Buildings with Velocity-Dependent Energy Dissipation Devices

Abstract

Energy dissipation devices (EDDs), specifically viscous dampers, mitigate the destructive effects of earthquakes on structures. The thesis provides an in-depth exploration of the working principles of EDDs, supported by numerical and experimental simulations from existing literature. It further highlights real-world applications of these dampers in retrofitting projects, demonstrating their practicality and effectiveness in enhancing seismic performance and reducing the risk of structural damage. The thesis also evaluates the proposed methods in the upcoming 2nd generation Eurocode 8 for designing and incorporating viscous dampers in existing structures. This evaluation is conducted through the simulation of an older multi-story office building, both with and without the inclusion of viscous dampers. The analysis identifies a significant vulnerability in the 8th story, which could potentially lead to structural failure during a significant ground motion. Utilizing the Non-Linear Response Spectrum Analysis (NLRSA) introduced by the 2nd generation Eurocode 8 and extending it to be compatible with an existing structure, a theoretical model was constructed. The incorporation of dampers, accounting for an additional 10% damping, results in an 11% reduction in the structure’s base shear and overturning moment demand, and an 11% decrease in story shear demand on the identified weak story. Drifts and displacements throughout the structure are reduced by 23% and 34%, respectively. The results from NLRSA were compared to those obtained from Response History Analysis (RHA), a more computationally expensive but inherently robust method. The NLRSA results exhibited good agreement with the RHA, albeit with a conservative bias ranging from approximately 10% to 35% across the evaluated parameters (e.g., base shear, story drift). However, it is worth noting that the implementation of NLRSA can be complex. Despite being presented as an alternative to RHA, both methods require the development of a non-linear structural model. In addition to the fact that NLRSA is subject to several limitations for its application, unlike the more versatile RHA. The findings underscore the substantial benefits of implementing damping devices, demonstrating their potential in enhancing structural integrity and emphasizing the importance of continuous innovation in structural engineering practice.

Date of Award	6 May 2024
Original language	American English
Supervisor	Andreas Kappos (Supervisor)