CIVIL SURVEY OF SOHAR -2 POWER PLANT
Civil Survey Inspection Report for Sohar-2 Power Plant,
Sultanate of Oman
Inspection Details
Customer
Location
Purchase Order No.
Date of Inspection visit
STOMO
Sohar Industrial Port Area
4600031950
24.8.2021 & 25.8.2021
By:
SOGEX Oman Co. LLC.
Al Qurum, Street 7,
Block 205, Plot 20, Way No.207,
Al Rawaq Building,4th Floor, Office No.406,
P.O. Box 1739/1170, P.C.112, Ruwi,
Sultanate of Oman. Muscat.
Phone: +968 2465 9769
Fax: +968 2469 4974
Contact Person: Mr. Harshad Dhada, Area General Manager
E-mail: harshad.dhada@sogexoman.com
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SYNOPSIS:
This report documents the Inspection / Investigation of Civil Works defaults & suggested measures
for Power Production at Sohar-2 Plant, Inspection undertaken during August 2021 for Suez Tractable Operation and Maintenance Company LLC. (eNGie STOMO), Oman.
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Contents:
1. Introduction
2. Examination of plant structures
2.1
2.2
2.3
Plant inspection visit
Inspection units
Inspection elements of civil structures
3. Unit wise inspection / observations
3.1
3.2
Seawater intake system
3.1.1
Seawater pipe Support Foundations
3.1.2
Instrument supports & cable trays
3.1.3
Electrical cable chamber & trench foundation
Waste water treatment plant
3.2.1
Acti flo unit
3.2.2
Waste water transfer underground pump house
3.2.3
Dosing pump for thickner
3.2.4
Floor at oil water separator and throughout treatment plant
3.2.5
External painting for all process tank, dyke wall of chemical tanks, chemical
unloading bay.
3.3
3.4
RO & DM water treatment plant:
3.3.1
HP pump foundations
3.3.2
Building side walls
3.3.3
Floor in chemical storage tanks and dosing pumps area
CCW pump house
3.4.1
Gratings
3.4.2
Support foundations & floor damages
3.5
Fuel oil storage tank – 11
3.6
Fuel oil storage tank - 12
3.7
Air compressor house
3.8
Work shop building
3.9
Car parking
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3.10
Safety office
3.11
Guard room
3.12
Potable & fire water tanks area
3.13
Fuel gas conditioning skid
3.14
EDG area
3.15
Fire water pump house
3.16
STG
3.17
Common GT-11&12, HRSG 11&12
3.18
Auxiliary boiler
3.19
Feed water pump house
3.20
Main electrical building.
4. Recommendations
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1. Introduction:
The plant (Sohar-2 IPP) is located approximately 200km northwest of Muscat in Oman, within the
Sohar Industrial Port Area, between the plot of the existing Sohar-1 IWPP and Sohar Aluminum
Power Plant. The facility entered into full commercial operation on 3 April 2013.
2 HRSGs
2 GTGs
1 STG
The plant consists of two Siemens AG SGT5-4000F gas turbines (GT), two triple pressure heat recovery
steam generators (HRSG) and a Siemens AG SST5-5000 steam turbine (ST). The condenser is cooled
via a once through seawater system. Seawater is extracted from the existing common intake (shared
facility) and discharged to an existing common outfall channel in accordance with the Seawater
Extraction Agreement. The gas turbines are fitted with by-pass stacks to enable the operation in open
cycle. Although capable of open cycle operation, the normal operating mode of the plant is in combined
cycle (CCGT) for higher thermal efficiency. At site reference conditions of 50°C ambient temperature
and 30% relative humidity, the plant has a net power capacity of approximately 744 MW at COD. With
this technology, the energy for electricity generation is obtained from the combustion of natural gas.
Hot combustion gases formed by the combustion of natural gas drive a gas turbine, which, in turn,
rotates an alternator to produce electricity. After driving the gas turbine, the exhaust gases are still hot
enough to produce steam in a heat recovery boiler (HRSG). The steam generated in the heat recovery
boiler drives a steam turbine, which rotates another alternator to produce additional electricity.
