Part 3 – Problem 02: A site class of D is assumed for this part. Using ATC hazard tool parameters such as S1, Ss are to be obtained. However, in the tool drop-down menu there are two site class D options (stiff soil-default). The two options provide the same Ss & S1 values, but the other parameters’ value are different. So what’s the difference between site class D(stiff soil) & site class D (default). And how is it possible that they both provide the same values for parameters Ss and S1 but different values for the other parameters?

The difference in choosing site class D (stiff soil) and the site class D (default) is stated in ASCE 7-16 section 11.4.3:”where the soil properties are not known in sufficient detail to determine the site class, Site Class D … shall be used unless the authority having jurisdiction or geotechnical data determine that Site Class […]

Part 4 – Problem 03: The deliverable states that on the given website we introduce the information already provided in the previous points. What diagrams are expected to be plotted and which option do we have to choose? (total deagregation, source:fault, source:grid, source:slab and source: interface) our solution:from the spectral period we chose peak ground acceleration and total deaggregation and provided screenshots with the diagrams.

Please plot the “total” deggregation for the spectral periods that we specified in the deliverable (not at PGA).