Civil and hydraulic engineering

Civil and hydraulic engineering (GWW in Dutch) is one of the major consumers of materials in the Netherlands. Every year, more than 20 million tonnes of material [source: SKAO (2018), roadmap for a climate-neutral infrastructure sector] is used to extend and improve our roads, canals, engineering structures (bridges, locks, etc.) and subsurface infrastructure. In many cases these objects are technically not very complex and designed for long term usage.

Aspects of circular civil and hydraulic engineering

Circular principles for civil and hydraulic engineering often focus on the material level. This includes, for example, reuse of existing material, extending the life of objects or materials, or – for temporary constructions – future disassembly. As a result, the application of circular principles in civil and hydraulic engineering often centres on the following three aspects:

  • Design for adaptability
  • Design for disassembly
  • Environmental impact of the materials used, taking into account their future reusability

During the implementation of a civil and hydraulic engineering project you should not only focus on the implementation costs, but also on the Total Cost of Ownership (TCO) or life cycle costs (LCC) In addition, always use a market consultation to validate which principles best fit your project.

Design for adaptability

Approximately 90% of engineering structures (e.g. bridges, overpasses and locks) are demolished when they are functionally outdated. However, they are not end-of-life. Long term adaptability is therefore an important principle to extend the service life of objects. This is particularly true for engineering structures.

For instance, a set of newly developed standard joints for movable bridges has increased their adaptability. For this example of Industrial, Flexible and Demountable (IFD) building, a Netherlands Technical Agreement (NTA) has been developed. The NTA describes the standard dimensions for the joints between various parts of a bridge, so they can be replaced easily and components can be reused in other bridges in the future. Work is currently on the way to build the first two new bridges designed according to IFD principles.

Design for disassembly

Occasionally, the need may arise to build a temporary structure, such as a passover or a cycle path. This may prompt the desire to be able to disassemble the product at some point in the future. For this reason, more and more circular civil and hydraulic engineering concepts are being developed that meet these needs. Think, for instance, of Plastic Road, a cycle path constructed from plastic waste. Or the circular flyover (Dutch) that has been developed by Van Hattum & Blankevoort for Rijkswaterstaat. Once its period of use has come to an end it can be dismantled and rebuilt elsewhere.

Another example is the circular road (Dutch) that has recently been built by Dura Vermeer: the company has offered the road ‘as a service’ to the Province of Overijssel, including maintenance and removal of the road when it is end-of-life.

Environmental impact of applied materials

For many civil and hydraulic engineering projects the task is relatively simple: build an object according to an agreed design. Environmental gains can be achieved by managing the environmental impact of the applied materials, for instance by means of a life cycle analysis (LCA). An LCA measures the environmental impact of the entire production system needed to deliver materials; energy consumed, extra materials, transport and emissions are all taken into account. Most LCAs show that the impact of reused materials is often relatively small compared to new materials. Instruments such as DuboCalc or EcoChain can help to determine the impact.

Investment costs, TCO and LCC

For many civil and hydraulic engineering projects, procurement is still based on price, more in particular the price of building. To achieve circular ambitions, you also need to consider product performance over the complete life cycle. This requires a different perspective on costing.  It makes more sense, therefore, to focus on Total Cost of Ownership (TCO) or Life Cycle Costing (LCC). The figure below shows the breakdown into various costs.

Different perspectives on costs. Source: PIANOo (2016) Life cycle costs as award criterion
Different perspectives on costs. Source: PIANOo (2016) Life cycle costs as award criterion

 

Tips

  • Select the circular principles you want to apply and clearly communicate your choice to market players in advance.
  • Find ways to procure management and maintenance together with the realisation of the project: this gives market players an incentive to increase quality.

Inspiring examples

Background information

Tool - DuboCalc

DuboCalc enables you to make transparent the environmental impact of a project, based on data in the National Environment Database.

Tool - EcoChain

Ecochain enables you to make transparent the environmental impact of a project, based on data from suppliers and value chain partners in the National Environment Database.

Suggestions and/or additions?