Score another small victory for more-constructible high-rises, especially in seismic zones. Results of recent load tests on a "sandwich" shear-wall assembly, designed to simplify and speed construction of core shear walls surrounded by steel frames, are equal to or better than anticipated, say researchers.The sandwich, called a dual-plate composite shear wall because its steel- plate walls are filled with lightly reinforced concrete, is not for use only in seismic zones. "It is a great system for multihazard mitigation because it is good for seismic, wind and gravity loads as well as blast resistance," says Ron Klemencic, president of Seattle-based structural
The market is generally healthy and steadily growing, and margins are up for large specialty contractors. Further, advances in design tools and owner demand for collaboration are giving subcontractors a seat at the table early on in projects.