Engineering services for the design dimensioning and operation of offshore  support structures



Offshore wind is the youngest department at Jörss – Blunck – Ordemann GmbH, founded in 2014. Nevertheless, the staff who work in this area have many years of professional experience.

The managing director, Dr. Lüddecke, has been gaining his professional experience in the offshore wind sector since 2006, Mr. Al Otaibi as head of support structures since 2011, Mr. Ostermann as head of loads and structural dynamics since 2009 and Dr. Haake as head of certification since 2004. All staff employed in this area have at least five years of experience in the offshore wind sector. With the interaction of structural design and load simulation departments, a holistic design approach is implemented at JBO, which includes all disciplines in order to develop weight and cost-optimized support structures.

Jörss - Blunck - Ordemann GmbH specializes in the following structures

Support structures of
Offshore wind turbines

Support structures of
Offshore substations

Platforms from
Offshore substations

Measuring masts

Planning and design

From the first sketch to the final approval

The team of engineers, consisting of experts in the field of steel construction, grouted connection, geotechnics, load calculation and installation cover the core competencies required for the development of new or innovative support structures which are also required for the design planning of offshore typical foundation structures.
Our main activities in the design and concept phase include:

  • Preparation of draft permits drafts
  • Determination of basics determination and creation of a park-specific design basis (for the German EEZ in accordance with BSH)
  • Creation of design briefs for the areas of load calculation and design verification of the support structure
  • Development of inovative foundation concepts
  • Preparation of parameter studies to optimize the foundation structure with regard to steel consumption, load impact and natural frequency behavior
  • Preparation of feasibility studies (FEED study)
  • Determination of the loading impacts and pre-dimensioning of the foundation structures.
  • Verification in conformity with BSH or according to regulations / guidelines to be agreed like DNVGL, NORSOK, DIN; ISO 19902 or API

Structural planning represents the actual core competence of the engineers working in the offshore wind sector.
We take on the following tasks as structural planning within the framework of implementation and workshop planning:

  • Implementation of integral load calculations taking into account the properties of the structure, the soil, environmental impacts and the operation-specific control of the wind turbine.
  • Establishment of static calculations for the ultimate limit state, including fatigue verifications and the serviceability limit state.
  • Execution of verifications based on beam framework models and using FE calculations.
  • Consideration of the verification for the final state or for operation as well as for the temporary construction and assembly states.
  • Verification for the sub-areas of steel construction, geotechnical engineering and grouted connection.

Your contact person

Dr.-Ing. Michael Schwedler

Key qualifications
- Structural design of offshore structures
- Layout design for offshore structures
- Project management
- Structural mechanics and structural dynamics
- Nonlinear modeling and analysis
- Numerical analysis expert (FEM)

Further experience and skills

- Numerical software: ANSYS, LS-DYNA, RFEM, Sofistik, InfoGraph
- Programming: C/C++, MATLAB

Publications | LinkedIn

Load simulation and structural dynamics

Experience in site-specific load analysis of offshore wind turbines

With the establishment of the Offshore Loads and Structural Dynamics department at the Osnabrück office in 2017, JBO has increased its focus on providing services related to the topic of offshore turbine and support structure load analyzes.

The load team, consisting of 5 internationally experienced load calculation engineers (total experience > 40 years), today covers the complete range of load services for the design of offshore wind turbines and support structures.

Under the leadership of Frank Ostermann, methods are being developed and applied in the department that which are ahead of the state of the art in order to enable economical and competitive offshore structural design. In combination with the offshore structural design department, a holistic design approach is implemented that includes all disciplines in order to develop optimized support structures.

