Modular construction methods for more environmentally friendly building

Mr Berndorfer, how long have you been working at Max Bögl, and what tasks are you responsible for?

» Claus Berndorfer: I have been working for Max Bögl for around 20 years and have been responsible for product development and innovation in the Infrastructure division for about five years.

You certainly have a good insight into the condition of our road and rail network. How would you describe it?

» Claus Berndorfer: The situation is similar for both; there is a great need for renewal and renovation on both the road and the railway. Too little has been invested in the maintenance of both in recent decades. After German reunification, the focus of investment was rightly on the new federal states because this is where demand was greatest. However, among the general public, there was a lack of awareness that the roads and bridges in the old federal states were not built to last forever. The sharp increase in heavy goods traffic on the roads has accelerated the ageing of bridges that were not designed for this purpose. Until a few years ago, rail transport was regarded as an obsolete model – at least in the local transport sector – and correspondingly little was invested.  Lines were shut down rather than modernised, and industrial tracks were dismantled. A radical paradigm shift is currently taking place here.

In view of the many necessary bridge renovation measures in Germany, do you see further approaches to making the construction measures more sustainable and faster?

» Claus Berndorfer: Yes, you have to start with the authorisation procedures, building law, and public procurement law. We should move away from a price competition towards a design competition with balanced and fair contract conditions. This means that whoever has the cleverest idea for solving a construction task wins the contract. In addition to price, construction time and sustainability must also be taken into account as evaluation factors. Unfortunately, the objection system has contributed to a huge step backwards here.

» Anton Braun: That’s correct! Until the mid-2000s, it was common for a company to either follow the administrative design or submit a secondary tender that not only fulfilled the task but also brought additional benefits. However, objections were repeatedly lodged, thereby delaying the realisation of the object. As a result, the administration stopped all secondary tender. This harms the projects and the innovative strength of the German construction industry. This is why we should once again authorise secondary tenders but drastically reduce the opportunities for objections and swiftly examine existing objections.

What challenges do you see for you personally as a civil engineer and for the construction industry with regard to the urgent implementation of GHG reduction in the construction sector?

» Claus Berndorfer: First, the quality of the components and building materials must be improved so that they have a longer service life. Furthermore, we should no longer construct our buildings as monoliths in which the failure of one component means the end for the entire structure. We should move towards a segmented construction method in which individual components can be replaced if necessary. The sensible use of materials is also extremely important. When building materials were still scarce, they were used only where they were actually needed. We have to resume this. The use of clinker-reduced concretes is also important. Prefabrication is the best way to meet these many challenges because it provides both high-quality building materials and the possibility of achieving better component qualities using industrial production methods.

How far have we come in this respect?

» Claus Berndorfer: There are countries that are already quite progressive. In the Netherlands, for example, circular bridges are already being built in line with the cradle-to-cradle concept. We’re not quite there yet in Germany, but we’re slowly making progress. I have high hopes that we will soon be successful in this endeavour. Max Bögl is a pioneer in prefabrication, circular construction, and the use of clinker-reduced concrete throughout Germany.

What measures do you see as useful in focussing more and faster on reducing CO₂ emissions?

» Claus Berndorfer: There are quite a few. In addition to the aspects already mentioned, the reduction in construction time is an important aspect. Construction site-related tailbacks sometimes lead to higher CO₂ emissions than the construction site itself. You should also take a look at the construction vehicles. They are currently often diesel-powered but could be replaced by electric ones. The public sector must create financial incentives here as it has already done in the private sector. The optimisation of component dimensions combined with the efficient use of building materials must also be brought into focus. To this end, the existing technical standards, guidelines, and regulations as well as the approval procedures for new types of construction, including the in-house approval or approval in individual cases, must be reconsidered in terms of content and time-line.

» Anton Braun: And this aspect should be included in the awards documents. After all, an environmentally friendly company can survive on the market only if the same competitive conditions are in place.

What are the advantages of modular construction for traffic routing?

» Anton Braun: The prefabricated construction method ensures shorter construction times because most of the work takes place in the factory. This reduces congestion times on site and thus has a positive effect on the environment.

Do you think that modular construction will be able to establish itself across the board in German road construction? Why?

» Claus Berndorfer: Yes, I assume so because it fulfils the current requirements quite well. At Max Bögl, we have the advantage of being able to address matters well in advance. We were already working on modular construction methods for transport routes before anyone even thought about the need to reduce construction time in order to save CO₂.

» Anton Braun: And the modular construction method offers a major advantage in terms of not only CO₂ savings but also construction technology and the skilled labour shortage. Nowadays, it’s hard to find employees who are willing to travel to assembly sites. In a pre-cast factory, it is much easier to reconcile the demands of family and career. And if the construction site is also a long way away, more CO₂ is emitted during the journey.

Where do you see bridge construction in 10 years?

» Claus Berndorfer: I assume that there will be more assembly and less pouring of concrete on German construction sites. The consequence will be the emergence of construction factories for prefabrication.