PDA Europe 2012 Annual Conference –Istanbul, 12-14 November A Famous Water Power plant in Rjukan...

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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)

• 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 - 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.

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?

PDA Europe 2012 Annual Conference –Istanbul, 12-14 November A Famous Water Power plant in Rjukan...

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