Introduction

It is well known that risks are inevitable in any type of business. From the point of view of large industrial bulk handling structures and equipment, efficient risk management is essential. In this context, even though the occurrence of a given event may be low, the consequences are usually high.

One of the stages in the risk management process is risk identification [3]. In the context of Structural Integrity, risks mainly arise from three contributing factors:

• Inadequate design of a structure or piece of equipment. In this case, the asset has already been designed with an associated risk;
• Condition of the equipment or structure in the field: degradation mechanisms, cyclical loads, improper use of the equipment and extreme weather events are factors that can compromise the resilience and structural safety of the asset [4];
• Improper maintenance of assets. Equipment requires a series of procedures for its maintenance and durability, and when this process is not carried out properly, it becomes another source of risk to consider.

Once this has been identified, management must include an analysis and then the definition of strategies to adequately control the offenders. The CARE methodology: Control of Assets for Structural Revitalization, created by Kot Engenharia, is a tool that combines the fundamentals of the main risk and asset management references to provide operational safety for equipment. The stages of the CARE methodology are shown in Figure 1:

Figure 1: Stages of the CARE methodology.

The aim of this article is to elucidate the application of all the stages of the methodology created by Kot and to show the gains in reliability and safety for the operations of one of its clients.

The Succes story is about one of Brazil's main iron ore export ports. The assets of port logistics systems must have high physical availability in order to meet the supply needs of ships while dealing with an environment of severe corrosiveness. This context, when coupled with existing machinery and structures that are exposed for long periods without proper Structural Integrity maintenance, often results in operational losses caused by emergency corrective stoppages.

Structural Integrity maintenance audit

Maintenance is a combination of technical and administrative actions, including inspection and supervision, aimed at maintaining or adapting an item to its required assignment [1]. For Structural Integrity, maintenance aims to prevent failures or other compromises at the level of equipment, civil or metallic constructions. These stages range from inspections to the installation of reinforcements or renovations.

In an environment where degradation mechanisms are present, Structural Integrity maintenance plays a fundamental role in establishing adequate risk levels for the continuity of operations. Kot Engenharia therefore carried out the first stage of implementing the CARE methodology at the port terminal: auditing the Structural Integrity maintenance processes.

The audit process consisted of visits and monitoring of daily maintenance activities, interviews with employees and an exhaustive analysis of the documentation on the assets and their maintenance plans. This work was able to identify the points of vulnerability in the client's internal process and then provide detailed recommendations to ensure procedures capable of preventing unwanted scenarios that could lead to loss of life, financial loss, damage to the environment and even reputational loss [2].

Inspection of assets

A fundamental stage in the CARE methodology is the inspection of assets. During the 10-month on-site monitoring, 100% of the 26 structures that make up the port terminal's production process were inspected. At this stage, any critical non-conformities were dealt with promptly.

Inspections were carried out visually and sensitively, complemented by non-destructive tests such as ultrasound and liquid penetrant. During this stage, shown in Figure 2, structural non-conformities are identified, such as: paint degradation, corrosion, deformations, cracks, as well as other non-conformities visible to the naked eye.

Figure 2: Visual inspection of assets.

Detailed inspections using non-destructive testing were carried out at the main locations, identifying possible structural non-conformities that could not be detected by visual sensitive inspection. Figure 3 shows the ultrasound test carried out on a highly responsible weld, as well as Figure 4, in which the liquid penetrant test was able to detect a crack with a high potential for collapse. These timely detections are fundamental to Structural Integrity and business safety.

Figure 3: Ultrasound test on welds.

Figure 4: Liquid penetrant test - Application (a) and revelation (b).

Structural verification of projects

Structural (metal and concrete) and mechanical design checks were then carried out on all 26 of the port terminal's assets. The design checks involve the use of technical engineering knowledge, combined with computer resources to check against regulatory criteria, in order to ensure that the assets adhere to a level of risk considered acceptable.

The structural verification process consists of an evaluation stage of all the asset documentation, followed by the preparation of a computer model using finite element software . As an example, Figure 5 shows the finite element model of a bucket wheel reclaimer, responsible for extracting material from the product stacks and loading it from the shipping line to the loading pier.

Figure 5: Finite element model of a bucket wheel reclaimer.

In the computer model, the material properties, geometric properties and boundary conditions are defined, such as the constraints and acting loads. The verification analyses are then carried out, such as the acting stress analysis (Figure 6) and the local buckling analysis (Figure 7), which were used to evaluate the bucket wheel reclaimer.

Figure 6: Result of the static analysis of the recovery portal.

Figure 7 : Result of the local buckling analysis of the reclaimer portal - Graphical representation of the eigenvector.

The results of the structural analysis are taken as the basis for defining the strategy for adapting and revitalizing the asset. Factors such as the criticality of the failures, the likelihood of an undesirable event occurring and the possibility of adopting immediate prevention and/or mitigation measures should be taken into account until the intervention strategy has been defined and duly implemented.

Monitoring

In cases where the structural analysis indicates the need for monitoring or field confirmation of the real need for reinforcement, data acquisition techniques can be used. Figure 8 and Figure 9 illustrate the situation in which it was necessary to calibrate the computer model, based on the methodology for obtaining stresses/deformations using strain gauges.

Figure 8: Positioning of the strain sensor.

Figure 9: Result of the extensometry analysis.

The data collected in the field, for the different operating regimes, is compared with the numerical results obtained via the computer model, indicating the need for calibration and adjustments to the calculations in order to represent the field condition with greater assertiveness.

Proposing solutions

In cases where structural analysis, monitoring or inspections indicate the need for structural intervention in the equipment, the best reinforcement alternatives are evaluated, taking into account aspects such as cost, efficiency, time and risk in the implementation process. For the design non-conformity identified in Figure 6 and Figure 7, at the bucket wheel reclaimer portal, the reinforcement shown in Figure 10 below was proposed:

Figure 10: Example of a Structural Reinforcement proposal.

Monitoring the implementation of solutions

As part of the support provided by Kot for the structural revitalization of the assets, in addition to designing the reinforcements, on-site monitoring of the installation was carried out. In this way, it is possible to assess adherence to regulatory requirements, and consequently the effectiveness of the proposed reinforcement. Figure 11 shows the location of the reinforcement previously shown in Figure 10. Figure 12 shows the monitoring and validation of the implementation of the reinforcement by means of the non-destructible liquid penetrant test.

Figure 11: Structural Reinforcement installed.

Figure 12: Monitoring and liquid penetrant testing of the reinforcement.

Conclusion

The example presented of Structural Calculation, proposed reinforcement and follow-up is just a sample of the CARE methodology implemented at the port terminal. All 26 assets responsible for material handling, from receipt to loading onto ships for export, had their integrity inspected and audited, with a view to revitalizing the assets. Figure 13 shows a compilation of the actions carried out during the application of the CARE methodology.

Figure 13: Compilation of actions for structural revitalization.

The reconditioning of the 26 assets allowed for greater physical availability, resulting in a reduction in costs with emergency corrective stoppages and mitigating risks to the business and the people involved in the process. In addition, the audit of maintenance procedures resulted in the creation of a new sector within the port operator, exclusively dedicated to Structural Integrity maintenance. The creation of this new area will allow the support provided by Kot Engenharia for the reconditioning of assets to be extended to the required operating time, with the necessary maintenance.

Kot has a team of qualified professionals ready to provide reliable, on-demand engineering solutions for your business. Contact our team for more information!

Follow our pages on LinkedIn, Facebook e Instagram to keep up with our content.