Over the last 50 years, the EU's transport network infrastructure expenditures related to its GDP has declined by almost 50%. This has resulted in an aged infrastructure, of which much has been built with the technologies and systems developed in the late 19th or early 20th centuries. The consequences are clearly visible through social and economical impacts: traffic delays, congestion, deficient bridges and structures, deteriorating roads and motorways.
To achieve economical, environmental and social objectives, the infrastructure renewal must be done in a rapid, cost-effective, high-quality and sustainable way by reducing production lead time, manufacturing and maintenance costs, and the environmental impact, by lowering energy consumption, waste production and recyclability, while at the same time enhancing new business models and specialised jobs. The bridges are important elements in these networks, in strategic and logistical terms, as well as in economical terms. To avoid the bridges becoming bottlenecks during the upgrading of these infrastructures, cost-effective, quick and sustainable construction concepts and technologies are needed.
HP FUTURE-Bridge project was co-funded by European Commission under the 6th Framework Programme of research and developed a complete workplan with the target to effectively compete against traditional bridges and jointly propose a new and effective concept to improve the development, in both new and renewal construction, of the European Surface Transport Networks.
The overall objective of the project was the development of a new high-performance and cost-effective construction concept for bridges based on the application of fibre-reinforced polymers (FRP) for rapid renewal, providing a longer lasting repair for these infrastructures in the New Member States.
The essential technical elements of the new concept were:
- Deck and beams of hybrid FRP (carbon-glass/thermoset-thermoplastic) composites and pillars of hybrid FRP concrete. The deck concept by itself was a solution for the renovation of existing deteriorated infrastructures;
- Multi-objective material optimisation for the intended design;
- Multivariable optimisation criteria that essentially attempted to compromise design objectives;
- Performance-based simultaneous engineering and manufacturing;
- On-site industrialisation;
- Flexible design and manufacturing for the one-off, small series and mass customisation;
- Development of mobile manufacturing lines;
- New hybrid material combinations for improved fire and high-temperature resistance;
Cost effectiveness is reached by optimising material and design, reducing manufacturing costs and lead times. High performance is achieved by performance-based design and manufacturing, and new materials. Energy efficiency is improved and environmental impact is reduced in the whole life cycle of the bridge by the reduction of energy consumption in the on-site manufacturing process and transport of materials and by improving recyclability through new thermoplastic resins.
The project was structured in nine different, yet well connected, work packages (WPs) with specific objectives. A life cycle cost model was developed, including social costs, in order to evaluate the FRP bridge decks sustainability. Multi-criteria decision making (MCDM) was employed to compare the alternative technology to conventional concrete and steel constructions. A new manufacturing methodology was defined, so as to reduce production costs and lead times, while new design concepts were utilised. Advanced materials and fire coatings were also developed and optimised. Finally, the project was assessed by the construction of pilot bridge solutions which demonstrated its achievements and allowed for its future commercial exploitation.
A normative review was carried out, along with an analysis of the existing infrastructure in different countries, which resulted in the definition of the most common bridge length. Furthermore, the requirements of the owners and operators of the structures and the socio-economic and cultural requirements were examined. Girder and arched bridge concepts were selected for further research. Both bridges were constructed using the same thermoset and thermoplastic systems and developed as part of the project.
The arch significantly reduced the loads and thus the material cost of the beam element and required a flexible deck. The concept was optimised in terms of geometry, support conditions and deck systems considering, at the same time, the most suitable manufacturing process. A special resin was developed and used in the joint systems to achieve the required strength. Moreover, the durability and composition of the utilised materials were extensively examined.
Three optimisation processes were applied in the girder bridge case to achieve the optimum cross-section for technical performance and cost-effectiveness. A finite element model of the designed beam was subsequently used for its refinement. The beam's manufacturing required the development of new machinery as well as a new type of creel. In addition, a real scale test was performed in order to assess the technical properties and feasibility of the proposal.
Two pilot girder bridges were subsequently constructed, monitored and tested in order to evaluate their performance with respect to fulfilment of the project objectives. The reduced weight of the bridges' components permitted the placement of the beams into position using a simple truck-crane. All obligatory tests were successfully completed
The technical feasibility of the HP FUTURE-Bridge concept has been proved and it has been approached in a cost-competitive manner. However, the consortium detected that whereas the design and material areas were well covered, further research would be necessary on manufacturing, as the lack of industrialisation in the manufacturing processes at a cost-competitive cost would result in decreasing the benefits achieved by the use of FRP against conventional materials.
The HP Future-Bridge project supposes an impulse towards the development of the composite materials in the frame of civil engineering. Thus far, all the requirements raised by the project have been entirely fulfilled it can be confirmed that the project has been developed successfully.
In addition to the competitive advantages provided by composite materials compared to traditional materials in economic and environmental terms, it makes them a discipline whose future is increasingly bright.
A patent has been submitted to the European Patent Office as a result of the technological developments within the project. In addition, new opportunities have arisen for FRP bridges in Spain and Poland (base countries of the two construction companies involved in the project). Moreover, new business relations are being established between the partners dealing with materials development and supply (OCV and Huntsman), manufacturing processes experts and machinery manufacturers (Mikrosam and VanWees) and contractors (Acciona and Mostostal).