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The individual gas turbines exhaust hot gases are directed into naturally circulated HRSGs, which
generate steam at three pressure levels. The high-pressure steam from each of the heat recovery steam
generators is combined in a common header and passes to the steam turbine as is the intermediate
pressure and low-pressure steam. A condensate pre-heater is integrated in the HRSG. This arrangement
enables higher efficiencies of the combined cycle power plant, by using the exhaust gas energy to
preheat the condensate before it passes towards the feed water pump and into the LP-system.
This Inspection report is based on discussions with STOMO officials, Physical inspections during
an inspection visit and documents received from STOMO. The remedial measures or technical
solutions suggested are indicative and these methods or alternatives may be used for rectification
works.
References:
Doc. No: OM1001-& CEC269-0904-000001
DESIGN CRITERIA FOR CIVIL AND BUILDING WORKS
Doc. No: OM1001-&ELH269-OOUZT-077747-077750
AREA CLASSIFICATION STG-10
Doc. No: OM1001-&ELH269-OOUZT-077744-077747
AREA CLASSIFICATION GTG 11 & GTG 12
Doc. No: OM1001-&ELH269-OOUZT-077740
AREA CLASSIFICATION OVERALL AREA
Doc. No: OM1001-&CLC129-OOUGX-060201-060203
WATER & WASTE WATER TREATMENT STRUCTURE FOUNDATIONS
Doc. No: OM1001-&CLC129-OOUGX-060231-060236
WATER & WASTE WATER TREATMENT ACTIFLO FOUNDATION
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2. Examination of plant structures:
2.1
Plant inspection visit:
A detailed plant inspection was carried out on 24th & 25th of August 2021, after mandatory
STOMO HSE induction, receipt of necessary & required Sohar Port entry pass & Sohar-2 plant
gate pass, STOMO HSE permits for working inside plant from STOMO.
A detailed plant inspection visit was covered with the following points:
Review of the overall plant civil structures condition and maintenance & cleaning
practices, including available plant building maintenance records, cleaning & painting
of concrete structure frequencies and procedures.
Studied original As Built GA drawings of the plant to identify exact location & number
of default points and further to verify the current status of these defaults and their potential
impact on the plant operations.
2.2
Inspection units:
The following units were examined:
1. Seawater intake system
2. Wastewater treatment plant
3. RO & DM plant
4. CCW pump house
5. Fuel oil storage tank-11
6. Fuel oil storage tank-12
7. Air compressor house
8. Work shop building
9. Car parking
10. Safety office
11. Guard room
12. Potable & fire water tanks area
13. Fuel gas conditioning skid
14. EDG area
15. Fire water pump house
16. STG
17. Common GT-11&12, HRSG 11&12
18. Auxiliary boiler
19. Feed water pump house
20. Main electrical building
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2.4
Inspection elements of civil structures:
During the physical examination, following civil structural elements were inspected for its
present condition and defects:
1. Plinth / Base Slabs
2. Pipe support foundations
3. Fire extinguisher foundations
4. Above & underground tank walls & base slab from outside & inside
5. Chamber/pit walls & base slab from inside
6. Manhole walls & base slab from inside
7. Pipe rack foundations
8. All step / cage ladder support foundations
9. SS grating support foundations
10. Ramps
11. Misc. civil structures like staircases / normal building outside walls / tiles on floor slab
12. Painting / coating on foundations / tank walls
13. Concrete surface finishing
14. Ground plinth beams
15. Concrete floor finishing
16. Reinforcement of columns, beams, walls etc.
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3. Unit wise inspection / observations:
3.1
Seawater intake system:
3.1.1
Seawater intake pump
Sea water intake system consists of 2 service cooling water pumps and 4 circulating
water pumps, connected piping with valves & instruments inline from intake pump house to
facility. Power supply for pumps drawn from switch gear building in intake system through
underground cable trenches. All Pumps has concrete pedestal and rested on main base slab.
