2020 Issue

29 specialized software, expertise and training. ASCE 7-16 attempts to point us to the correct method (see the figure below). Although the code allows an SRA for any site, its The June 10th Continuing education seminar was sponsored jointly by local chapters of ASCE, DFCM, EERI, GI, SEAU, SEI and the UGS. Byron Foster is a geotechnical engineer at Kleinfelder and a Ph.D. candidate in Civil Engineering (geotechnical and structural emphasis) at the University of Utah. • Is the building period > site period? • Do you have measured values for the shear wave velocities in the soil? • Is the rock depth several thousand feet deep, but you only have information on what the soils are in the upper 100 feet or so? • Does the firm conducting the work have experience passing rigorous peer review by seismic experts for the method that will be conducted? While IBC 2018/ASCE 7-16 provides detailed design approaches, we are still learning from designing and pricing alternatives so that we can know when it will make sense for the structural engineer to use an exception versus using the results of a site-specific seismic assessment. I n the meantime, given the potential for significate sched - ule delays and added costs from the exceptions, we must all continue to inform our clients about the need for these new studies. applicability should be assessed on a project-by-project basis by considering the pros and cons of both methods. For competent soil conditions, a Ground Motion Hazard Analysis tends to be more appropriate than an SRA. The bottom line is that a specialist in this type of work needs to determine which method is applicable. In deciding which method is needed and who should do the work, you should consider the following factors: • What is required by IBC 2018 and ASCE 7-16? • What is the importance of the structure? Hospitals, police stations, and other important public buildings should receive particular attention.