Key Civil & Structural Issues
Transcript of Key Civil & Structural Issues
-
8/17/2019 Key Civil & Structural Issues
1/27
CIVIL AND STRUCTURES KEY ISSUES AND ACTIONS
FOR SUCCESSFUL PROJECT EXECUTION
OF LARGE THERMAL POWER PLANTS
POWER LINE MEET 22ND AND 23RD MAY 2012
S K KODANDARAMAIAH
Director(BD) & CEO
Sunil Hi Tech Engrs Ltd
-
8/17/2019 Key Civil & Structural Issues
2/27
INDUSTRY PERSPECTIVE AND EXPECTATIONS
• Capacity to add 15000mw/ year
• Managing costs with Civil and structures being about 20% of EPC cost &
45-50% of BOP Costs
• Cycle t ime Pressures
- 250/300mw 24-26 months
- 500/600mw 32-34 months
- 660mw 44 months• Needs about 50% of Labour needs of a Power plant
• Better Lay Out management with reduced Land availabili ty
• Project delays related to Labour non availabili ty
• Civil and Structures key input for Electro Mech packages
• Cut down of delays of BTG/Mech packages of 6 to 12 months
due to Civil works• Concreting requirement 4M M3 and Structural reqt of 5 lac MT/year
• Focus on improving Engg inputs and Optimization of BOQ
• Increased mechanization to reduce manpower
• Better interface management & Engg Co ord to reduce delays
• Sound planning and sequencing of work
-
8/17/2019 Key Civil & Structural Issues
3/27
CONTRACT STRUCTURE AND RESPONSIBILITIES
Owner/EPC
Contractor
Owners
Engr
Structural
Civil & StrBTG & BOP
Detailer
Fabrication
Erection
Raw Mats
From
Steel Plants• Res for Civil & Str • Infrastructure
• Raw Mat Supply• Providing Civil fronts
• Plant Engg• Engg Drgs
• Fab. Drawings
• Cranes
• Welding eqpt
• Skilled/Unskilled
• Painting
• Bought out items
OR
Civil
Excavation
Architectural& Buildings
concreting
• Batching plant
• Other equipment
• Sand & Metal
• BOIs,Cement & Steel
• Bar bending• Labour
-
8/17/2019 Key Civil & Structural Issues
4/27
Un certainty in the Soil conditions and below ground work
Infrastructure of Land development, Temporary roads, drains
Availabili ty of Metal and Sand
Key engg inputs from BTG Vendor & BOP Elect/Mech packages
Key layout issues and land availability constraints
Storage yard and Fabrication yard space availability
Inadequate investment in Infrastructure Roads, drains, power & water
Engg co ordination issues between Civil and other areas
Interfacing issues between Civil and Structures
Interfacing issues between Civil and Electro- Mech
Non availabili ty of labour carpenters, barbenders, welders, fitters
Seasonal labour strength depletion and turn around
Delivery of Critical steel sections in Rolled and Plate sections Volatility of steel prices
Major Delays in Civil & Structural works
- Between Boiler & ESP
- Bunkers on the LHS – General delay of 4 to 6 months
CIVIL & STRUCTURAL WORKS KEY ISSUES
-
8/17/2019 Key Civil & Structural Issues
5/27
Concreting in Different Areas
% age of
concreting
0
10
20
30
40
50
60
NDCT /
Chimney
Buildings Flooring
work
Foundation
Super Str.
