Performance-based seismic design is on a roll, thanks to recent, first-of-their-kind shake-table tests that proved the viability of a “rocking” braced frame that moves seismic design beyond life safety toward build-for-repair. The steel frame not only survived shaking that was 1.75 times stronger than the Northridge earthquake, it returned to its original plumb position after shaking, thanks to post-tensioned strands. Damage was limited to a replaceable fuse, as planned. Slide Show Photo: NEESR-SG The system, tested in Japan, allows an owner to go beyond the minimum code requirements and commission a structure engineered to be repaired after a quake. Related
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.