EXPANSION JOINT SYSTEM
An expansion joint system including mechanically fused elements for bridging a gap between spaced-apart adjacent structural members is provided. During an emergency operation that is caused by large movements occurring within the vicinity of the expansion joint gap, one or more mechanically fused elements may break away to improve system predictability, or to limit damage to the expansion joint system, the surrounding underlying structural members, or both.
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This application claims the benefit of the filing date under 35 U.S.C. §119(e) of U.S. Provisional Application For Patent Ser. No. 60/874,759 filed on Dec. 13, 2006.
TECHNICAL FIELDA mechanically fused expansion joint system for bridging a gap between spaced-apart, adjacent structural members is provided. The mechanically fused expansion joint system is useful in constructions such as roadway constructions, bridge constructions, and other constructions where it is desirable to accommodate large movements that occur in the vicinity of the expansion joint gap between the structural members.
BACKGROUNDAn expansion joint gap is purposefully provided between adjacent structural members for accommodating dimensional changes within the gap occurring as expansion and contraction due to temperature changes, shortening and creep caused by pre-stressing, seismic cycling and vibration, deflections caused by live loads, and longitudinal forces caused by vehicular traffic. Expansion joint systems may be utilized to accommodate the movements in the vicinity of the gap, but still permit flow of traffic across the gap.
Roadway and bridge constructions typically are designed to withstand particular maximum movements and forces without damage. As the level of movement and forces to which a construction is designed to endure without damage increases, the expense of the expansion joint design to accommodate the movements and forces increases. High energy events which produce large movement and large forces in these constructions, as a result of seismic activity, tsunamis, freak waves or rogue waves, strong winds, or other activity, are rare and as the energy level of an event increases, the rarity of the event also increases. As such, designs to fully accommodate high movements and minimize damage due to high movements and forces from high energy events can become unreasonably expensive in light of the rarity of these high energy events.
During a high energy event resulting in large movements occurring within the vicinity of the expansion joint gap, the entire expansion joint system and surrounding underlying structural members are typically damaged. Not only do such events result in substantial costs to repair the damaged structural members but the expansion joint system usually needs to be replaced as well.
Therefore, the relevant industry still demands a cost-effective expansion joint system to accommodate large movements and forces in expansion joint gaps in response to high energy events, whereby the expansion joint system can effectively mitigate damage from rare large movements and large forces in constructions resulting from high energy events.
SUMMARYProvided is an expansion joint system for bridging a gap between adjacent structural members, the system comprising a member for bridging a gap between two spaced apart structural members and mechanically fused housings and/or mechanically fused connectors that are designed to break in response to the application of pre-determined loads to the system.
According to certain embodiments, the expansion joint system for bridging a gap between spaced-apart structural members comprises a load bearing member bridging said gap; a housing having a fused portion: and a support member positioned below said load bearing member and bridging said gap, said support member at least partially housed within said housing and slidable therein.
According to further embodiments, the expansion joint system for bridging a gap between spaced-apart structural members comprises a load bearing member bridging said gap, wherein said load bearing member is engaged by a mechanically fused connector to a mechanically fused portion of said structural member.
Disclosed is an expansion joint system that is installed in a gap between adjacent structural members. The expansion joint system includes mechanically fused components that are designed to break or otherwise yield in response to the application of loads that exceed design limits for the system. The fused components permit the expansion joint system to break away from the underlying structural members with limited damage to the expansion joint system or the structural members.
The expansion joint system may be utilized in roadway, bridge, and tunnel constructions to accommodate large movements in the vicinity of the gap. Depending on the particular application, the expansion joint system may be a modular type, a cover plate type, an interlocking finger type, or any other type. Because the expansion joint system is not damaged, it can be reinstalled to the underlying bridge or roadway structure after the high energy event.
A modular type expansion joint system comprises a plurality of transversely extending, spaced-apart, vehicular load bearing members; longitudinal support members positioned below the vehicular load bearing members and extending longitudinally across the expansion joint gap; and a housing for accepting ends of the longitudinal support members for controlling the movement of the ends of said support members. Seals are generally provided between the vehicular load bearing members and between vehicular load bearing members and edge members.
