l-03 spring loaded foundation-presentation

7/31/2019 L-03 Spring Loaded Foundation-presentation

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CHANGE OF CATENARY READINGS SIMHADRI 2X500 MW


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FOLLOWING HAS BEEN REPORTED FROM THE ABOVE POWER STATION:

CHANGE IN CATENARY READING OF SIMHADRI 1 AFTER FLOATING OF

TG DECK.

CHANGE IN CATENARY READINGS (BEARING PEDESTAL HEIGHTS) AT

SIMHADRI UNIT-2 WITH FOLLOWING CONDITIONS:

- CONDENSER NECK NOT WELDED TO TURBINE.

- COMPLETE WEIGHT OF MACHINE NOT YET ERECTED ON

TG DECK.

- TIE ROD BOLTS OF FEW SPRING ASSEMBLIES FOUND LOOSE, OTHERS

COULD NOT BE CHECKED DUE TO ACCESSIBILITY

PROBLEMS.

SITE WAS ADVISED TO MAKE FOLLOWING MEASUREMENTS:- BETWEEN TG DECK AND COLUMN TOP.

- BETWEEN SPRING ASSEMBLIES (REFER THE ENCLOSED SKETCH).

DATA HAS BEEN RECEIVED FROM SITE INDICATING MAJORITY OF

SPRING ASSEMBLIES HAVING BEING LOADED BEYOND THE EXPECTED

DESIGN LOAD.




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THE ABOVE FACTS PROVE THAT ELEVATION OF THE DECK KEEPS

CHANGING WITH ADDITION OF LOAD ON TG DECK EVEN PRIOR TO

UNLOCKING OF SPRING ASSEMBLIES. ERECTION ENGINEERS AT

SIMHADRI SITE ARE FINDING IT DIFFICULT TO FINALISE THE

REFERENCE FOR CENTERING OF CYLINDER, ALIGNMENT AND

CATENARY OF THE MACHINE.

MOVING DECK HAS RESULTED IN FREQUENT CHECKING OF

CENTERING AND ALIGNMENT READINGS. THIS HAS RESULTED IN

INCREASE OF ERECTION TIME.


CONCLUSIONS


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CONCLUSIONS

FROM THE READINGS TAKEN AT SIMHADRI, ANY ONE OF THE

FOLLOWING MAY BE TRUE:1. ERROR IN COMPUTING THE DESIGN LOAD OF TG DECK

ALONGWITH EQUIPMENT.

2. INADEQUATE STIFFNESS OF SPRINGS.

ACTION PLAN FOR SIMHADRI-2


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REFER TO ERECTION PROTOCOLS. READINGS SET DURING

PLACEMENTS OF SPRING ASSEMBLIES BEFORE CASTING OF TG

DECK.

NO NECK WELDING OF CONDENSER TO TURBINE TO BE DONE.

IF TAG WELDED, REMOVE THESE.

UNLOCK ALL TG DECK SPRINGS ASSEMBLIES AND FLOAT THE

TG DECK.

CONDUCT NECESSARY SHIMMING TO ACHIEVE THE ELEVATION

AND CATENARY OF THE MACHINE.

LOCK ALL TG DECK SPRING ASSEMBLIES WITH SUFFICIENT

MARGIN FOR FURTHER LOADING OF TG DECK. WHILE DOING

THIS ACTIVITY, REFER TO BENCH MARK AND BEARING

PEDESTAL ELEVATION READING TAKEN BY TURBINE ERECTION

RECORD READINGS.

GERB TO PROVE THE HEALTHINESS OF SPRING ASSEMBLIES

SUPPLIED FOR SIMHADRI.

ACTION PLAN FOR SIMHADRI-2

ISSUES


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SITE FEEDBACK INDICATES INCREASE IN ERECTION

CYCLE TIME.

NO FLEXIBILITY IN SEQUENCE OF ERECTION ACTIVITIES.

NO APPRECIABLE GAIN IN VIBRATION LEVEL ON

MACHINE WITH

SPRING LOADED TG DECK.

INCREASE IN OVERHAULING TIME OF TURBINES WITH

SPRING

LOADED TG DECK.

PROTECTION FROM SEISMIC LOADS.

PRECAUTION FROM SEISMIC LOADS NOTED.

GE / ALSTOM MAKE TURBINES DO NOT ENCOURAGE USE

OF SPRING LOADED TG DECK.

ISSUES

WHAT SHOULD BE BHELS STRATEGY FOR FUTURE SETS ?

ACTION PLAN FOR FUTURE SETS:


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TASK

DURING ERECTION ELEVATION OF TG DECK SHOULD NOT CHANGE

WITH CHANGE OF LOAD IN TG DECK. TO ACHIEVE THIS WE PROPOSE:

GERB SHOULD PROVIDE BOTH SIDE LOCKING IN SPRING

ASSEMBLIES AS IN CONDENSER SPRING ASSEMBLIES.

