Marco Rosignoli – Bridge Building Expert

Marco Rosignoli has more than 20 years of experience in bridge construction and design. (Source: San Francisco Public Press)

Marco Rosignoli is an expert in bridge design, construction, forensic engineering, consulting and education, with over 37 years of experience in 21 countries. Through a two-part series, Rosignoli gave readers an in-depth look into emerging megacities and their infrastructure needs. According to Rosignoli, efficient transportation is the key to an economically competitive city, and megacities will call for mega-sized bridges made of high-quality steel. Read on to find out more.

Part one: Ask an Expert: Building Bridges for Megacities

Part two: Ask an Expert: Building Bridges for Megacities – Part 2

Naim Josefi – Fashion Designer

Naim Josefi is an innovative designer who mixes fashion and technology. (Source: Naim Josefi)

Naim Josefi runs a fashion company based in Stockholm, Sweden, and is widely known for winning Project Runway Sweden back in 2012. Josefi is a fashion designer who is blurring the boundaries between science and fashion as his projects include steel dresses, 3D printed shoes and laser-printed jeans. Find out why the designer chooses to work with steel and incorporate new technologies into his art.

Read on: Ask an Expert: Fashion Forward with Steel

Professor Bill Arnold – Oil Industry Expert

Bill Arnold is a professor in the practice of energy management at Rice University’s Jones Graduate School of Business. Previously, Professor Arnold was Royal Dutch Shell’s Washington director of international government relations and senior counsel for the Middle East, Latin America and North Africa for 16 years.

Bill Arnold is an Energy Management Professor at Rice University. (Source: Society of Petroleum Engineers)

Professor Arnold gave readers an insider’s analysis of the rapidly-changing oil industry marked by unpredictable oil prices. He says, in the midst of change, there are newly-developing business opportunities and alternative sources of fuel such as natural gas that will subsequently create more demand for high-quality steel.   

Find out more: Ask an Expert: The Role of Steel in a Changing Oil Industry

Park Jong-jae – Automotive Columnist

Park Jong-jae is a motorsports columnist and the former editor-in-chief at F1 Racing Korea. Back in May, Park contributed a two-part series on POSCO GIGA STEEL. In the first part, Park reinforced the need for lightweight materials in the auto industry and highlighted some of the most successful cases of POSCO GIGA STEEL application from POSCO’s partners including GM Korea and Ssangyong Motors.

2016 Chevy Cruze Body Structure with POSCO GIGA STEEL. (Source: World Auto Steel)

Read more: Ask an Expert: POSCO GIGA STEEL Opens Door to the Future of the Auto Industry

In part two, he took readers through the 6 different types of POSCO GIGA STEEL and how they can benefit different parts of a vehicle.

There are 6 types of POSCO GIGA STEEL. (Source: Astro Awani)

Find more information: Ask an Expert: POSCO GIGA STEEL Goes Beyond the Limits of Traditional Lightweight Materials

Gil Bruvel – Steel Artist

Gil Bruvel is a veteran artist who creates sculptures using stainless steel. (Source: Gil Bruvel)

Gil Bruvel is an artist who works with stainless steel to create beautifully crafted sculptures of the human form. For the past 40 years, Bruvel has dedicated himself to painting, drawing and sculpting. He worked on a series of stainless steel sculpture for his Flow Series that depict aspects of nature mixed with the human body. Check out his creations and learn more about why Bruvel chooses to work artistically with steel.

Take a look: Ask an Expert: Capturing the Fluidity of Life in Ribbons of Steel – An Interview with Gil Bruvel

POSCO’s Masters of Korea

Every year, POSCO names its Masters of Korea. These masters are employees who have become experts in their respective fields through years of hard work and dedication. All 3 Masters of 2017 contributed to POSCO by developing new technologies, coming up with groundbreaking ideas and finding solutions to make POSCO safer, more efficient and highly competitive in the global steel industry. Find out who they are and their journey to becoming the POSCO Masters of Korea.

Master Nam Tae-Gyu has 40 years of experience working for POSCO.

Master Nam Tae-Gyu: POSCO Masters: 40 Years in the Making

Suh Gwang-Il examines machinery at a POSCO steel mill with colleagues.

Master Suh Gwang-Il: POSCO Masters: A Cold Rolling Expert

Master Kim Yong-Hoon played a key role in automating POSCO’s production systems.

Master Kim Yong-Hoon: POSCO Masters: Leading the Way Towards Automation

Thank you to the experts that helped make the Steel Wire shine like steel in 2017. In 2018, we look forward to even more opportunities to collaborate with even more experts to help provide you, our readers, a deeper understanding of steel and its applicability across industries.

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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