The seals may be flexible and compressible and, therefore can stretch and contract in response to movement of the vehicular load bearing members within the expansion joint gap. The seals may be made from a durable and abrasion resistant elastomeric material. The seals are not limited to any particular type of seal. Suitable seals that may be used include, but are not limited to, strip seals, glandular seals, and membrane seals.
The housings for accepting ends of the support members may include structures such as, without limitation, boxes, receptacles, chambers, containers, enclosures, channels, tracks, slots, grooves or passages, which include a suitable cavity for accepting the end portions of the support members and permits the desired movement of the support member within the housing. The top wall of the housing may be mechanically fused to provide a break-away portion in response to an emergency high energy condition.
Expansion joint systems are designed to accommodate movement of adjacent structural members relative to one another such that, as the gap between the adjacent sections changes in size or shape, traffic may still flow across the gap. Generally, the amount of change in the gap which an expansion joint system can accommodate is limited such that there is a minimum gap condition and a maximum gap condition which may occur without causing some damage to the expansion joint system, or the adjacent structure, or both. As used herein, an operation which closes the gap below the above referenced nominal minimum gap condition or opens the gap beyond the above referenced nominal maximum gap condition will be referred to as an “emergency operation”. Expansion joint systems which comprise mechanically fused elements include elements, assemblies, or both that are designed to break at or above predetermined loads produced by emergency operations. Furthermore, the elements and assemblies are designed to break in specific ways in order to limit damage to the system, its surroundings, and/or to improve system performance predictability. According to certain embodiments, mechanically fused elements or assemblies are designed to break in a predetermined sequence during an emergency operation.
According to certain embodiments, the expansion joint system include housings for accepting components of the expansion joint system and which include fused portions that are designed to break away in response to the application of an excessive load. The expansion joint system may comprise a modular-type expansion joint system including housings for accepting components of the expansion joint system and which include fused portions that are designed to break away in response to the application of an excessive load. The modular-type expansion joint system includes a plurality of transversely extending vehicular load bearing members, longitudinal support members having opposite ends extending longitudinally across the expansion joint, and housings having fused portions for accepting ends of the longitudinally extending support members. The longitudinal support members have one end slidably housed within a mechanically fused housing. The mechanically fused housing is embedded within the structural member or within elastomeric concrete in the block-out region of the structural member. During an emergency operation, a portion of the mechanically fused housing breaks or yields in some pre-selected manner in order limit damage to the expansion joint system and its surroundings.
According to other embodiments, the expansion joint comprises mechanically fused connectors which connect the expansion joint system to adjacent structural members. Without limitation, the expansion joint system comprises a modular-type expansion joint system including mechanically fused connectors which connect the expansion joint system to adjacent structural members. The modular-type expansion joint system includes a plurality of transversely extending vehicular load bearing members, longitudinal support members having opposite ends extending longitudinally across the expansion joint, and housings having fused portions for accepting ends of the longitudinally extending support members. The longitudinal support members have one end slidably housed within housings. The mechanically housings are embedded within the structural member or within elastomeric concrete in the block-out region of the structural member. The expansion joint system further includes edge members, which are known in the relevant industry as “edge plates”. The edge members are disposed on opposite longitudinal sides of the transversely extending vehicular load bearing members. The edge members are connected to the underlying structural members by mechanically fused connectors. During an emergency operation, a portion of the mechanically fused connectors break or yield in some pre-selected manner in order limit damage to the expansion joint system and its surroundings.
According to further illustrative embodiments, the mechanically fused connectors join the edge members of the modular-type expansion joint system to mechanically fused portions of the underlying structural elements. The joint comprises mechanically fused connectors which connect the expansion joint system to adjacent structural members. The modular-type expansion joint system includes a plurality of transversely extending vehicular load bearing members, longitudinal support members having opposite ends extending longitudinally across the expansion joint, and housings having fused portions for accepting ends of the longitudinally extending support members. The longitudinal support members have one end slidably housed within housings. The mechanically housings are embedded within the structural member or within elastomeric concrete in the block-out region of the structural member. The expansion joint system further includes edge members, which are known in the relevant industry as “edge plates”. The edge members are disposed on opposite longitudinal sides of the transversely extending vehicular load bearing members. The edge members are connected to the underlying structural members by mechanically fused connectors. During an emergency operation, a portion of the mechanically fused connectors and/or fused portions of the underlying structural members break or yield in some pre-selected manner in order limit damage to the expansion joint system and its surroundings.
