Core technical questions
"What is the difference between ultimate limit state (ULS) and serviceability limit state (SLS)?" ULS represents structural failure: the structure should not collapse under design loads. SLS represents conditions that affect normal use: excessive deflection, cracking, vibration, or durability problems. Eurocodes require separate checks for both, applying different partial safety factors. Many structural problems are SLS failures: a structure that deflects excessively may be unfit for use even if it does not collapse. "What are the main soil investigation methods and when would you use each?" Standard Penetration Test (SPT): measures soil resistance in boreholes, cheap, widely used, gives density and bearing capacity correlations. Cone Penetration Test (CPT): continuous profile of soil resistance, better for layered soils and soft ground. Trial pits: direct visual inspection of shallow soils. Pressuremeter: in-situ stiffness in stiff clays and rock. Laboratory tests: Atterberg limits, grading, consolidation testing for clay settlement.
Design and calculation questions
"How would you design a simply supported reinforced concrete beam?" Determine loading (dead load, live load, partial factors per EN 1990), calculate bending moments and shear forces, design flexural reinforcement using Eurocode 2, check minimum and maximum reinforcement limits, design shear links, check deflection at SLS, check cracking at SLS, detail the reinforcement, produce drawings. Show you follow a systematic design process and check output against code minima and engineering common sense.
Project and commercial questions
"How do NEC and JCT contracts differ?" JCT contracts are traditional forms widely used in building projects: clear, well-tested provisions but less collaborative in managing change. NEC contracts are used predominantly in infrastructure (HS2, Highways England, Network Rail specify NEC4): project management-oriented, require proactive early warning of issues, use a compensation event mechanism for change management. Know which contract form is standard in your target sector and be able to discuss its key mechanisms.
Behavioral questions
"Tell me about a time you identified a risk on a project." Specific risk (technical, commercial, or programme), how you identified it (site inspection, design review, programme analysis), how you raised it (early warning notice under NEC, risk register update), and what the mitigation was. Show you are proactive about risk and communicate formally, not just informally. "Describe a project where you had to balance engineering requirements with cost or programme constraints." Show you understand that civil engineering is a commercial as well as a technical profession.