Sea Water Intake
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Observation:
Sea water stagnation surrounding the pumps pedestrals, pipe supports and instrument supports.
Severe Corrosion & Surface cracks are seen from outside surface of foundation base finishing with
erosion of epoxy painting, Concrete Grouting has been broken / damaged.
Probable cause & remedial measures:
Probable cause:
Inappropriate slope in floor to flow back into sump or drain resulting in water stagnation on the floor.
This stagnated sea water coming in contact with concrete and metal structures, supports, cable
conduits, etc. reacting badly.
seawater on concrete may deteriorate from the combined effects of chemical and physical processes
below:
Sulfate attack
Leaching of lime (calcium hydroxide)
Alkali-aggregate expansion
Salt crystallization from alternate wetting and drying
Cracks, spalls, mortar erosion, and corrosion stains are visible signs of deterioration that causes
increased porosity and decreased strength.
Remedial measures recommended:
Corrosion of this sort will surely destroy concrete over time unless it is properly protected. A
barrier is needed between the concrete and the salt water that will stop water, chlorides and
oxygen from reaching the inner reinforcement of the structure i.e a protective coating which
resists sea water.
Proper slope to be maintained in floor surrounding pump pedestrals towards the drain/sump to
avoid stagnation of saline water.
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete Grouting layer has totally broken/damaged at any corner of the foundation, then
new concrete grouting to be applied with epoxy painting.
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3.1.2
Seawater Intake Pipe Support Foundations:
Pipe Support Foundations:
Observation:
The cracks are on seawater pipe foundation base. Concrete Grouting has been broken / damaged.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water may mixed and incorrect cement grade.
Extreme weather conditions.
Concrete placement problems.
Soil strength under the concrete pedestal.
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete layer has totally broken/damaged at any point of the Foundation then new concrete
foundation to be casted, and apply epoxy painting. Before going for new foundation soil under
foundation shall be compacted.
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3.1.3
Instrument supports and cable trays:
Instrument & cable tray support
Observation:
The impression of corrosion on cable trays, cable conduits and instrument support due to stagnation
of saline water, reacting aggressively with metal supports and concrete pedestrals. Cracks are seen
on surface. Concrete Groutings has been broken / damaged.
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Probable cause & remedial measures:
Probable cause:
Inappropriate slope in floor to flow back into sump or drain resulting in water stagnation on the floor.
This stagnated sea water coming in contact with concrete and metal structures, supports, cable
conduits, etc. reacting badly.
seawater on concrete may deteriorate from the combined effects of chemical and physical processes
below:
Sulfate attack
Leaching of lime (calcium hydroxide)
Alkali-aggregate expansion
Salt crystallization from alternate wetting and drying
Cracks, spalls, mortar erosion, and corrosion stains are visible signs of deterioration that causes
increased porosity and decreased strength.
Remedial measures recommended:
Corrosion of this sort will surely destroy concrete over time unless it is properly protected. A
barrier is needed between the concrete and the salt water that will stop water, chlorides and
oxygen from reaching the inner reinforcement of the structure i.e a protective coating which
resists sea water.
Proper slope to be maintained in floor surrounding pump pedestrals towards the drain/sump to
avoid stagnation of saline water.
Seal cracks, gaps & joints in concrete to prevent reoccurrence and protect the foundations.
If the Concrete foundation has totally broken/damaged at any corner of the foundation, then
new concrete foundation to be casted, apply epoxy painting.
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3.1.4 Electrical cable chamber & trench foundation:
Electrical cable chamber & trench foundations
Observation:
Damaged electrical cable chamber & trench base. Concrete has been broken / damaged.
Concrete reinforcement is exposed.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water may mixed and incorrect cement grade.
Extreme weather conditions.
Concrete placement problems.
Remedial measures:
Chip and remove debris, Reconstruct the broken area, Replaster the surface where plastering appears
damaged, Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence
and protect the foundations.
