An Investigation on Soil Amplification through Site Factors Used in Seismic Design Codes

Table 4

Site coefficients for the short period (S_S) region.

Local site classes	Site coefficient SS for code, average, and for 84% safety
	0.1	0.25	0.50	0.75	1.00	1.25	1.50
ZB	—/0.85/1.41	0.90/0.91/1.50	0.90/0.99/1.63	0.90/1.09/1.70	0.90/1.09/1.68	0.90/1.09/1.61	0.90/1.09/1.61
ZC	—/1.38/1.64	1.30/1.30/1.66	1.30/1.10/1.63	1.20/0.92/1.67	1.20/0.92/1.65	1.20/0.91/1.58	1.20/0.90/1.57
ZD	—/1.23/1.45	1.60/1.09/1.50	1.40/0.82/1.52	1.20/0.57/1.56	1.10/0.56/1.55	1.00/0.63/1.49	1.00/0.59/1.50
ZE	—/1.07/1.50	2.40/0.83/1.48	1.70/0.55/1.50	1.30/0.33/1.54	1.10/0.33/1.53	0.90/0.42/1.50	0.80/0.36/1.48
ZF	—/1.71/1.75	—/1.62/1.65	—/1.33/1.68	—/1.19/1.71	—/1.20/1.68	—/1.13/1.54	—/1.12/1.54

Values not included in 2018 IBC [50] but given in 2018 TBC [6]. Group not included in the codes.