Structural engineers inspecting Christchurch’s six steel structures designed with eccentric bracing to resist seismic loads found that five performed well in the shallow Canterbury earthquake that devastated the city on Feb. 22. But the engineers are curious about why two eccentric-braced bays of a three-story parking garage did not fare well—one fractured and the other deformed. The garage did not collapse, thanks to redundancy in the overall structure. “This is the first time the level of excitation of an earthquake was at least as large as or has exceeded the design basis in an area where steel, eccentrically braced frames
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.