Your contact person

Dipl.- Ing. Frank Ostermann

Key qualifications
- Experience in the offshore wind industry since 2009
- Expertise in offshore load certification and design process
- Expert knowledge in hydrodynamics and seismics
- Expert knowledge on project specific certification of wind turbines
- Technical contract negotiations
- Project as well as personell management and process optimization
- Expert knowledge in structural dynamics of wind turbines
- Implementation of engineering processes

Further experience and skills

- Member of IEC61400-3 working group
- FE-Software: ANSYS, ASAS, LPile
- Load simulation: Flex5, Bladed, HAWC2
- Programming: C#, EXCEL/VBA
- MS Project, MS Visio

Publications | LinkedIn

Overview of the services offered

  1. Site specific load analysis
  2. Load studies
  3. Load examinations
  4. Due Dilligence / Owners eng.


  • Fully integrated wind-wave load simulation
  • Management and technical leadership
    of integrated load analysis processes
  • Hydrodynamic load calculation
  • Metocean data interpretation
  • Earthquake design & seismic load analysis
  • Cluster concept development

LOAD STUDIESwindrad bild

  • Concept design studies
  • Feasibility studies
  • Load studies for environmental parameters
  • Sensitivity studies / dynamic assessment
  • Load studies for controller optimization
  • Load reassessment for lifetime extension


  • Load examinations in the scope of
    project certifications (basic/detailed design)
  • Turbine and support structure load checks
  • Accredited for BSH standard design
  • Examination of the design basis
    and the design brief documentation


  • Support in due diligence processes with
    technical load expertise
  • Load process and documentation check and
    advice as a third party opinion ("Owners Engineer")
  • Creation of design basis documents

Extract of the load-specific design experiences

Period of time

Scope of services (scope)

United Kingdom

Location-specific, fully integrated load analysis (BLADED)

2019 – 2020

Single site – dynamic load analysis (JBOOST)

2019 - 2020

Location-specific hydrodynamic load analysis
Site-specific seismic load analysis

2015 - 2016

Location-specific, fully integrated load analysis (FLEX5)
Location-specific hydrodynamic load analysis

2016 -2017

Location-specific, fully integrated load analysis (FLEX5)
Location-specific hydrodynamic load analysis


Location-specific, fully integrated load analysis (FLEX5)
Location-specific hydrodynamic load analysis

United Kingdom

Location-specific, fully integrated load analysis (FLEX5)
Location-specific hydrodynamic load analysis

2018 -2019

Location-specific, fully integrated load analysis for optimization
the controller settings (BLADED)

United Kingdom

Review and advice of the load calculation process (FLEX5)

Validation projects
2018 - 2020

Validation of an aeroelastic simulation code (BLADED)
Validation of an aeroelastic simulation code (FLEX5)

Concept studies
worldwide: 2017 - 2020

> 20 load analyzes for concept design / FEED studies (wind /
Wave / earthquake / ice) for international projects (BLADED)

Hydrodynamic load competence

The JBO software JBOOST allows an effective hydrodynamic load analysis on the overall system,
either in time or in the frequency domain. Core properties are listed below:

Time Domain Hydrodynamics

  • Wave load calculations acc. to IEC61400-3-1 (2019) or DNVGL-ST-0437 (2016)
  • High resolved hydrodynamic coefficients (spatial and temporal)
  • Embedment of non-linear extreme wave in sea state
  • Consideration of breaking wave impact acc. to latest industry findings (spilling / plunging)
  • Efficient generation of load time series for fully integrated load analysis
  • Advanced methods for implicit integration of extreme current speeds in stream function formulation
  • Advanced methods for met ocean data interpretation and condensation for load analysis
  • Consideration of loading from unidirectional or bi-directional sea states (swell + wind sea)
  • Existing and trained hydrodynamic load exchange interfaces to WTG supplier

Frequency Domain Hydrodynamics

  • Calculation of conceptual FLS support structual loads within seconds based on minimum turbine data (monopile)
  • Demonstration of methodology in more than 4 detailed design processes
  • Consideration of full site specific structural and environmental conditions
  • Load determination for individual site sizing as an optimization task in the design process
  • Method has been certified in several wind farm projects for detailed single location design
  • Integration of turbine parameter (detailed damping assumptions)
  • Perform detailed parameter studies for design optimization of e.g. diameters, bottom stiffnesses, damping, cone positions, turbine types etc.
  • Allows for convergence acceleration of integrated load analysis process
  • Integration of aerodynamic wind loads

Jörss - Blunck - Ordemann GmbH was and is involved in various roles in offshore wind design processes
(with regard to the hydrodynamic load determination):

  • Provision of hydrodynamic loading time series for integration in turbine software (time domain)
  • Implementation of fully integrated load analyzes based on JBO hydrodynamic loads (time domain)
  • Single site design based on frequency domain methods
  • Testing of hydrodynamic loads using frequency domain and time domain analyzes
  • Hydrodynamic loads for pre-design studies (frequency domain and time domain)

Applied advanced methods have been confirmed by certifiers in several projects.
Further hydrodynamic load services for the secondary steel design are being offered (wave run-up
impact, vortex-induced vibrations, etc.)

