Method of constructing the approach and main spans of a cable stayed segmental bridge
AssigneeFigg and Muller Engineers, Inc.
InventorJean M. Muller
Life of this patent
Estimating the term…
Abstract
A method of constructing the approach and main spans of a cable stayed segmental bridge as the main span is constructed as a smooth continuation of the approach spans without the need for special equipment or different box girder deck sections. The approach spans are constructed each in succession from opposite sides of the main span after which the main span continues from opposite sides toward a midpoint, while the cable stays are installed. For a two-wide box girder bridge, delta frames interconnect side-by-side box girders at the anchor locations of the cable stays for thereby transferring the static and dynamic loads of the main span toward the center plane of support of the cable stays.
Claims9
A method of constructing a segmental bridge from like concrete box girders, the bridge having a main span of a predetermined length, and a plurality of interconnected approach spans at opposite ends of said main span, each of said approach spans having a length substantially less than said predetermined length of said main span, and said main span being defined by a pair of longitudinally spaced apart main span piers, said approach spans being defined by pairs of longitudinally spaced apart approach span piers, a last of said approach spans being defined by one of said approach span piers and one of said main span piers, the method comprising the steps of:
- (A) first constructing each of said approach spans toward said opposite ends of said main span, said constructing step for each of said approach spans comprising:
- (a) extending a pair of transversely spaced apart assembly trusses between one of said pairs of approach span piers which define one of said approach spans, said trusses being movably supported on opposite sides of said one of said pairs;
- (b) completely spanning the distance between said one of said pairs by loading precast concrete box girders one-at-a-time on to said trusses from one of said approach span piers which is located a greater distance from said main span compared to the spacing of the other of said approach span piers from said main span, each of said girders having transversely extending wings supported on said spaced trusses;
- (c) sliding said box girders in succession in a direction toward said main span, after being loaded on to said trusses, until a first of said girders directly overlies said other approach span pier;
- (d) connecting said first box girder to said approach span other pier;
- (e) abutting the succeeding girders against said first girder and to each other and connecting all of said girders to one another;
- (f) moving said assembly trusses so as to extend between another adjacent pair of said longitudinally spaced approach span piers which define another of said approach spans adjacent said one approach span, one of said another adjacent pair comprising said other approach span pier and the other of said another adjacent pair being spaced closer to said main span compared to said one pier of said another adjacent pair;
- (g) repeating said steps (b), (c), (d) and (e) for said another approach span;
- (h) repeating said steps (f) and (g) for further adjacent pairs of longitudinally spaced approach span piers defining further adjacent approach spans and for said last approach span at which said main span is reached;
- (i) erecting permanent pylons at the locations of said main span piers;
- (B) then from said last of said approach spans adjacent said main span,
- (aa) cantilevering and connecting concrete box girders successively to each other, as a continuation of said last approach span, from said main span piers toward one another until the midpoint between said main span piers is reached;
- and
- (bb) during step (aa), supporting said main span from each of said pylons by extending a plurality of permanent cable stays from each of said pylons to designated ones of said girders of each of said last approach spans.
A method of constructing a two-wide segmental cable stayed bridge from like precast concrete bridge girders of a predetermined depth connected side-to-side and end-to-end, the bridge having a main span of a predetermined length and a plurality of approach spans at opposite ends of said main span, each of said approach spans having a spacing substantially less than said predetermined length of said main span, the method comprising the steps of:
- (A) first constructing each of said approach spans toward said opposite ends of said main span, said constructing step for each of said approach spans comprising:
- (a) assembling pairs of said girders side-by-side and end-to-end entirely between a first pair of transversely spaced apart piers and a second pair of transversely spaced apart piers longitudinally spaced from said first pair and defining one of said approach spans, said assembling being carried out from said second pair toward said first pair, and said second pair being located closer to said main span compared to the distance of said first pair therefrom;
- (b) connecting a first pair of said box girders to each other at adjoining sides and to said second pair of piers;
- (c) connecting remaining pairs of said girders to each other at adjoining sides and to adjoining ends of adjacent pairs;
- (d) repeating said steps (a), (b) and (c) for further approach spans until said main span is reached, a pair of longitudinally spaced pylons defining said main span;
- (B) thereafter, from the last of said approach spans adjacent said main span, constructing said main span by
- (aa) cantilevering further pairs of precast concrete box girders, similar to said girders employed in step (A), successively to each other, as a continuation of said last approach span, from said pylons toward one another until the midpoint between said pylons is reached;
- (bb) connecting said girders of said further pairs respectively to each other at adjoining sides and at adjoining ends of adjacent pairs thereof;
- (cc) during steps (aa) and (bb), supporting said main span from each of said pylons by extending a plurality of permanent cable stays from each of said pylons to designated ones of said cantilevered girders and to designated ones of said girders of each of said last approach spans;
- (dd) anchoring said cable stays to said designated ones of said girders at respective locations centrally between the connected adjoining sides thereof;
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- (ee) at only said respective locations, connecting transverse load carrying members of said predetermined depth between said girders side-by-side for providing anchor blocks for said cable stays and for transferring static and dynamic loads of said main span and of said last approach spans to the central plane of support at said cable stays.
Dependencies are inferred from the claim text.