Getting an interview call is half the job done, but what about the second half? Every time you prepare to attend an interview, first thing you ask yourself is what are the questions the interviewer going to ask. Especially, when you are a fresher, you have no clue what the questions are gonna be. So, I wanted to share my experiences from my interviews as a structural engineer and from the graduate recruitment programs I’ve led in my company.
Over the past six years of my career as a Structural Engineer, I’ve been interviewed four times to the role of structural engineer. For the record, two of them I got through and two I was put down in the final round of face to face interview. I’m currently working as Bridge Design Engineer at JACOBS Engineering Services, Hyderabad.
In this article, I don’t intent to discuss typical sections of an interview like self-introduction, and group discussion in some cases. There are lot of articles out there which can help you with those. Here, I want to focus on freshers and graduates, attempting for their first Structural Engineering Job.
Structural Engineer Interview Pattern
Generally, any technical structural interview will aim at covering three basic aspects of engineering which are Analysis, Design and Application. Except for the first question, all the questions asked to you will be based on how you answer to the first one. Furthermore, most design MNCs take an approach of selection process rather than rejection process, so be confident when you answer and try to drive your interview. Moreover, it is easier if prepare well for an interview and you set out the topics first. Let me try to explain each aspect one by one.
Analysis of Structures
Firstly, analysis of structures, whether it is manual or computer aided, is the corner stone of any structural design. If analysis itself is wrong, then everything that follows is useless. This is the reason why a seasoned interviewer always starts with basics of structural analysis. Irrespective of how savvy you are at software based analysis, you must be able to demonstrate your strong basics in structural analysis. Your focus must be on following aspects
Boundary conditions
Structural boundaries dictates the degrees of freedom for any design component. Ask me what are the two boundaries that can possibly occur in this field? “Its the earth or another structure”. Defining and idealizing the support conditions and restrains are the most important steps in structural analysis. It defines the nature of forces generated in a design member.
Hence, you must be ready to answer any questions associated with various support types like Fixed, Pinned, Roller, Hinges and how these boundaries are achieved. For example, a bridge pier founded on pile foundation can be assumed to be fixed at base, when flexibility of piles are ignored.
GeoTechnical & Geological Aspects
Structural engineers and GeoTechnical engineers work hand in hand. Hence, it is important to know the concepts in geotechnical engineering. In small consultancies there will not be any separate geotechnical team. Structural engineer will have shared role in those cases. For this reason, structural engineers must know the basic geotechnical analysis and design.
You must focus on types of foundations, behavior of shallow and deep foundations, stability of structures, earth pressures calculations and effects of ground water.
Loads on structures
Loads acting on a structure depends on the type of structure and its boundary conditions. So you must have a reasonable understanding about the types of structures the particular consultant is involved in. For example, bridge design consultants gives specific focus on vehicular live loads, associated effects, settlement effects along with strain induced effects like creep, shrinkage and temperature. Prestressing is a widely used technology. Engineer must know the behavior of structure under prestressing loads.
Engineer should have a clear idea about the applicability of these loads as well. For example, differential settlement effects on superstructure can be ignored for simply supported bridge spans. Engineer must know the nature of loads like concentrated loads, uniform, varying and time-dependent loads. You must have a basic understanding about dynamic load effects and analysis, like response spectrum analysis or time history analysis.
Nature of Forces and Deformation
Design demand calculation is the first step of design process. Questions on force calculation is one area where I’ve seen freshers struggle. If you are attending an interview for fresher or junior engineer level, be prepared to draw Bending Moment, Shear force and deflection diagrams for any idealized load pattern since it is the prerequisite for being a design engineer.
Engineer must recollect the behavior of structure under various design load and the nature of forces. For example, nature of temperature induced deformations, creep effects or live load effects. Axial force effects like tension and compression, and effects like torsion, warping and twisting should be given importance while preparing for interview.
Design of Structural Components
Materials
If you are aiming for a successful career in structural engineering, you must master any three key ingredients in our field which are Steel, Concrete and Wood. Wood is not a popular construction in my country, although in my first job I’ve done quite a lot of work in wood design, up to five storeys high.
Before using any structural material, engineer must have a clear understanding of these materials under load actions, especially stress-strain curves. Focus on areas like structural steel, reinforced concrete, pre-stressed concrete, steel composite constructions. In case of reinforced concrete, focus on stress limits, creep, crack width calculations and reinforcement limits. In case of pre-stressed concrete, refresh loss calculation and material properties of prestressed bars and strands.
Limit States of Design
Most of the international structural design codes use principles of Limit State Design compared to its obsolete counterpart Working Stress design. Understanding the differences and advantages is important to exploit these provisions in design. Under limit state design, engineer must be capable to differentiate various limit states of Serviceability, Strength, Extreme limit state and Fatigue. You must also know the importance of each limit state. For example, it is not necessary that a structure passing strength limit state will satisfy serviceability requirements.
Have an understanding about basic limits under each category. For example, serviceability limit states ensures the serviceability of the structure through the design life by limiting deflection, stresses in material, crack widths, stability etc. On the other hand Strength or Ultimate limit state ensures enough reserve capacity against collapse of structure. Checks are performed for ultimate moment and shear capacities under the action of ultimate loads.
Failure modes
Design check are performed to prevent various modes of failure. Engineer must understand nature and modes of failure. For example, in reinforced concrete, it is flexural, crushing or shear failure. Steel members are governed by wider failure modes like flexural buckling, torsional buckling shear, fatigue. Read and understand the basics of these failure modes and its applicability in design of structural members like columns and beams.
Structural Engineer Experience & Application
Do not underestimate your experiences during project work, seminars and dissertation. It portrays your interest in the subject and your passion to be a structural engineer. Interviewer will be keen to know the objectives and outcomes of your project work.
I suggest to use this opportunity wisely since it will help you to demonstrate your technical knowledge and design acumen. Prepare well to answer questions from your seminar and project work. Moreover, be clear on what you did and how it was useful.
If you have undergone any internship, published papers or attended seminars, this is the right time to feature those. Explain where you had done internship, what all were your responsibilities and what you learned there. All these will be counted towards your interview score.
Further, explain your software capabilities and how you have applied them in your project and seminar works or during your course tenure. If possible, understand the software that the company is using currently and try to learn those design packages.
Finally, refrain from beating around the bush, maintain a good attitude throughout the interview and display your urge to learn the design. Show that you respect professionalism and ethics at workplace.
Good luck!