Abstract: A device for transporting and placing a bridge (1) of an offshore oil rig onto a floating or stationary mounting structure (3). The device has two parallel floating barges (10) for mounting the bridge (1). Each barge has a set of vertical movement rams (11) that move the bridge between a position of bearing on the barges (10) and a position of bearing on the structure (3). Each barge (10) has at least one assembly (15) for controlling the roll of each barge (10) in relation to the bridge (1) during the placement of the bridge onto the mounting structure (3). The assembly includes at least two rams (16) that are carried by the barge (10) and are located on both sides of the longitudinal axis of the barge (10). Each ram (16) is connected to the bridge (1) by a connecting member (17) that has rigid pull and flexible compression.

Abstract: A device for transporting and placing a bridge (1) of an offshore oil rig onto a floating or stationary mounting structure (3). The device has two parallel floating barges (10) for mounting the bridge (1). Each barge has a set of vertical movement rams (11) that move the bridge between a position of bearing on the barges (10) and a position of bearing on the structure (3). Each barge (10) has at least one assembly (15) for monitoring the roll of each barge (10) in relation to the bridge (1) during the placement of the bridge onto the mounting structure (3). The assembly includes at least two rams (16) that are carried by the barge (10) and are located on both sides of the longitudinal axis of the barge (10). Each ram (16) is connected to the bridge (1) by a connecting member (17) that has rigid pull and flexible compression.

Abstract: The process for assembling long sections (11) of booms of support legs of an oil platform comprises machining an inclined flat surface (15) on the whole of the length of each main face of a rectangular plate (12), machining a groove behind each flat surface (15), machining an inclined chamfer on longitudinal edges of a stiffener (13), placing a stiffener (13) on each main face of the rectangular plate (12), welding each stiffener (13) to the rectangular plate (12), under a vacuum from the exterior by means of an electron beam, in the region of the chamfers and the flat surfaces so as to produce a section (11), and heat treating the section (11).

Abstract: The locking device for a self-raising oil platform comprising a shell (1) mounted to be movable along legs (2) by means of raising mechanisms comprising output gear pinions cooperative with racks (3) mounted on at least a part of the length of the legs (2), comprises a toothed member (6) forming a counter-rack (6a) mounted on the shell of the platform, means (7) for shifting the toothed member (6) transversely of the direction of the rack with which the device is associated for engaging the teeth of the toothed member in the teeth of the rack (3) or for disengaging them from the teeth of the rack, clamping plates (13) connected to the toothed member and clamping counter-plates (15) connected to the platform, and means (20) for clamping the plates and counter-plates together so as to lock the toothed member (6) in position in the rack.