From Rubble to Resilience

Abstract

Türkiye faces a dual challenge: high seismic vulnerability and large-scale construction and demolition waste. In cities such as Istanbul, ageing reinforced concrete residential buildings remain exposed to significant seismic risk. While ongoing urban transformation continues to generate large quantities of concrete and brick rubble. Seismic assessment and retrofit procedures are typically carried out building-by-building, making this process time-intensive and difficult to scale across the many vulnerable structures. Additionally, construction and demolition waste is still mostly directed to landfills, despite its potential as a material resource for structural strengthening.

This thesis develops a design framework in which seismic retrofitting is approached as both a structural assessment problem and a material supply problem. This framework is positioned behind the logic that the vulnerable building stock is assessed as the target of seismic strengthening, while demolition waste from the same urban transformation context is investigated as a potential resource for producing the retrofit components. In this way, the retrofit demand is defined by the structural workflow, while the material workflow explores how this demand could be supplied through locally available recycled concrete and brick aggregates, making this vulnerable building stock part of the material cycle that can support renewed seismic resilience

The research focuses on a representative Turkish building typology: mid-rise reinforced concrete moment-resisting frame apartment buildings. A survey-based workflow is proposed in which on-site building data is collected through a structured assessment form and translated into a parametric Grasshopper model. This model generates a simplified building geometry, calculates seismic loads using an equivalent static approach, and supports structural evaluation through Karamba3D analysis combined with analytical capacity checks in accordance with the relevant Turkish and European structural codes. These checks identify key vulnerability parameters, including excessive inter-storey drift and insufficient member capacity.

The identified vulnerabilities guide the choice of retrofit intervention, which is supported through a designer-led selection of suitable strategies, such as column jacketing or shear wall interventions. These types of interventions create the link between the two research tracks: the structural workflow defines the retrofit need while the material workflow explores how this need could be met through modular components made from recycled construction and demolition waste.

For this purpose, concrete and brick aggregates are processed into recycled aggregate inputs for modular retrofit components for column jacketing and shear wall interventions. Supported by a designed recycling process aimed at reducing impurities in the waste stream. The material investigation therefore supports the structural workflow by translating the selected retrofit strategies into a more resource-efficient and accessible supply system.

The result is a design-driven proof of concept for a faster, typology-based, and resource-aware retrofit workflow. In which the structural parametric workflow generates a retrofit demand by identifying what fails, where, by how much, directly informing which interventions are needed where to prevent collapse, while the material track designs the whole system of supplying locally sourced retrofit elements derived from demolition waste.