Assessing the Stability of Masonry Structures (part 1): Classical and Equilibrium Methods

The persistence of some of the oldest structures in the world in masonry has demonstrated the high potential for masonry structures to last through various conditions over long periods of time. Masonry’s compressive strength is extraordinarily high – it is estimated that a stone pillar would have to be 2 kilometers tall in order to fail by crushing. [1] As a result, in contrast to materials such as concrete and steel that make up most of present-day structures, the limit state of masonry is often dictated by its geometry and not its material properties.

Research into the stability of masonry structures is valuable for two main reasons. Firstly, this research enables us to understand and preserve the structures of the past. Many structures of rich cultural heritage are made of masonry, but their stability is challenged by environmental and anthropogenic threats, such as earthquakes or terrorist attacks. [2–6] The second reason is forward-looking. In some areas of the world, masonry materials are abundant and are thus the most economic choice of building material. An understanding of stability in masonry structures can make possible design tools for materially efficient structures.

Examples of masonry structures are given below. Philadelphia City Hall (1901) is the world’s tallest masonry structure at 167 meters height. [A] The King’s College Chapel (1515) in Cambridge, UK is not even a fifth of the height of Philadelphia City Hall, but the complex geometry of its fan vaults make it a compelling study of masonry stability. [B] Finally, the Armadillo Vault (2016) is a prime example of how an understanding of masonry stability can inform efficient design today. [C]

Methods and theories of structural analysis for masonry structures

The structural analysis of masonry arches and structures have preoccupied countless scientists since the 17th century. In this post, studies on 1. Classical methods and 2. Limit state analysis (including equilibrium analysis and kinematic analysis) are presented. A future post will explore 3. Numerical modeling and discuss existing studies that use each method to assess masonry structures. A more comprehensive overview of studies on each analysis method can be found in [7–9].

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What I am thinking: form making artist Maria Blaisse

Maria Blaisse is a Dutch visual artist and designer. She authored the book “The Emergence of Form”, in which she discusses her in-depth research into form in various materials and the numerous application possibilities, both autonomous and product-oriented.

Sigrid Adriaenssens: Why and how do you generate curved forms?

Maria Blaisse: discovering the curved lines .. while experimenting with incisions  in a rubber inner tube ( for a party of my children)  and while putting the forms on my head  something amazing happened. Then I realized I touched an energy field. I am still working with it.

I found the potential of the inner and outer curve of a torus. The inner curve generates energy and form, while spiraling centripetal. It was the most powerful thing to discover, the outer curve spiraling centrifugal loses form and energy. In my book the emergence of form you can see this research based on one form and one structure from here one can design any form or structure without any waste.

Variations on rubber inner tube – Copyright of Maria Blaisse

In your book “The emergence of form”, you state “form is ‘frozen’ movement”.  Please explain and illustrate that idea?

A form is always part of a movement. I found out while editing film that the stills have the most impact: the form is energized.

systematic variations in gauze structures based on one form  .png

Systematic variations in gauze structures based on one form – Copyright of Maria Blaisse

In your design approach, you emphasize beauty (wanting to ‘move’ people) but also material and energy efficiency. Why is that important to you and to society?

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A seismic retrofit for an adobe church in the Peruvian Andes

The Peruvian countryside is dotted with earthen buildings dating back to the Spanish conquest of the Americas. The Spanish adapted traditional European building typologies to the locally available construction material: earth.Many of these earthen buildings have stood the test of time and have become of great monumental value to local communities and visitors alike. Some of them, however, have suffered extensive damage, or even fatal collapse due to one of the threats in the new world not so critically shared by Spain: earthquakes. While buildings were soon adapted and retrofitted to resist seismic action, the combination of the low-strength adobe (mud-brick) and high regional seismicity has remained a concern for many – if not all – subsequent generations.

Remains of earth-cane barrel vault roof of a church near Ica, Peru that collapsed during the 2007 Pisco earthquake. (Image Tim Michiels, copyright The Getty Conservation Institute)

Today, relatively little attention is given within the academic community to the engineering and seismic design of earthen buildings. Despite the availability of advanced structural design codes, powerful calculation tools, and extensive material research labs, experts still struggle to characterize the behavior of masonry buildings, and especially earthen structures, during earthquakes. Thus, designing sensible and non-intrusive intervention techniques to preserve often languishing adobe monuments is a major ongoing challenge.

Front facade of the church of Kuño Tambo (Image Sara Lardinois, copyright The Getty Conservation Institute)

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