BP Deep Water Sump Assessment and Concrete Repair Design

Beta Scope

The scope included the following:

Carrying out the detailed visual structural inspection of the deep water sump prior to plan shutdown. Our team carried out the inspection in the confined space after preparing all the risk assessment for BP approval.
Preparing the scope for intrusive testing ( concrete strength and rebar corrosion) and NDT testing (chemical analysis, carbonation, and chloride ion content).
The structural assessment of the sump walls which were working as unpropped cantilevers (RC walls subjects to earth pressure and surcharge leading to biaxial bending).
Designing and specifying materials required for the structural repairs.
Supervising repairs on site.

Background

Beta Design Consultants acted as structural engineering consultant for Bechtel UK who were responsible for the asset refurbishment of BP Rosetta Gas Plant in Egypt (Giza Fayoum Gas Plant). We inspected, assessed and designed repairs and strengthening for the gas plant civil and structural facilities that required refurbishment including the deep water sump.

The client’s future plan for the plant required the assessment and life extension of all civil and structural facilities to ensure they have a service life of 25 years.

Challenges

The task presented unique challenges due to its location, maintenance history and client requirements. These challenges included:

Strict programme to agree, tender and execute the works during a shutdown period of 12 months.
Tight budget due to pre-forecast capital expenditure.
Plant location on the Mediterranean coast, subject to a very corrosive coastal environment.
Typically harsh petrochemical conditions (oily and chemical contaminants) affecting civil and structural facilities.
The plant location in a seismic area (near Alexandria) meant all design had to consider seismic forces and seismic code requirements (ASCE 7-10 and AISC 341 Seismic Provisions).