The invention relates to a shell coupling (40) for coupling pairs of pipes, having two half-shells (46, 48′) which, in the coupling state, bound a circular opening (60) for through-passage of the pipes and, at their one end, can be pivoted in relation to one another, via an outer articulation (44), about an articulation axis-parallel to the circular opening (60) and, at their other end, can be connected to one another in a releasable manner via a clamping mechanism (51), with the pipes which are to be coupled being clamped in the process. In order to reinforce the pipe connection to the concrete placing boom, and to improve the force transmission which is necessary in this region, it is proposed, according to the invention, that the shell coupling (40), which is designed as an add-on coupling, has a mounting plate (52) which has a retaining structure (54) by means of which at least one force-transmission element (50) formed on one of the half-shells (48′) is accommodated in a form-fitting and force-fitting manner. The at least one force-transmission element (50) here expediently has a cross-sectionally wedge-shaped contour, the retaining structure (54) forming at least one wedge mount (56), wherein the mounting plate (52) and the one half-shell (48′) can be connected to one another by means of at least one clamping screw (66), with the force fit being made in the process in the wedging direction of the force-transmission element (50) and of the retaining structure (54).