Abstract: A reinforcing bar support for joining concrete structures, having a hollow body of prismatic shape and formed by a front part and by a cover part. The front part features a front side scheduled to be installed in the concreted main wall, two longitudinal narrow sides and two cross sides. The sides are so designed that the cover part can be clamped to the front part and released therefrom. The front side is provided with a longitudinal center groove and equidistant cross grooves, with the cross grooves used for marking holes to be drilled later, which holes are scheduled to receive the leg ends of the reinforcing bars.