• TG & Bunker Floors Critical• Str completion key
• Buildings Delay due to
- Engg
- BOI items
- Const material
- Labour
• Major augmentation at the
time of LU and Coal firing
• Serious manpower shortages
-
8/17/2019 Key Civil & Structural Issues
6/27
VARIOUS INTERFACING ISSUES TO BE TACKLED
Completing the Furnace bottom AH works beneath O meter along with
Boiler Foundations
Simultaneous commencement of work in
- Boiler area
- ESP Area
- TG Area( A, B & C rows)- Commencement of Fabrication of TG Structures
Engg drgs of TG Building str from grid 0 to 7 at the time of commencement
CEP pit and CWP drgs release early to Facili tate A and B row foundation
continuity
Mill side foundations on the RHS along with Boiler work up to O level
Aux col interfacing with CW Pit and its eng drg release
Completion of Aux col foundations prior to TG Deck casting
CEP sump along with the liners to be finished prior to TG Deck work
Also priorit ize the foundations for duct ing between ESP to Chimney
planning Foundations work of Transfer Points & Boi ler to ESP
AB Bay f loor at the operating level on A row and B row side
-
8/17/2019 Key Civil & Structural Issues
7/27
Areas Needing Attention
From Project Events Points of View
Sl No Description(Boiler)
Event Remarks
1 Ducting work not
complete
LU & CF • Boiler inside duct
• BOF to ESP
• Duct Foundation inputs issues
• Manpower & Welders problems
• Shortfall of 30 to 40%
2 Coal Piping & Mills
completion
Problems
Syn & CF • Foundations
• Mat feeding issues
• Prob of erecting coal pipes
• CHP & AHP Civil work problems
3 Left side Milling
system
Full Load • Affects 3000 to 5000mt of Boiler work
• Late foundation readiness
• Integration of TPs, Gallaries, FeederFloor,Bunkers,Mills & Coal piping
4 LU & CF shortfalls
from the beginning
LU & CF • At HT/LU about 20% shortfall
• At CF 10 to 15% shortfall
• Water & Elect systems civil delays
Major Shift in Atti tude: Do Initial LU with Coal Firing
-
8/17/2019 Key Civil & Structural Issues
8/27
Sl
No
Description
Others)
Event Remarks
5 Mismatch between
TG Deck and TG
building Readiness
TG
Erection
Start
• CEP/CW Piping in terface delays
• Aux Col Readiness &Deck support
removal
6 Left side Bunker
Structure
Full
Load
• Late start/Foundations availability
• Inadequate Cranes & manpower
• Mat feeding problems
7 BOF to ESP
Foundations & Str
• For Ducts
• For FD/PA Fans
• Fan Handling str
• TPs of CHP
• PAPH Str
LU/CF/F
ull Load
• Prioritizing FD & PA fan foundations
• How to accommodate Duct &TP
foundations
• working on TPs, Ducting & Fans
simultaneously
8 Pipe rack
• Foundations
• Structures
LU/CF • Early s tart can help events
• Interfacing and approach issues to be
worked out
-
8/17/2019 Key Civil & Structural Issues
9/27
Critical out look on Thermal Power Cycle
times(500-600mw units)
Boiler Island:• Civil Engg and Initial Civil works very critical
• BLU and Coal firing to be most cri tical
• Other events can only be inputs for the above
• Typically @ HT, the physical shortfall of LU work is 15-20%
• For full load operation the physical shortfall can continue to be 10-15%
• Major input delays from Civil Side
Problem Areas:
• Not identifying the Commissioning sequence at the time of Civil
works for
Milling system(RHS OR LHS), Duct ing system between Boiler andESP
• Too many civil works at a time between Boiler & ESP
- Duct foundations & Duct work
- Fan Foundations & Fans erection
- CHP Transfer point foundations & Transfer Point Erection
-
8/17/2019 Key Civil & Structural Issues
10/27
TG Island Side
• Interfacing of CEP Pit, CW Piping along the A and B row of TGBuilding
• Aux column foundation work and structural work around theTG Deck & Operating Floor completion with TG Building work
Key Cycle times with Proper interface management
• Foundation start to LU :25-27 months
• LU to CF: 3 - 5 months
• TG Side Foundation start to EOT Crane+TG Deck-12-14M• TG Start to Barring Gear 12 months
-
8/17/2019 Key Civil & Structural Issues
11/27
TG Deck and Structure up to 660 MW
Sl.no
Project Unit TG Deckcasting
comp. in
TG Bldgwith TG
floor
readiness
