Skip to content

Week 32 – Calcio-crazy Roma, and Reed Centering for Roman Concrete Vaulting

April 19, 2010

Stadio Olimpico, Roma

Today was a huge day for calcio (soccer) here in Rome.    The top level Italian soccer league (Serie A) has two local entries  – A.S. Roma, the team from here in the city of Rome, and S.S. Lazio, representing the larger region of which Rome is a part.   Both teams are covered on the front page of the local sports pages.   Whenever Rome plays their archrival Lazio, it’s a very big deal, and emotions run high – it’s like Red Sox versus Yankees in baseball or Michigan vs. Ohio State in college football.   Today, not only were Roma and Lazio playing in a late season game, but Roma had the chance to move into first place with a victory.   Cafés and bars in Rome were packed and spilling out into the street.  Roma defeated Lazio 2-1 to move into first place…  I was in my apartment when the game ended, but I knew the outcome from all the horns I heard beeping in the streets, and all the joyous shouting.

Entrance to the Stadio Olimpico, with mosaics and a dry, disused Fascist-era fountain in the foreground

Fascist era mosaics in the approach to the Stadio Olimpico, executed in the ancient Roman style, but with modern themes

Last Monday morning, a group of us from the American Academy took an architectural walking tour of the Foro Italico (“Italian Forum”), formerly the Foro Mussolini.   The Foro Italico is a remarkable athletic complex of fascist modern architecture, mostly from the 1930’s, though expanded and modified for the 1960 Olympic Summer Games in Rome.  As part of the Foro Italico tour, we were taken inside the Stadio Olimpico – the huge soccer stadium that is the home field of A.S. Roma.  

Since A.S. Roma had played the day before, workers were cleaning the stands of litter from the game.   After a game in the U.S., the stands of stadiums tend to be littered with beer cups, coke cups, and cardboard trays from hot dogs, nachos, etc.    Not here in Rome.   After the A.S. Roma game, the majority of the litter in the stands consisted of two things: 


Debris at Stadio Olimpico after a Roma game. Photo by Robert Hammond.

  1. cigarette butts
  2. small black and red plastic canisters that contain a shot of espresso (very strong black coffee)  mixed with  a shot of grappa (a strong alcohol made from grape skins)


The secondary (street) facade of the Villa Medici, Rome

Also this past week, the noted French preservation Architect Didier Repellin was kind enough to give me an insiders tour of the Villa Medici (c. 1576).   Napoleon Bonaparte moved the French Academy in Rome into the Villa Medici in 1803, housing the winners of the prestigious French Prix de Rome from 1803 until 1968.  It stills houses the French Academy.  The Villa Medici is visible from all across Rome with its perch above and just slightly to the left of the Spanish steps, although this façade facing the city is actually the rear façade.   The much more elaborate front façade faces the private gardens to the northeast.

Primary (garden) facade of the Villa Medici, Rome (c. 1576)

Beneath the Villa Medici runs  the ancient Roman aqueduct Aqua Virgo (it was renamed the Acqua Vergine when it was rebuilt during the Renaissance).  The Acqua Vergine stills supplies the water to the famous Fountain of Trevi.  

One highlight of my insider’s tour of Villa Medici was walking inside an old, abandoned settling chamber for the aqueduct that connects to the basement of the Villa Medici.  The settling chamber is a huge, vaulted room, built of Roman concrete, where sand and sediment would settle out of the water, and the clean water would flow on to the rest of the city.   Basically, water flowed in and filled this huge room, this settling chamber, and with the reduced velocity of water in the chamber, the sand and settlement settled to the bottom.   The clean water at the top of the chamber flowed out through outlet pipes that are 5-6 feet off the floor.  A simple idea, low tech idea that works well – settling chambers for the stormwater systems (e.g., drainage from streets and highways) still work the same way today, although on a smaller scale.

Although I’ve seen many examples of vaulted Roman concrete construction, I saw something in the settling chamber vault construction that I hadn’t seen before, and that relates to last week’s discussion on efficiency in Roman concrete construction.  Now that I’ve thought about it, it makes perfect sense to me that I would NOT have seen it in any buildings or prominent structures, but that I would see it here, in an underground utilitarian structure that was never seen by the public, and was only seen by maintenance crews inside the aqueducts. 

