Assessing the Stability of Masonry Structures (part 2): Numerical and Physical Modeling

QUICK UPDATE:  Demi just had her paper published ‘Assessing the Stability of Unreinforced Masonry Arches and Vaults: A Comparison of Analytical and Numerical Strategies’, in the Journal of Architectural Heritage.  You can find it here

—————

This post is second in a series covering different assessment methods for stability of masonry structures. Part 1 covered classical and equilibrium methods; this post covers suitable numerical modeling techniques as well as different examples of physical modeling for masonry stability.

4. Numerical modeling

Several methods of numerical modeling for masonry structures exist, as demonstrated by the flowchart in Fig. 10.

numericalflowchart
Figure 10: Overview of numerical modeling methods for masonry structures, adapted from [41] with [8]
As the first level of Fig. 10 suggests, numerical modeling of masonry structures can be divided into four main categories: macro-modeling, homogenized modeling, simplified micro-modeling, and detailed micro-modeling. Asteris et al. [41] provide discussions, summarized below with some additions where noted, on the differences between these modeling approaches. Fig. 11 also depicts the different numerical modeling approaches. In this section, macro-modeling and simplified micro-modeling are the focus.

modelingstrategies
Figure 11: Illustration of different strategies for modeling true masonry sample (a): (b) one-phase macro-modeling, (c) two-phase micro-modeling, and (d) three-phase micro-modeling [41]

4.1 Macro-modeling: masonry as a one-phase material

The macro-modeling approach models both bricks and mortar (or all bricks, in the case of dry masonry) as a homogeneous continuum as in Fig. 11(b). As the subsets under macro-modeling in Fig. 10 suggest, these numerical models are typically finite element models.

Continue reading “Assessing the Stability of Masonry Structures (part 2): Numerical and Physical Modeling”

What to see when visiting Cambridge, UK

Our Princeton alum, Anjali Mehrotra, is currently pursuing a PhD in historic masonry structures at the University of Cambridge, UK. We asked Anjali to take us on a campus tour in search of structural surfaces. This is what she showed us. There is an abundance of vaulted structures in Cambridge, including the main gates of Corpus Christi College, Trinity College and St John’s College, which … Continue reading What to see when visiting Cambridge, UK

Our ultimate top 20 book list for 2016

As the holidays are approaching and as your loved ones – yet again – run out of inspiration for your holiday gift… the Form Finding Lab comes to the rescue. We present you a list of our favorite books on engineering, architecture and anything in between. Happy holidays, The Form Finding Lab. Compiled by Tim Michiels, with contributions of Sigrid Adriaenssens, Victor Charpentier, Demi Fang, … Continue reading Our ultimate top 20 book list for 2016

Adaptive Reuse: How can we make old buildings more sustainable?

One of the most important tasks engineers face today is the design of sustainable structures. Through form finding, use of efficient and/or local materials, and external systems, a plethora of new environmentally responsible buildings exist today. These advanced structures seem to be the answer to reducing the building sector’s staggering carbon emissions, but what about old, historic architecture? What role do these buildings play in our sustainable future?

Tearing down all structures that aren’t explicitly sustainable isn’t necessarily best for the environment, as additional energy is required for demolition as well as construction of a replacement structure. Furthermore, these buildings also hold cultural and historical relevance, acting as roots that tie us to the people and virtues who came before. Old post offices, banks, schools, office buildings, and retail locations may never find their place in history textbooks, but their vernacular styles, as well as the people and events that populated their interiors, make them worthy of preservation. Sustainable design isn’t restricted to the environment; social and cultural sustainability should also be of our concern.

In order to understand how to best include these buildings within our sustainable agenda, it is important to look at their current environmental impact compared to most infrastructure found today. According to the National Institute of Building Sciences’ Whole Building Design Guide, “historic buildings are inherently sustainable.” Adaptive reuse of old structures not only ensures the maximum use of material lifespans but also reduces waste. These claims are corroborated by life cycle analysis (LCA) tests, demonstrating that “reusing older buildings result in immediate and lasting environmental benefits.”

Though these structures may not be as energy efficient as new high-tech ones, LCAs found that performance is not overwhelmingly compromised, as many existing buildings already have sustainable features. With the lack of significant climate control technology at the time of their construction, the form and materials of many old buildings were inherently efficient, trapping heat in the winter and releasing heat in the summer. Features include thick walls, shutters, overhangs, awnings, and high ceilings for air circulation and light admittance. Therefore, these sustainable features will be retained when rehabilitating and renovating them for contemporary use. Thus, with their waste reducing benefits, as well as their current level of performance, the best way to make old buildings sustainable is to use them.

frick
The original Frick Laboratory at 20 Washington Street. (Image courtesy of Denise Applewhite, found on Princeton University’s website

Continue reading “Adaptive Reuse: How can we make old buildings more sustainable?”