The mechanically fused expansion joint system will now be described in greater detail in conjunction with illustrative
At the nominal minimum gap condition, as shown in
Referring to
The mechanically fused connectors 30 may comprise fasteners, welds, brazings, or adhesives engaging the edge members 32 of the expansion joint system 10 with the structural elements 26 and 28. Without limitation, fasteners may include bolts, screws, rivets, nails, and pins. Without limitation, the fasteners may comprise materials selected from the group consisting of steel, aluminum, brass, bronze, titanium alloys, magnesium alloys, or combinations thereof. In some embodiments, the mechanically fused connectors 30 are designed to undergo a tensile, compressive, or shearing load sufficient to cause tensile, compressive, or shearing breakage of the mechanically fused connectors 30, thereby freeing the expansion joint systems from the underlying structural members 26, 28.
As shown in
As shown in
The boundary region is defined by one or more boundary elements 38 and 40. A boundary element 38 and 40 may be any component which creates a boundary region. In certain embodiments, the boundary element 38 and 40 is a plate, strap, beam, angle, channel, rod, tube, bead, fiber, or strand. The boundary element 38 and 40 may comprise a metal, a polymer, a ceramic, a glass, or a composite material. The boundary element 38 and 40 comprises steel, aluminum, brass, or bronze. In certain embodiments, the boundary element 38 and 40 intentionally creates a region of weakness coinciding with the boundary region. Without limitation, regions of weakness may be established by creating stress risers, stress concentration points, perforations, or otherwise selectively weakening a particular region. In certain embodiments, the boundary element 38 and 40 intentionally creates a region of strength coinciding with a region bordering the boundary region. Without limitation, regions of strength may be established by eliminating stress risers, eliminating stress concentration points, addition of reinforcement materials, or otherwise selectively strengthening a particular region.
In certain embodiments, the expansion joint system 10 comprises terminal margins 42 and 44 between structural elements 26 and 28 and edge members 32. The terminal margins 42 and 44 separating the structural elements 26 and 28 from the edge members 32, may be at least partially filled with a transmission material 46 selected from the group consisting of steel, aluminum, tungsten carbide, silicone, polyurethane, or some combination thereof. Transmission materials 46 may be applied along the shearing region 48 between the edge members 32 of the expansion joint system 10 and the structural elements 26 and 28. As shown in
A difference in the types of materials selected for transmission materials 46 may be used to determine the sequence in which mechanically fused elements break during an emergency operation. Other variables being equal, in a system wherein the transmission material 46 in one terminal margin 42 or 44 is softer than the transmission material 46 in the opposing terminal margin 42 or 44, the mechanically fused connection 30 on the side having the softer transmission material 46 will break before the connection on the side having the harder transmission material 46. A person of ordinary skill in the art can select these design criteria without undue experimentation in order to produce a desirable breakage sequence amongst mechanically fused elements. As shown in
As shown in
During emergency operations producing gap widths less than the nominal minimum gap condition, the strain which the mechanically fused connector 30 will encounter prior to breakage will result in only low stresses in a soft terminal element material 46 and therefore the edge members 32 transfer only low stresses to the abutting portions of the structural elements 26 and 28. During emergency operation at gap widths greater than the nominal maximum gap condition, the terminal margin will open and therefore the edge members 32 transfer no stresses to the abutting portions of the structural elements 26 and 28.
