Bridges are among the oldest structures used by mankind. From meeting purely utilitarian necessities, bridges have evolved with time to become symbols of human progress, of cities and entire countries. Among the thousands of bridges around us are the bridges that we all admire, the bridges that are the symbols of the eternal human aspiration for building longer and taller, stronger and faster. …
In 1967, there was a sudden collapse of the Silver Bridge, a pin-connected link suspension bridge over the Ohio River at Point Pleasant, West Virginia, that resulted in a loss of 46 lives. As a result, a 1968 federal act initiated a national bridge inspection program that recognized the need for periodic and consistent bridge inspections. The first National Bridge Inspection Standards (NBIS) were developed in 1971. …
Orthotropic steel decks (OSDs) have been used commonly in long-span bridges to reduce self-weight, and therefore improve the spanning ability of these bridges. The OSDs are usually covered with a 2- to 3-inch-thick asphalt wearing course. Under cyclic heavy traffic loads, these steel decks are susceptible to fatigue cracks, while asphalt overlays can suffer from cracking and shoving problems. Both issues compromise the serviceability and durability of the bridge deck. …
Many chemical, pharmaceutical, laboratory and general industrial facilities have requirements for storage of chemicals, gasses, fuels, lubricants, and other hazardous materials used in everyday operations. When stored appropriately and not subject to puncture, spillage, and exposure to flame or other ignition sources, these materials are benign and safe. …
When major building codes are not in agreement on specific structural members, confusion and uncertainty are propagated among design engineers. In this case, the industry may need to start a conversation with code authorities for clarification.
Three issues specific to the design of post-tensioned members are currently treated differently by the American Concrete Institute’s Building Code Requirements for Structural Concrete and Commentary, ACI-318 (2014), and Europe’s Design of Concrete Structures – Part 1-1 General rules and rules for buildings, European Code EC2 (2004). For any designer working globally, these two code documents define the design of post-tensioned members. …
Log cabins have been around for a long time. The first evidence of these structures dates back to the Bronze Age in northern Europe.
They were used as temporary shelters because they were easy to assemble and disassemble. Fabrication and shaping of the logs were minimal and required very little work. …
Structural engineering is undergoing a profound change towards a life-cycle-oriented design philosophy to fulfill the continuously increasing demand from societal, political, economic and environmental needs. In this approach, the classical point-in-time design criteria are extended to account for more comprehensive time-variant performance indicators over the entire service life. …
Design, modeling, and analysis are keys to the success of today’s bridge projects. The next generation of bridge modeling software requires that the model is purpose-built for bridge designers and contractors who need to create, construct, maintain, and document a wide variety of bridge information throughout the lifecycle of the bridge. …
Lake Wobegon is a fictional Minnesota Town from A Prairie Home Companion, a popular public radio show by Garrison Keillor. One of the show’s famous lines about the town is:
“…the little town that time forgot and the decades cannot improve … where all the women are strong, all the men are good-looking, and all the children are above average.” …
The process of (abductively) creating a diagrammatic representation of a problem and its proposed solution, and then (deductively) working out the necessary consequences, such that this serves as an adequate substitute for (inductively) evaluating the actual situation. …