Evaluation of bond behavior of beam reinforcement before yielding passing through reinforced concrete interior beam-column joint

摘要

In this paper using the available data on interior reinforced concrete beam-column joints tested by the authors, the evaluation method of bond behavior of beam bars before yielding passing through the joint has been proposed. Here the severalinfluencing factors were analyzed and quantitatively evaluated. The following conclusions can be made:(1) The relationship between average bond stress in a joint region ({left sub}oτ{sub}(av)) and tensile strain of beam bars at the column face ({left sub}o250L舺sub}(st)) was formulated for the single layered bar arrangement and for the outer bars of thedouble layered bar arrangement, in which the effect of the bar diameter to column depth ratio, concrete compressive strength, axial compressive stress levels of columns, and the ratio of top to bottom reinforcement areas were considered.(2) Applying the {left sub}oτ{sub}(av)- {left sub}oε{sub}(st) equation, the relationship between average bond stress in a joint and tensile strain at the column face of the inner bars of the double layered bar arrangement ({left sub}iτ{sub}(av)- {leftsub}iε{sub}(st)) could also be evaluated by considering the deformation condition due to shear distortion and shear cracking widths of the joint panel.(3) The strain distribution of beam bars at the column face could be evaluated by considering the relationships of {left sub}oτ{sub}(av)- {left sub}oε{sub}(st) and {left sub}iτ{sub}(av)- {left sub}iε{sub}(st).