Device for controlling the spacing of the plates on a bridging arrangement for expansion joints in bridges or the like

Apparatus for controlling the lateral spacing between adjoining members having upper and lower surfaces, comprising

• first flexible means deformable in shear extending transversely from a lower surface of one of the adjoining members;
• second flexible means deformable in shear extending from a lower surface of another of the adjoining members spaced a distance from the first flexible means;
• and
• means having an upper surface and a first and second end for connecting the extensions of the first flexible means at said first end and the and second flexible members;
• wherein the flexible means form a plurality of chains interlinking the adjoining members;
• and
• wherein at least one of the chains has maximum stress when the spacing between the lateral members is minimum and the spacing of the first and second flexible means is a first distance and said chain is positioned alternately with another of the chains which has minimum stress when the spacing between adjoining members is minimal and the spacing of the first and second fIexible means is a second distance;
• wherein the flexible means interconnecting the lower surfaces of the adjoining members to the upper surface of the connecting means are disposed to exert a constant bias on the members in all positions of the spacing therebetween so that as the spacing between the adjoining members varies, a decrease in the pressure exerted on some of the flexible means is compensated by an increase in the pressure on another of the flexible members.

A device for controlling the spacing of parallel elements of a bridging arrangement for an expansion joint in a bridge or the like, said elements comprising two edge beams that define said expansion joint and at least one plate, cross members bridging said expansion joint, and one or more said plates running parallel between said edge beams and mounted on said cross-members, the device comprising:

• a plurality of connectors that are resistant to bending having a first and second end;
• a first and second plurality of resilient members, each secured at one end to a first and second one of said elements and, at the other end, to a first and second end of one of said connectors;
• each connector and two of said resilient members securing two of said elements together, said resilient members deforming resiliently in shear in response to changes in the separation between said plates and said edge beams;
• said resilient members and said connectors forming at least two control chains connecting all of said plates to one another and to two of said edge beams;
• each element and connector having an upper and a lower surface and each resilient member being connected to an element lower surface and a connector upper surface such that each of said resilient members of at least one control chain is disposed a first distance to have zero or virually zero shear stress when said joint is closed and increase as the opening of said joint increases;
• each of said resilient members of at least one other control chain being connected to an element lower surface and a connector upper surface such that each of said resilient members of said other control chain is disposed a second distance to have zero or virtually zero shear stress when said joint is open to the maximum and increases as said joint narrows;
• and
• wherein said control chains are spaced apart from one another in the parallel direction of said elements so that an even number of control chains having maximum stress when said joint is closed alternate with an equal number of control chains having maximum stress when said joint is opened.