Behavior of Bent Bar Anchorages
John Minor and James O. Jirsa
Appears on pages(s):
anchorage (structural);bars;bond (concrete to reinforcement);hooked reinforcement;reinforced concrete;reinforcing steels;structural engineering.
The object of the study was to examine some of the factors which influence the anchorage capacities of bent deformed reinforcing bars. Eighty specimens containing bars bent to different geometric configerations were tested to determine the effect of bond length, angle included in the bend, inside radius of bend, and bar diameter on the deformation and strength of hooked bar anchorages. Of primary interest was the measurement of slip between the bar and the concrete at several points along the anchored bar. The load-slip curves obtained were used to compare the performances of different bar geometries. The results indicated that at a given bar stress, the longer the angle of bend or the smaller the radius of bend, the greater will be the slip. Ultimate strength of hooked bar anchorages is about the same as that of straight bars. For the pratical joint design detailing, the results indicate that 90 deg hooks are preferable to 180 deg hooks. To reduce the slip the radius of the hook should be as large as pratical.