The Union Bridge, connecting Waterford and Lansingburgh, New York, was the first to cross the Hudson River in its 154 mile course from New York harbor northward. It was located near a long time ford and ferry crossing. The first act leading to the bridge was passed by the legislature on April 15, 1800 when it authorized building of toll bridges across the Hudson River. Nothing was done until late 1802 or early 1803, when a group of the leading men of Waterford and Lansingburgh proposed the formation of the Union Bridge Company to build a toll bridge at the site. …
In 2010, promoters and marketers agreed to construct a very visible power-generating project utilizing solar and wind in one of the busiest urban locations in the world – Times Square, New York. The power generated from this installation would provide lighting for the Ricoh billboard in the center of Times Square, with excess power stored in large batteries for periods of no sunlight and calm winds. At the inception of the project, photovoltaic panels had become fairly commonplace, but large vertical turbines utilizing wind resources to generate power had not been undertaken to this magnitude. From an environmental standpoint, the reduction of 52 short tons of carbon dioxide per year was very attractive. When CBI Consulting became involved, the scope of work was simply to confirm compliance of the 40-foot-long structure with the New York State Building Code. …
In the past few years, building for natural disasters – already a consideration for structural engineers – has been thrust into the public eye after recent tornados wiped out entire cities and took many American lives. Moore, Okla., Joplin, Mo., and Tuscaloosa, Ala. are all recent examples of areas that have experienced the greatest losses, both in infrastructure and human life. Engineers in the construction industry work to stay aware of these challenges when setting out to build safe, strong and durable buildings for tenants and occupants. …
After experiencing “Gravity” at the theater, I left with a sense of inspiration and awe at witnessing an excellent film, a story about experts, highly trained astronauts, professionals, the best at what they do, able to focus in the most dangerous and stressful circumstances, with a calm reliance on their extensive training to deal with almost any situation. For those who haven’t seen the movie, Sandra Bullock and George Clooney are on a spacewalk when an accident causes everything to go terribly wrong. As depicted in the movie, maintaining focus on their training wasn’t easy, but was faithfully done with amazing results. …
Structural Forum is intended to stimulate thoughtful dialogue and debate among structural engineers and other participants in the design and construction process. Any opinions expressed in Structural Forum are those of the author(s) and do not necessarily reflect the views of NCSEA, CASE, SEI, C3Ink, or the STRUCTURE® magazine Editorial Board.
The Bay Bridge is one of the grandest engineering achievements in American history, as described in the Feature article this month. However, the recent renovation has not added a single lane to relieve traffic congestion, which has a negative impact on the Bay Area and California economies. There is one obvious solution for the problem – to build a second crossing between San Francisco and Oakland on an alignment approximately parallel to the original bridge. …
In recent years, it has become more desirable, and in many cases necessary, for architects and engineers to design buildings and structural frames with beams and girders of limited depth. Shallower structural depth allows building floor-to-floor height to be lowered and the amount of materials used – such as exterior cladding, interior walls, partitions, and stairs – to be reduced. In high-rise building construction, it allows extra floors to be added within the proposed building height. On expansion projects, a shallower structural depth helps facilitate the need to match the existing floor elevations. …
Frank Heger was a vanguard of the engineering industry, a visionary with his work, and a champion for public safety. From the late 1970s to 1982, the author witnessed the evolution of Frank’s most well-known work in geodesic spheres, “Spaceship Earth” at Disney’s Epcot Center. In 1980, he developed the revolutionary Soil-Pipe Interaction Design Analysis (SPIDA) software – the first-ever computer program combining heavy mathematical and theoretical computations for the design of buried pipe systems. In addition, Heger performed outstanding investigative work for the L’Ambience Plaza Collapse in 1987, which led to receiving the 1992 Construction Index Excellence Award for his personal research into the matter. …
Skidmore, Owings & Merrill LLP was an Outstanding Award Winner for the Lee Hall III project in the 2013 NCSEA Annual Excellence in Structural Engineering awards program (Category – New Buildings $10M to $30M).
The integration of form and structure is implicit in the earliest known definition of architecture – Vitruvius’ ideal of “firmness, commodity, and delight.” The design of Clemson University’s newest addition to their School of Architecture, Lee Hall III, is a case study in the contemporary application of this ageless idea in a space that aspires to instruct its design-oriented occupants every day. …
Cast-in-place (CIP) concrete bridge decks are typically reinforced with steel. However, poor durability resulting from steel corrosion has resulted in the use of alternative noncorrosive reinforcement materials. As part of this effort, glass fiber reinforcement polymer (GFRP) reinforcement bars have been used as structural reinforcement for CIP concrete bridge decks. GFRP is a noncorrosive composite material made of glass reinforcing fibers and a vinyl ester resin matrix. In axial tension, GFRP is elastic with brittle rupture at ultimate. Relative to grade 60 steel reinforcement, GFRP tensile strength is about 150%, the elastic modulus is about 20%, and the unit weight is about 25%. Thus, given the material’s high strength and low stiffness, serviceability of GFRP reinforced bridge decks will be an important consideration in design. …
The definition of high strength concrete continues to change. This change occurs as the art of achieving a particular strength is reduced to practice, and the structural requirements push at the edge with needs for higher strength. One such example is the CN Tower in Toronto, with its required strength in 1976 of 5000 psi. At that time, this was difficult to achieve. Today 5000 psi concrete is routinely used and produced without special precautions. …