UHPC - a material for many applications in onshore and offshore wind energy production

UHPC Ultra High Performance Concrete has been used for many years in offshore wind

and onshore wind energy production.

We produce our UHPC for these applications. The new grades UHPC are currently being tested and will be available to the market later this year.

Monopile wind turbine designs are still the most widely used standard foundation design in many coastal areas. Jackets -, Gravity base -, Tripods - and Tri-piles systems are also used depending on requirements and needs.

UHPC grouting is used in all foundation techniques.

Monopiles

UHPC grouting material is used for the connection between monopile and transition pieces.

We estimate that more than 2000 monopiles worldwide have been installed with UHPC grouting and transitions pieces.

At the moment we are working on the 4th generation of grouting material. In addition to the technical improvements, the fulfillment of a wide variety of environmental requirements is the prime objective of the development.

Benefits of using UHPC grouting material for the transition piece

• Extremely high strength
• Very good fatigue properties
• Minimal shrinkage
• Extreme bond between UHPC grouting material and steel
• Fast setting development
• Very high inner cohesion
• No mixing with sea water
• Absolutly seawater resistant
• Very low hydration heat
• No corrosion

Tripile

A Tripile foundation consists of three steel piles driven into the seabed after which a three-legged transition piece structure is slid into the three piles. The overlaps between piles and transition piece are grouted with UHPC concrete.

The UHPC concrete connections evenly distribute the forces from the three-legged transition piece to the piles

Tripod

A Tripod support structure/foundation is secured in place by driving three piles into the seabed through a sleeve in each of the three corners.

UHPC concrete is pumped into the annuli between pile and sleeve to ensure a strong and durable connection.

Jacket

Jacket foundations are secured to the seabed by four piles placed in a sleeve in each corner and driven into the seabed. Jackets are generally considered to be better than monopiles for seabeds where the substrate is poor or deeper water. So here UHPC grouting can be used in the "transition piece" and in the lower foundation.

Gravity foundations

Are well suited for rocky sea beds. The complete foundation system can be manufactured on land and then pulled into position with a ship and then sunk. Depending on the design, the entire foundation piece can be made from UHPC. UHPC will be perfect for slip casting the entire foundation.

                                                       
After the use of UHPC grout in offshore wind energy generation, the experience gained in onshore wind energy production has also been exploited.

Steel Tower

So far, steel towers in cylindrical or conical segment construction have been the state of the art.

Depending on the required hub height, up to five segments were mounted on top of each other. With the new tower heights, the segment diameters are getting bigger and bigger and the road transport between production and the site is becoming an ever greater problem.

Concrete Tower

More and more, as an alternative to steel towers, concrete towers are also produced and assembled in cylindrical, conical or polygonal segments. A disadvantage compared to the steel towers is the high wall thickness, which makes larger foundations necessary

The advantage is

• Favorable vibration characteristics, which leads to reduced noise emissions.
• Long life expectancy
• An ideal solution for high tower high and large rotor diameter
• Transport cost savings due to possible on-site manufacture
• The use of special UHPC concrete grades can lead to slender constructions and thus rougher component weight.
• Lower component weight can also make the foundation dimensioning more favorable, which can lead to cost reduction. The material experiences in the offshore transitionpiece technology can also be of advantage when using UHPC grout in the imbed ring assembly (connection tower / foundation).
• Since UHPC concrete of high quality have virtually no pore formation, they are extremely resistant to corrosion.
• There are little or no maintenance costs.
• The individual segments can be transported more cheaply than is possible with the steel segments.
• On-site fabrication is the use of slipforming is another option including the use of local concrete raw materials for the production of high-quality UHPCs.
• Furthermore, it is possible to produce extremely exact segments with UHPC grout material, which requires no or very little post-processing of the segment abutment surfaces.
• Our UHPC materials reach at least 70% of their rated strength in less than 48 hours, which can lead to lower manufacturing costs for segment production and delivery times can be drastically reduced.

Hybrid towers

This type of tower construction is a combination of concrete (lower part) and steel construction (upper part). IT combines most of the advantages of steel tower and accentuated tower technology. Here, too, the use of UHPC can lead to additional benefits and savings in terms of material and financial resources.
A segment construction or on-site casting by slipforming are possible. This reduces the costs of transport and reduces the foundation geometries.

 

WPE DK International

Phone: 0049 176 601 73146
E-mail: info@wpe-dk.dk
Homepage: www.wpe-dk.com

                                                        

UHPC concrete as structural construction and corrosion protection material in Offshore projects

UHPC concrete is through its properties, such as
high E-modulus, high strength, and low
permeability excellent for rehabilitation,
protection and strengthening of offshore structures.

The splash zone is without doubt one of the more
aggressive environment for wood, concrete and/or
steel. Here you have the movement of the water
inducing wear on the structures, high level of
 oxygen inducing a perfect corrosive environment.
In salt water chlorides are present all over but
combined with good access of oxygenthis zone is
where the problem is.
 In icy regions ice sliding by
a structure will tear and wear the structure. UHPC
is here an ideal protection layer.


Splash zone protection is in general made on pillars
standing in water, and is made by creating a mold
around the pillar and cast the UHPC into the
mold.
When the UHPC has set the mold can be removed.

In case of wood pillars wood will usually rot over
time, leading to insufficient load bearing capacity of
the pillars. A mold can be placed around the pillar
and a UHPC pillar is created by casting.



Oil and gas platforms

When oil is pumped out of the ground the buttom

of the ocean will sink, which means that the
platform itself will sink slowly. As the ocean will
cover more and more of the legs of the platform
the wave forces influencing the platform will
increase over time. Eventually the strength of the
platform is not high enough to sustain heavy
storms.
 The strengthening of the platform is done
by filling the legs or part thereof with UHPC. This
will stiffen the structure and increase the strength
of this. By special engineering it is possible only
to fill part of legs, ie areas of the connections of
the steel.


Harbour fronts


Harbour fronts, piers and jetties are usually
subjected to splash zone issues a long with the
occasional impact by ships.
Splash zone issues being hammered with ice
and debris and of course the corrosion from salt,
water and oxygen.
 UHPC has the necessary
strength and impact resistance to withstand these
forces and the impermeability of the UHPC
prevents chlorides, water and oxygen in
penetration the protection layer which makes
corrosion impossible.



 

WPE DK International

Phone: 0049 176 601 73146
E-mail: info@wpe-dk.dk
Homepage: www.wpe-dk.com