Some materials used in conventional construction have very predicable design characteristics as compared to other materials used in conventional construction. One such material is steel. A designer can specify the shape, material, and installation of a steel component and predict its performance criteria with very high precision. In applications where high precision prediction of a particular performance criteria is critical, one option to promote such predictability is to include materials having very predictable properties in such a way that their performance controls overall performance. In certain embodiments, the selection of breakage sequence of mechanically fused elements composed of materials having predictable properties is used to increase the predictability of an entire system. Without limitation, and for purposes of illustration only, a predictable mechanically fused element having a breakage load that is well known may be used in conjunction with a less predictable mechanically fused element having a breakage load that is less well known in such a way that the predictable mechanically fused element breakage occurs before the less predictable mechanically fused element and in such a way that breakage of the more predictable mechanically fused element subjects the less predictable mechanically fused element to a load very likely to cause its breakage. By so doing, the predictability of breakage criteria of the entire system mirrors the predictability of breakage criteria of the more predictable mechanically fused element.
While the mechanically fused expansion joint system has been described above in connection with the certain embodiments, it is to be understood that other embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function of the mechanically fused expansion joint system without deviating therefrom. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments may be combined to provide the desired characteristics. Variations can be made by one having ordinary skill in the art without departing from the spirit and scope of the mechanically fused expansion joint system. Therefore, the mechanically fused expansion joint system should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the attached claims.
Claims
1. An expansion joint system for bridging a gap between spaced-apart structural members comprising:
- a load bearing member bridging said gap;
- a housing having at least one fused portion; and
- a support member positioned below said load bearing member and bridging said gap, said support member at least partially housed within said housing and slidable therein.
2. The expansion joint system of claim 1, wherein said housing comprises a top wall, a bottom wall, side walls, and a rear wall, wherein said top wall is mechanically fused.
3. The expansion joint system of claim 3, further comprising at least one edge member supported by said longitudinal support member, said edge member being engaged by a mechanically fused connector to one of said structural members.
4. The expansion joint system of claim 3, wherein said edge member is engaged by a mechanically fused connector to a mechanically fused portion of a structural member.
5. The expansion joint system of claim 4, wherein said mechanically fused portion of said structural member is separated from the remaining portion of said structural member by a boundary region created by a boundary element.
6. The expansion joint system of claim 5, wherein said boundary element is selected from the group consisting of a plate, a strap, a beam, an angle, a channel, a rod, a tube, a bead, and combinations thereof.
7. The expansion joint system of claim 6, wherein said boundary element comprises a material selected from the group consisting of metal, metal alloy, polymer, ceramic, glass, composite material, and combinations thereof.
8. The expansion joint system of claim 7, wherein said boundary element creates a region of weakness coinciding with the boundary region.
9. The expansion joint system of claim 8, wherein said boundary element creates a region of strength coinciding with a region bordering the boundary region.
10. The expansion joint system of claim 4, wherein said mechanically fused connector comprises a connector selected from the group consisting of a mechanical fastener, a braze, a solder, a weld, and an adhesive.
11. The expansion joint system of claim 10, wherein said mechanically fused connector comprises a mechanical fastener.
12. The expansion joint system of claim 11, wherein said mechanical fastener is selected from the group consisting of bolts, screws, rivets, nails, pins and combinations thereof.
13. The expansion joint system of claim 12, wherein said mechanical fastener comprises a material selected from the group consisting of steel, aluminum, brass, bronze, titanium alloys, magnesium alloys, and combinations thereof.
14. The expansion joint system of claim 4, comprising a terminal margin between said edge members and said structural members.
15. The expansion joint system of claim 14, wherein said terminal margin is at least partially filled with a transmission material.
16. The expansion joint system of claim 15, wherein said transmission material is selected from the group consisting of a metal, a metal alloy, a polymeric material, a composite material, and combinations thereof.
17. The expansion joint system of claim 3, comprising a plurality of mechanically fused elements.
18. The expansion joint system of claim 17, wherein at least a portion of said mechanically fused elements are designed to break in a particular sequence.
19. The expansion joint system of claim 4, comprising a plurality of mechanically fused elements.
20. The expansion joint system of claim 19, wherein at least a portion of said mechanically fused elements are designed to break in a particular sequence.
21. An expansion joint system for bridging a gap between spaced-apart structural members comprising:
- a plurality of transversely extending, spaced-apart load bearing members;
- a housing having a fused portion; and
- a support member positioned below said transversely extending, spaced-apart load bearing members and extending longitudinally across said gap, said support member at least partially housed within said housing and slidable therein.
