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Using UHPC to improve box-beam bridge performance

Pouring ultra-high-performance concrete (UHPC) for longitudinal joints—the material could offer new benefits in box-beam bridge design and construction. Images courtesy Ohio University’s Russ College of Engineering and Technology

Out of the many types of bridges used across the country, adjacent prestressed, concrete box-beams have become popular for short and medium spans. Since these bridges are cost-effective, fast to construct, and easy to design, they are preferred by many state and local agencies. Currently used in about two-thirds of the country, many of these bridges are now approaching the end of their life span. Ultra-high-performance concrete (UHPC) could offer game-changing advances for this type of structure.

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Brick Cladding: Helping keep moisture out

Maintaining a consistently dry wall assembly requires incorporating a proper drainage plane. Photos courtesy Boral America

by Crysta Thomas

Every year, the summer solstice marks the beginning of summer in the Northern Hemisphere, followed by humidity interchanged with dryness. Periods of intermittent rain showers followed by stretches of blistering heat are common and these climate variations can lead to an increase in wall moisture. This moisture can negatively impact the safety and structural integrity of buildings.

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Epoxy types: A guide for specifiers

Ideally, a bonded anchor should be installed into concrete of known compressive strength. Engineers who specify epoxy anchors also specify the compressive strength to ensure the epoxy can achieve its published bond strength.  If the compressive strength or overall integrity is unknown, they sometimes require field testing of the embedded anchor to determine if the concrete is good enough. Photos courtesy MiTek Builder Products

by Martin Ruch and Jim Collins, PhD, PE

Epoxy types vary widely, and specifiers need to note such attributes as nozzle time, gel time, load time, sag, cure time, and chemical resistance—each property will affect what makes the product ideal for the intended application. When searching for the proper epoxy to specify, it is important to note there are three general classes—pure epoxy, polyester resins, and epoxy acrylates—that break out in different ways with respect to properties and performance.

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