AURECON SOUTH AFRICA (PTY) LTD
Civil Engineer in Port Elizabeth

Asia is home to many of the world’s longest bridges and has a strong pipeline for future construction, much of it driven by the increasing prosperity and bold infrastructure programmes of the region’s developing economies. The natural environment of the region also presents several unique challenges, and as technology advances and expertise grows, increasingly innovative solutions are being engineered. Japan is home to the longest suspension bridge in the world (which is actually made up of three suspension bridge structures), the 4 015 m Kurushima Bridge which links the islands of Honshu and Shikoku. But given the pace of infrastructure development worldwide, it’s unlikely these records will stay untouched for long. The leading role of Japan, China and Hong Kong (which is home to Stonecutters Bridge, one of the most complex cable-stayed bridges in the world) in bridge building born out of geographical necessity. For Japan and Hong Kong there is the need to connect their many islands; while in China, the landscape is characterised by long and wide rivers. Although bridges are a significant investment, governments understand that their creation can boost a nation’s prosperity, providing supply chain routes for goods, services and people. The bridge, which will link Dhaka with the isolated western region of the country, is one of the largest bridges under development worldwide, yet Bangladesh remains one of the poorest countries in Asia. Both the Philippines (a network of islands) and Vietnam (criss-crossed by many long rivers) are in the middle of considerable development programs. Construction will start in 2017, with completion in 2020, and its introduction will further boost the flow of goods and people to the island, supporting economic growth. Another interesting feature of bridge building in the developing economies of Asia is the advancement in design and building methods. Using precast segmental construction requires higher levels of geometry control and the technical work for the cantilevering is more detailed, but with modern design programmes that work is becoming easier. Design-wise, we see a stronger preference for cable-stayed designs versus suspension bridges, not only throughout Asia but worldwide. At the same time we’ve seen a rapid acceleration in the span sizes for cable-stayed bridges. We are confident we can design bridges that will withstand earthquakes, even if surrounding buildings do not. For example, in many countries where long span bridges are planned, there is insufficient research on the loadings that will apply in the event of a major typhoon. In these instances we have to use whatever local data is available and adapt it for use within international design codes. Modern cable-stayed and suspension bridges are now very aerodynamic, and their designs allow air to move more easily over the deck sections, minimizing wind forces. With our wind analysis, we are able to model how wind behaves, using computational fluid analysis to see its effects around the structure. The technology is a major progression, allowing our designers to understand structures better than ever before. We used that video to calculate how the traffic was split by category, timing and more. This allowed us to determine the worst-case load scenario based on actual data, rather than simply applying the design parameters of the code, which are always the most conservative. At Aurecon we take a design-led approach to our work, which we believe is essential to supporting the ambitious bridge development programme underway in Asia. The success of current and future bridge projects is crucial to the advancement of Asia’s economy.