On 23 March 2007 our informant for the discipline of civil engineering was Prof.ir. J.W. Bosch, who is a professor at the Delft University of Technology, where he researches underground space technology. Combined with his work in Delft, Bosch works in the field of civil engineering. He is construction manager for the Amsterdam Noord/Zuidlijn, an underground line from the north to the south of Amsterdam.

Different mindsets

In this interview Bosch spoke to us about his work. He divides his time between two posts. This differs to the extent that they require different ‘mindsets’. This became clearly visible when we questioned him about the claims and outcomes of civil engineering. Bosch explained in the interview that engineering results and methods are needed at each of the two positions, but that these are emphatically different at the two positions.

Each mindset features specific methods and specific results. In the ‘Amsterdam mindset’, the aim is building a structure, the new underground metro line. For this purpose new technologies need to be developed and tested, primarily on a practical trial and error or design by testing basis. The construction plans should be realized safely, on time, within the agreed budget. The technology is tried first in a test situation before it is applied on the construction site. In the ‘Delft mindset’, on the other hand, the aim is to understand and develop new technologies, to facilitate the construction process and to bring technology to a new level. This requires theoretical insight in applied science to understand the process. New technologies are analyzed by means of computer simulations, mathematical analysis and test models. For example, a PhD student could investigate the main cause of a phenomenon that occurs, leading to hypotheses that must then be tested.

The required results

All structures that civil engineering produces will be used, some directly, some indirectly. A civil engineer is constantly aware of this. It permeates his or her talk about the results of civil engineering. A construction is used, and therefore it is supposed to be functional. To produce it a civil engineer should not damage anything or anyone, so the risks should be diminished. Finally, lay people for aesthetic reasons could appreciate a construction.

The risk reduction

Civil engineering is about creating society, but not solely. It is about creating and understanding. By means of that understanding civil engineers are capable of specifying the risk factor for new technologies. Risk profiling is a growing trend of the last half-century. Both in practice and in theory civil engineering is all about containing risks. Safety cannot be measured, but risks can. This use of the knowledge of civil engineering is not driven by civil engineering itself, but by politicians. Politicians always want to know what the risks are, in regards to money and time. Politicians prefer applications of technology that have been used before. Civil engineering is given the liberty of innovating, because that is necessary since the world is ever changing. Each time new solutions and therefore new technologies are required. This means that each time a different kind of research is required. This constant process of innovating makes the field of civil engineering very dynamic.

In both theory and practice, the importance of safety is warranted by the risk factors, which in that way determine foremost the appreciation given for the claims and outcomes. The calculated risk factors separate the knowing from the trying. Where in practice more appreciation is given to a solution, in research hugely complex mathematical models are favoured, which realise a higher reliability of the technology than possible before.

Functionality

In Holland civil engineering is focused on research and technology into ground and water. There is a saying that God created the world, and the Dutch created theirs. In any given society civil engineering can be thought of as part of its nature. Civil engineering has a purely pragmatic premise, which does not underlie any other sciences. One always has to be conscious of the relevance of the research for one’s own society. Engineering carries out not research for it’s own sake, but research on demand. This is clearly visible with the Dutch. Civil engineering is at the base of a society and so it is also under the control of that society. In the Netherlands politicians decide on what civil engineering can research and create. In this the time-bound element of civil engineering is shown.

Aesthetics

Not to be neglected when one reflects on the importance of claims and outcomes of civil engineering is the aesthetic aspect. In practice this is nowadays valued more than in the past. This recent development has changed the way of working of engineers. In the past they worked alone with the sole purpose of functionality: nowadays aesthetics influences the chosen technology more and more. Therefore architects are more involved with the civil engineering side of the projects.

The methods

Although all civil engineering is concerned with the innovation of technologies, the approaches vary. How one finds new technologies and works with them, and whether one is theoretically or more practically one’s minded, depends on the mindset. This illustrates the diversity of the civil engineering discipline, whether theoretical or practical.

Trial and error

A lot of underground engineering is required for the Noord/Zuidlijn project. Bosch supervises the required engineering. Civil engineering’s main priority is lowering risks. A project such as that in Amsterdam has a responsibility towards the society in which it produces its technologies. In Amsterdam civil engineers have to create a solution that is safe. When a problem arises that requires an engineering solution, Bosch and his team search for a solution. Once the solution is found or created he is also responsible for the integration of that technology into the project and for its success or failure once it has been integrated.

When a solution is proved reliable, the engineers in practice have no need to know fundamentally why this specific solution works or works best. This approach can be seen as the method of trial and error. Before the rise of civil engineering in its current form, this was the primary method. In this method certainty is based on experience. For instance, when a carpenter builds a bridge out of wood he or she knows how thick the wood has to be from experience, because he or she has seen what happens when the wood is too thin. Of course one should be aware that the method of trial and error is a part of a constant process because of its use of new errors as problems and therefore it can sustain itself as a primary method.

In practical engineering, as in Amsterdam, the technology of trial and error has been extended beyond learning from earlier results or trying new solutions.

As was the case in the Noord/Zuidlijn project, when they used a full-scale trial-test for compensating grouting. They injected pipes horizontally under the buildings. True these pipes at different points a cement mixture is injected in the ground under the buildings. This technology was known to give either fractures or balls of cement as result. At the project the cement mixture was composed in such a way as to make balls instead of fractures in the ground. The technology still worked, the difference between fractures and balls is more important for a researcher. When they researched the phenomenon, they tried to discover which cement mixture or what kind of ground would give balls instead of cracks, and which was better. When balls are formed they support the sand even better and the buildings are safer when drilling the tunnel for the underground line. And so a new technology was improved. Still, this is far more similar to the old method than same methods now used by researchers in laboratories.

Proven technology

Theory and practice are in constant interaction: the research of civil engineering could not exist in its current form without this. However, finding new technologies without the use of trial and error is possible only through research as undertaken in Delft. The focal point of the science with which Bosch occupies himself in Delft is understanding the forces of nature, not solely risk reduction. At Delft University of Technology risk reduction goes beyond knowing that a solution works: there the researchers also want to understand why this technology works the way it does. In the case of the carpenter for instance all calibrations would be important, not just the one which is required for the specific bridge under construction.

Nowadays, analytic calculations by computers in a lab provide a proven technology with at least the same risk profile as trial and error. With this kind of calculation engineering is using mathematics to a much larger extent than before. Mathematics is an instrument, used for instance to develop models. Validation is about the correctness of the method developed. For in the credibility of these claims and outcomes validation is of course essential. The reliability of these claims and outcomes is based on specific methods, which can be verified in the field. The degree of reliability of a claim or outcome is provided by the possibility to verify that claim or outcome. Only then is the degree of reliability reflected in the risk factor given to a proven technology.

This interview is published in the booklet written as a result of the 2006-2007 Honours Class “Ethnography of the Academic Disciplines”.