CHALLENGES FOR THE WORLDWIDE BRIDGE ENGINEERING COMMUNITY FOR THE XXI CENTURY
Javier Manterola Armisén
Carlos Fernández Casado, S.L.
Will new composite materials displace construction conventional materials? Which new typological structures will this new situation bring then?
Hong Kong, China
In the last couple of decades several long sea crossing bridges have been built, some in Europe but with the majority in East and South-East Asia. A common feature of these bridges is that whilst they are long, in excess of 40 km, they have been built in relatively shallow water with depths in the region of 30m. However longer crossings across much deeper water and/or in extreme environmental conditions are being contemplated, such as the Gibraltar crossing between North Africa and Europe, the Red Sea crossing between Yemen and Djibouti, the Sunder Straits crossing between Sumatra and Java ,the ambitious west coast highway across deep fjords in Norway.
As a practicing engineer and not an academic I would like to see the application of academic research and theory into practical realisations. By their very nature large bridges can only be financed by public sector clients who have to use the money wisely , which means building bridges with a much greater service life in excess of 300 years rather than the current norm of 100-200 years. The realization of bridges with a longer service could require innovative steps such as:
Step-change in design approach. Bridge engineering needs to emulate other industries such as automotive and aircraft industries where parts of the vehicle or aircraft are replaceable. Whole parts of the bridge should thus be able to be replaced. It is apparent that substructure foundations and tall towers may not be replaceable but superstructure including cables should be able to be replaced.
The superstructure and cables and or parts of it could be made of composite materials or a combination of composite and traditional materials of concrete and steel. This could mean shorter service life of these elements but with the ability for them to be replaced, which would lead to a much longer service life of the bridge as a whole. This would avoid the situation that the US is currently facing where bridges with only a life of 70-75 years are being demolished and replaced with entirely new bridges.
Use of lighter composite materials would mean a reduction in weight leading to longer spans and thus reducing the number of piers and towers in deep water.
Further advances in fabrication off-site and installation of longer and lighter superstructure modules by larger floating cranes and /or specialist and innovative erection plant
Application of off-shore oil platform technology to install tall prefabricated substructure modules in much deeper waters, with replaceable protective systems to concrete substructure elements/parts in the splash and spray zones thus extending the service life of the substructure.
Technical Director Strasky, Husty and Partners
The current period is characterized by a development of high-strength concrete, steel and composites. Modern structures effectively combine girders, arches and cables. Clever and adaptive systems are being used for construction. All these facts allow us to design longer spans, longer structures and to construct more efficient bridges. However, we should be aware that our structures are not monuments; the structures should have a form that is inherent in the constraints of the site and which best accomplish the function of bridging the site. We should not build the most economical bridges, but reasonable, structurally efficient structures.
Michel Virlogeux Consultant SARL
As bridge designers we have a decision social, economical and political responsibility.
We have to develop projects adapted to the society needs.
We have to design safe structures to guarantee the users safety.
We have to limit construction and maintenance costs to save public money. Meaning that we are not designing for show, for our own reputation but in the public interest.
And our bridges will last, hopefully, a least a century so that we have to design light and elegant structures, adapted to and respectful of their site and of the local culture.
This has been my goal, it will be yours.
António Adão da Fonseca
Faculty of Engineering – University of Porto
Humanity needs the XXI Century to be the Intelligent Century. Equally, Bridge Engineering should go forward into Intelligent Bridging.
Leonhardt, Andrä und Partner Beratende Ingenieure VBI AG
Bridges are one of the most important structures of our man-made landscape.
They dominate highly visible our natural or urban surroundings and we cannot detract us from their visual impression.
Bridges have always reflected the technical progress and the innovative capacity of their society.
It is therefore one of the most important tasks for bridge engineers to design aesthetical pleasing structures as fundamentals to create an environment worth living in.
To achieve technical outstanding solutions which are fulfilling aesthetical, economical, environmental, sustainable and durable requirements the bridge engineers must not only be educated in the basics of the structural analysis especially in the practice of sophisticated computer software.
Instead they also need a very good training in the fundamentals of aesthetics to create a positive environment, practice in detailing the complex structures in order to transfer the statical calculations into buildable structures and a very good knowledge in the task of building the structure in a simple and economic way.
Sumitomo Mitsui Construction
The extradosed bridge, a new type of structure that emerged in the late 20th century in Japan, has spread worldwide, its popularity testifying to its usefulness. With advances in research and development of new materials and technology, I believe that the 21st century will bring about the no-maintenance bridge. This will put an end to the struggle against reinforced concrete deterioration, a battle fought by engineers and researchers ever since the invention of reinforced concrete in the second half of the 19th century. It will also be a sustainable solution that benefits humanity. Realizing the no-maintenance bridge is the key challenge for bridge engineering in the 21st century.
Engineers will have to find their way in the global evolution of the society which trends to push for standardisation, low price and poor quality. Codes, regulation and standards have the bad tendency of trying to cover everything not leaving any room of manoeuvre for major evolution anymore. Keeping their freedom of mind and their creativity while coping with the standards will be one of the big challenges of the next generation.
To be able to progress with our structure and to make them more and more skilled to their use, independence, creativity and liberty are essential but they need to be applied and not straight away restricted by stupid rules. If we want to keep the profession attractive and motivate young and dynamic people to enter in that business we have to give them the opportunity to be active to push their ideas forward and to show them that creativity is one of the most important tool to progress and that it is possible to end up positively.
If we cannot succeed, engineers will become a single office workers filling formulas and excel sheets!
Arne Frederiksen Bæksted
Bridge engineers of 2015 and the next century are challenged with the complexity of infrastructure projects in an increasingly urbanized and populated world. Bridge engineers are requested to design and build bridges that are getting longer and longer but also in increasingly demanding environments for longer design service life, faster and smarter construction whilst having to also consider minimum environmental impact. A major challenge is to invent and utilize new proven and codified technologies and materials and apply these under energy reduced production.
Department of Bridge Engineering, Tongji University
Shanghai, P.R. China
The excess of bridge spans has always been the inspiring pursuit for the bridge engineers. Due to the rapid evolvement in bridge engineering in recent years, fast, reliable and durable connections by bridges with enormous spans have become a more ambitious challenge. New industrial construction technologies are developed with distinct characteristics such as standardized design, industrialized production, mechanical construction, and informed management. These technologies express the conception of sustainability in a comprehensive way, and are getting wide adoption around the world. Also, the bridge performance prediction and assessment supported by big data is becoming the cutting-edge technology for the management and maintenance of existing bridges. In the era of big data, more diverse and accurate numerical simulation tools are explored to assist bridge engineers in understanding the four-dimensional features of bridges in full range. More rational and better based management strategies are expected by adopting these tools. In the coming future, bridge engineers are expected to welcome the novel development in bridge engineering with joyful, open and positive attitudes.