A gap jumping overhead crane for use with two parallel runways each having a first and second end and a gap between their first and second ends. The crane has a hoist mounted on a bridge having opposing ends that extends between the two parallel runways. The bridge is slidably mountable to the two parallel runways at each of its ends by an end truck. Each end truck has two ends and at least three load wheels attached to the end truck. At least two of the load wheels are separated by a distance greater than the size of the gap to permit the crane to cross the gap in the runways.

A vertically-adjustable gantry assembly installation adapted for removal or placement of a train bridge-span of the type which spans and is supported by two piers, comprises a gantry assembly positioned on load-bearing first ground-support locations, the gantry assembly comprising a gantry and a ground-engaging vertical support and lift system, the vertical support and lift system adapted for supporting a combined weight of the gantry and a bridge span in at least one operational vertical position above respective bridge span support-surfaces of the piers including a position corresponding to a disembarking plane in which the leg portions are extended from a stowed position to an extent at least sufficient for the gantry assembly to self-liftoff the pre-installation conveyance system onto the first ground-support locations to effect the gantry assembly installation.

A vertically-adjustable gantry assembly installation adapted for removal or placement of a train bridge-span of the type which spans and is supported by two piers, comprises a gantry assembly positioned on load-bearing first ground-support locations, the gantry assembly comprising a gantry and a ground-engaging vertical support and lift system, the vertical support and lift system adapted for supporting a combined weight of the gantry and a bridge span in at least one operational vertical position above respective bridge span support-surfaces of the piers including a position corresponding to a disembarking plane in which the leg portions are extended from a stowed position to an extent at least sufficient for the gantry assembly to self-liftoff the pre-installation conveyance system onto the first ground-support locations to effect the gantry assembly installation.

A structural support that can be used as a truss girder bridge crane, or the like. The support includes one or more rows 13 of segments 15, that are arranged in side by side relation along the length of the support. Each row 13 has extending there through at least one tensioning element 14 which is anchored at opposite ends of the row and is pretensioned with respect to the row in order to hold the segments of the row together. A support preferably includes one row 13 of segments 15 in a lower chord 11 of the support and another row 13 of segments in an upper chord of the support. Vertical framework is mounted between the chords with ends secured adjacent the segments 15 by the tensioning element. The individual segments and the tensioning elements may be directed to a construction site at the location of use and assembled into rows and the appropriate structural construction.

A structural support that can be used as a truss girder bridge crane, or the like. The support includes one or more rows 13 of segments 15, that are arranged in side by side relation along the length of the support. Each row 13 has extending there through at least one tensioning element 14 which is anchored at opposite ends of the row and is pretensioned with respect to the row in order to hold the segments of the row together. A support preferably includes one row 13 of segments 15 in a lower chord 11 of the support and another row 13 of segments in an upper chord of the support. Vertical framework is mounted between the chords with ends secured adjacent the segments 15 by the tensioning element. The individual segments and the tensioning elements may be directed to a construction site at the location of use and assembled into rows and the appropriate structural construction.

A support installation includes support members for supporting an electric cable, a tower crane, a mast and a jib linked to an upper portion of the mast. The jib and the mast respectively extend according to a jib direction and a substantially vertical mast direction. The support members are secured to the jib and disposed at a plurality of locations distant according to the jib direction. The support members extend transversally to the jib direction to protrude laterally from the jib. The jib is cantilevered when the support installation is in the service configuration.

A support installation includes support members for supporting an electric cable, a tower crane, a mast and a jib linked to an upper portion of the mast. The jib and the mast respectively extend according to a jib direction and a substantially vertical mast direction. The support members are secured to the jib and disposed at a plurality of locations distant according to the jib direction. The support members extend transversally to the jib direction to protrude laterally from the jib. The jib is cantilevered when the support installation is in the service configuration.

A foldable gantry (10) comprising a beam (12) and a first leg assembly (14), the first leg assembly (14) being pivotally mounted at a first end (16) of the beam (12) such that the first leg assembly (14) can move between a first, stowed, position and a second, deployed, position.

A foldable gantry (10) comprising a beam (12) and a first leg assembly (14), the first leg assembly (14) being pivotally mounted at a first end (16) of the beam (12) such that the first leg assembly (14) can move between a first, stowed, position and a second, deployed, position.

A gantry crane adapter for a two-post lift includes a pair of angle brackets, each of which has a first, horizontal leg and second, vertical leg. The first leg includes an aperture, and a short hook extends in parallel, spaced relation along an outer surface of the second leg. The hook of each bracket is received in the slot in a carriage in a respective post of the two-post lift to removably connect each bracket to the respective carriage, with the first, horizontal legs of the respective brackets projecting toward each other. A load bearing beam is positioned across the brackets such that an internally threaded boss at each end of the beam is received in an aperture in a respective bracket, and a bolt with a washer is threaded down into the boss, to support and retain the load bearing beam across the angle brackets.