DOI: 10.17603/ds2-k2ac-hk90
title: Pendulum LiF-UPTS walls (30 kips Total PT Force)
title: in Collaborative Research: Self-Centering Pendulum Shear Walls in Buildings via Nonlinear Elastic Kinematics

description: Project Description
This project addresses a critical challenge in structural engineering, which is to develop building systems designed with Lateral Force Resisting Systems that can resist extreme natural hazards, such as hurricanes and earthquakes, with minimal or no damage. The research explores an innovative structural design concept for unbonded, post-tensioned, reinforced concrete shear walls (UPSWs). These walls interact with foundations via a curved surface, enabling lateral load resistance and damage-free performance through a pendulum-type motion. The primary focus is on leveraging system geometry and nonlinear kinematics, rather than relying on traditional material failure limit states, to achieve resilient and sustainable buildings.
Data Reusability
The data generated from this project—including analytical, numerical (finite element), and experimental findings—will be made publicly available through the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot at DesignSafe-CI. This ensures accessibility for researchers, practitioners, and educators, who can reuse the data for:
•	Developing new design methodologies for damage-free building systems.
•	Benchmarking numerical models for innovative lateral load-resisting systems.
•	Educational purposes, such as undergraduate and graduate tutorials or design courses.
Uniqueness of the Project
The uniqueness of this project lies in its revolutionary approach to structural design:
Damage-Free Structural Systems: Traditional designs aim to constrain deformations, while this project embraces deformations, utilizing them to achieve resilience.
Pendulum Motion Concept: The use of a circular foundation interface enables walls to glide without separation, ensuring self-centering behavior and minimal damage during extreme events. Minimal to no damage is achieved because the extended contact between the wall and the base significantly reduces compression stresses, bringing them hundreds of times below the concrete's compressive strength.
Elastic Instabilities for Energy Dissipation: Elastic meta-materials and multi-stable structures provide controlled energy dissipation, representing a novel application of nonlinear elastic instabilities in large-scale structures.
Integrated System Geometry: Unlike traditional systems limited by material response, this project integrates system geometry and deformations into the design process for improved performance.
Audience
The primary audience are likely to include members of the engineering community such as:
Researchers: Those exploring advanced structural systems and sustainable design philosophies.
Practitioners: Engineers and architects interested in damage-free, resilient building designs.
Students and Educators: Undergraduate and graduate learners using project findings as a learning tool.
Policymakers and Stakeholders: Professionals advocating for resilient infrastructure solutions.
Outreach Groups: Middle and high school students through targeted STEM activities promoting interest in engineering careers.
ACI committee 550: ACI Committee 550: This research has the potential to influence the development of alternative rocking wall systems and their design methodologies, which could be incorporated into the ACI 550-6 and ACI 550-7 design documents.
This project not only advances the design of innovative lateral force-resisting systems envisioned to meet performance and economic objectives but also promotes education and community engagement, making meaningful contributions to both theory and practice.
description: A single pendulum LiF-UPTS wall test unit was tested multiple times under increasing levels of PT force. For each PT level the test wall was subjected to fully reverse incremental cycling loading. In this test unit the PT force was 133-kN (30-kip),  which corresponds to correspond to 24% of the threaded bars allowable design force.
After applying the initial post-tensioning (PT) force, testing progressed by subjecting the wall to three fully reversed cycles at each incremental displacement level. This testing protocol followed the loading cycles provided in the research article by Brown et al. and is in agreement with the established minimum experimental requirements stated in ACI 550-6.