India

India’s government is incentivizing the use of steel by providing construction grants for regions that need revitalization. This government money is fueling growth and increasing steel consumption in regions across the country. Some predict that India will increase its rank and surpass China as the top consumer of steel in 2018. This is because India has not yet achieved the level of development China has. In China, the economy is shifting. For years, much of China’s economy was made up of companies in the manufacturing industry, but with a growing upper and middle class, many of China’s industries are going from factories to office spaces. Services are expected to increase in China and lead to a decrease in the need for supplies like steel.

Indian steel consumption is rising thanks to new development projects. (Source: Quora)

SEE ALSO: India: A Rising Sun in the Global Renewable Energy Industry

ASEAN (Association of Southeast Asian Nations)

Vietnam and the Philippines have been named two countries to watch in the ASEAN region. Unlike China and Japan, which have relatively more established economies, Vietnam and the Philippines are still in the development phase. Their rapid development is due in part to the growth of e-commerce. As the Vietnamese and Filipino governments race to build stronger countries, they’ll need steel to make improvements in the country’s infrastructure. Many of the cities in the region are outdated and in need of a total remodel. From creating a solid infrastructure to building offices and housing, steel will be in high demand in Vietnam and the Philippines in 2018.

Many ASEAN cities like Ho Chi Minh City pictured above is ripe for growth and development. (Source: Visa2Vietnam)

CIS (Commonwealth of Independent States)

CIS, also known as the Russian Commonwealth, is a confederation of 11 states made up of Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine and Uzbekistan. While Russia is the biggest and most powerful member state, the developing states are eager to catch up. CIS countries will undergo development projects including major infrastructure construction. Such state-level projects will require large amounts of steel and CIS countries will have to vamp up its own production as well as meet its needs through imports. As CIS countries develop, their citizens quality of life will likely increase, and they are expected to consume more goods such as cars and appliances made of steel as well.  

CIS member states are ripe for development and steel consumption in 2018. (Source: The Kremlin)

Japan

In the summer of 2020, Japan is set to host the biggest global summer games event. The government is investing significantly in this effort to build new sports facilities and other structures to accommodate the global event. A new stadium itself is said to have a budget of over USD 2 billion, and most of the construction will require steel. Japan already has some of the best infrastructure in the world. But it will need to adapt in order to accommodate the large number of visitors Tokyo will host over the three-week event.

Japan will need to build many sports venues such as its new stadium pictured above for 2020. (Source: CNN)

The United States

In the United States, the steel market is consumer-driven, and steel is a USD 113 billion industry. The U.S. is already the largest importer of steel by a wide margin. But the U.S. demand for steel is expected to increase. Steel is used for construction, infrastructure, energy, production, packaging, appliances and manufacturing. Many cities in the U.S. are expanding and improving their infrastructure. Cities like New York and San Francisco have aging buildings and transportation systems that need to be revitalized. Steel construction is also a way of creating more energy efficiency. As U.S. cities move to become more conservative with their natural resources, steel is one of the ways to reduce energy use. Things like steel reinforcements, steel roofs and other upgrades make buildings more efficient. Many household appliances and automobiles are also made of steel. As U.S. consumers purchase household appliances, cars and buildings, the U.S. demand for steel will continue to grow in 2018.

While 2018 will not likely see 2017 rates of growth, the steel industry will continue to grow as demand for steel-based goods increases. As developing countries become more dependent on modernized infrastructure, housing and conveniences, the steel industry will continue to show growth for the foreseeable future. Even in China, where manufacturing is beginning to slow down, there is a great demand for steel. In developing smart cities, for example, steel and technology work together to create more efficient cities for all citizens. Steel infrastructure will play a major role in the improvement of cities across the globe for years to come.

Biggest Challenges in Bridge Construction

The major challenges for building urban bridges are the availability of skilled labor, access to urban areas and environmental compatibility.

A worker paints the Anzhaite Long-span Suspension Bridge in Jishou, Hunan, China (Source: The Daily Mail)

Building bridges in megacities with the current scarcity of skilled labor will require a massive recourse to prefabrication. In a few circumstances, prefabricated bridge units will be transported on water with tugs and barges, which will allow the use of heavy, large units. In most cases, prefabricated bridge units will be transported on the ground through congested urban roads, which will lead to the use of light, modular units.

