Specialist Services

NSE can offer expert advice to clients experiencing problems with structural cracking, hair-line cracking, spalling and rebar corrosion, Alkali-Silica Reaction (ASR), structural failure, dusting, crazing and plastic shrinkage.

Our services include site investigations, structural analysis of failed (or failing) structures using finite element methods (FEM), providing expert opinions based on visual inspections or concrete analysis and acting as expert witnesses in cases that require these services. All our investigations are presented to our clients by way of structured reports that are fully reviewed internally, with the option for external review if the client so wishes.

South African engineers have long been able to ignore seismic design of structures, since South Africa is generally regarded as a low risk seismic zone. However, the recent changes to the loading codes have enforced the requirement to include seismic loads as part of all structural designs. Furthermore, with firms now competing in a global market for projects worldwide, it is imperative that engineers are able to competently design structures with seismic loading in mind.

Due to NSE’s extensive experience in the nuclear industry (and the extensive experience of the NSE founders prior to establishment of the company), our analysis and design processes have been adapted to suit the rigorous standards and requirements of the nuclear industry. This has resulted in a standard design procedure that has included seismic design criteria since the establishment of the company.

Vibration in structures is undesirable for various reasons – increased noise, uncomfortable conditions perceived by human occupants, poor mechanical plant performance and in severe cases, increased structural loads. Our experience in this field can assist clients in solving structural and mechanical problems.

The natural frequency of a structure plays a large part in determining the effects that forced vibrations have on the structure. Forced vibrations are typically produced by mechanical equipment, especially reciprocating or rotating equipment or equipment that is out of balance. There are generally two methods to resolve problems due to vibration - change the mass acting on the structure, or change the stiffness of the structure. Our analysis of the structure allows as to perform sensitivity analyses in order to determine the best technique to overcome the problems experienced, based on cost and efficient use of resources.

The behaviour of structures subject to extreme transient loading and temperatures experienced during blasts and fires is unpredictable. By utilising FEM analysis software and non-linear analysis techniques, we can assist clients in predicting the likely behaviour of structures and possible failure scenarios.

Fire can affect the load distribution on structures, as well as the material properties of the structure. Transient analysis techniques allow us to vary the loading as well as the material properties over the expected duration of the fire. Entire structures can be analysed for global effects (catastrophic structural collapse) or local effects, such as beams sagging, collapse of walls, failure of floor slabs and failure of roof members. The results of the analysis can be further utilised in order to provide recommendations for strengthening of members or for changes to material to increase the fire rating of the structure, thereby reducing the risk of loss of life due to fire.

We are able to estimate the seismic capacity of power plants or other plants where seismic loads may play an important role in the continued safe operation of the plant. This is based on hazard assessments and walk-downs of the plant including visual inspections of the structural and mechanical equipment by highly experienced engineers, with backup calculations for components that appear marginal.

Our US based partner Rizzo, and collaboration with various European based companies, affords us access to recognised industry experts in the fields of equipment qualification, structural qualification and hazard and risk identification and assessment. As a result, clients that use this service can be guaranteed that they obtain a high quality assessment of their plant and can implement changes or repairs as a result of the findings.

Extreme events are rare events that are difficult to predict and difficult to quantify. We have experience in the quantification of hazards complimented by analysis and design of extreme loading conditions such as high seismic loads, vapour cloud explosions, impact loads and high wind or tornado conditions.

Our experience with extreme event analysis is generally related to reinforced concrete analysis and design. Using some of the best FEM software available and analysing structures using the Abaqus non-linear solver has allowed us to develop standard design specifications for concrete walls, slabs and columns to withstand the loads experienced during a typical vapour cloud explosion. This allows us to be highly responsive to clients who need to analyse structures that may be subject to this type of transient loading.

Utilising the same methodology, we are also able to perform analyses related to more concentrated transient loading such as airplane impact or vehicle impact on structures. This form of analysis is typically time-consuming and demanding on computer resources. Our partnerships with various expert FEM companies allows us access to computer resources and expert information critical to the analysis of these events.

Our services include hazard and risk assessment, geological surveys, oceanographic analysis as well as services for the licensing of nuclear facilities. Our advanced analysis services include fragility studies, seismic walk-down and audit services (mechanical and structural) as well as site response, ground motion and soil stability studies.

We are also able to develop seismic response spectra from input time histories and vice versa, utilising software developed by our in-house engineers. We have extensive experience related to the analysis of various structures, both concrete and steel, and are able to provide clients with an end to end analysis and design service, from soil analysis to final structural design.

Our quality procedures are developed in order to comply with stringent nuclear requirements, and all work undergoes an extensive review process. Our company complies with the requirements of ISO 9001.