TRUNION GATE RESISTANCE ANALYSIS

Applied on Diablo Dam, Diablo WA

Robert Gordon| May 7, 2015

| 2

DIABLO DAM GENERAL INFO

• Built: 1927-1929

• Concrete Arch Dam With Gravity Abutments

o389 feet high

o1180 feet at crest

o19 Tainter Radial Gate 20’-6” wide, 18’ to max. Lake

oGates 1-3 Automated in ~1980

oGates 4-19 Operated by Portable Hoist

oNormal Usage Sequence is 2, 3, Teens

| 3

MOTIVATION FOR WORK

• Folsum Tainter Gate Failure

• FERC Part 12 Inspection Item

oModel and Determine Maximum Acceptable

Friction

oFriction Test Gates and Determine Current

Condition

| 4

PRELIMINARY TESTING

• Contracted Consultant For:

oFEA Model of Gate

oDetermine Method to Test

oTest and Determine Friction Factor on a Portion of

the Gates

• SCL Assisted with Initial Testing

| 5

METHOD OF TEST TO DETERMINE TRUNNION

FRICTION

• Cantilevered Beam (73” long) Temporarily

Mounted at Each Trunnion

• Digital Dial Indicator Mounted at The End Beam

• Serial Connection Between Indicator and PC

• Data Collected Using PC Running LabVIEW

• Collect Continuous Data at 10 Hz

• Raise Gate 1 Foot and 2 Foot

| 6

FRICTION TEST RESULTS

• Gate 2 Friction

o0.9 Right

o0.6 Left

•Maximum

Acceptable

Friction Factor

0.3: this is

about

0.56mm*2

| 7

ACCESS TO LOCATION

• Constructed Work

Platform

• Install Gate Restraint

| 8

REMOVAL OF TRUNNION BUSHING CARRIER

• Remove Lead Paint on Trunnion

• Remove 18 1” Rivets Per Side

• Remove Bushing Carrier

| 9

TRUNNION PINS

• Trunnion Surface Corroded ~0.025” deep

| 10

•Machined With Climax PL2000 Portable Lathe

oRemoved ~0.050” off Diameter

oPolished to ~10 Ra

| 11

IMPROVEMENTS TO BUSHING

•Original Bushing had 1 Port with “X” Grove

~+/- 30 Degree of Coverage

•New Bushing (Improve Grease Distribution)

oOuter Circumferential Groove

o4 ports OD to ID

o4 Distribution Bars

o2 Circumferential Grease Dams

| 12

BUSHING CARRIER WORK

• Bore Was Damaged From Bushing Movement

•Medium Porosity Casting

• Counter Bore Bolt Holes

| 13

REASSEMBLY OF TRUNNION

• Bolted Both Sides Together

oSocket Head Cap Screws

oNordlock Lock Washers

| 14

FINAL TESTING

• Dry Gate Opening Test With Beam/Indicator

• Conduct Full Gate Opening

•Wet Gate Opening Test With Beam/Indicator

| 15

TRANSDUCER, LOCATIONS, AND FIXTURES

| 16

SIMPLIFIED LABVIEW DAQ CODE

| 17

ACCESS TO INSTRUMENTED LOCATION

| 18

PRE RING TEST

| 19

WET GATE FRICTION TESTING DATA

• Repaired Trunnion Friction ~0.07

| 20

ALTERNATIVE METHODS TO MEASURE FRICTION

•Mount Strain Gages on Involved Elements

• Strain Gage on Transferable Beam

• Laser/Camera/Burn Paper

• Encoders on Gate Hub

• Load Cells on Hoist Cable/Actuator

| 21

KEY FEATURES IN TESTING SYSTEM

•Need Real-time Indications During Testing

•Method to Archive Test Data

• High Resolution

• Rigid Test Fixtures/High Natural Frequencies

•Weatherproof & Robust

| 22

FUTURE WORK

• Refurbish of All 19 Gates To Greaseless Design

oReduced Future Labor Costs From Greasing

oBronze Bushing Cost ~= to Greaseless Bushing Cost

oLess Environmental Waste

o Instigation Cost Same

o Improved Worker Safety

| 23

NEW GREASELESS BUSHING/TRUNNION DESIGN

• Turn Existing Trunnion to Round and Smooth

• Thermally Shrink Fit Stainless Steel Sleeve to

Trunnion Shaft

• Bore Out Cast Bushing Carrier for New Greaseless

Bushing

• Add Two Energized O-ring Seals on

Trunnion/Bushing Ends

OUR VISION To set the standard—to deliver the best customer

service experience of any utility in the nation.

OUR MISSION Seattle City Light is dedicated to exceeding our customers’

expectations in producing and delivering environmentally

responsible, safe, low-cost and reliable power.

OUR VALUES Excellence, Accountability, Trust and Stewardship.