We think sustainable urban planning is new – but the ancient Romans were recycling buildings millennia ago

“Hmm, we can reuse this.” The Colosseum. Image: Getty.

In any debate on new construction in our urban centres you are likely to hear phrases like sustainable urban planning, adaptive reuse and recycling heritage – so much so that anyone would be forgiven for thinking that these were modern concerns.

However, these principles have a long history in the ancient world. Anywhere permanent materials such as marble and granite were used to build monuments and infrastructure, recycling and reuse followed.

The ancient Roman world is littered with examples of architectural recycling. Under the banner spolia studies, archaeologists and art historians have increasingly focused attention on the hows and whys of reuse in antiquity.

Ancient architectural recycling falls into two broad categories: adaptive reuse of immovable structures, when a building or monument is renovated and its primary function changes; and reuse of architectural elements, where both functional and decorative material is removed from one building to be incorporated in another (spolia).

While this is often associated with changes in ideologies, there is also evidence of opportunistic recycling following disasters. These events created a surplus of materials that could be salvaged for new constructions.

Same aesthetic, new function

In the hearts of Rome and Istanbul, the capitals of the ancient Roman and Byzantine empires, stand the Pantheon and Hagia Sophia. These iconic and celebrated public buildings were adapted for different religious purposes throughout history. Both maintained their heritage aesthetic, while renovating their function.

The Pantheon was adapted from a pagan temple to a consecrated church in 609CE. The exterior Pantheon was largely unchanged, while the interior was stripped of its pagan elements.

Hagia Sophia was adapted from a Christian basilica to an Islamic mosque following the fall of Constantinople to the Ottomans. The exterior required only the addition of minarets. The interior was whitewashed to cover the rich mosaics of its previous life.

Civic buildings, too, were prime candidates for adaptive reuse, thanks to the rich materials and design of their original constructions.

The restored Library of Celsus, Ephesus, with excavated ancient water pipes in the foreground. Image: author provided.

At the newly listed UNESCO World Heritage site of Ephesus, the tourists’ visit culminates at the impressive multistorey Library of Celsus. Originally built in the second century, an earthquake and fire destroyed the library and its holdings in 262CE.

The impressive facade of the library was salvaged and adapted 100 years later into a nymphaeum, a public water fountain. The adaptive process incorporated other recycled materials from nearby public monuments, mostly marble blocks and free-standing sculpture, fitting the change in function. This reuse gave the non-functional, but already historic, structure a new life.

Recycling as propaganda

The Arch of Constantine is possibly the most referenced structure in spolia studies. Dedicated in 315, the arch celebrates Constantine’s victory over his rival Emperor Maxentius at the Battle of Milvian Bridge.

The Arch of Constantine, where recycling even serves the purpose of propaganda. Image: Steve Kershaw/creative commons.

First noticed by Raphael, the arch was built from a mixture of new and recycled decorative building material. Scenes of animal hunts, religious sacrifice and historic battles were taken from monuments built in the second century CE, including those of the emperors Hadrian, Trajan and Marcus Aurelius. These scenes represented the “golden years” of Rome’s past.

Constantine didn’t just simply recycle these pieces; he reworked the stone faces of Rome’s greatest emperors into his own image. With this act, the emperor takes on all the great qualities of his predecessors and sets himself up as the rightful leader of Rome. This recycling takes us into a world of political propaganda, something the Romans were renowned for.

This bold inclusion of old material in a new monument for Rome led to a whole new recycling trend in architecture. Decorative elements such as columns, capitals and architraves were given new life in buildings of the fourth century CE.

The trend became so popular that new laws were created to protect public buildings from being stripped of their decoration. Only if a building could not be restored was it permitted to recycle that building’s materials.

Opportunistic recycling

Natural disasters and invading armies often left ancient monuments in ruin. These created a stock of marble, granite and sandstone that could be reused in new constructions.

The theatre at Nea Paphos, the scene of archaeological excavations since 1995. Image: Paphos Theatre Archaeological Project, University of Sydney/author provided.

In Nea Paphos, Cyprus, a devastating earthquake destroyed the 8,500-seat theatre in 365CE. Instead of being rebuilt, the theatre became a useful source of marble and stone. Many of the columns and decorative architecture were carried off to be reused in the new Chrysopolitissa basilica, 300 metres down the road.

In Athens, a late Roman fortification wall is a hodgepodge of recycled materials. Image: F. Tronchin/Flickr/creative commons.

In Athens, the invading Heruli destroyed several public buildings in 267-8 CE. However, this left behind a good supply of reusable materials. The Athenians recycled many elements, from column drums to relief sculpture, in a large fortification wall circling the heart of the city. Today, the wall appears as a hodgepodge of recycled elements from Athens’ classical past.

In 2004, the Australian Department of the Environment and Energy released a document supporting adaptive reuse. This booklet said:

Historic buildings give us a glimpse of our past and lend character to our communities as well as serving practical purposes now.

In 2011, the renamed department released a guide to help realise new recycling opportunities related to construction and demolition. These principles are part of our general thinking about urban planning. However, it is clear that this is not a new approach to sustainable urban development. Rather, it continues an ancient tradition of recycling.The Conversation

Candace Richards is acting senior curator at the Nicholson Museum, University of Sydney.

