Influence of Active Confinement on Behavior and Strength of Reinforcing Steel Anchorages

Abstract

The strength and behavior of large-diameter reinforcing steel bars with straight anchorages were experimentally investigated. The anchorage details are typical of monolithic girder-column connections used in bridges and buildings in the midcentury. Eleven subassemblage column specimens were examined with different anchorage lengths, bar groupings, amount of transverse steel, and externally applied column axial forces. Test results showed an increase in anchorage capacity because of the presence of transverse steel and externally applied axial force. Experimental results were compared with contemporary design specifications which do not currently account for the beneficial effects of column axial compression acting transverse to the splitting plane. A modification factor was developed to account for the presence of active force applied transverse to the splitting plane to determine anchorage capacity that better estimated the available capacity of the anchorages.