Earthquake load determination competence

Seismic analyzes in the execution and concept phase
have already been carried out for wind farms in earthquake regions
(Taiwan, South Korea).
In the role of the foundation designer were the following
responsibilities were covered:

  • Responsibility for earthquake eimpacts
    including interpretation of the seismic measurement data
  • Development of the cluster concept for earthquake analysis
  • Design review for seismic impact

Certification and examination offshore / periodic inspections

Every detail on the test bench

Jörss - Blunck - Ordemann GmbH is acting as Appointed Inspector according to BSH with its certification office. The basis for certification is BSH Standard 7005: 2015-12.
The certification office under the leadership of Dr.-Ing. Gerrit Haake works with in-house experts from the fields of steel construction, concrete construction, connections (grout, flange etc.), welding (international welding engineers - IWE), FROSIO III, geotechnics engineering, load calculation, structural dynamics and monitoring, as well as other external experts for operational components.

One focus since 2015, one focus has been on supporting offshore wind farms during their operating phase, which is expressed in the following examination and certification activities:

  • Annual Periodic Inspections (PI)
    Examination report for supporting structures
    Issuance of the Summary Verification Reports [BSH doc. 250/450/550]
    as well as the certificates of conformity [BSH doc. 252/452/551]
  • Large component replacements / repair works that require an examination
    on the basis of the execution phase according to BSH Standard
    Issurance of the Verification Report [BSH doc. 251]
  • Modification / reconstructions that require an examination on the basis of
    the design phase and the execution phase according to BSH Standard
    Issurance of the Verification Report [BSH doc. 251]
  • Updates or changes to the Concept for the Periodic Inspections incl. test and inspection plan
    Issurance of the Verification Report based on [BSH doc. 248]
  • Changes to the Operations Manual
    Issurance of the Verification Report based on [BSH doc. 246]

The Summary Verification Report on the Periodic Inspection has a special position here, as all relevant inspections, maintenance,
repairs and structural changes are summarized here within the annual campaign.
In addition, existing obligations from the project certificate or from one of the Verification Reports listed above will be continued
and closed with appropriate evidence. JBO performs the following services in the course of the exams:

  • Random supervisions of inspections or repair works or reconstructions on offshore support structures (all common offshore certificates and protective equipment (PPE) are available)
  • Improvement of the inspection processes through preliminary briefings and lessons learned talks as well as training of the personnel carrying out out the inspections on site
  • Expert examination of the PI support structure or repair and reconstruction work on the basis of inspection and investigation reports including evaluation of findings and preparation of an expert's report.
  • Examination of the PI of an entire wind farm (support structure, operating structure, submarine cable) or repair and reconstruction work regarding conformity with the BSH standard.
  • Issuance of Conformity Certificate according to BSH standard construction to a Verification Report
  • Participation in status meetings with the BSH and clarification of open questions.

Your contact person

Dr.-Ing. Gerrit Haake

Key qualifications
- Experience in offshore wind since 2004
- Experience in integral load analysis, project and type certification
- Expert knowledge in structural dynamics
- Experience in controller adaption for load reduction
- Assessment of support structures by case studies
- Validation of loads by measurements (for type certification)
- Member of several work councils for guidelines
- Acquisition and management of several R&D projects
- Recurring tests and certification according to BSH
- Examination and certification of repair works, modifications and component replacements (Großkomponententausch) acc. to BSH
- Creation / testing of WKP concepts
- Creation of a design basis / design basis for project developers

Further experience and skills

- FEM programs: ANSYS, RStab, Stab2D, FEAP
- Programing: MATLAB, Java, Visual Basic
-Load simulation: Bladed, S4WT
- Document management system: Teamcenter, EcoDoc


If you require further information feel free to contact us