We are an offshore structural engineering company for unique structures, focusing on projects where the safe operation and efficiency requires in-depth detailed analysis combined with creative design. Our high quality service and expertise have made us a preferred outsourcing destination for a world class provider of drilling equipment for the high-efficieny drilling market.
We are delivering structural solutions for the client’s benefit, providing a reduced overall cost of the specific project.Applying the relevant codes for each specific project and minimizing the neccesarry changes on client’s application/structure – thus reinforcing the weak points – to achieve optimized load capacity. The high level offshore structural engineering solutions provide longer lifetime, furthermore the operational conditions become significantly safer.
Most of the services outsourced are related to design services around patented products, therefore we treat our client's intellectual property confidentially. NeerS Engineering works with clients in the long term; this has resulted in 80% of our business coming from repeat clients and acknowledgement for significant contribution to the bottom line of their products and brands. The key factor to the success of our Engineering outsourcing services is domain expertise and good engineering judgment in the field of offshore structural engineering.
Our company is located in Europe, harmonizing projects with the aid of Internet, thus we can deliver offshore structural engineering services to clients based anywhere on the globe.
Gathering all project information and examining the possible operational and parked sequences to achieve realistic load combinations.
All details are checked for the governing forces both by hand calculations and beam/FE modeling for maximum reliability.
Load level for critical parts are again controlled together with client to ensure only necessarry changes addressed. Reinforcement solutions provided and negotiated with client to reach optimum solution.
A design manual is compiled for external supervision (DNV, ABS …etc) and archive purposes.
We have calculated the critical live load on structure for several positions – to achieve realistic loading.
The complex structure of derrick top has been modelled in detail, with several hinges, trusses and springed supports.
This showed several critical points, -which due to the strict dimensional limitations-, had to be examined in depth. We have checked the plastic capacity of the multispan vertical rails, and have found these parts to be satisfactory. Nevertheless some parts had to be reinforced, but in a limited number and region.
When checking a Lower Guiding Arm, we have looked at the possible loading scenarios, and the results of a possible equipment failure. We have found that the previously used design loads are low, and the environmental loads could cause the LGA fold back (as the cylinders switch off at an overloaded case). This in turn would have resulted in a potential loss a Drill-pipe bottom guideance. The control cabin was nearby, therefore we had to take action, and re-design this equipment.
The telescopic arm of a Lower Guiding Arm had sliding pad connections between the inner and outer box section. Due to serviceablity – the pads were in the middle of the webs, thus creating a large hole on the box and furthermore severe bending moments. We have checked this situation both with hand calculation and FE modeling. As a result – both the main section and the details have been reinforced.
The full setback conditions (loading) have been significantly increased for general DP/DC Fingerboard lockfingers. Nevertheless the original size and geometry had to be kept as close as possible in the new design.
Checking each part and consulting with equipment designer, resulted in a very different optimized shape. The corners had to be rounded, to avoid large peak stresses in this region. Finally a casted element, was the solution.
The design of several Gantry Crane was checked: first evaluating the possible loading scenarios and finding the governing situations. The main beam model of the crane was checked in several positions.
Also the main SWL (safe working load) was applied in the most realistic way. The sling arrangement was taken into account.
All details have been checked, and some found to be critical. These have been reinforced and have found a possible solution together with the project designer.
The Drillfloor Manipulator Arm is placed on the drillfloor. There is a pedestal between drillfloor and DFMA. A slewing frame/gear is fixed on the pedestal, which is able to move rotate.
Support conditions are allways significant element of analysis, as these can alter final results greatly.
Connection between slewing frame and pedestal in reality
Our first results showed, peak stresses mainly at the slewing frame supports. At these points the connection between slewing frame and pedestal was modelled with a vertical beam (bolt). The pedestal was modelled with a 1250mm*1250mm 750mm long vertical beam which were connected to the bolts by non-structural beams
Connection between slewing frame and pedestal in 1st model
We tried to avoid unnecessary changes of a finished design, therefore we looked at the displacements. We have found that these were not reliable (16mm) hence we have changed support conditions by defining supports at bolt ends. At bolt-beam top (at slewing plate) we have added horizontal supports to take shear forces, and on bottom we allowed all possible forces due to slewing frame and pedestal connection. Also we used the exact bolt length. To get real displacement at bolt end we definied a spring (acting in bolt axis) modeling the pedestal capability to take vertical force.
Connection between slewing frame and pedestal in 2nd model
Thanks to all these changes, the stresses have been reduced at the critical points, while we have kept the bolt end's displacement within reasonable range. Finally we did not need to ask for any changes of this detail.
The Guide Dolly is designed to keep the DDM assembly in center well position while travelling up and down the derrick (tripping) and to transfer the torque of the DDM (drilling) into the derrick structure.
A new service loop bracket was added to this design at bottom horizontal beam of the Dolly. This bracket is holding all cables (electricity, mud).
We have checked the whole dolly and this new detail, and have found that the dolly is OK, but this new bracket is highly overstressed:
Due to the complexity of the detail, we have also checked it with a Finite Element model. Hot spot areas also find at stiffeners connecting in unfavourable way.
We have proposed a simple solution, whereas the bracket was lowered, to achieve a direct contact to existing RHS profile, thus avoiding unwanted extra stresses. Furthermore, several stiffeners have been lengthened, to avoid high forces in middle of RHS.
Max Von Mis – Reinforced model
as a subcontractor of Aker MH (=Maritime Hydraulics) (Kristiansand)
We have finished over 150 offshore structural engineering projects for our client on a large number of rigs.
FEM – Rules for Heavy Lifting Appliances (loading, stress, fatigue calculation)
EuroCode1: Basis of design and actions on structures
EuroCode3: Design of Steel structures
MSZ 15021 Építmények teherhordó szerkezeteinek erőtani tervezése (Design of load bearing structures of buildings)
MI-04.133-81 Méretezési irányelvek földrengési hatásokra (Design guidelines for earthquake/seismic impacts)
MSZ 15022 Vasbeton szerkezetek (Reinforced concrete structures)
MSZ 15023 Falazott szerkezetek (Masonry structures)
MSZ 15024 Acél szerkezetek (Steel structures)
MSZ 15025 Faszerkezetek (Wooden constructions)
DNV – Det Norske Veritas Rules and Technical Notes
NS3479 – Prosjektering av bygningskonstruksjoner (Loading criterias for buildings)
NS3472 – Prosjektering av stalkonstruksjoner (Design of Steel structures)
ASCE – Design of Blast Resistant Buildings in Petrochemical Facilites
ANSI - NDS: National Design Specification for Wood Construction
TIA/EIA – Structural Standards for Steel Antenna Towers and Antenna Supporting Structures