Anchorage by T‐heads is stiffer than anchorage by hook or bend. Additionally, compression stresses in transversal direction (the confinement effect) is delivered effectively by the head plate. The high capacity of the head‐to‐bar connection allows HRC‐T‐headed bars to be loaded up to the rupture of the reinforcing steel (“bar break”).
The effects of confinement
increase in concrete strength
increase in compression strain (possibility of absorbing energy by plastification)
slower strength decrease after crushing of the concrete (ductile behaviour)
Reinforcement of a reload‐test: observe same length of T‐headed bars
Result of reload test: no buckling of bars supported by T‐heads in repaired area and relocation of the plastic hinge
The shaded area is confined by the action of the T‐headed bars: buckling is prevented; concrete strength and compression strain are increased.
Application at anchorage points of pretension reinforcement