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across the joint, and provide a weakened plane in the wall to control the cracking of the walls. Type A has a parting strip of sheet steel along the joint with one side waxed. Type B has a construction joint key along the joint with one face of the joint painted with sealing compound.

Reinforced concrete cover slabs over five-ply membrane waterproofing covered the transformer deck and the control room roof. The cover slabs were sloped to drain and were provided with tooled grooves filled with joint compound spaced at a maximum of approximately 10 feet on centers.

To relieve tensile stresses induced by shrinkage, contraction joints were used at the base of the powerplant where the temperature changes are very small. The contraction joints differ from construction joints in that sealing compound is used to destroy bond between placements and the reinforcement steel is not continuous across the joint.

85. Foundation and Stability Analysis. Loading conditions tending to cause instability and flotation for powerplants are normally most severe before placement of second-stage concrete and installation of equipment. It is also important to assure stability during construction. The stability analyses were completed for the two separated parts of the building which were: (1) the control and main unit bays, and (2) the service bay. In all of the stability studies, full uplift pressures were assumed effective over the entire base area. Forces inducing instability were uplift, earthquake, wind, deflection of the dam, and horizontal hydrostatic loads including penstock water pressure and tailwater. Forces inducing stability were dead loads, fixed live loads, cohesion and friction with foundation materials, hydraulic thrust on the turbine runner, and water in the turbine and penstock. Suitable design criteria for the loadings for stability were determined from the construction program and operating criteria.

Stability of the first-stage concrete construction with or without the superstructure was determined from the capacity curves of the diversion tunnel (fig. 16) with no storage of water behind the dam. A tailwater elevation of 5610.6 for the uplift and horizontal hydrostatic pressures was established from a maximum discharge of 18, 000 second-feet from the diversion tunnel.

Stability of the completed or partially completed powerplant was investigated with the dam completed and the reservoir filled and using the maximum and minimum tailwater elevations shown on figure 15 for the uplift and horizontal hydrostatic pressures. The maximum tailwater elevation 5616.9 at the powerplant was determined from the spillway capacity of 28, 800 second-feet, the outlet works capacity of 4, 000 second-feet, and the maximum discharge of powerplant turbines of 4, 260 second-feet. The reservoir back of the dam created a large uplift pressure underneath the dam and the main unit bays of the powerplant. This uplift pressure was reduced by the addition of two rows of foundation drains, one row under the dam and one row under the penstock gallery of the powerplant. The final uplift pressure head of water by use of these foundation drains was determined to be 17 feet above the tailwater surface. 1/ The 17 feet of uplift does not occur under the control bay and the service bay.

The deflection of the dam, the result of filling the reservoir after completion of the first-stage concrete for the powerplant, required an expansion joint between the structure on the dam and the upstream powerhouse wall. A sponge-rubber expansion joint filler, in lieu of coated corkboard joint filler, was installed in this expansion joint (sec. 84). The physical properties of the joint filler permitted transfer of only that portion of the horizontal compressive forces through the expansion joint that the designs for powerplant stability and walls would tolerate.

The factors of safety for flotation, overturning, and sliding for the powerplant were adequate. However, at the service bay to assure a larger factor of safety against overturning and to reduce the maximum foundation pressure at the upstream corner of the service bay, it was decided to drill and grout anchor bars into the foundation rock. The governing conditions for design are summarized on figure 114.

1/Phillips, H. B., and Allen, I. E., "Uplift Pressures on Flaming Gorge Dam and Powerplant," memorandum, Bureau of Reclamation, April 29, 1958 (unpublished).

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Sliding (Q factor) Overturning

100% A.

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EL 55629

FACTORS OF SAFETY
Flotation

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120 Downstream

13 Downstream

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GENERAL NOTES

Factors of safety are defined by the following formuise:
Flotation • {W(vertical forces)/EU (split forces

Sliding (Q factor)+ (2Ntan •A)/H 2 summation of vertical forces,
c. cohesion, A-area of base in compression; EH. summation of harve forces.
Overturning⋅ & RM (righting moment)/$OM (overturning moment)

The following foundation properties were used for the analyses:
Coefficient of internal friction(tan) for concrete on rock-00
Conesian (shear strength for concrete an rack · 300psi.

Bond strength in tension between concrete and reck

For the properties of the rock foundation, see report Technical Data
for use of the Board of Consultents, Flaming Gorge Den, Colorade
River Storage Project, dated September 10, 1958"

Average compresse strength of rock. 17.400 psi.

Average tensile strength of rock 900pai

Weight assumptions

Reinforced concrete 190 las per ca. A

Structural steel 4500 per cu A.

Water-62.5 lbs per ca. N

Larth, dry. 10

per eu, saturated. 130 s per ca.

