Citation: Hu, Y.; Khatiwada, P.; Tsang, H.-H.; Menegon, S. Site-Specific Response Spectra and Accelerograms on Bedrock and Soil Surface. CivilEng 2023, 4, 311–332. https://doi.org/10.3390/ civileng4010018 Academic Editor: Angelo Luongo Received: 31 December 2022 Revised: 23 February 2023 Accepted: 8 March 2023 Published: 16 March 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Article Site-Specific Response Spectra and Accelerograms on Bedrock and Soil Surface Yiwei Hu 1, * , Prashidha Khatiwada 1 , Hing-Ho Tsang 2 and Scott Menegon 2 1 Department of Infrastructure Engineering, The University of Melbourne, Parkville, VIC 3010, Australia 2 Department of Civil and Construction Engineering, Swinburne University of Technology, Hawthorn, VIC 3122, Australia * Correspondence: huyh1@student.unimelb.edu.au; Tel.: +61-4-5205-1664 Abstract: This paper is aimed at serving the needs of structural engineering researchers who are seeking accelerograms that realistically represent the time histories of earthquake ground in support of their own investigations. Every record is identified with a specific earthquake scenario defined by the magnitude–distance combination and site conditions; the intensity of the presented records is consistent with ultimate limit state design requirements for important structures in an intraplate region. Presented in this article are accelerograms that were generated on the soil surface of two ex- ample class C e sites and two example class D e sites based on site response analyses of the respective soil column models utilizing bedrock excitations as derived from the conditional mean spectrum (CMS) methodology. The CMS that were developed on rock sites were based on matching with the code spectrum model stipulated by the Australian standard for seismic actions for class B e sites at reference periods of 0.2, 0.5, 1 and 2 s for return periods ranging from 500 to 2500 years. The reference to Australian regulatory documents does not preclude the adoption of the presented materials for engineering applications outside Australia. To reduce modeling uncertainties, the simulation of the soil surface ground motion is specific to the site of interest and is based on information provided by the borelogs. The site-specific simulation of the strong motion is separate to the CMS-based accelerogram selection–scaling for obtaining the bedrock accelerograms (utilizing strong motion data provided by the PEER). The decoupling of the two processes is a departure from the use of the code site response spectrum models and has the merit of reducing modeling uncertainties and achieving more realistic representation of the seismic actions. Keywords: conditional mean spectrum; site-specific response spectrum; seismic design; intraplate earthquakes; stable regions; low to moderate seismicity 1. Introduction The selection of accelerograms that are suitable for use in intraplate regions of low to moderate seismicity represents a challenge to civil engineers and researchers in the field in view of the very limited number of strong motion accelerograms that have been recorded in these regions. Research into stochastic ground motion modeling has managed to resolve a great deal of unknowns by means of seismological modeling which makes use of low-intensity recordings from well-studied stable regions, such as Central and Eastern North America (CENA) to help develop credible ground motion models without relying on a large database of strong motion records [1–8]. Seismological modeling serves the purpose of scaling ground motions recorded from small magnitude earthquake events to a much larger magnitude event, in addition to modifying the frequency behavior of the ground motion to take into account variations in crustal conditions within intraplate regions around the globe, provided that relevant geophysical parameters of the targeted region have been determined [9–14]. CivilEng 2023, 4, 311–332. https://doi.org/10.3390/civileng4010018 https://www.mdpi.com/journal/civileng