22. The expansion joint system of claim 21, wherein said housing comprises a top wall, a bottom wall, side walls, and a rear wall, wherein said top wall is mechanically fused.
23. The expansion joint system of claim 21, further comprising at least one edge member supported by said longitudinal support member, said edge member being engaged by a mechanically fused connector to one of said structural members.
24. The expansion joint system of claim 23, wherein said edge member is engaged by a mechanically fused connector to a mechanically fused portion of a structural member.
25. The expansion joint system of claim 24, wherein said mechanically fused portion of said structural member is separated from the remaining portion of said structural member by a boundary region created by a boundary element.
26. The expansion joint system of claim 25, wherein said boundary element is selected from the group consisting of a plate, a strap, a beam, an angle, a channel, a rod, a tube, a bead, and combinations thereof.
27. The expansion joint system of claim 26, wherein said boundary element comprises a material selected from the group consisting of metal, metal alloy, polymer, ceramic, glass, composite material, and combinations thereof.
28. The expansion joint system of claim 27, wherein said boundary element creates a region of weakness coinciding with the boundary region.
29. The expansion joint system of claim 28, Wherein said boundary element creates a region of strength coinciding with a region bordering the boundary region.
30. The expansion joint system of claim 24, wherein said mechanically fused connector comprises a connector selected from the group consisting of a mechanical fastener, a braze, a solder, a weld, and an adhesive.
31. The expansion joint system of claim 30, wherein said mechanically fused connector comprises a mechanical fastener.
32. The expansion joint system of claim 31, wherein said mechanical fastener is selected from the group consisting of bolts, screws, rivets, nails, pins and combinations thereof.
33. The expansion joint system of claim 32, wherein said mechanical fastener comprises a material selected from the group consisting of steel, aluminum, brass, bronze, titanium alloys, magnesium alloys, and combinations thereof.
34. The expansion joint system of claim 24, comprising a terminal margin between said edge members and said structural members.
35. The expansion joint system of claim 34, wherein said terminal margin is at least partially filled with a transmission material.
36. The expansion joint system of claim 35, wherein said transmission material is selected from the group consisting of a metal, a metal alloy, a polymeric material, a composite material, and combinations thereof.
37. The expansion joint system of claim 23, comprising a plurality of mechanically fused elements.
38. The expansion joint system of claim 37, wherein at least a portion of said mechanically fused elements are designed to break in a particular sequence.
39. The expansion joint system of claim 24, comprising a plurality of mechanically fused elements.
40. The expansion joint system of claim 39, wherein at least a portion of said mechanically fused elements are designed to break in a particular sequence.
41. The expansion joint system of claim 21, comprising seals extending between said transversely extending, spaced apart load bearing members, and between said transversely extending, spaced apart load bearing members and edge sections of expansion joint system.
42. The expansion joint system of claim 41, wherein said seals are flexible and compressible.
43. The expansion joint system of claim 42, wherein said seals comprise an elastomeric material.
44. The expansion joint system of claim 43, wherein said seals are selected from strip seals, glandular seals, and membrane seals.
45. The expansion joint system of claim 44, wherein said seals are strip seals.
46. An expansion joint system for bridging a gap between spaced-apart structural members comprising:
- a load bearing member bridging said gap, wherein said load bearing member is engaged by a mechanically fused connector to a mechanically fused portion of said structural member.
47. The expansion joint system of claim 46, wherein mechanically fused connector and mechanically fused portion of said structural member are designed to break in a particular sequence.
48. The expansion joint system of claim 47, wherein the load bearing member comprises a plurality of transversely extending, spaced-apart load bearing members: and the system further comprises support members positioned below said transversely extending, spaced-apart load bearing members and extending longitudinally across said gap; housing for accepting ends of the longitudinally extending support members; and edge members engaged by mechanically fused connectors to a mechanically fused portion of said structural members.
Type: Application
Filed: Dec 7, 2007
Publication Date: Jun 26, 2008
Applicant: Construction Research & Technology GmbH (Trostberg)
Inventor: Paul BRADFOPD (West Falls, NY)
Application Number: 11/952,572
International Classification: E01D 19/06 (20060101);