Gustavo J. Parra-Montesinos is coming to the rescue of concrete-frame designers and contractors in earthquake country, long bedeviled by rebar-congested coupling beams that span openings in seismic shear walls. By testing concrete mixes rich with steel fiber, the structural engineer-researcher has demonstrated that designers can slash the amount of diagonal rebar in the beams. The innovation could make work simpler, faster and less costly.