Research is getting under way to develop prescriptive code language and performance-based design guidelines for a “rocking frame” structural system that relies on vertically post-tensioned shear walls for seismic resistance. The system promises to improve seismic performance, reduce rebar congestion and enhance constructibility, says the engineer developing it. Photo: Courtesy of Tipping Mar Placing vertical post-tensioning tendons in ducts in concrete shear walls is known to reduce rebar congestion and simplify construction. Drawing: Courtesy of Tipping Mar “We believe these advantages could significantly impact seismic design and construction of mid-rise and high-rise concrete buildings,” says Steven Tipping, president of structural
The 2016 Summer Olympics boating and swimming events have put an international spotlight on what has been a long-running problem in Rio de Janeiro—untreated sewage and trash are clogging up major bays and waterways.