Equivalent fluid pressure of earth, dry 50 lbs. per sqft; saturated 05 lbs per sq. M

Generator 600,000 lbs. each

Turbine 500,000 lbs each

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86. Design of Reinforced Concrete. Structural frames, walls, slabs and massive concrete, as shown on figures 115, 116, and 117, were designed as monolithic, continuous frame structures employing the elastic frame methods of slope deflection and moment distribution to determine the stresses existing in the indeterminate members due to the loading conditions imposed on the structure. Columns, pilasters, beams, and girders were in general designed as frames. Walls and floors, wherever possible, were designed as two-way slabs in order to reduce the reinforcement steel requirements.

(a) Control Bay. --The walls and footings of the substructure below the floor at elevation 5607.25 were designed for the loads of the structure above and to transfer by shear and bending the varying bearing pressures on the footings, as determined from the stability analysis, to the massive concrete of the unit bays. The walls below the floor were vented to the tailrace to eliminate unbalanced horizontal hydrostatic loads, and only the horizontal earth loading of the backfilled cells was used in designing the walls. The venting of the walls also eliminated the remaining uplift pressures coming from under the toe of the dam. The floor at elevation 5607.25 was designed for full hydrostatic uplift of tailwater to elevation 5616.9.

The intermediate structure and superstructure consisted of monolithic frames supporting floors and walls at the b-, d-, and 2-lines. The b- and d-line frames became more rigidly supported after completion of the second-stage concrete floors at elevations 5607.25 and 5621.00. The 1-line wall was considered as a pin-connected frame because of the structural steel beams supporting the roof. The a- and 1-line walls were designed for tailwater hydrostatic loads, and the e-line wall was designed to resist the pressures caused by the deflection of the dam against the sponge-rubber joint filler.

(b) Main Unit Bays. --The principal design features of the substructure, consisting of the concrete below elevation 5593.50, were the bottom slab of the draft tube, the draft tube pit without second-stage concrete, and the slab under the sump. The slabs of the draft tubes and the draft tube pits were designed for the upward pressures along the construction joint between the first-stage concrete and the mass concrete at elevations 5571.50 and 5574.50 from loadings determined from the stability analyses base pressures. The slab under the sump was also designed for the upward loadings determined from the stability analyses base pressures. The maximum tailwater hydrostatic pressures did not govern the designs. The slabs were designed as continuous members with the walls and piers, with the accompanying horizontal hydrostatic pressures applied to the walls and piers. The concrete over the draft tubes was designed for temperature and shrinkage requirements. The floor slab at elevation 5593.50 over the sump was designed as a two-way slab fixed on four sides. This slab was placed later after the shrinkage and temperature changes had taken place in the adjacent massive concrete sections.

The designs of the boxlike first-stage concrete intermediate structure around the turbine and generator pits were dependent upon the loadings from the reactions of the superstructure structural steel frames and the maximum tailwater horizontal loading to elevation 5616.9.

The analysis of the superstructure structural steel frames was based on an assumed fixed condition at the base of the steel columns. It was assumed that the thickness of the e-line wall and the stiffening effect of the floor slab at elevation 5621.00 at the a-line wall would provide sufficient rigidity to justify the fixing of the steel columns. The values of the moments and shears obtained from the supersturcture analyses were applied directly to the top of the e-line wall and the a-line pilasters. The a-line wall and pilasters were designed to resist these forces as a minimum. The effects of the moments, shears, and normal loads were carried through the wall and columns to the crosswalls at the 3-, 5-, 7- and 9-lines. An analysis of the crosswalls was then completed by a method for calculating stresses at rigid corners where the extreme fibers are not parallel. The e-line wall was designed as a cantilever to include the effects of moments, shears, and normal loads from the structural steel columns on the e-line wall between the crosswalls. The a-line wall was designed for the hydrostatic loading by panel coefficients as a plate continuous on three sides and free at the top. The walls and pilasters of the a-line wall became more rigidly supported after placement of second-stage concrete floors at elevations 5607.25 and 5621.00.

The superstructure walls were designed for the lateral loads of wind and earthquake by panel coefficients as plates and continuous with or over the supporting structural steel

framework.

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EL 5620.50

-Type A contro! jts

5-6 Sq recess
E1.5620. 58-

€1.5620.83

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EL 562100

3E1.5619.17

1307

13-0

·21-0

557250

-30-2

912

Type A control its-
..VCJ

EL 5619.17

E156205

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Type 8 control pts

·30-25

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Unit 1

Unit 2

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For general concrete outline notes, see 40-0-5432.

Structural Arrangement drawings are preliminary and are subject to change pending final design.

Typical constuction joints are shown; additional joints may
be required

Seals shown in horizontal construction joints are Type 2
metal seals. Seals shown in vertical construction joints
are Type F rubber waterstops

For details of keys in construction joints, see 40-0-5249.
For stub wall construction joints, see 40-0-5248.
For control joints, Types A and B, see 40-0-5250 and 5251.
Second stage concrete not in this contract and not shown on
Structural Arrangement drawings

Floor elevations are to the top of monolithic finish.
For metal seals and rubber waterstops see 40-D-5268
and 40-0-4567 respectively.

+6-0

15-31-15-3

13-3

-15-3-15-3

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PLANS

CONVER, COLORADO

091-0-13

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