One-Piece Welded Reinforcement Grids as Lateral Confinement Reinforcement

摘要

The development in California, USA over the past twenty years of a unique one-piece confinement reinforcement product called Welded Reinforcement Grids (WRG) has resulted in 2000 tons of WRG being installed in California's tallest concrete building and also the world's tallest precast concrete building in a zone of highest seismicity. Often more than thirty pieces of hoops and cross ties are replaced with just one WRG resulting in the elimination of rebar congestion, and reduction of time and labor to assemble rebar cages, set rebar cages, set forms and pour concrete because protruding hooks are eliminated and rebar cages with WRG are very distortion resistant. Recent shake table tests proved that the superior ductile performance of WRG reinforced low rise concrete structures will allow a fifty percent reduction of principal reinforcement steel now required by present day seismic codes. Very tall concrete buildings are now being rapidly constructed in high intensity seismic regions, at lower cost, when constructed with high strength concrete and WRG manufactured with high strength steel to dimensional tolerances of ±3 mm.