Abstract: A movable and dynamic work after construction linking two points separated by a natural or man-made obstacle, allows the permanent crossing of this obstacle. The work includes a deformable apron (1) which extends between said two points. The work comprises a set of elongated elements (2, 3). An assembly of several pairs of elements (2, 3) is disposed along the apron (1). The work comprises drive means (8) disposed at one end or at both ends of said work for adjusting the apron (1) lengthwise. The drive means (8) are arranged so that, when the means (8) are actuated, they drive the assembly of the pairs of elements (2, 3), so as to bulge the central portion of the apron (1) when the means (8) are actuated.