Spillway gate system

A spillway gate system for use as a navigation dam in which individual spillway gates may be serviced. The spillway gate system comprising a spillway including abutments at opposite ends thereof; wherein at least one of the abutments includes a cavity therein having a bottom surface; a removable bulkhead covering the cavity in the abutment; a plurality of water control gates hinged to the spillway; a service crane movable along the spillway and including a dewatering caisson; and a seal for sealing the caisson to the gates and to the bottom surface of the cavity.

FIELD OF THE INVENTION 
This invention relates to gated spillways such as those used for navigation 
dams and the associated means of servicing individual spillway gates. More 
particularly, this invention relates to the design of a service crane 
which can dewater and service all of the gates on a spillway including 
those nearest each abutment. 
BACKGROUND OF THE INVENTION 
Service cranes are known for use on gated dam spillways. Most large 
navigation dams incorporate an overhead bridge mounted crane which is used 
to place dewatering bulkheads and lift gate system componants. In order to 
minimize the need for complete dewatering of individual gates, tainter 
gates which are hinged above the downstream waterline are frequently used. 
Bulkhead slots are provided either upstream only or both upstream and 
downstream to permit dewatering. Such installations are extremely 
expensive in large part because of the need for piers and an overhead 
craneway. 
Simple mechanical wickets which are operated from a work boat have a lower 
initial cost than the tainter gate installations, but are labor intensive 
to operate. Service for such mechanical wickets, if required, is provided 
by a boat positioned caisson. 
Bottom hinged hydraulic gates can be installed without piers. In this case, 
it is required that a large area be dewatered without the benefit of piers 
should the gates require maintentance. 
Pneumatic spillway gates such as those described in U.S. Pat. No. 4,780,024 
and U.S. Pat. No. 5,092,707 can be economically made in shorter lengths 
than hydraulic gates, resulting in a smaller size of dewatered area being 
required for servicing the gates. 
SUMMARY OF THE PRESENT INVENTION 
In accordance with the present invention there is provided an improved 
gated spillway comprising a concrete spillway with a plurality of bottom 
hinged gates mounted thereon, a service crane which incorporates a 
dewatering caisson, and abutments with removable bulkheads at each end to 
which the endmost gates seal while in the raised position. The service 
crane rides on guides or rails which are integral with or mounted directly 
to the concrete spillway. The removable bulkheads cover extensions of the 
spillway to which the lower edge of the caisson can seal. The extensions 
of the spillway preferably have profiles which are identical to the 
profile of the top surface of the lowered spillway gates. The individual 
gates are configured to seal to the spillway and minimize lateral water 
leakage under adjacent gates into the dewatered caisson when the caisson 
is being used to dewater a gate requiring inspection or service. One or 
both of the removable bulkheads may enclose a docking station where the 
service crane can be parked out of the way of navigation traffic and water 
borne debris. 
In one embodiment of the invention, the service crane caisson would be 
fixed to the crane structure and would incorporate a movable sealing means 
such as an inflatable seal which would be used to seal to the lowered 
gates and to the spillway surface immediately upstream and downstream of 
the gates. 
In another embodiment of the invention, the service crane caisson would be 
movable vertically either as a whole or in parts in order to accomplish a 
seal to the lowered gates and spillway extension. 
In another embodiment of the invention, the service crane would incorporate 
means such as ducted water jets which could be used to clear sediment from 
the crane trackways and the area under the caisson seal including the top 
surfaces of the gates and the spillway surfaces immediately upstream and 
downstream of the gates.

DETAILED DESCRIPTION OF THE INVENTION 
Spillway gate systems which include the unique service crane arrangement of 
this invention are comprised of mutiple bottom hinged spillway gates. A 
preferred spillway gate construction is described in application Ser. No. 
08/490,643, filed Jun. 15, 1995 still pending, and a subsequent pending 
application Ser. No. 08/518,620, filed Aug. 23, 1995, both incorporated 
herein by reference. 
FIGS. 1 and 2 show a spillway gate service crane positioned over a gated 
spillway. The service crane 1 includes a conventional overhead crane 2, a 
watertight caisson 3, support wheels 4, an upstream guide wheel 5, an 
inflatable seal 6, a rack fixed to the spillway for service crane 
positioning, a watertight engine room 8, a storage area 9, and a work 
platform 10. Dewatering pumps would be included but are not depicted on 
the drawings. Drive pinion assemblies 11 are shown in FIG. 2. An upstream 
faring 12 reduces flow induced forces on the structure. 
FIG. 3 shows the spillway 13 without the service crane 1. A sealing surface 
14 is provided on the spillway upstream of the gates and a sealing surface 
15 is provided downstream of the gates to permit the caisson to seal to 
the spillway. 
FIG. 4 illustrates the details of the relationship between the upstream 
craneway 16, the upstream guide rail 17, the spillway gates 19, the 
positioning rack 7, and the downstream craneway 18. FIG. 5 illustrates the 
same system except with the gates 19 in the raised position. 
FIG. 6 illustrates the position of the inflatable seal 6 relative to the 
gates 19. 
FIG. 7 illustrates one embodiment of the caisson hull designed to minimize 
flow induced forces on the service crane. 
FIG. 8 illustrates the use of optional closable penetrations in the caisson 
which allow the service crane to move across raised gates. 
FIG. 9 showns a hull and craneway arrangement which facilitates loading 
equipment by crane to and from a work boat. 
FIG. 10 shows in one embodiment, the position of the inflatable seal over 
the upstream hinge portion of the gates 19. 
FIG. 11 shows the service crane in a docked storage position in the 
prefferred embodiment of this invention. 
FIGS. 11a, 11b and 11c show the method by which the service crane is 
positioned over the various individual spillway gates. 
The contoured surfaces 20 of the cavities within the abutments 22a and 22b 
closely approximate the profile of the gates so that with the bulkheads 
21a and 21b removed, the service crane 1 can straddel the outermost gates 
23a and 23b. In another embodiment the service crane could be sized to 
service several gates simultaneously. The crane used to service the gates 
ocould be used to position the abutment bulkheads 21a and 21b. 
Alternatively one face of the service crane could be used as a seal 
surface for the adjacent gate. FIGS. 12 and 12a illustrates the position 
of the inflatable seal 6 relative to the gates 19. 
FIG. 13 illustartes an alternatve embodiment of the upstream and downstream 
craneways 
FIG. 15 illustrates a seal configuration which simultaneously seal adjacent 
gates to each other and to the spillway, sealing to the spillway being 
desirable in order to exclude leakage into the dewaterred caisson. 
FIG. 16 illustrates the effect of flow on debris clearing from the rack. 
Alternative means of movably sealing to the gate panels is shown in FIG. 
17. 
FIG. 18 illustrates in one embodiment the relative position of the guide 
wheels 5, the drive pinions 11 and the other componants. 
FIG. 19 illustrates the preferred shape of the upstream guide wheel 5. 
FIG. 19a illustrates the water flow path over the upstream guide rail. 17. 
FIG. 20 illustrates the relative position of the abutment recesses, the 
bulkheads and the positioning rack.