was index of initial damage for fire resistance performance.(4) Fire behaviors of the initial damage of the R.C. eccentric compression columns were studied. The final destruction of the eccentric compression column, distribution of cross-section temperature field and axial deformation were observed, the law of distribution of temperature impacted by initial damage was drawn.(5) According to the measured cross-section temperature, cross-section bearing capacity of five eccentric compression columns at high-temperature was theoretically analyzed. Against to degeneration on mechanical performance of materials and reductionon section dimension of R.C. column post-fire, primarily discussion was carried out on the calculation method of residual bearing capacity, which was named equivalent corss-setion economization.