Sheath for a structural cable of a construction work, methods of installation and maintenance

A structural cable of a construction work, comprising:

• an upper anchorage;
• a lower anchorage;
• load-bearing tendons extending along a path of the structural cable between the upper and lower anchorages;
• and
• a sheath in which the load-bearing tendons are housed,
• wherein the sheath comprises:
• sheath segments assembled along the path of the structural cable;
• at least one supporting rope extending along the sheath segments and having an upper end connected to the construction work adjacent to the upper anchorage;
• and
• connectors for connecting the sheath segments to the at least one supporting rope,
• wherein the connectors are configured to block relative upward movement of the at least one supporting rope with respect to the sheath segments and to allow relative downward movement of the at least one supporting rope with respect to the sheath segments.

A method of installing a sheath for a structural cable of a construction work, the structural cable having a path between an upper anchorage and a lower anchorage, the sheath having a number N of sheath segments, the method comprising:

• mounting at least one supporting rope with an upper end adjacent to the upper anchorage;
• for each integer n such that 1≤n≤N:
• inserting the at least one supporting rope into the n-th sheath segment;
• connecting the n-th sheath segment to a supporting rope;
• and
• lifting first to n-th sheath segments along the at least one supporting rope,
• wherein connectors are provided to block relative upward movement of the at least one supporting rope with respect to the sheath segments and to allow relative downward movement of the at least one supporting rope with respect to the sheath segments.

A maintenance method for a structural cable of a construction work, the structural cable comprising:

• an upper anchorage;
• a lower anchorage;
• load-bearing tendons extending along a path of the structural cable between the upper and lower anchorages;
• and
• a sheath in which the load-bearing tendons are housed,
• wherein the sheath comprises:
• sheath segments assembled around the load-bearing tendons along the path of the structural cable;
• at least two supporting ropes extending along the sheath segments, each having an upper end connected to the construction work adjacent to the upper anchorage;
• and
• connectors for connecting the sheath segments to the at least one supporting rope,
• wherein the connectors are arranged to block relative upward movement of the at least one supporting rope with respect to the sheath segments and to allow relative downward movement of the at least one supporting rope with respect to the sheath segments,
• the maintenance method comprising replacing a first one of the supporting ropes by a second supporting rope while the assembled sheath segments are supported by at least another one of the supporting ropes,
• wherein replacing the first supporting rope by the second supporting rope comprises:
• disconnecting an upper end of the first supporting rope;
• coupling a lower end of the second supporting rope to the upper end of the first supporting rope;
• pulling a lower end the first supporting rope to remove the first supporting rope while installing the second supporting rope;
• and
• connecting an upper end of the second supporting rope adjacent to the upper anchorage.