A.03.09_Drawings.pdf

SLUICE MAINTENANCE BULKHEAD DESIGN

Design Documentation Report

Isometric View of new Bulkhead

PURPOSE

The purpose of designing and fabricating this bulkhead is to provide Bluestone Dam with a functional one-piece bulkhead to facilitate maintenance and inspection of the sluice features of the outlet works. The intent of this bulkhead is to be used for sluice dewaterings of relatively short duration, such as inspections or minor maintenance. If a bulkhead is to be placed and remain for extended periods of time, the original sluice bulkhead must be used. If a bulkhead is necessary for a period of in which pool forecast is projected to reach EL 1413.0 or greater during the time a bulkhead is needed, the project's original sectional sluice maintenance bulkhead shall be used. This one-piece bulkhead shall be reserved and only used for periods when pool projections are not expected to exceed EL 1413.0. In NO case shall this bulkhead be set for the purpose of removing a gate(s) from service in that respective sluice. The sluice gates MUST be operable in the sluice that this bulkhead is to be set in. Prior to use, a standard operating procedure (SOP) should be coordinated and generated from operations and engineering and stored in FEM attached to this bulkhead asset.

The design effort is funded through Operations as described in the subject TSWO. A

REFERENCES

1. ETL 1110-2-584

2. EM 1110-2-2105 DESIGN OF HYDRAULIC STEEL STRUCTURES, 31 March 1993

(superseded by ETL 584).

3. AISC STEEL CONSTRUCTION MANUAL, 15TH EDITION

4. BLUESTONE RESERVOIR PROJECT ORIGINAL CONSTRUCTION DRAWINGS,

SHEETS 023N-UB-40/1, 40/2, 40/32, 40/36, 40/46, 40/49, 40/52, 40/80, 40/81, 57/1, 57/3, 57/13, 57/14, 60/25, 60/26.

5. Bluestone Derrick Crane Drawings - Appleton Marine, Inc., Drawing BMD-0618, Crane

Outline Model: EB-120-60-27.5

6. Technical Service Work Order (TSWO) - Hl 18-290809A

BACKGROUND

The existing sluice bulkhead is an original project feature and consist of seven (7) stackable units and a designated lifting beam. The bulkhead is designed for loading to the original maximum design pool for Bluestone Lake of EL 1520.0. Although functional, the bulkhead is very time consuming and cumbersome for project personnel to set and Operations personnel desire a bulkhead requiring less time and labor resources to set that may be utilized for shorter duration maintenance/inspection activities.

The maximum capacity of the crane utilized to set this bulkhead is 27,000 lb. In order to design a one-piece bulkhead and stay below this maximum weight, a lower design head is provided. To prevent the bulkhead from being overloaded, the bulkhead will be designed so that it will be overtopped at pool elevations above EL 1413.0. By designing the bulkhead to overtop/equalize at EL 1413.0 the bulkhead can be kept light enough as a one-piece unit so that the existing crane can accommodate the bulkhead while at the same time ensuring that the design loading cannot be exceeded by additional pool height. Providing a bulkhead for protection over the top of the sluice invert of EL 1414.0 will result in a greater bulkhead weight as well as risk the bulkhead being overstressed should the pool exceed the specified design load.

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BULKHEAD SECTION

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FIGURE 1 - Original Drawing and representative photos of the existing bulkhead units.

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FIGURE 2-As-built drawings of the sluice maintenance bulkhead

PLACING AND RIGGING

The bulkhead will be designed to be lifted with a 2-piece wire-rope bridle. Consideration was given to utilizing the existing lifting beam; however due to the significant increase in load the existing beam would contribute to the overall pick load (approximately 3,500 lb for the beam and designated sling), and the unnecessary procedure of latching/unlatching for setting multiple units to provide the closure, a conventional 2-piece bridle was selected. The sling will be long enough so that in the event it is necessary to unhook the load block from the sling it can be done by lowering the crane load block to a work boat and dogging the sling off on the trash rack structure. The lugs will be located offset of the center of gravity so that the bulkhead is suspended in relatively the same position as the face of the dam (80.5 DEG from horizontal or 6:1 slope). Maintaining the bulkhead in this position when rigged and lowered will aid in placing the bulkhead in its designated slot. With the bulkhead positioned vertical, it would likely prove challenging to manipulate it into the slot on the 6: 1 slope.

DESIGN ASSUMPTIONS

Bottom of Sluice Intake-EL 1383.0 Top of bulkhead guides -EL 1432.05 Spillway Crest-EL 1490.0 Design Pool-EL 1413.0-top of bulkhead

Top of sluice opening-1414.0 Bluestone Lake seasonal pool-EL 1410.0 Bulkhead opening recess width 17' -11" clearance.