GERB TO RECONSIDER THE AMOUNT OF ADDITIONAL PRE-

STRESSING.

FOLLOWING ADDITIONAL PROTOCOLS NEEDS TO GENERATED

WHILE PRE-STRESSING THE SPRINGS AT SITE FOLLOWING

MEASUREMENTS TO BE NOTED:

GAP BETWEEN SPRING ASSEMBLY WITH TIE BOLTS LOOSE

(FREE LENGTH OF SPRINGS) AT FOUR LOCATIONS.

FORCE REQUIRED TO PRE-STRESS TO THE DESIRED VALUE

TO COMPUTE SPRING INDEX AND COMPARE WITH DESIGN

VALUE FOR EACH SPRING ASSEMBLY.



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RANDOMLY SELECT FEW SUCH PRESTESS SPRING

ASSEMBLIES, LOOSENING ITS TIE ROD. MEASUREMENT FREE

LENGTH AND CAMPARE WITH FREE LENGTH REFERENCE

COMPRESSION.

ALL READINGS AS DEPICTED IN THE SKETCH TO BE TAKEN

WITH INSIDE MICROMETER, LOCATION OF THE READING TO

BE DEFINED, IDENTIFIED AND PUNCHED (USE METALMARKER, WHERE PUNCHING CANNOT BE CARRIED OUT).

LOCATION OF MEASUREMENT A SHOULD BE CHIPPED AND

SMOOTHENED TO AVOID ANY DISTURBANCES DUE TO

LOOSE CONCRETE.

BEFORE FLOATING OF TG DECK PUT FOUR DIAL GAUGE

INDICATORS ON TOP OF TG DECK. SET IT ZERO W.R.T. TG FLOOR.

CHECK AND RECORD THE READINGS AFTER FLOATING OF TG

DECK.




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VENDOR TO GIVE INSTALLATION MANUAL TO PROVIDE A

STEPWISE INSTRUCTIONS AND NUMBER OF PROTOCOLS TO BE

GENERATED.

BHEL TURBINE ERECTION ENGINEER TO INVOLVE DURING THE

COMPLETE INSTALLATION OF DECK SPRINGS.



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SCHEMATIC FOR GERB SPRING

TIE ROD

SHIM

TG DECK

TG COLUMN

NOTE:

1. THESE READINGS ARE IN

ADDITION TO READING

TAKEN BY GERB ON THE

PROTOCOL DOCUMENT.

2 TURBINE ENGINEER

ALONG WITH CIVIL

ENGINEER TO ASSOCIATE.

A. STICK MICRO METER READING AT FOUR

LOCATIONS BETWEEN DECK AND

COLUMN. MARK THE LOCATION OF

READING (USE METAL MARKER).

B. STICK MICROMETER READING AT FOUR

LOCATION OF EACH SPRING ASSEMBLY.

C RECORD TOTAL THICKNESS OF SHIMHEIGHT AND NUMBER OF SHIMS.

A AB B

C


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TIE

ROD

SCHEMATIC FOR M/S GERBS CONDENSER SPRING ASSEMBLY

SHIM

JACK

BOLTS

CONDENSER

FOUNDATION

CONDENSER

BOTTOM PLATE

BACK


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MOUNTING RECORD AT SIMHADRI UNIT-2 BY M/S GERB

Sl No Gr No Type

1 2 TVEH-750 25 5 30 229 5 16 5

2 1 T-1030 25 5 30 226 5 22 5

3 1 TVEH-750 25 5 30 226 5 16 5

4 2 T-650 25 5 30 229 5 16 5

5 2 T-650 25 5 30 229 5 16 5

6 2 T-1200 25 5 30 229 5 16 5

7 1 TVEH-750 25 5 30 226 5 17 5

8 2 T-1200 25 5 30 229 5 17 5

9 2 T-1200 25 5 30 229 5 14 5

10 2 T-800 25 5 30 229 5 14 5

11 2 T-1200 25 5 30 229 5 18 5

12 2 T-1030 25 5 30 229 5 20 5

13 2 T-650 25 5 30 229 5 13 5

14 1 TVEH-750 25 5 30 226 5 17 5

15 2 T-950 25 5 30 229 5 16 5

16 1 T-1030 25 5 30 226 5 23 5

17 2 T-650 25 5 30 229 5 16 5

18 1 T-950 25 5 30 226 5 22 5

19 2 T-500 25 5 30 229 5 19 5

20 1 TVEH-750 25 5 30 226 5 18 5

21 1 T-950 25 5 30 226 5 22 5

22 2 T-1030 25 5 30 229 5 24 5

23 2 T-800 25 5 30 229 5 16 5

24 1 T-950 25 5 30 226 5 19 5

25 2 TVEH-750 25 5 30 229 5 14 5

26 2 T-800 25 5 30 229 5 17 5

27 2 TVEH-750 25 5 30 229 5 14 5

28 2 T-800 25 5 30 229 5 19 5

Shim

Thickness

Actual

(mm)