EOT Cranereadiness
TG Bldg. Structurewith floors
readiness
(In months) (In months) MT (In months) MT
1 DB
Power
(600 MW)
# 1 13 months 15 Months 11 Months 2900 MT 18 months 6500 MT
# 2 18 months(Anticipate
d)
21 Months(Anticipated)
17 months(Anticipate
d)
2900 MT 23 months(Anticipate
d)
6000 MT
2 Koradi
(660
MW)
# 8 14 months 18 months 12 Months 3000 MT 21 months
(Anticipate
d)
5200 MT
# 9 21 months
(Anticipate
d)
23 months
(Anticipated)
18 Months 2500 MT 27 months
(Anticipate
d)
5200 MT
# 10 26 months
Ant ic ipated
28 months
Ant ic ipated
24months
Ant ic ipated
2500 mt 32months
Ant ic ipated
5200mt
3 Vallur
(500MW)
# 1 14 Months 750 MT 27 Months 6500 MT
# 2 19 Months 2000 MT 40 Months 6500 MT
NEED TO MATCH THE DECK AND FLOOR SCHDULES
-
8/17/2019 Key Civil & Structural Issues
12/27
KEY PROBLEM AREAS OF BTG CIVIL WORKS
-
8/17/2019 Key Civil & Structural Issues
13/27
TEMPORARY FRAMING ARRANGMENT FOR INSERTS WORK OF TG DECK
FOR 660MW L&T MHI DESIGN
-
8/17/2019 Key Civil & Structural Issues
14/27
SUPPORT FROM DEVLOPERSSUPPORT FROM DEVLOPERS
• Liberal investment in Infrastructure
• Infrastructure of Roads, Drains, Sewerage system,Lighting
- to with stand Indian Monsoon(2 seasons)- Fit for movement of heavy cranes(200-400mt) & HeavyDumpers
• Establishing reliable Construction & Water supply
• Drinking water facility
• Adequate Lighting arrangements
-
8/17/2019 Key Civil & Structural Issues
15/27
CIVIL WORKS-Improving Schedules
o Simultaneous excavation on Boiler, RHS of Mill, ESP & Duct Supportso Explore possibi lity of Civil works between Boiler & ESP before
commencement of Boiler Erection
o Start the TG area foundation along with Boi ler
o For AB,BC bay along w ith Aux columns for Floor work
o Prioritise Floor castings & use Deck sheeting's
o Use cranes for Erection of Cribs erection for TG Deck/or cuplockso Provide Hard crusted surface for Fabrication Area
o Provide clear approach roads & Drains
o Commence Fabrication of Structures along with Excavation
o Complete the TP foundations before Boiler Hydraulic test
o Erection of Bunkers wi th Cranes or Jacking System
o Prioritise the completion of main control and ESP control room
o Kick start of Water system side of Civil workso Focus on the Cable and Pipe racks as a parallel activity
GOOD START IN CIVIL WORKS ENABLES MEETING SCHEDULES
-
8/17/2019 Key Civil & Structural Issues
16/27
QUANTUM OF STEEL STRUCTUES FOR LARGE
POWER PLANTS
Sl No Area 250mw 500/600mw 660mw Remarks
1 Power House Str 5000 6500 7500
2 Bunker Str 3500 5000 6000
3 Pipe Racks 600 1500 2500 Common
4 Service Building 750 1800 2000 Common
5 ESP Cont Room 250 400 500
6 Comp House 100 150 200 Common
7 Air washer Room 150 200 250 Common
8 Work shop Building 200 350 400 Common
9 CWP House 500 1000 1200 Common
11050 16900 20350
FOR MULTIPLE
UNITS 2 2 5Capacity in MW 500 1000/1200 3300
Total Structures 19900 28500 76350
Coal Handling Str 5000 9000 15000
24900 37500 91350
Per MW Steel use in
MT 50 31 28
-
8/17/2019 Key Civil & Structural Issues
17/27
APPLICATION IN MEGA AND ULTRA MEGA PROJECTS
1000/1200mw and >3200mw
Total Quantum of work 37500mt / 1,00,000mt
Completion schedule 36 / 45 months per unit
Packaging can be part of main Civil works or in BTG civil work for BTG Area
TG Building has two or three bays( Typ for 2 x 600 MW :- 42mx240m)
Bunker on the left and Right side of Boiler or between TG building & Boiler
70% Plates and 30% Rolled Sections
Material Handling is a major input
Fabrication Area Reqt is about 30000m2 to 50000m2
Can be 7 to 10% of Project Costs
Transfer points betn Boiler & ESP can be part of main Str Package
-
8/17/2019 Key Civil & Structural Issues
18/27
TYPICAL BUNKER SHELL SECTIONAL VIEW FOR ONE UNIT
Bunker Shell RCC
SS Hopper
ABCDE
FEEDER
FLOOR
TRIPPERFLOOR
BUNKER
SHELL
BUNKERHOPPER
22.4m
56.6m
Deck Sheet
Cladding for Bunker Sealing
N
M
-
8/17/2019 Key Civil & Structural Issues
19/27
A
• COLUMN HT. OF BUNKER SUPPORTSTRUCTURE IS :- 68.0 m
• SAME HAS BEEN FABRICATED &
ERECTRED IN 3 PARTS
• 1st PART is OF 27.0 m IN LENGTH
WEIGHING 60.0 MT
• 2nd Part is OF 17.0 m IN LENGTH
WEIGHINH 22.00 MT.
