The structure has on an open up side wall a lower swivel flap wall (1) which is connected to an upper lift wall (2) by a flexible draw element (6) and gearing mechanism. This gearing mechanism has a roller (12) swivel mounted on the superstructure to swivel on a swivel radius (A) about the turning point of a swivel bearing (13) mounted on the guide (14) of the lift wall (2). A spring (19) can be mounted on the lift wall running parallel to the longitudinal extension of same and an elastic draw element (16) is guided over a roller (25) swivel mounted in the upper area of the lift wall and is fixed on the superstructure at its end opposite the spring so that the spring is pretensioned both in the closed and open state of the lift wall.
