ETL 1110-2-536
31 Dec 94
intakes at 5-ft intervals along two sides of the tower.
The quarry area was developed using a dozer (Cat
These portals, sealed as sediment from periodic
D9C) and ripper. A crushing operation was set up,
impoundment, accumulates against the structure. The
and consisted of a primary jaw crusher, an impact
structure is designed to be an unmanned project.
crusher, and two roller crushers. The RCC mix
Discharged water flows through a 48-in. outlet pipe
required 29 to 32 percent of each rock product,
cast in the RCC dam and training wall into an impact
2.5-in. rock, 3/4-in. rock, fine aggregate, and approxi-
basin. Subsequent low velocity flows are channelized
mately 6 percent added silt. Approximately 50 per-
and eventually discharged into the natural channel.
cent of the total required aggregate was produced
prior to the start of RCC placement.
d. Floodway channel.
(2) Design parameters require the RCC to attain
a minimum compressive strength of 1,400 psi at one
(1) A natural water course below the dam,
year of age. Static stability requires cohesion values
incised into the canyon, channels water flow until it
of 35 psi at the base of the structure, and lesser val-
reaches the city limits where the natural channel
ues in the upper regions of the dam. Subsequent
widens out at west 7th Avenue and Vancouver. At
dynamic analyses determined that lift joints also had
that point the channel improvements consist of a
to attain cohesion values of 50 psi in the upper
concrete intake structure with trash racks and an
regions of the structure. It was determined that the
earthen dike to funnel flows of 400 cfs into a buried
specified construction system had to provide joint
conduit consisting of a 78-in. reinforced concrete
quality that resulted in shear cohesion values exceed-
pipe. The conduit proceeds east on West 7th Avenue
ing 50 psi. The resulting mix attains a 1-year com-
then north on Rainier Street to the golf course where
pressive strength of 2,200 psi, and displays laboratory
it flows out from a concrete stilling well and follows
cohesion values of 95 psi and 150 psi for unbedded
a natural drainage path through the golf course.
and mortar-bedded lift joint configurations, respec-
From Canal Drive, which borders the golf course on
tively, at exposures of 24 hr at 70F. The paste-to-
the north side, the water flows through a 6- 8-ft
mortar ratio is approximately 0.50, the mortar volume
concrete box culvert with a capacity of 620 cfs under
is 23 percent, and the workability level is approxi-
Canal Drive to the Burlington Northern Railroad fill
mately 15 sec, measured using the modified vebe
where a 78-in. diameter steel culvert was jacked
apparatus.
through the fill to be able to pass flows up to 620 cfs
with 3-ft of freeboard on the railroad fill.
(3) Great economy is achieved when RCC pro-
duction and placement can proceed uninterrupted at a
(2) Downstream of the railroad fill, a 200-ft
consistent production rate. Repeatedly changing mix
floodway dike was constructed to elevation 383.5
designs (e.g., for upstream and downstream richer
between Highway 395 fill to the high ground near the
RCC zones) creates placing problems, and limits
Union Pacific Railroad. An opening was left in the
equipment selection. Consequently, only a single
dike to allow train traffic to continue, with a stockpile
RCC mixture was produced for Zintel Canyon Dam,
of material near by to fill in the opening when flows
so that continual plant changes were not required.
exceed. The lower Zintel Canyon water course, also
This is especially beneficial for continuous mixing
know as Tweedt Canyon Drain, is a combination of
operations, since there is usually no convenient
natural flow channels, low bridge crossings, and
method of instant and frequent mix changes. Several
culverts crossings under embankments. Depending
other mixes were used on the project. A higher
upon flow magnitude, water will either flow com-
cement content mix, with an air entraining admixture,
pletely through the area in a series of existing
was used for the top two ft of the stilling basin slab,
channels and culverts or escape the watercourse and
as well as for the top four lifts of the dam. A low
proceed to the east of Highway 395 overpass to the
cement content mix, with an air entraining admixture,
Columbia River.
was used for the top four lifts of the training walls.
e.
Construction operations (Photos C-1 through
(4) Precast panels for vertical face construction
C-7).
were fabricated in a commercial precast facility
100 miles from the project and then trucked to the
(1) Crushed basalt rock (140,000 tons) for the
site. The panels, 4 ft by 16 ft in width and 4 in.
RCC was produced from a quarry located only a few
thick, were keyed along the horizontal joints. The
hundred feet upstream of the dam right abutment.
C-2
Previous Page
