A Famous Water Power plant in Rjukan

PDA Europe 2012 Annual Conference –Istanbul, 12-14 November

A Famous Water Power plant in Rjukan

Amund Geicke


The Rjukan Chain

Google maps


The Rjukan Chain

Frøystul

Såheim

Inlet Moflåt

Dam Dale

Dam Mæland

Vemork

Krokan

Skarsfoss

Outlet MoflåtInlet Mæl

Outlet Mæl

Norsk Hydro


The Rjukan Chain


Construction

• Vemork 1911

• Såheim 1915

• Frøystul 1926

• Moflåt and Mæl 1952-57


Why is it famous?


History of the Vemork plantAmong the worlds largest power plants in 1911.

The Vemork factory in front of the power plant.

From 1934 the factory produced heavy water


The Vemork Raid(s)

• Operations Grouse and Freshman, October 1942


The Vemork Raid

• Operations Grouse and Freshman, October 1942


The Vemork Raid(s)

• Operation Gunnerside, February 1943


The Vemork Raid(s)


The Vemork Raid(s)


The Vemork Raid(s)


The Vemork Raid(s)

• Bombing, November 1943

• 143 B-17's


The Vemork Raid(s)

• Sinking of D/F Rjukan

• Timed bomb


Back to the future…

• Project initiated and planning startet in 2009.

• Inspections and concrete sampling in 2011 and 2012.

• Excecution of repair and construction works during production stops in the summer months of 2011-2014.


Design basis

• Operating time 20 years

• Low focus on visual appearance.


Scope 2012

Frøystul

Såheim

Inlet Moflåt

Dam Dale

Dam Mæland

Vemork

Krokan

Skarsfoss


Outlet Mæl


Skarsfoss

New dam

Inlet Skarsfoss

Demolish dam 2014

Inlet tunnel to Vemork

2 gates


Inlet Skarsfoss


Inlet Skarsfoss - Damages

Freezing/thawing and Cracking caused by alcali-aggregate reaction (AAR).


Inlet Skarsfoss - assessment

• Coating will not stop AAR

• The cracking will have very small consequences the next 20 years


Inlet Skarsfoss

Original scope:

•Mechanical concrete repairs.

•Polyurea on everything.

Resulting scope after inspection:


•New structural elements.


Scope 2012

Frøystul

Såheim

Inlet Moflåt

Dam Dale

Dam Mæland

Vemork

Krokan

Skarsfoss


Outlet Mæl


Dam Krokan- Damages

Freezing/thawing and cracking caused by AAR


Dam Krokan- Damages


Dam Krokan- Damages


Dam Krokan - assessment

The structure does not have sufficient load bearing capasity.


Dam Krokan - Scope

Original scope:


•Polyurea on everything.


•New Dam Krokan.


Scope 2012

Frøystul

Såheim

Inlet Moflåt

Dam Dale

Dam Mæland

Vemork

Krokan

Skarsfoss


Outlet Mæl


Spillway wall - damages

Leaching caused by poorly compacted concrete.

Cracking from AAR

Damages also downstream.


Spillway wall - assessment

• Concrete of varying quality. Especially in the lower parts of the wall.

• Difficult access downstream.


Spillway wall - Scope

Original scope:•Mechanical concrete repairs.•Polyurea on the upstream side.

Resulting scope after inspection:•New concrete wall on the lower parts.•Mechanical concrete repairs.•Polyurea on the upstream side.


Scope 2012

Frøystul

Såheim

Inlet Moflåt

Dam Dale

Dam Mæland

Vemork

Krokan

Skarsfoss


Outlet Mæl


Dam Mæland

Dam MælandMåna river

Inlet duct

Inlet Moflåt

Gate housing

access to river

Såheim outlet

El. inst


Dam Mæland

Spillway wall

Dam, walls, bridge etc – Repair works on all concrete surfaces and railings etc.

Coffer dam


Dam Mæland


Mæland - Bridge

Damages:

Rebar corrosion and freezing/thawing


Mæland - Bridge

Original scope:


•Polyurea coating on top.



•Polyurea coating on top.


Mæland - Pillars

Damages:

Cracking caused by AAR


Mæland - Pillars

assessment:

•Small consequences of cracking on vertical surfaces.

•Coating will not stop AAR

•Possible increased risk of damages from freezing/thawing with coating.

•Damages have little impact on the load bearing capasity.


Mæland - Pillars

Original scope:•Mechanical concrete repairs.•Polyurea coating.

Resulting scope after inspection:•Mechanical concrete repairs.•Roof over horisontal surfaces.•Cleaning.


Mæland - Walls

Damages:



Mæland - Walls

assessment:






Mæland - Walls

Original scope:


•Polyurea coating.



•Cleaning with ultra high pressure. Removing old coating.


Mæland - Baseplate

Damages:

Cracking caused by AAR and Freezing/thawing


Mæland - Baseplate

assessment:

•Risk of full disintegration of baseplate within the next 20 years.

•The baseplate is critical for the function of the sealing injection screen.

•Repair costs will be almost as high as the construction cost of a new slab.


Mæland - Baseplate

Original scope:



•New Baseplate


Mæland - Ducts

Damages:



Mæland - Ducts

assessment:






Mæland - Ducts

Original scope:


•Polyurea coating.



•Cleaning with high pressure.


Pictures 2012

Downstream wall Mæland


Pictures 2012

Core from spillway wall Såheimstoppen.


Pictures 2012

Pillar Mæland.


The new Dam Krokan


Downstream wall MælandWhy don't we coat this?


Pro coating

• Appearance


Against coating

• Massive structures not depending on reinforcement.

• The opposite side may not always be dry. Risk of freezing/thawing damages behind coating.

• Compressive strength of concrete increases with AAR.

• Structural integrity may not always be intact.


Can you coat this?

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A Famous Water Power plant in Rjukan

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