If the Concrete layer has totally broken/damaged at any point then new concrete wall to be casted &
applied with epoxy painting.
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3.2
Waste water treatment plant:
3.2.1
Actiflo unit:
Actiflo unit
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Observation:
There is serious leakage from the actiflo unit, Though the temporary action (replastering done) taken
on concrete wall surface, leakage still exists.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water and incorrect cement grade.
Extreme weather conditions.
Concrete placement problems.
Insufficient curing
Remedial measures:
The surface looks wet and, in this case, it is recommend to do the PU injection grouting. Then wait
for 24 hours to get it dry and once it is dried, grind the surface and give the PU coating.
High pressure PU injection grouting:
Injection grouting is a process of filling the cracks, open joints, voids, or honeycombs, in concrete
or masonry structural members, under pressure with a material that cures in place to produce the
desired results like strengthening a structure and prevent water movement
Grout is a flowable plastic material and should have negligible shrinkage to fill the gap or voids
completely and should remain stable without cracking, de-lamination or crumbling. There are
different types of grouts such as cement grout, polymer-cement slurry, epoxy, urethane, and highmolecular-weight methacrylate (HMWM).
These grout materials are selected for particular type of concrete or masonry repair work based on
the compatibility of the grout with the original material. If Proper grouting material is not selected,
the desired objectives of the grouting process would not be achieved.
5steps for injection grouting:
1. Drilling and inserting of injection ports
2. Protection of work areas
3. Grouting using a high-pressure grouting machine
4. Removal of injection ports & sealing up
5. Ensure no leakage
For detailed procedure and method statement from international standardized service provider refer
Crack Injection Method Statement by “SIKA’’ from www.sika.co.uk
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Recommendations:
Outer surface of the Concrete units shall be painted.
Internal surface shall be coated with poly urethane/any protective coat for saline & chemical water.
Avoid direct contact of sea water with concrete structure.
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3.2.2
Waste water transfer underground pump house:
Under ground pump house (Leak from skimmed oil pond)
Observation:
There is serious leakage from the underground pump house of oil water separator in waste water
treatment. Though the temporary action (replastering done) taken on concrete wall surface, leakage
has not been arrested.
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Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water and incorrect cement grade.
Workmanship quality.
Remedial measures:
The surface looks wet and, in this case, it is recommend to do the PU injection grouting. Then wait
for 24 hours to get it dry and once it is dried, grind the surface and give the PU coating.
High pressure PU injection grouting:
Injection grouting is a process of filling the cracks, open joints, voids, or honeycombs, in concrete
or masonry structural members, under pressure with a material that cures in place to produce the
desired results like strengthening a structure and prevent water movement
Grout is a flowable plastic material and should have negligible shrinkage to fill the gap or voids
completely and should remain stable without cracking, de-lamination or crumbling. There are
different types of grouts such as cement grout, polymer-cement slurry, epoxy, urethane, and highmolecular-weight methacrylate (HMWM).
These grout materials are selected for particular type of concrete or masonry repair work based on
the compatibility of the grout with the original material. If Proper grouting material is not selected,
the desired objectives of the grouting process would not be achieved.
5steps for injection grouting:
1. Drilling and inserting of injection ports
2. Protection of work areas
3. Grouting using a high-pressure grouting machine
4. Removal of injection ports & sealing up
5. Ensure no leakage
For detailed procedure and method statement from international standardized service provider refer
Crack Injection Method Statement by “SIKA’’ from www.sika.co.uk
Recommendations:
Outer surface of the Concrete units shall be painted.
Internal surface shall be coated with poly urethane/any protective coat for saline & chemical water.
Avoid direct contact of sea water with concrete structure.
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3.2.3
Dosing pumps for thickner:
Thickner dosing Pumps
Observation:
Pump base frame, pipe supports corroded badly, floor also have signs of damage.
Probable cause & remedial measures:
Probable cause:
Chemical spillage
Remedial measures:
Floor & pump pedestal shall be protected from the chemical,
Clean rusted surface on the floor, base frame and support structure with wire brush, Paint with
Epoxy/PU coating to protect from corrosion. On floor it is recommended for Chemical resistant tiles
at rich chemical areas.
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3.2.4
Floor at oil water separator area:
Floor at oil water separator
Observation:
The cracks are seen from surface of Floor.
Probable cause & remedial measures:
Probable causes:
Extreme temperature variations, improper mixing of cement, Salt water mixed while mixing, Curing
done with sea water, soil shirkange etc.
Remedial measures:
Seal cracks, gaps & joints in floor with the cement, and do apply protective coating also or tiles to
protect from further damage due to sea water and chemical spillage
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3.2.5
External painting for all process tanks, dyke walls of chemical tanks,
chemical unloading bay:
Concrete tanks and walls in waster water treatment plant
Observation:
In Wastewater Treatment area all process structures like clarifier, thickener, Dyke walls of chemical
storage tanks, Unloading Bay found un painted.
Anticipated defects:
Due to not painting of concrete structures in chemical & Saline atmosphere and at high temperatures,
fumes of strong acids and chemical spillages damage concrete, develop cracks and leakages occur.
Action required:
Suitable Painting for chemical and Saline atmosphere shall be done at the earliest.
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3.3
RO & DM plant:
3.3.1 HP pump foundations:
HP pump base frame with foundation
Observation:
Floor, Foundation, cable trays & supports are badly corroded surrounding the pump.
Probable cause & remedial measures:
Probable cause:
Sea water and chemical spillage.
Remedial measures:
All corroded area to be cleaned and painted with suitable protective coating, as per OEM
recommended painting procedures. Floor also should be cleaned and coated or flooring to be with
chemical resistant tiles. Arrest leaks.
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3.3.2 Building side walls:
Side walls
Observation:
Damage in cement plastered wall near by the door on both sides, steel reinforcement is exposed.
Probable cause & remedial measures:
Probable cause:
Curing done with sea water
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water and incorrect cement grade.
Concrete placement problems.
Remedial measures:
Cement exposed area should be chipped, replastered and painted before the steel get corroded and
spread though out the wall.
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3.3.3
Floor in chemical storage tanks and dosing pumps:
Chemical day tanks & RO rack
Observation:
Due to chemical and sea water spillage, floor at chemical day tank and RO skids floor is damaged
and grating is being corroded badly.
Probable cause & remedial measures:
Probable cause:
Chemical & sea water spillage.
Remedial measures:
Suitable tiles for chemical area and FRP gratings are Suggested.
Arrest the leaks if any.
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3.4
CCW pump house:
3.4.1 Gratings:
CCW pump house
Observation:
All gratings in closed cooling water system are badly corroded.
Probable cause & remedial measures:
Probable cause:
Resistance of GI is not durable to harsh corrosive atmosphere of saline water spillage.
Remedial measures:
Recommended to replace GI with FRP gratings.
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3.4.2 Foundation & floor damage:
Pump foundations and pipe supports
Observation:
Pump foundation, floor, pipe supports corroded.
Probable cause & remedial measures:
Probable cause:
Sea water spillage
No protective coating on the floor and foundations.
Remedial measures:
All corroded area to be cleaned and painted with suitable protective coating, as per OEM
recommended painting procedures. Floor also should be cleaned and coated or flooring to be with
chemical resistant tiles. Arrest leaks.
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3.5
Fuel oil storage tank -11
Fuel oil storage tank-11
Observation:
Roof of tank corroded aggressively. This is carbuncle type pitting corrosion, starts as blisters &
results in isolated holes. This is form of corrosion under insulation (CUI). CUI damage may be
highly localized. In some localized cases, the corrosion can appear to be carbuncle type pitting
(usually found under a failed paint/coating system)
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Probable cause & remedial measures:
Probable cause:
Defective blasting and painting application. Intruding moisture is the key problem causing CUI.
Major cause suspected as the moisture during blasting and painting.
Remedial measures:
CUI Mitigation is best achieved by using appropriate paints/ coatings and maintaining the
insulation/sealing/vapor barriers.
Repair procedure to be followed as per API standard.
Thorough surface preparation to be carried out either by dry or wet blasting.
Repaint with specified paint as per the Design approved
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3.6
Fuel oil storage tank -12
Fuel Oil Storage tank -12
Observation:
Roof of tank corroded aggressively. This is carbuncle type pitting corrosion, starts as blisters &
results in isolated holes. This is form of corrosion under insulation (CUI). CUI damage may be
highly localized. In some localized cases, the corrosion can appear to be carbuncle type pitting
(usually found under a failed paint/coating system)
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Probable cause & remedial measures:
Probable cause:
Defective blasting and painting application. Intruding moisture is the key problem causing CUI.
Major cause suspected as the moisture during blasting and painting.
Remedial measures:
CUI Mitigation is best achieved by using appropriate paints/ coatings and maintaining the
insulation/sealing/vapor barriers.
Thorough surface preparation to be carried out either by dry or wet blasting. Repainted with
specified paint as per the Design approved.
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3.7
Air compressor house: Compressor foundation:
Compressor foundation:
Observation:
Surface cracks on compressor foundation.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Vibration of the system
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete layer has totally broken/damaged at any corner of the Foundation then new concrete
grouting to be applied with epoxy painting.
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3.8
Workshop building:
Work shop building
Hair line crack
Edges of wall damage
Tile damage in washroom
Observation:
Hair line cracks on the wall, corner edges of the wall damaged in several places, tile in washroom
about to fall.
Probable cause & remedial measures:
Probable cause:
• Poorly-graded aggregate.
• Deviation from mix ratio.
• Workmanship quality.
• Concrete placement problems.
• Alkali-Aggregate reactions.
Remedial measures:
Cleaning of Crack:
This is the first and foremost step in the repair of hairline cracks in the concrete. Inspection of crack
is done if any stains have penetrated the crack and have discolored the concrete, the stains have to
be addressed before the repairing the crack.
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2. Selection of Sealant
The sealant is a filler material that is penetrated into the crack. The ideal sealant must have low
surface tension and low viscosity. These two characteristics allow the liquid sealer to penetrate
deeply into the crack.
Crack repair materials for concrete are often polymer-modified cement grouts, silicone or latex
caulking, or epoxies. Polymer-modified cement grout is the typical material used to fill pinholes
and voids in concrete during manufacture. If cracks occur before the concrete is sealed, this is often
the material used to repair them.
3. Application of Sealant
The selected sealer is applied on the substrate by using a squeegee and/or in combination with a
roller. The application process must be carried out for at least 5-10 mins to ensure penetration.
4. Curing
Proper curing must be ensured to complete hardening of sealant. The warmer the temperature, faster
the curing, lower the temperature, the longer it will take.
** Precautions
Repairing hairline cracks can be challenging because making the cracks vanish takes skill,
forbearance, practice and a good eye for colour matching. One definition of a hairline crack is a
crack that hasn't opened up.
That means there is very little room to fill it with anything but a very low-viscosity liquid. Since
most hairline cracks don't affect the structural integrity of a countertop, sealing and concealing the
crack are the main goals of a repair.
Edges of the wall to be brushed with layer of cement and painted.
Damaged tile in wash room to be fixed with durable urethane caulk to prevent reoccurrence.
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3.9
Car parking:
Car parking area
Observation:
Severe corrosion on the roof and steel structure.
Probable cause & remedial measures:
Probable cause:
Saline atmosphere, improper painting.
Remedial measures:
Repair the corroded areas, perform surface preparation by buffing, emery or wire brush, clean
corroded areas, apply primer and 2 coats of epoxy or poly urathene paint of each 100 microns.
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3.10
Safety office:
Safety training office
Observation:
Tile at the corner edge of the wash basin in wash room damaged.
