PSI - Issue 78

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 78 (2026) 418–425

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers Keywords: RC Building;Damping;NRHA;Rayleigh Damping;Modal Damping; Abstract The damping model and its e ff ects on the structural response computed with Nonlinear Response History Analysis (NRHA) requires further investigation, as the physical meaning of the available damping models and their influence on the response are not very clear. This study applies the two most popular damping models, Modal and Rayleigh, to the seismic analysis of a representative six-story Italian reinforced concrete building designed for gravitational loads only. Two structural configurations are considered, with and without masonry infills. NRHAs were performed using 45 pairs of unscaled ground motion records. The goal is to evaluate the e ff ects of these two damping methods and of the damping values on the building’s demand, alongside their practical implications for computational e ffi ciency. The ability of a structure to dissipate or absorb energy from dynamic forces, like vibrations, is known as damping.In simple terms, a structural model’s damping capacity is the percentage of its total vibration energy that lost during one cycle.There are two main types of damping: hysteretic damping and additional damping. Hysteretic damping refers to the energy lost due to the material’s response during cyclic loading (Terrenzi and Spacone, 2025). It’s essentially the energy dissipated by the material itself.Additional damping is used to capture energy losses that the model doesn’t (or can’t) explicitly address. These can include phenomena like the cyclic opening and closing of concrete cracks, or the thermal energy dissipated as materials heat up and cool down during loading and unloading cycles.This paper aims to analyze various approaches for modeling additional damping in structures, quantify their impact, and recommend ways to prevent unexpected e ff ects (Terrenzi et al., 2024). Our discussion will focus on the two most common damping approaches implemented in OpenSees software (Mazzoni et al., 2006): Rayleigh damping and modal damping (Wilson and Penzien, 1972; Chopra and McKenna, 2016). XX ANIDIS Conference Influence of damping in nonlinear dynamic analysis of existing Reinforced Concrete buildings Marco Terrenzi a, ∗ , Enrico Spacone a a University G. dAnnunzio of Chieti-Pescara - Department of Engineering and Geology, Viale Pindaro 42, Pescara 65127, Italy 1. Introduction

∗ Corresponding author E-mail address: marco.terrenzi@unich.it

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of XX ANIDIS Conference organizers 10.1016/j.prostr.2025.12.054