Roman concrete vaults in a settling chamber beneath the Villa Medici, with striated impressions left by marsh reed centering (formwork)

Since no one really cared whether these utilitarian, underground vaults were visually uniform or not, they used a technique for the “formwork” during construction that didn’t create a perfectly uniform semicircle, but that was much faster and less labor intensive than having carpenters construct wooden formwork from planks and boards.   In today’s terms, it was also more green and sustainable, in that it used a readily renewable local resource, with less processing and less embodied energy (far less than in the planks or boards sawed from mature trees used for conventional formwork or centering).   Didier Repellin pointed out to me that the underside of the Roman concrete vaults in part of the settling chamber have long narrow impressions in them, from reeds, and you can actually see fragments of old reeds still stuck to the underside of the vaults in some places.   During construction, they bend marsh reeds across from wall to wall, in a roughly semi-circular shape, and then used the reeds as centering (formwork) for the Roman concrete vaults above.  Although the old reeds are obviously quite brown and dried now, I suspect they used freshly cut green reeds, as they would be flexible enough to bend to a semi-circular shape.   Since the reeds are relatively thin (roughly the diameter of a pencil), and have limited strength, I also suspect that they constructed a thin initial layer of concrete (perhaps a couple inches thick), let that concrete cure (harden) and stiffen the reed formwork, before proceeding with additional construction and weight. 

Remnants of marsh reed centering in the underside of the Roman concrete vaults

In antiquity, marsh reeds grew abundantly in and around Rome, as the Tiber was not yet channelized, and flooded regularly.  Thus, marsh reeds where a local, abundant, readily renewable, natural material.

The apparent construction method of these Roman concrete vaults with marsh reed centering makes me recall an excellent lecture that I heard John Ochsendorf of MIT delivered to the Boston Society of Architects Historic Resources Committee some years ago.   John described how Gothic cathedrals, and Inca grass fiber suspension bridges are two very different examples of sustainability.  The Gothic cathedrals, built of cut stone, are high embodied energy, but are sustainable because they provide great durability, and amortize that embodied energy over many, many centuries of service.  The Inca suspension bridges, although they need to be rebuilt almost yearly, are sustainable because they are build using rope hand made from grasses that grow on the hillsides at the bridge site – thus they are built using a local, readily renewable, sustainable, natural material, that grows naturally on the site, and thus they have extremely low embodied energy and are readily renewable. 

It strikes me that the construction of the Roman concrete vaults with local marsh reed centering (formwork) is not only fast and efficient in terms of construction, but that it also combines these two paradigms of sustainability in a very clever, logical manner.   It uses the sustainable, renewable, low embodied energy, but non-durable material (the marsh grass) as a temporary material that can degrade shortly after use, without any adverse effect on the overall strength or durability of the structure.  Furthermore, it also uses this non-durable marsh reed as a temporary material to facilitate (e.g., make more cost effective, more time efficient, less labor-intensive, and less resource-intensive) this highly durable construction (unreinforced Roman concrete vaulting) that has stood for millennia.

Reed centering in the Roman concrete vaults beneath the Villa Medici, Rome

4 Comments leave one →
  1. Karen Yasinsky permalink
    April 26, 2010 2:59 am

    Dear Matthew,
    I will be at the academy next year with my husband and son and have really enjoyed your blog. I am looking for a school for my 6 yr old. I saw some kids photos on your blog and wondered if you could let me know who has children in primary school so I could contact them. We are looking into english speaking schools. Many thanks and also, we heard you did a lot of research on health ins. Any recommendations?
    Kind regards, Karen Yasinsky

    • mbronski permalink*
      May 5, 2010 11:56 am

      Dear Karen-
      You and your family have a very wonderful year ahead of you!. I’ll e-mail you about overseas healthcare options/research I did, and connect you via e-mail with the Fellows here who have elementary school age kids, so you can discuss school options with them.

  2. Diederik permalink
    August 23, 2010 10:22 am

    Hi Matthew,

    I`m a PhD at the faculty of Architecture at the ETH Zürich in Switzerland. I`m working on the use of fabric for concrete formwork and was very excited to find your blog on Roman reed centering. Do you think the reeds were simply placed parallel, as self-supporting elements, or did you see signs of a second direction, in effect making this a woven, fabric-like formwork?

    I found another source online, who speculates as much (calling them mats) based on vaults in Mauritania, but your photos, to me, suggest otherwise.

    Any thought would be great, as I`m preparing a paper on the history of fabric formwork (I`ll reference this blog).


  3. March 14, 2014 1:36 am

    Great delivery. Sound arguments. Keep up thhe great spirit.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: