US4953280A
Expired / Lapsed
US
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Method of manufacturing prestressed concrete culverts
Assignee: Gifford-Hill and Co Inc
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Filing: 1990-01-11
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Granted: 1990-09-04
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Expires: 2010-01-11
Abstract
Abstract A method of manufacturing a three-sided culvert includes prestressing tendons in the culvert form. A series of prestressing tendons are secured within a form adapted for casting a concrete culvert having three orthogonal sides. The prestressing tendons are utilized in the top slab of the three-sided culvert and are positioned within the form prior to the pouring of concrete therein. Reinforcing steel can be eliminated along with the costs associated therewith and a culvert configuration can be provided with enhanced strength and improved material properties. Such culverts may thus be provided in modular form for placement upon foundations at remote locations for the creation of bridges, drainage areas and the like.
Inventors
- 👤 James K. Kitzmiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:26
CPC Classifications
E; E01; E01F; E01F5/00; E01F5/005; B; B28; B28B; B28B23/00; B28B23/02; B28B23/04; B28B7/00; B28B7/0029; B28B7/0088; B28B7/24; B28B7/241; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49789; Y10T29/49826; Y10T29/49863; Y10T29/49874
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
358 words
A method for efficiently manufacturing a plurality of three-sided, reinforced modular concrete culverts in an upside-down position, each of said culverts comprising two opposite sidewalls and a top slab formed therebetween, said method comprising the steps of: providing a casting table having two opposite sidewalls, said sidewalls forming a pour cavity therebetween, said pour cavity providing for the formation of the top slabs of said plurality of inserted modular concrete culverts; providing at least two adjacent pairs of sidewall forms, each sidewall form having a first sidewall form part and a second sidewall form part opposite to said first sidewall form part, said first and second sidewall form parts when in engagement with each other forming a chamber therebetween within which reinforcing steel is placed, each pair of sidewall forms in cooperation with said pour cavity of said casting table providing for the formation of each of said modular concrete culverts including said opposite sidewalls and said top slab formed therebetween; positioning at least one prestressing tendon in said pour cavity of said casting table; securing reinforcing steel within said chamber of each of said sidewall forms; resting said at least two adjacent pairs of sidewall forms upon and across said casting table sidewalls in a generally parallel, spaced relationship one to the other, said chambers projecting generally perpendicularly upward from said casting table sidewalls, thereby providing for the formation of adjacent concrete culverts; stressing said at least one tendon by exerting a force from outside said pour cavity; pouring concrete into said pour cavity of said casting table and over said at least one prestressed tendon; pouring concrete into said chambers of said at least two adjacent pairs of sidewall forms; cutting said at least one tendon at an intermediate point between said two adjacent pairs of sidewall forms; removing said at least two adjacent pairs of sidewall forms; and separating said plurality of inverted modular concrete culverts into individual reinforced modular concrete culverts, said plurality of inverted modular concrete culverts disposed in side-to-side relationship along said casting table, said individual modular concrete culverts each having first and second opposite sidewalls and said top slab formed therebetween.
Claim 2
Independent Claim
358 words
A method for efficiently manufacturing a plurality of three-sided, reinforced modular concrete culverts in an upside-down position, each of said culverts comprising two opposite sidewalls and a top slab formed therebetween, said method comprising the steps of: providing a casting table having two opposite sidewalls, said sidewalls forming a pour cavity therebetween, said pour cavity providing for the formation of the top slabs of said plurality of inserted modular concrete culverts; providing at least two adjacent pairs of sidewall forms, each sidewall form having a first sidewall form part and a second sidewall form part opposite to said first sidewall form part, said first and second sidewall form parts when in engagement with each other forming a chamber therebetween within which reinforcing steel is placed, each pair of sidewall forms in cooperation with said pour cavity of said casting table providing for the formation of each of said modular concrete culverts including said opposite sidewalls and said top slab formed therebetween; positioning at least one prestressing tendon in said pour cavity of said casting table; securing reinforcing steel within said chamber of each of said sidewall forms; resting said at least two adjacent pairs of sidewall forms upon and across said casting table sidewalls in a generally parallel, spaced relationship one to the other, said chambers projecting generally perpendicularly upward from said casting table sidewalls, thereby providing for the formation of adjacent concrete culverts; stressing said at least one tendon by exerting a force from outside said pour cavity; pouring concrete into said pour cavity of said casting table and over said at least one prestressed tendon; pouring concrete into said chambers of said at least two adjacent pairs of sidewall forms; cutting said at least one tendon at an intermediate point between said two adjacent pairs of sidewall forms; removing said at least two adjacent pairs of sidewall forms; and separating said plurality of inverted modular concrete culverts into individual reinforced modular concrete culverts, said plurality of inverted modular concrete culverts disposed in side-to-side relationship along said casting table, said individual modular concrete culverts each having first and second opposite sidewalls and said top slab formed therebetween.