A floating crane lifts prefabricated deck sections onto the San Francisco-Oakland Bay Bridge (Source: San Francisco Public Press)

The availability of deck assembly areas and the interference of construction operations with adjacent infrastructure are additional challenges that will govern the bridge design process. As such, incremental launching construction from aerial platforms will see new applications, especially when combined with on-site welding of field splices among modular bridge units. The welding of field splices will also allow for optimized segmentation of bridge units, diminish the cost of field splices, and will relax the fabrication tolerances of the units.

Size Determines Cost, Cost Determines Everything Else

When constructing a bridge for an urban area, the size of a bridge governs the construction process. in turn, the construction cost of a bridge determines the materials and technology. Technology includes labor and investment in special construction equipment. The quantities of structural materials for a bridge depend on the design loads of the bridge, the flexural and shear span of the bridge units, and the mechanical strength of the material.

The Jiaozhou Bay Bridge in China is the longest sea-crossing bridge in the world (Source: The New York Times)

Small and large-scale bridge projects are both necessary in megacities and demand will only increase in light of the newly emerging megacities all over the world. When looking at both the construction of new bridges and the maintenance of existing bridges, the number of small-scale projects will definitely be larger than the number of large-scale projects. The impact these construction projects will have on the mobility of people and goods within a megacity is massive.

Although one may assume large-scale bridge projects with a larger budget will allow for design optimization and the efficient use of high-grade steels, scale economies in competition with other megacities will govern the availability of construction materials and workforce. Eventually, the scarcity of structural materials will lead to the efficient, eco-friendly use of steel and concrete in large and small-scale bridge projects alike.

Prefabrication and Incremental Launching for Bridge Construction

It is true that small-scale bridge projects have smaller budgets for technology, which limit design optimization and construction mechanization and increase the labor demand. Therefore, small-scale bridges will most likely be procured as packages of multiple bridges to acquire scale economies and a more efficient use of materials with the optimized design of modular units.

On the other hand, large-scale bridge projects allow for massive investment in special construction equipment, which will facilitate the prefabrication of modular bridge units in smart, eco-friendly factories. It will also diminish the labor demand of site assembly and the need for complementary infrastructure in an urban environment, as well as enhance the quality and durability of the final product.

Thus, large-scale bridge projects will be designed for modularity and have prefabricated standardized units with asynchronous production lines. Parts of the bridge will likely have different cycle times, just-in-time delivery, and require minimal site operations. Overall, construction technology and risk management of the trans-disciplinary relationships of mechanized construction will dictate the design of large-scale bridge projects in megacities.

Workers assemble a prefabricated bridge in Pennsylvania, U.S. (Source: Roads and Bridges)

Small-scale bridge projects will take advantage of incremental launching technologies. Launched bridges minimize the interference between deck construction and the obstruction to overpass, and this is a major advantage for urban bridges designed to overpass congested infrastructure. Launched bridges do not require extra clearance to support the deck during construction, which simplifies connecting the bridge with existing roads and railways. Launched bridges do not require additional right-of-way as the deck is built behind the abutment and incrementally pushed into position. Additionally, the construction area is far from the infrastructure to overpass, which minimizes the risk for workers and the traveling public.

Incremental launching applied to a bridge deck construction process (Source: CARLOS FERNANDEZ CASADO S.L)

Materials For the Future Generation of Urban Bridges

Steel and concrete are the most common materials for bridges. In the field of steel bridges, high-grade steel will reduce the self-weight of bridge superstructures and the cost of piers and foundations. New composite systems and mechanized plate corrugation will increase the buckling capacity of unstiffened web panels and compression flanges to avoid the use of welded stiffeners.

In the field of prestressed concrete, new steels for rebar will offer higher strength and corrosion resistance to increase the durability and service life of the next generation of urban bridges. Post-tensioning materials are already extremely efficient, and the challenge will revolve around finding new duct systems and passivating materials to able to avoid the quality concerns raised by cement grouts.

Full-span precasting has been employed in thousands of spans of high-speed railway projects and in hundreds of spans of light-rail transit projects. Both steel and prestressed concrete bridges will be present in the mass transit systems of megacities, and both types of bridges are perfectly compatible with steel decks should high-grade steel turn out financially competitive over prestressed concrete in the megacity-oriented life cycle cost analysis.

Modern large-scale bridge projects are designed for 75 or 100-year service life in the USA. The use of renewable protective materials can easily meet this target in steel bridges, but the evolution of design loads and service conditions of urban bridges is hard to predict. Steel bridges offer a major advantage over prestressed-concrete bridges from this point of view, as they are more adaptable and can be modified, strengthened and adapted to new use conditions.

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