Seismic Retrofit and Performance Evaluation of Low-Cost Housing Using Recycled Polypropylene-Geogrid Composite in Seismic Zones

Project Abstract

This research investigates a cost-effective seismic retrofit strategy for low-cost housing using recycled polypropylene-geogrid composites to enhance structural performance in seismic zones. The study addresses the vulnerability of informal and low-cost housing to earthquake-induced damages and aims to develop a sustainable retrofit approach that leverages locally available materials, reduces waste, and minimizes disruption to residents. The methodology combines material characterization, structural testing, and numerical modeling to evaluate the effectiveness of polypropylene-geogrid composites as reinforcement in key structural elements such as retrofitted walls, slabs, and joints. Material characterization includes mechanical properties, durability under moisture and temperature fluctuations, and long-term interaction with concrete and masonry substrates. Composite assemblies are designed to optimize confinement, tensile strength, and energy dissipation without significantly increasing self-weight or cost. Full-scale experiments are conducted on representative wall panels and small- to medium-scale frame assemblies subjected to lateral cyclic loading, simulating typical seismic demands. The experimental program investigates various retrofit configurations, including grid-reinforced masonry shells, geogrid-applied overlays, and hybrid systems integrating buckling-restrained elements with polypropylene reinforcement. Nonlinear static and dynamic analyses are performed to capture deterioration mechanisms, cracking patterns, and load redistribution under increasing seismic intensity. The numerical models are calibrated against experimental results and validated through parametric studies across earthquake intensity, wall aspect ratios, and material variability. The research also evaluates constructability, installation time, and compatibility with existing construction practices to ensure scalability in mass housing programs. Life-cycle assessment and cost-benefit analysis are integrated to compare the proposed retrofit with traditional approaches, highlighting reductions in material costs, waste generation, and construction downtime. Results indicate that the recycled polypropylene-geogrid composite provides significant improvements in lateral stiffness, maximum drifts, and energy dissipation with minimal increases in thickness and self-weight. The retrofit demonstrates enhanced post-cracking behavior, delayed collapse mechanisms, and improved residual strength, leading to higher overall resilience under design-basis and near-fault ground motions. Sensitivity analyses identify critical factors such as geogrid orientation, corrosion resistance to alkaline environments, and interface bonding between composites and substrate materials. The findings are translated into design guidelines and detailing practices suitable for policymakers, engineers, and field crews working in resource-constrained settings. The study concludes with recommendations for standardized testing protocols, quality assurance measures, and maintenance practices to ensure durability and performance over the service life of retrofitted low-cost housing. The overarching contribution advances sustainable, affordable seismic resilience by transforming waste polymers into functional reinforcements that bolster structural integrity, reduce environmental impact, and support rapid post-disaster recovery for vulnerable communities.

Project Overview

What This Project Is About

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A plain-language overview of the topic and what the project investigates.

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The Problem It Addresses

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What problem or gap this project tackles and why it matters to the field or society.

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Objectives of the Project

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1. Identify low-cost housing materials and typical seismic risks in target regions. 2. Explore recycled polypropylene-geogrid composites as a retrofit option. 3. Evaluate simple performance indicators like strength, stiffness, and ductility. 4. Compare retrofit performance with conventional methods using easy-to-understand metrics. 5. Provide practical guidelines for safe implementation in communities.

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What You Will Do Step by Step

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1. Review basic literature on seismic retrofits and polypropylene-geogrid composites. 2. Collect or simulate material samples and prepare retrofit configurations. 3. Conduct simple laboratory tests to assess strength and deformability. 4. Analyze results using straightforward calculations and visual comparisons. 5. Develop a user-friendly retrofit protocol for low-cost housing. 6. Create a checklist for field setup and safety considerations. 7. Validate findings with peers or instructors and refine as needed. 8. Document a clear, practical report with figures and practical recommendations.

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Expected Outcome

A practical retrofit approach using recycled materials that improves seismic performance of low-cost housing, with simple design guidelines and an accessible record of how to implement it in real communities.