This article was originally published on The Conversation. Read the original article.


 

 
 
 
 

How bad is the air pollution on the average subway network?

The New York Subway. Image: Getty.

Four more major Indian cities will soon have their own metro lines, the country’s government has announced. On the other side of the Himalayas, Shanghai is building its 14th subway line, set to open in 2020, adding 38.5 km and 32 stations to the world’s largest subway network. And New Yorkers can finally enjoy their Second Avenue Subway line after waiting for almost 100 years for it to arrive.

In Europe alone, commuters in more than 60 cities use rail subways. Internationally, more than 120m people commute by them every day. We count around 4.8m riders per day in London, 5.3m in Paris, 6.8m in Tokyo, 9.7m in Moscow and 10m in Beijing.

Subways are vital for commuting in crowded cities, something that will become more and more important over time – according to a United Nations 2014 report, half of the world’s population is now urban. They can also play a part in reducing outdoor air pollution in large metropolises by helping to reduce motor-vehicle use.

Large amounts of breathable particles (particulate matter, or PM) and nitrogen dioxide (NO2), produced in part by industrial emissions and road traffic, are responsible for shortening the lifespans of city dwellers. Public transportation systems such as subways have thus seemed like a solution to reduce air pollution in the urban environment.

But what is the air like that we breathe underground, on the rail platforms and inside trains?

Mixed air quality

Over the last decade, several pioneering studies have monitored subway air quality across a range of cities in Europe, Asia and the Americas. The database is incomplete, but is growing and is already valuable.

Subway, Tokyo, 2016. Image: Mildiou/Flickr/creative commons.

For example, comparing air quality on subway, bus, tram and walking journeys from the same origin to the same destination in Barcelona, revealed that subway air had higher levels of air pollution than in trams or walking in the street, but slightly lower than those in buses. Similar lower values for subway environments compared to other public transport modes have been demonstrated by studies in Hong Kong, Mexico City, Istanbul and Santiago de Chile.

Of wheels and brakes

Such differences have been attributed to different wheel materials and braking mechanisms, as well as to variations in ventilation and air conditioning systems, but may also relate to differences in measurement campaign protocols and choice of sampling sites.

Second Avenue Subway in the making, New York, 2013. Image: MTA Capital Construction/Rehema Trimiew/Wikimedia Commons.

Key factors influencing subway air pollution will include station depth, date of construction, type of ventilation (natural/air conditioning), types of brakes (electromagnetic or conventional brake pads) and wheels (rubber or steel) used on the trains, train frequency and more recently the presence or absence of platform screen-door systems.

In particular, much subway particulate matter is sourced from moving train parts such as wheels and brake pads, as well as from the steel rails and power-supply materials, making the particles dominantly iron-containing.


To date, there is no clear epidemiological indication of abnormal health effects on underground workers and commuters. New York subway workers have been exposed to such air without significant observed impacts on their health, and no increased risk of lung cancer was found among subway train drivers in the Stockholm subway system.

But a note of caution is struck by the observations of scholars who found that employees working on the platforms of Stockholm underground, where PM concentrations were greatest, tended to have higher levels of risk markers for cardiovascular disease than ticket sellers and train drivers.

The dominantly ferrous particles are mixed with particles from a range of other sources, including rock ballast from the track, biological aerosols (such as bacteria and viruses), and air from the outdoors, and driven through the tunnel system on turbulent air currents generated by the trains themselves and ventilation systems.

Comparing platforms

The most extensive measurement programme on subway platforms to date has been carried out in the Barcelona subway system, where 30 stations with differing designs were studied under the frame of IMPROVE LIFE project with additional support from the AXA Research Fund.

It reveals substantial variations in particle-matter concentrations. The stations with just a single tunnel with one rail track separated from the platform by glass barrier systems showed on average half the concentration of such particles in comparison with conventional stations, which have no barrier between the platform and tracks. The use of air-conditioning has been shown to produce lower particle-matter concentrations inside carriages.

In trains where it is possible to open the windows, such as in Athens, concentrations can be shown generally to increase inside the train when passing through tunnels and more specifically when the train enters the tunnel at high speed.

According to their construction material, you may breath different kind of particles on various platforms worldwide. Image: London Tube/Wikimedia Commons.

Monitoring stations

Although there are no existing legal controls on air quality in the subway environment, research should be moving towards realistic methods of mitigating particle pollution. Our experience in the Barcelona subway system, with its considerable range of different station designs and operating ventilation systems, is that each platform has its own specific atmospheric micro environment.

To design solutions, one will need to take into account local conditions of each station. Only then can researchers assess the influences of pollution generated from moving train parts.

The ConversationSuch research is still growing and will increase as subway operating companies are now more aware about how cleaner air leads directly to better health for city commuters.

Fulvio Amato is a tenured scientist at the Spanish National Research CouncilTeresa Moreno is a tenured scientist at the Institute of Environmental Assessment and Water Research (IDAEA), Spanish Scientific Research Council CSIC.

This article was originally published on The Conversation. Read the original article.