Claim 3
Dependent Claim
43 words
The method as set forth in claim 1 and further including the step of forming an angulated form region in the area of intersection between each pair of said sidewall forms and said casting table for the creation of a haunch region therein.
Claim 4
Dependent Claim
37 words
The method as set forth in claim 1 and further including the step of disposing a plurality prestressing tendons in said pour cavity of said casting table in generally parallel spaced relationship along a single plane therein.
Claim 5
Dependent Claim
54 words
The method as set forth in claim 3 and further including the step of disposing said plane of said parallel prestressing tendons within said pour cavity in generally parallel spaced relationship with one surface of said casting table for affording an equidistant relationship between said plane of said parallel prestressing tendons and said surface.
Claim 6
Dependent Claim
41 words
The method as set forth in claim 3 wherein said prestressing tendons are each comprised of multi-strand cables and said step of stressing said cables includes the step of securing said cables outwardly of said casting table in said stressed relationship.
Claim 7
Dependent Claim
41 words
The method as set forth in claim 3 wherein said prestressing tendons extend through said pour cavity of said casting table in an interconnecting array for facilitating the expedited fabrication of said plurality of modular concrete culverts in said side-to-side relationship.
Claim 8
Dependent Claim
49 words
The method as set forth in claim 6 and further including the step of tensioning said tendons extending through said pour cavity of said casting table, whereby the tension throughout said pour cavity is the same such that the tension in each formed top slab is also the same.
Claim 9
Dependent Claim
43 words
The method as set forth in claim 7 and further including the steps of pouring concrete into said pour cavity of said casting table with said interconnecting array of common tendons extending therethrough prior to the pouring of concrete into said chambers thereof.
Claim 10
Dependent Claim
47 words
The method as set forth in claim 3 and further including the steps of filling said pour cavity of said casting table with concrete, allowing said concrete to stiffen, and filling said chambers with concrete while said concrete of said pour cavity presents a wet edge thereto.
Claim 11
Dependent Claim
40 words
A method as recited in claim 1, wherein said step of pouring concrete into said pour cavity of said casting table precedes said step of pouring concrete into said chambers of said at least two adjacent pairs of sidewall forms.
Claim 12
Dependent Claim
64 words
A method as recited in claim 10, wherein said step of pouring concrete into said pour cavity of said casting table and said step of pouring concrete into said chambers of said at least two adjacent pairs of sidewall forms are separated by a step of waiting until said concrete poured into said pour cavity stiffens to the point of presenting a wet edge.
Claim 13
Dependent Claim
39 words
A method as recited in claim 11, wherein said casting table has an inner bottom and further including the step of disposing said at least one tendon in a plane parallel to the inner bottom of said casting table.
Claim 14
Dependent Claim
26 words
A method as recited in claim 12, wherein said plane is generally orthogonally disposed in relation to said at least two adjacent pairs of sidewall forms.
Claim 15
Dependent Claim
64 words
A method as recited in claim 11, wherein said step of providing at least two adjacent pairs of sidewall forms further includes the step of constructing each of said sidewall forms by providing an inside sidewall form and an outside sidewall form and matingly engaging said inside sidewall form with said outside sidewall form in an oppositely disposed relationship thereby forming said chambers therebetween.
Claim 16
Dependent Claim
47 words
A method as recited in claim 14 and further including the step of constructing each of said inside and outside sidewall forms by providing a plurality of sections and assembling said sections together thereby permitting variation in the height of each side of said modular concrete culverts.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |