Issue 3

All the articles published in the March 2016 issue.

Not so long ago, a journalist asked me an interesting question: “Do you believe the work of the structural engineer can ever be replaced by artificial intelligence”. I think she was somewhat taken aback when I answered “Yes”.

But before the esteemed readership of this magazine floods Verulam with missives of indignation, let me explain that I qualified my answer; I postulated that while almost all the technical work undertaken by structural engineers at every level could, in theory, be overtaken by artificial intelligence (and that it would be highly complacent of us as a profession to assume our more “left brained” tendencies were irreplaceable) the art of the structural engineer would always remain.

Which begs the question, as structural engineers, what do we really mean by design? When I was at university over 30 years ago, much of our course work was taken up learning the hard, number-crunching ways of analysing structures, while “design” lessons generally involved practising the use of codes and standards to select and detail structural elements. For the 21st-century structural engineer, these are processes which can now be almost entirely automated. Our real value comes in understanding when and how to apply the increasingly complex tools at our disposal to deliver value and creativity to our clients and stakeholders.

So in this special issue of The Structural Engineer, we set out to describe how far our profession has come, and where it might be going, in the development of digital design tools, and what this might mean for structural engineers of the future.

A glance at this special issue’s contents will reveal how much computer technology underpins much of today’s practice. What is perhaps surprising is that today’s status has been reached from a zero start over the working life of engineers now retiring – and almost explosively over perhaps half a working life, from the mid-1990s. The challenges of coping with today’s technology, let alone what is going to happen in the next decade, are formidable.

The use of computers has resulted in immensely beneficial changes for structural engineers, both at the operational level of designing and at the conceptual level of making us think more carefully about the processes that we use and how they should be used. However, there is much disquiet about the risks involved in computer use.

A main strategy for guarding against such risk is to use what is called the “reflective approach”. This implies that one adopts a degree of scepticism about all received and generated information; one is open to ideas; one poses and seeks answers to questions; one makes personal assessments and reassessments and seeks advice from others, especially from experts; second or more opinions are sought if appropriate; when faults are found or improvements can be made, action is taken; an appropriate amount of resource is allocated to seek to ensure reliable outcomes.

Use of reflective thinking is fundamental to good engineering practice. Computer use does not diminish the need for it.

The choice of structural engineering software today is very wide. However, a lack of comparison data makes it difficult for engineers to make a well-informed decision about which software tools would be the best fit for their practice or for a particular project.

This article considers some of the factors affecting choice of software, such as technical criteria, usability and interoperability, and describes a selection tool developed by BuroHappold Engineering to enable the firm’s project teams to make an appropriate choice of software when embarking on a new project.

When considering lean design and construction in the building industry, we often draw inspiration from the manufacturing industry. But despite many positive moves in recent years, the construction industry – and building design in particular – is one which often requires bespoke, client- and site-specific solutions and not commodity production.

Nevertheless, by dissecting and interrogating the whole process of creating building structures, we can still draw efficiency and marginal gains at each step of the way.

As design engineers, our focus is often on day-to-day problem-solving in relation to a particular project or engineering challenge. Perhaps less frequently do we consider the same application of engineering to the design process itself.

This article will explore how we in AECOM are currently using technology to improve the efficiency of the design process, while at the same time empowering the structural engineer to be more creative, and take a more central role on multidisciplinary projects. Case studies range from large-scale stadium projects down to small, but complex, pavilions, and how the methods can be applied to other projects through a cultural shift that capitalises on the accessibility of digital technology.

Some engineering problems are simple, like linear analysis; others are difficult, like non-linear analysis; but there is a third group: those that are complex. Complex problems are those where there are many possible answers that have to be explored and assessed before a decision is made as to which is the best one.

This article will discuss the principal concepts of design optimisation, then look at the various suitable techniques and make suggestions as to where they might be used by structural engineers. These methods include quasi-Newton, gradient, simulated annealing, Monte Carlo, genetic algorithms, particle swarms, neural networks, form-finding, and evolutionary topology optimisation.

While the article will not be exhaustive (which would take several books), it will provide sufficient examples and typical formulas so that those interested can start to explore this fascinating subject.

Finite-element analysis involves inherent approximations and numerical errors. In addition to these, the increasing size of structural models and the use of automated workfl ows for creating them can lead to hidden user errors in these models. In order for an engineer to have confidence in the analysis results, it is necessary to be aware of how these errors manifest themselves in models, what impact they have on analysis results and, most importantly, how they can be detected. We present novel numerical techniques that the analyst can use to “debug” their models and verify the accuracy of their analysis results. These techniques have been implemented in software and have been successfully used by practising engineers working on real life projects.

Modern computer-aided calculations are a significant advantage in the design of structures, whether simple or complex. Software developers invest in the development of tools that are increasingly simple to use; engineers then use those tools to develop and, to a large extent, test the possible structural configurations. The software will then, in many cases, present design calculations and code checks allowing a semi-automated documentation of the design.

The underlying questions are: how do we know that the results are reasonably correct; and who is responsible if there is a failure? The answer to the second question is that the Chartered Engineer leading the design project is responsible; the answer to the first point is quality assurance. For engineering analysis, the major tools for quality assurance are the twin processes of verification and validation (V&V). In very simple terms, verification is the demonstration that the mathematics and numerics are correct; validation is the demonstration that the idealisation of the physics is correct.

As V&V underpin any quality assurance system, this paper discusses the need for V&V and indicates who is primarily responsible for the two processes: software developer or design engineer.

The design of structures using computer software is prevalent throughout the industry. It provides quick analysis of structures that can be readily incorporated into Building Information Modelling (BIM) systems such as Revit. However, while the use of such software is essential in the present-day design office, it should be recognised that hand calculations and sketches are an important part of an engineer’s toolbox in establishing a “feel” for the structure that they are designing.

Without an engineer’s inherent understanding of what a structure can and should be doing, which is generally established through years of training and experience, it is quite possible for design and analysis software to produce serious errors that would otherwise be easily caught by the use of common sense and hand calculations.

This article aims to provide a “good practice” summary for engineers in the early stages of their career, while also serving as a reminder for those with more experience.

This article describes how cutting edge parametric-based engineering techniques have been used to achieve the detailed design of 2500 complex steelwork connections for the exoskeleton of the new City of Dreams hotel in Macau, China. It discusses the tools, methodology and strategy employed by the engineering team to automate the difficult and time-consuming process of creating, verifying and documenting the geometrically challenging, large-scale steel connections using finite element methods within an ambitious timescale of just 12 months.

This paper describes the digital parametric design and fabrication optimisation that was carried out on the recently-completed Qatar Faculty of Islamic Studies building in Doha, Qatar. The processes, tools and techniques used are described, with background given about the issues and decisions that led to their development and implementation. The benefits we believe these tools brought to the project are also discussed, from the point of view of both the building’s construction and Arup’s internal workflow.

The paper focuses on the building’s roof structure, which is completely free-form, architecturally defined by a 3D doubly-curved NURBS surface. The roof’s surface area is approximately 13 500m2 and is constructed from curved plate girders, each one unique. The roof’s geometry ranges from areas with a radius of curvature of approximately 500m, therefore relatively flat, to areas of high curvature with a radius of 5m or less.

Some expertise in the use of technical software, often developed in a final-year project, is a necessary skill for graduates in civil or structural engineering, argues Professor Roger Johnson, although this poses several questions.

There is a strong case for exposing undergraduate students to structural analysis software, argues Jon Carr of The University of Sheffield. While the case for structural design software is less compelling, this also offers potential learning benefits.

Institution Past President, Tim Ibell, welcomes the creative possibilities of the digital revolution in structural engineering and urges universities to widen the appeal of the profession to school-leavers with interests other than maths and physics.

Structural engineers should embrace the creative possibilities offered by a virtual, digital world, believes Tristram Carfrae, if they are to transcend the limitations of their own experience.

Tim Lucas of Price & Myers envisages a not-too-distant future in which automation is extended to assembly on site, giving engineers full control of the building process and licence to explore their wildest design dreams.

David Sanderson, Product Development Manager, Engineering Structures Division, Trimble, gives his perspective on developments in structural engineering software and asks whether it is time to starting thinking in terms of “design and analysis”, if not just “design”.

This introduction to advanced modelling techniques will likely be of interest to senior engineers seeking background knowledge on the use of analysis software for specialised structural design.

This month's letters include further discussion on the concept of "reasonably practicable" and on web buckling of steel beams.

Upcoming events at Institution HQ and around the regional groups.

In this section we shine a spotlight on papers recently published in Structures – the Research Journal of The Institution of Structural Engineers. Structures is a collaboration between the Institution and Elsevier, publishing internationally-leading research across the full breadth of structural engineering which will benefit from wide readership by academics and practitioners. Access to Structures is free to Institution members (excluding Student members) as one of their membership benefits, with access provided via the “My account” section of the Institution website. The journal is available online at: www.structuresjournal.org

We continue this section with another steel quiz brought to you by the SCI. This month’s topic is bolts. Answers will be published in the April issue.