# Experimental investigation of progressive instability and collapse of no-tension brickwork pillars

## TL;DR

This study experimentally and analytically investigates the progressive instability and collapse of no-tension brickwork pillars under eccentric loading, revealing load capacity, stress distribution, and collapse modes.

## Contribution

It introduces new analytical expressions for deformed shape and stress distribution, validated by photoelastic experiments on polymethyl-methacrylate pillars.

## Key findings

- Photoelastic tests confirm analytical predictions.
- Eccentricity significantly affects stress distribution.
- Collapse modes vary with eccentricity.

## Abstract

The progressive instability behaviour of compressed dry-stone rectangular pillars loaded with an eccentric load is assessed experimentally and compared with the theory. Photoelastic compression tests were designed and executed on polymethyl-methacrylate brickwork pillars to reveal, i) the load-bearing capacity of the structure and the load-lateral displacement relation, ii) the effect of the eccentricity in the stress distribution along the structure, iii) the collapse mode of the system at high eccentricity. By employing a no-tension material model with linear behaviour in compression, new analytical, closed-form expressions for deformed shape of the structure, location of the neutral axis in a generic cross section and axial displacement are provided. The photoelastic stress analysis outcome fully confirms the analytical predictions for both low and high eccentricity loadings.