We are living in one of the great ages of engineering marvels with engineers creating higher, longer and more spectacular structures than ever before. Needless to say, bridge buildings have journeyed a long way since the days of prestressed, steel decks, and truss bridges. They defy gravity and reach out across great divides. Driving across them, we take them for granted but it often epitomises engineering intrepidity and prowess. In the same league, a signature bridge is a bridge that is unique in style and innovation. It is an icon or landmark to the area. It often identifies with the local culture and heritage. It is an engineering prowess to reach uniqueness in design.
Orchestrated visionarily, bridge engineering showcases some of the most awe-inspiring engineering of a country. Engineers can now build bridges of astonishing height, length and beauty. Designers try to outdo each other with the boldness of their creations but increased ambition means overcoming risk. One of the most ambitious bridges in the world is the Stonecutters Bridge spanning the Rambler Channel in Hong Kong, connecting Nam Wan Kok, Tsing Yi to Stonecutters Island. The Stonecutters Bridge has pushed the boundaries of what’s possible in engineering marvel.
The promulgation of the Constitution of Nepal, 2015 ushers in ‘great campaign’ of infrastructural development in the country. From east to west, from north to south, infrastructural milestones are being laid out. Often heard, fake or authentic, signature bridge construction news continuously reverberates in Nepali noggin.
About a month ago, signature bridge construction over the Tinau River in Butwal flooded online news media. However, in reality that was in fact an election tactic by a few stakeholders. Truly speaking, Nepal has a few great locations that are ideal for signature bridges. For example, the Narayani River in Narayanghat, the Seti River in Pokhara, a few “vista points” on the mid-hill highways, etc. deserve signature bridges. Among them, the most prominent one over the Narayani River in Narayanghat.
The Narayani River Bridge on the East-West highway connects Gaindakot Municipality of Nawalparasi district in Lumbini Province with Narayanghat in the Bagmati Province. The East-West highway is the primary artery for the country’s expanding economy. Thus, the bridge over the Narayani River at this location is more than just a bridge. It is a vital link in the whole infrastructure chain of roads, stadium, airports, tunnels and causeways sprawling in the east, west and central, making it a perfect location for a signature bridge.
Many cities around the world are often identified by signature bridges such as the Golden Gate Bridge in San Francisco, the Tower Bridge in London, Sydney Harbour Bridges in Sydney, and Stonecutters Bridge in Hong Kong. These bridges are iconic in status not only now but were also in the past and likely in the future, too. They meet the traffic demand now and years to come as well. The proposed signature bridge in Narayanghat should achieve a similar iconic status when it is completed and should be a monumental addition to Chitwan’s alluring tourism.
The construction of a signature bridge has been a buzzword among infrastructure and transport pundits in Nepal. Recently, the Department of Roads (DoR) has even called a tender for the construction of a signature bridge over the Narayani River in Narayanghat. However, it is proposing to build a two-lane bridge which is very myopic. In choosing whether to build a single - or double-lane bridge, it is a common practice worldwide to use the best available data on expected traffic volumes, accident records, vehicle sizes, and season and time-of-day of use.
The current bridge which was built almost 40 years ago is a two-lane bridge, and what is utmost short-sightedness is that the DoR is again proposing a two-lane bridge at that location even after four decades. Worst yet, the Butwal-Narayanghat road section is currently expanding from two lanes into six lanes in the settlement areas and four lanes in the forest areas to meet the traffic demand of the East-West highway. Can a two-lane bridge over the Narayani River adequately transport the accumulated traffic across the bank now and in the future? Forget about the future traffic demand, a two-lane bridge at this location does not even meet today’s traffic demand.
In structural engineering, there is a constant battle between economy and safety. In parallel, in developing countries like Nepal, there is always a constant battle between “needs” and “available resources”. In general, signature bridges are costly, require the state-of-the-art advanced bridge engineering skills, and are not built often. If built, it will have to meet the current and future traffic demand for at least the next 50 years. The Golden Gate Bridge in San Francisco was built about 80 years ago with the anticipation of the future traffic demand for the next 100 years. One may argue that, due to the limited budget, the DoR is capable of constructing only a two-lane bridge now and probably constructs another two-lane bridge in the future.
Yet, the DoR has to spend the same or even more money (due to inflation and others) to make another two-lane bridge in the future. Based on my experience on signature bridge construction around the world, the signature bridge construction cost is not linearly proportional over the number of lanes if constructed all at once, but certainly linearly proportional or even more if constructed in installments. Therefore, the DoR should reconsider the Narayani River Bridge tender call before it is too late.
(With global experience in analysis and design of high-rise buildings, bridges and non-conventional structures in the USA and Japan for the last 25 years, the author is the Director of CivilPark International Co. Ltd, a global engineering firm.)