Expected

Settlement

(mm)

Prestressing and setting 31.10.2000

Spring Unit

Static

Deflection

Mounting

Deflection

(mm)

Prestressi

ng Value

(mm)

Spring

Height

Prestressing

value

(mm)

Shim

Thickness

Theoretic

(mm)

18.02.2002

1 2 3 4

226.9 227.3 228.7 228.6

222 224.1 225 224.5

226 226.9 226.1 225.8

226.4 226.1 225.2 225

226.9 225.4 226.3 227

226.3 225.8 227.4 228.1

225.6 225.7 225.1 225.8

228.1 227.9 225.6 226.2

228.7 228.6 227.9 226.2

226.3 227.2 226.5 225.6

225.5 226.3 226.6 226

227.6 226.6 227.5 225.9

227 226.2 226.7 227.2

224.8 225.2 225.6 224.8

226.4 225.3 226.8 228.2

225 225.6 224.6 224.4

227 227 224.7 226.2

224.4 223.5 223.2 223.7

228.7 228 227.5 226.8

225.6 226 226.8 226.3

223.9 224 222.8 223.2

223.2 227.7 227.9 228.5

225.8 226.4 225.8 225.4

224.7 223.4 223.3 222

227.8 228.5 229 229

227.5 228.1 227 227.8

225.3 224.9 223.3 225.1

225.1 225 225.2 226

Releasing and adjusting

Spring Height After Releasing

(mm)


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MOUNTING RECORD AT SIMHADRI UNIT-2 BY M/S GERB

Sl No Gr No Type31 1 TVEH-750 25 5 30 226 5 20 5

32 1 T-1030 25 5 30 226 5 26 5

33 1 TVEH-750 25 5 30 226 5 19 5

34 2 T-650 25 5 30 229 5 16 5

35 2 T-650 25 5 30 229 5 19 5

36 2 T-1200 25 5 30 229 5 18 5

37 2 TVEH-750 25 5 30 226 5 18 5

38 2 T-1200 25 5 30 229 5 18 5

39 2 T-1200 25 5 30 229 5 23 5

40 2 T-800 25 5 30 229 5 28 541 2 T-1200 25 5 30 229 5 25 5

42 2 T-1030 25 5 30 229 5 18 5

43 1 T-650 25 5 30 226 5 19 5

44 1 TVEH-750 25 5 30 226 5 16 5

45 1 T-950 25 5 30 226 5 22 5

46 2 T-1030 25 5 30 229 5 19 5

47 2 T-650 25 5 30 229 5 15 5

48 1 T-950 25 5 30 226 5 23 5

49 2 T-500 25 5 30 229 5 16 5

50 1 TVEH-750 25 5 30 226 5 16 551 2 T-950 25 5 30 229 5 20 5

52 1 T-1030 25 5 30 226 5 22 5

53 2 T-800 25 5 30 229 5 18 5

54 1 T-950 25 5 30 226 5 20 5

55 1 TVEH-750 25 5 30 226 5 18 5

56 2 T-800 25 5 30 229 5 18 5

57 2 TVEH-750 25 5 30 229 5 16 5

58 2 T-800 25 5 30 229 5 20 5

Expected

Settlemen

t

(mm)

31.10.2000Prestressing and setting

Spring

Height

Prestressi

ng value

(mm)

Shim

Thickness

Theoretic

(mm)

Shim

Thickness

Actual

(mm)Spring Unit

Static

Deflection

Mounting

Deflection

(mm)

Prestressi

ng Value

(mm)

18.02.2002

1 2 3 4224.3 227 226.3 223.8

225 225.3 224 224.8

226.5 226.6 226.8 226.5

227.5 227.1 226.3 226.8

227 227.6 225.4 226.2

225.7 226.2 227 226.4

229 229.1 229 229

227.1 227.1 226.3 227

222 226.5 227 222

226.6 226.4 227.1 226.5227 227.4 225.5 225

227.5 227.8 228.8 228

224.7 224.5 223.6 223.8

225.9 225.2 226.3 226.2

224 223.7 223 223.6

226.6 225.9 228.6 227

227.6 227 227.3 226.4

224.3 225.1 224.1 224.8

229 228.3 224.9 225.8

226.7 225.9 226.7 226.9228 227.5 227.6 227.2

224 224.5 225.3 224.8

226.5 227.4 227.4 227

224.1 222.3 222.2 222

223.7 225.3 226.2 225.1

226.7 226.8 227.3 226.9

226 224.4 222.2 223.5

226.1 226.3 222.9 222.9

Releasing and adjusting

Spring Height After Releasing

(mm)

BACK


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l-03 spring loaded foundation-presentation

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