Probable cause & remedial measures:
Probable cause:
Deviation from mix ratio.
Saline water and incorrect cement grade.
Workmanship quality.
Concrete placement problems.
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence.
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3.11
Guard room:
Guard room
Observation:
Repaired areas on walls are unpainted.
Probable cause & remedial measures:
Remedial action: Apply suitable paint to protect from cracks
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.12
Potable & fire water tanks:
Potable and fire water tanks area pipe supports
Observation:
The cracks are seen from outside surface of potable water tank area support.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Deviation from mix ratio.
Saline water may mixed and incorrect cement grade.
Extreme weather conditions.
•
Concrete placement problems.
•
Soil strength under the concrete pedestal.
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete layer has totally broken/damaged at any point of the Foundation then new concrete
foundation to be casted, and apply epoxy painting. Before going for new foundation soil under
foundation shall be compacted.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.13
Fuel gas conditioning skid:
Fuel gas conditioning skid:
Observation:
Honey comb type of concreting defect in the foundation.
Probable cause & remedial measures:
Probable cause:
Defect due to which cavities and hollow pockets are formed and coarse aggregates become
prominently visible in the concrete structure.
It may occur due to improper concrete workability and concrete pouring practice, excessive
water in the concrete mix, inadequate formwork rigidity and waterproofing, etc.
Remedial measures:
The repair process involves removing loose material, cleaning the affected area, applying suitable
repair material, and then curing to gain adequate strength.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.14
EDG area:
EDG area:
Observation:
Cracks on the floor and foundation.
Probable cause & remedial measures:
Probable cause:
• Rapid drying of the concrete
•
Excess water in the concrete mix
•
Pouring of improper strength concrete on the floor
•
Inadequate control joints
•
Pouring concrete on the frozen ground
Remedial measures:
seal the patches to keep the water-resistance as well as stain-resistance of the concrete. You can use
polyurethane to seal the floor. Apply the polyurethane using a brush or a roller to work the coat deep
into the rough patch.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.15
Fire water pump house:
Fire water pump house :
Observation:
Cracks on the floor and foundation.
Probable cause & remedial measures:
Probable cause:
• Rapid drying of the concrete
•
Excess water in the concrete mix
•
Pouring of improper strength concrete on the floor
•
Inadequate control joints
•
Pouring concrete on the frozen ground
Remedial measures:
seal the patches to keep the water-resistance as well as stain-resistance of the concrete. You can use
polyurethane to seal the floor. Apply the polyurethane using a brush or a roller to work the coat
deep into the rough patch.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.16
STG:
STG building
Observation:
Cracks on the Floor and foundation. No painting for the floor.
Probable cause & remedial measures:
Probable cause:
• Rapid drying of the concrete
•
Excess water in the concrete mix
•
Pouring of improper strength concrete on the floor
•
Inadequate control joints
•
Pouring concrete on the frozen ground
Remedial measures:
seal the patches to keep the water-resistance as well as stain-resistance of the concrete. You can use
polyurethane to seal the floor. Apply the polyurethane using a brush or a roller to work the coat deep
into the rough patch.
Floor should be painted for longer life to protect from saline atmosphere, high temperatures.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.17
Common GT-11&12, HRSG 11& 12
Common GT-11&12, HRSG 11& 12
GT-11area
GT-1
GT-11
Transformer area hydrant
pipe pedestral crack
HRSG
Observation:
Cracks on the floor and foundation. Paint peeled off .
Probable cause & remedial measures:
Probable cause:
• Rapid drying of the concrete
•
Excess water in the concrete mix
•
Paint damaged due to improper surface preparation and application.
Remedial measures:
seal the patches to keep the water-resistance as well as stain-resistance of the concrete. You can use
polyurethane to seal the floor. Apply the polyurethane using a brush or a roller to work the coat deep
into the rough patch.
Remove damage paint, clean the surface , apply primer and repaint.
