A recent series of dynamic tests demonstrates that there are several types and doses of steel-fiber reinforcement that can be used in performance-based seismic design of coupling beams—headers that link openings in concrete shear walls—to reduce rebar congestion.
A new study of high-sensitivity gravimeter and seismometer data—recorded just before and during the magnitude-9.0 earthquake on March 11, 2011, in Tohoku-Oki, Japan—describes a promising new data collection and analysis methodology that could give authorities time to issue advance warnings and secure vulnerable systems before earthquakes strike.
Moving from the lab to the field, a highway off-ramp bridge under construction in Seattle features memory-retaining metal rods and bendable concrete designed to provide the structure with flexibility sufficient to withstand a major seismic event.
Structural engineer Cary Kopczynski once penned a prediction: “There may come a day in the not-too-distant future when concrete building structures will commonly be reinforced with a combination of steel fibers and steel reinforcing bar.
Since Los Angeles joined San Francisco Bay Area cities last October in tightening seismic standards for non-ductile concrete buildings and multi-family, wood-frame structures with parking underneath (ENR 11/9/15 p. 16),
seismic retrofit work in those cities has been booming.
Because it can moderate the damaging effects of earthquakes, base-isolation is a technique used primarily in seismically active regions. ENR takes a look at some of the largest applications of base-isolation technologies in the world.