SIZE EFFECT OF NORMAL SECTION BEARING CAPACITY OF REINFORCED CONCRETE COLUMNS

In order to investigate the size effect of normal section bearing capacity of reinforced concrete columns， three different section size，including 300，500 and 700mm，six reinforced concrete columns were tested． The change rule of normal section size bearing capacity，reinforcement strain，concrete strain，neutral axis height and strength coefficient with the section size was analyzed． The results indicate the deformation capacity of concrete under compression zone is decreased as section size increased． For large size specimen，the code value of concrete ultimate compressive strain is larger． Normal section bearing capacity is decreased as section size increased，the more large level deformation increase，the more obvious the size effect of normal section bearing capacity becoming． Then on the basis of experiment，a practical model of normal bearing capacity of reinforced concrete column considering size effect on concrete was proposed，the safety coefficient of large size specimen is consistent with results of small size specimen．