• 3rd Part is OF 22.0 m IN LENGTH
WEIGHINH 14.00 MT. 22.0 mtr
feeder
floor
Bunker
supporting
str
Tripper floor
Roof floor
METHODOLOGY OF BUNKER STRUCTURE AND BUNKER SHELL ERECTION
150 MT Capacity crane
-
8/17/2019 Key Civil & Structural Issues
20/27
A
•BUNKER SHELL ARE SUPPORTED ON
TWO ROWS OF COLUMNS MRK M & N.
• BUNKER SHELL HT. IS 12.5 m
• SAME IS BEEN FABRICATED & ERECTED
IN 3 PARTS
•1st PART IS 5.0 MITER HEIGHT AND
WEIGHT IS AROUND 15.00 MT
•2nd PART ALSO 5.0 MITER HEIGHT
WEIGHT AROUND 15.00 MT
•3rd PART IS 2.50 MITER WEIGH AROUND
7.50 MT . 22.0 mtr
feeder
floor
Bunker
supporting
str
Tripper floor
Roof floor
METHODOLOGY OF BUNKER STRUCTURE AND BUNKER SHELL ERECTION
150 MT Capacity crane
N
M
-
8/17/2019 Key Civil & Structural Issues
21/27
A
•THE BUNKER SHELL 1ST PART WITH 4NOS STUB COLUMN RESTED ON DIRECT
BUNKER SUPPORTING STRUCTURE
TOWARDS M-ROW WERE ERECTED.
• AFTER PROPER ARRESTING THE SAME
2ND PART AND 3RD PART WERE
ERECTED.
• AFTER THAT TRIPPER FLOOR BEAM
AND ROOF BEAM WERE ERECTED.
• SS HOPPER ALONG WITH THE RING
BEAM HAD BEEN ERECTED.
•FINALLY N- ROW BRACINGS & BEAMS
HAD BEEN ERECTED.
22.0 mtr
feeder
floor
Bunker
supporting
str
Tripper floor
Roof floor
METHODOLOGY OF BUNKER STRUCTURE AND BUNKER SHELL ERECTION
150 MT Capacity crane
N
-
8/17/2019 Key Civil & Structural Issues
22/27
BOLTED STRUCTURES ADVANTAGES & DISADVANTAGES
Structures present status
• General practice of Fab & Ern @ site
• Make shift arrangement for fabrication
• Design by Customer & Detailing by Contractor
• Material supply by mostly customer
• Site erection of welded joints
• Erection tolerances can be flexible
• Welding by MIG/MAW welding
• Schedules 30-40 months for 500/600mw units
Bolted Design Requirements
• All the structures including cols, main &sec beams
of bolted design
• Needs factory manufacture with NC/3 axis m/cs
• Very close tolerances for manufacturing & Ern
• Transportation logistics to be worked out
• Local MM logistics for storage @ site
• Design and Detailed Engg to be with Owner
• Raw material supply with the Vendor
• Manufacturing to gear up to handle 60 to 80mt wts
• Large infra and area to be created for offsite work
Advantages
• Factory made work, better quality
• Erection can be faster
• No need for large infrastructure at site
• No burden of raw material procurement
• Welding work can be eliminated
• Saving in cycle time if properly managed
• work can be done with less work force
• CENVAT benefits can be taken
Disadvantages
• Fab + Ern cost go up by 20 to 25%
• ED on factory dispatch's on site work
• Transportation cost extra on large components
• No flexibility on managing matching items
• Non sequential supplies can delay the site work
• can nullify the advantages if shipments are non sequenti
• Addl cost for site storage and MM
• High levels of accuracy for manufacturing & tolerances
• High levels of erection accuracy reqd
• Detailing to be done by Customer
• Total cost per MT can go up by 10-12%
-
8/17/2019 Key Civil & Structural Issues
23/27
MAJOR PROBLEMS AND CHALLENGES FOR STRUCTURAL
WORKS IN POWER PLANTS
Structural and Civil works are to be integrated for better execution
Very poor infrastructure at site for Fabrication yard and Movement of material
Major mat. availability problems with Plates of 32mm,36mm,40mm &
Rolled sections ISMB 300,400,500 & 600
General Delay of 3 to 5 months in Critical Steel Sections
Volatili ty in Steel Prices
Manufactur ing capacity of higher sections limited and mismatch between
Site reqt and Steel Plant Roll ing plans Engg input issues between Mechanical inputs for Civil Const Drgs
