In the design of high-strength concrete structures, special attention must be paid to provide sufficient ductility and shear capacity. Experience has shown that the use of conventional stirrups to ensure these properties is limited for areas which are moderately congested. For highly congested areas the use of a recently developed stirrup type becomes almost inevitable. This type is a straight bar anchored by T-shaped heads friction-welded on the bars end. It is called the T-headed bar. The properties of T-headed bars have been tested extensively. The behavior is well documented with respect to: - the anchorage properties (load-slip relationship capacities) - the properties under cyclic loads - the use as shear reinforcement By using T-headed bars it is possible to ensure the required ductility and shear capacity of high-strength concrete structures. Practical experience has been gained during the performance of the latest Condeep structures.