Load and Resistance Factor Design (LRFD) Design Methodology is used, in accordance with

ETL 1110-2-584.

All plate material will consist of 50ksi yield strength. The skin plate and the W-shapes (main girders) will be specified as Fracture Critical Members (FCM) due to the positioning of the skin plate on the downstream side of the bulkhead. Fabrication will be to AWS Dl.5.

All primary structural members are designed for full Hydrostatic Load to the top of the bulkhead unit (EL 1413.0). It is noted for record that this design loading is a very frequent event and the bulkhead will overtop and equalize pressure above 1413.0. To ensure that the bulkhead loading is equalized in a timely manner after the pool elevation exceeds 1413, two (2) 4" diameter pipes (riser pipes) are provided through the top girder web with inlets at the design elevation of 1413.0 and terminating on the downstream side of the skin plate of the bulkhead at EL 1410.0. The intent as that if the pool is projected to exceed EL 1413.0 the bulkhead should be removed.

However if circumstances exist that require the bulkhead to be left in place, it is imperative that at least one of the sluice gates be closed in the respective sluice that bulkhead is set upstream of so that pressure will be able to equalize and prohibit hydrostatic forces above design load ..

Instructions to end-user will be included on the drawings to state:

• EL 1413.0 is the maximum design elevation for this bulkhead. At pool EL 1413.0 the riser pipes will permit flow into the sluice to equalize loading on the bulkhead.

• If the pool is expected to exceed EL 1413.0 and the bulkhead is to remain in place in the bulkhead slot, ensure that the sluice gates are CLOSED in that sluice so that the pressure can adequately equalize within the sluice.

• Ensure the inlets and outlets of the equalizing riser pipes clean and clear of debris prior to setting the bulkhead.

DESIGN

In order to utilize the existing embedded bulkhead frame and guides, a similar guide system is used consisting of roller wheels. The bulkhead, which is relatively tall at over 31 ', must be placed into a slot on a 6 vertical to 1 horizontal slope. Figure 3 shows the sluice Bulkhead Guides. Figure 4 shows a cross-section view of the bulkhead embedded metals and the original bulkhead end frame.

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FIGURE 3 -Photo of sluice guides drawings

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FIGURE 4-Existing Trash Rack Details from the as-built drawings

Ultra high molecular weight polyethylene (UHMW-PE) will be used for bearing on the face of the bulkhead along each side and a J-bulb rubber seal along both sides and the bottom.

A Pressure equalizing valve will be installed in the bulkhead to facilitate removing the bulkhead from the slot.

The out to out width of the existing bulkhead guide wheels, as taken from the drawings and field confirmed is 214 ¼". The slot clearance is 215". The new bulkhead will be specified at 213 ¼" out to out of the guide wheels to provide 1" additional clearance total.

WEIGHT

At an estimated weight of 20,300 lb, the new bulkhead will be approximately 4,900 lb heavier than the weight of one of the existing stackable bulkhead units and the associated lifting beam.

The bulkhead will be placed utilizing the Bluestone Derrick Crane which has a maximum capacity of27,000 lb.

PRIMARY MEMBER CAPACITY AND DEMAND

Skin plate, intercostals, and primary girders are designed utilizing LRFD methodology and are detailed in the design computations. The diaphragms are considered brace points for the primary horizontal girders. Following is a summary of the required strength of primary structural members, and the capacity.

W21x44 Horizontal Girder (Gl, G2, G3, G4)

Shear capacity, Vnqm = 102 kip Moment Capacity, Mnqm = 3633 kip-in

Max Shear Demand, Vu = 63 kip Max Moment Demand, Mu (kip-in) = 3260 kip-in

W18x35 Horizontal Girder (G5, G6, G7, G8)

Shear capacity, Vnqm = 87 kip Moment Capacity, Mnqm = 2506 kip-in

Intercostal

Shear capacity, Vrnpa = 55 kip Moment Capacity, Mnqm = 163 kip-in

Skin Plate

Shear Demand, Vu = 43 kip Max Moment Demand, Mu (kip-in) = 2230 kip-in

Max Shear Demand, Vu = 12 kip Max Moment Demand, Mu (kip-in) = 142 kip-in (based on 33" tributary spacing and 48" vertical span)

The calculated minimum thickness required = 0.36 in.

Thickness provided= 0.375 in

Lifting Lug Capacity = 36 k Demand = 13.5 k (27k crane pull/2)

STORAGE

Although the storage system is not part of this design, initial discussions in the field with operations personnel and site observations show that the work platform immediately above the penstocks, monoliths 16 to 23, EL 1495. This will allow the bulkhead to be stored in the same orientation that it will be in when placed.

FIGURE 5 -Photo (left) and cross-section view from original drawings of the work platform above penstocks showing proposed area of bulkhead storage.