Transportation bott lenecks for Heavy items at site- Poor Roads
Availability of skil led welders and f itters & Material Handling Equipment
Mismatch with the events of Mechanical fronts w ith Civil and Str fronts
like
- EOT Crane Readiness in TG hall
- TG Building readiness for Mechanical Erection
- Bunker Structure for Coal Firing system of Boiler
- Bunker readiness for Coal firing
- CHP Transfer point Erection Problems( Very tall structures)
-
8/17/2019 Key Civil & Structural Issues
24/27
CAPABILITIES & LEARNINGS
Critical steel sections in manufacturing to be augmented for timely supply
Better to discuss with the steel supplier at the beginning with tentative sections
Need for Deployment of Higher Capacity cranes of 150mt to 250mt
Present capacity to be increased by about 30-50% for 12th Plan Objectives
There is a general shortage of experienced good Civil and Structural Engrs.
Shop manufacturing as a substitute to site fabrication can be an alternative
Bolted structure can be an alternative to Welded structure for site joints
Investment in site infrastructure for proper Fab Yards, Roads and Approaches
Development of skilled welders and Fitters for site work
Development of more agencies for Fabrication detailing drawings
Safety standards for tall structures erection to improve
Suitable Price Escalation for Steel Price volatility cover up
-
8/17/2019 Key Civil & Structural Issues
25/27
FOCUS AREAS KEY ACTIONS
Boiler Foundations • To excavate the Mill side foundations on RHS• To do Bottom ash hopper foundations to GL
A, B Structure column erection • CEP and CWP engg clearance for RCC work• Engg drgs for Cols, bracings, Floors ,trusses
• Heavy lift crane
Floors in AB and BC Bay • Readiness of Aux cols• Deck sheeting arrangement
TG Deck work/TG operating floorreadiness
• Cup lock/staging arrangement• Inserts incorporation with proper material handling
• Bar bending and placement arrangement for
reinforcement
• UPV testing arrangement & Deck support
dismantling
Foundations between Boiler & ESP
& TPs
• Priority for Duct and Fan Foundations for LU
• Priority for TP foundations for CF
• Sequencing of foundations, duct work and CHP
work & clearances
• Erection of TPs the most difficult structure
BOP Bui ldings( DM plant, CWP
House, FOPH,Aerator,Service
building, APH, Silos
• Labour arrangement
• Shuttering & staging material
• Drgs
• Clearances
-
8/17/2019 Key Civil & Structural Issues
26/27
SAFETY RECORDSAFETY RECORD – –
Civil & structure packageCivil & structure package
-
8/17/2019 Key Civil & Structural Issues
27/27
LOOKING AHEAD……
Engg inputs to be ahead for 3 to 5 months progress of site work Adequate and t imely investment in Roads, Drains, Const Power & Infra
Improve mechanization and reduce dependence on labour
- More Use of Boom placers, concrete pumps
- Use of Deck sheeting for floor work
- Use of RMC wherever it is feasible
- Use of higher capacity cranes and more in nos
- Use of Tower cranes for Building works
Pre pone CHP Civil works between Boi ler and ESP by 6 months
Better integration of Civil and Structural works of TG Building
Invest in Monsoon preparation on temporary works
Switch over to Bolted structure for major structural work
HR init iatives for Strengthening Civil and Structural Supervision
Improving Construction safety records Provide differential rates for concreting of Buildings & Floor works
Proper escalation clauses for Cement and Steel price volatility
Prioritize Bunker work on RHS and LHS
Plan for LU with Coal firing instead of Coal firing for Full load operation