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


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


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


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


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


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


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


8/27

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


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


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


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


12/27

KEY PROBLEM AREAS OF BTG CIVIL WORKS


13/27

TEMPORARY FRAMING ARRANGMENT FOR INSERTS WORK OF TG DECK

FOR 660MW L&T MHI DESIGN


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


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


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


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


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


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


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



N

M


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



N


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%


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)


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


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


26/27

SAFETY RECORDSAFETY RECORD – –

Civil & structure packageCivil & structure package


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

Documents

Key Civil & Structural Issues