August 2021
Page 43 of 48
CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.18
Auxiliary boiler :
Auxiliary boiler
Observation:
Cracks on the Floor and foundation. No painting on the floor & foundation. grating corroded.
Probable cause & remedial measures:
Probable cause:
Rapid drying of the concrete
Excess water in the concrete mix
Paint damaged due to improper surface preparation and application.
Remedial measures:
seal the patches to keep the water-resistance as well as stain-resistance of the concrete. You can
use polyurethane to seal the floor. Apply the polyurethane using a brush or a roller to work the
coat deep into the rough patch.
GI Grating replace with FRP Grating.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.19
Feed water pump house:
Feed water pump house
Observation:
A diagonal crack on the wall, cracks are seen on pump foundation.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate.
Vibration of the system
Excess water in the concrete mix
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete Grouting layer has totally broken/damaged at any corner of the Foundation then new
concrete grouting to be applied with epoxy painting.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
3.20
Main electrical building:
Main electrical building stair and wall
Observation:
Surface cracks observed of the wall, under the stair, few areas unpainted.
Probable cause & remedial measures:
Probable cause:
Poorly-graded aggregate..
Extreme weather conditions.
Workmanship quality.
Concrete placement problems.
Remedial measures:
Seal cracks, gaps & joints in concrete with durable urethane caulk to prevent reoccurrence and
protect the foundations.
If the Concrete Grouting layer has totally broken/damaged at any corner of the Foundation then new
concrete grouting to be applied with epoxy painting.
August 2021
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
4.0 Summary:
The civil structures in the plant, are generally look good the plant
Table 4 presents the recommendations with respect to civil work defects / problems and other
general points for STOMO.
Table 4:
Sr.
Name of Unit
Major Civil work Issues
Recommendation
No.
1
Seawater intake system
Pump
foundations 1. Proper slope should be
cracked
/
broken,
maintained in floor to avoid
corrosion.
stagnation of sea
water.
2. New concrete grouting
to be made &applied
with epoxy painting.
2
Waste water treatment
Severe
leaks
from 1. Suggested to do Poly-urathene
concrete
tanks,
No
injection grouting to avoid leaks.
painting on concrete 2. Painting should be done for all
structures.
the concrete structures,
3. Rich Chemical area should be
with chemical resistant tiles.
3
RO &DM water
Heavy corrosion on base 1. Surface preparation
treatment plant
frame of pumps, Gratings
with painting should be
corroded,
floor
at
done.
chemical day tank is 2. Recommends for FRP
being damaged due to
gratings.
chemical spillage.
4. Reconcreting damaged areas
5. Recommends
Chemical
resistant tiles at chemical tanks
area to protect the floor.
4
CCW pump house
Gratings
are
badly 1. Recommends for FRP
corroded.
gratings
5
Fuel oil storage tank-11
6
Fuel oil storage tank-12
8
Air compressor House
August 2021
Severe corrosion on roof
due to poor workmen
ship.
Severe corrosion on roof
due to poor workmen
ship.
Surface
cracks
on
Compressor foundation.
Reblasting and repainting as per API
650
Reblasting and repainting as per API
650
New concrete grouting
to be made &applied
with epoxy painting.
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CIVIL SURVEY OF SOHAR -2 POWER PLANT
Sr.
No.
9
10
11
12
13
14
Name of Unit
Work shop building
Major Civil work Issues
Recommendation
Cracks on wall, Tile damage in
wash room.
Structural repair with
new concrete grouting to
be applied.
Car parking
Corroded steel structure
To be re painted.
Safety office
Tile damage in wash room
Structural repair with
new concrete grouting to
be applied.
Guard room
Unpainted repaired patches
Painting to be done.
Main electrical building Cracks in outside surface wall
New concrete grouting
plaster
to be applied with
painting
Auxiliary boiler area.
Cracks in concrete support New concrete grouting
foundations & concrete finish to be applied with epoxy
erosion
painting.
Signed by:
Name:
Date:
August 2021
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