Patent US5097558A successfully refreshed from Google Patents.
US5097558A
Expired / Lapsed
US
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Prestress retention system for stress laminated timber bridge
Assignee: CONNECTICUT THE, University of
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Filing: 1990-06-14
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Granted: 1992-03-24
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Expires: 2010-06-14
Abstract
Abstract A stress laminated timber bridge deck is disclosed. The deck includes a transversely extending laminate of longitudinally extending timbers and a system for prestressing the laminate. The prestress system includes a pair of longitudinally extending stress distribution channels disposed on opposite sides of the laminate, a number of transversely oriented threaded tension rods, and threaded members, threadably engaged with the tension rods, for tensioning the rods. A disc spring assembly is disposed on each of the tension rods and compressed between the respective stress distribution channels and respective threaded members to reduce the effective stiffness of the deck and thereby reduce prestress losses due to wood creep and temperature variation. A method for measuring prestress in a tensioning rod of the deck of the present invention is disclosed. The method includes the step of comparing the overall height of the disc spring assembly disposed on the rod to a previously determined load-deformation relationship for the disc spring assembly disposed on the rod.
Inventors
- 👤 Michael L. Accorsi
- 👤 Richard P. Long
- 👤 Edward F. Sarisley, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:38
CPC Classifications
E; E01; E01D; E01D19/00; E01D19/12; E01D19/125; E01D2101/00; E01D2101/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
A bridge deck, comprising: a transversely extending laminate of longitudinally extending timbers; means for prestressing said laminate, said means for prestressing comprising; a plurality of transversely oriented tension rods; and stress distribution means for distributing tensile force from said rods to said laminate; and disc spring means, operatively associated with at least one of said tension rods, for reducing the effective stiffness of the bridge deck to reduce loss of prestress.
Claim 2
Dependent Claim
71 words
A bridge deck, comprising: a transversely extending laminate of longitudinally extending timbers; means for prestressing said laminate, said means for prestressing comprising; a plurality of transversely oriented tension rods; and stress distribution means for distributing tensile force from said rods to said laminate; and disc spring means, operatively associated with at least one of said tension rods, for reducing the effective stiffness of the bridge deck to reduce loss of prestress.
Claim 3
Dependent Claim
48 words
The bridge deck of claim 1, wherein, the deck extending transversely from a first side to a second side, wherein, the stress distribution means further comprises a pair of stress distribution channels extending longitudinally along the sides of the laminate in operative association with said means for prestressing.
Claim 4
Dependent Claim
57 words
The bridge deck of claim 1, wherein the laminate comprises a plurality of timbers, said timbers each having a top edge, a bottom edge and a pair of opposed transverse surfaces extending between the edges, wherein said timbers are oriented parallel to each other an are disposed on edge in side by side contact with each other.
Claim 5
Dependent Claim
57 words
The bridge deck of claim 2, wherein said laminate defines a plurality of longitudinally spaced apart transverse boreholes therethrough and wherein each of the transverse rods extends from a threaded first end through one of the boreholes to a threaded second end and further comprising threaded means, threadably engaging each of said ends, for tensioning said rods.
Claim 6
Dependent Claim
58 words
The bridge deck of claim 4, wherein said threaded means comprises a plurality of threaded fasteners and wherein said disc spring means comprises a plurality of disk springs wherein each disk spring is disposed on an end of one of said rods and is compressed between one of said stress distribution channels and one of said threaded fasteners.
Claim 7
Dependent Claim
37 words
The bridge deck of claim 5, wherein a plurality of disc spring washers are disposed on each end of each rod and are compressed between one of the stress distribution channels and one of said threaded fasteners.
Claim 8
Independent Claim
150 words
A method for reducing prestress losses in a stress laminated timber bridge deck, said bridge deck including a transversely extending laminate of longitudinally extending timbers, a pair of longitudinally extending stress distribution channels disposed on transversely opposite sides of the laminate, said laminate and channels defining a plurality of longitudinally spaced apart transverse boreholes extending therethrough, a plurality of tension rods, each of said tension rods extending from a first threaded end through one of the boreholes to a second threaded end and a plurality of threaded members, each of said threaded members threadably engaging one of the threaded ends of one of said rods, comprising: disposing disc spring means on at least one of said rods between one of said stress distribution channels and one of said threaded members; and tightening said one of said threaded members to tension said one of said rods to prestress said bridge deck.
Claim 9
Independent Claim
150 words
A method for reducing prestress losses in a stress laminated timber bridge deck, said bridge deck including a transversely extending laminate of longitudinally extending timbers, a pair of longitudinally extending stress distribution channels disposed on transversely opposite sides of the laminate, said laminate and channels defining a plurality of longitudinally spaced apart transverse boreholes extending therethrough, a plurality of tension rods, each of said tension rods extending from a first threaded end through one of the boreholes to a second threaded end and a plurality of threaded members, each of said threaded members threadably engaging one of the threaded ends of one of said rods, comprising: disposing disc spring means on at least one of said rods between one of said stress distribution channels and one of said threaded members; and tightening said one of said threaded members to tension said one of said rods to prestress said bridge deck.
Claim 10
Dependent Claim
13 words
The method of claim 7, wherein the resilient means comprises a disc spring.
Claim 11
Dependent Claim
16 words
The method of claim 7, wherein the resilient means comprises a plurality of stacked disc springs.
References Cited (Backward Citations)
US3682466A
Cited
US3856242A
Cited
US3873079A
Cited
US4023242A
Cited
US3980016A
Cited
US3968010A
Cited
US4262888A
Cited
US4281726A
Cited
US4434863A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-03-24 | 1995-09-23 | 1996-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-24 | 1999-09-23 | 2000-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-24 | 2003-09-23 | 2004-03-24 | $7700.00 | Window Closed / Lapsed |