Post-tensioning anchorage with equalized tendon loading

A wedge for an anchorage system for post-tensioned concrete reinforcement, the anchorage system including a tendon and an anchor having a flange with a front surface and a rear surface, the anchor having at least one wedge receiving bore, the wedge receiving bore having a tapered interior surface, the wedge receiving bore extending through the flange portion, the wedge comprising:

• an internal surface formed prior to contact with the tendon so as to contract as the wedge is drawn into the wedge receiving bore and engage an outer surface of the tendon, the internal surface so formed so as to include:
• a first section with a first taper angle, the first taper angle being defined by the angle between an imaginary line extending from the first section and a longitudinal axis of the wedge, and
• a second section with a second taper angle, the second taper angle being defined by the angle between an imaginary line extending from the second section and the longitudinal axis of the wedge, the first taper angle being less than the second taper angle,
• the first section being near a front side of the wedge and the second section being near a rear side of the wedge;
• and
• an external surface formed prior to contact with the wedge receiving bore to engage the tapered interior surface of the wedge receiving bore of the anchor and contract as the wedge is drawn into the wedge receiving bore;
• wherein the internal surface includes a first section with a first taper angle, the first taper angle of the internal surface being defined by the angle between an imaginary line extending from the first section of the internal surface and the longitudinal axis of the wedge, and a second section with a second taper angle, the second taper angle of the internal surface being defined by the angle between an imaginary line extending from the second section of the internal surface and the longitudinal axis of the wedge, the first taper angle of the internal surface being less than the second taper angle of the internal surface, the first section of the internal surface being near a front side of the wedge and the second section of the internal surface being near a rear side of the wedge so as to equalize the distribution of compressive forces over the first and second sections.

An anchor for a post-tension concrete reinforcement, the anchor comprising:

• a body having a flange portion with a front surface and a rear surface;
• and
• a bore extending through the flange portion, the bore having a first section with a first taper angle and a second section with a second taper angle, the first and second sections being formed prior to contact with a wedge which is received by the bore, the first section being near the front surface and the second section being near the rear surface, the first taper angle being defined by the angle between an imaginary line extending from the first section and a longitudinal axis of the bore, the second taper angle being defined by the angle between an imaginary line extending from the second section and the longitudinal axis of the bore, the first section configured to engage a wedge along substantially an entire length of the first section, the second section configured to engage the wedge along substantially an entire length of the second section so as to equalize the distribution of compressive forces over the first and second sections;
• wherein, the length of the second section is less than one tenth the length of the first section.