Sunday, April 19, 2009

Day 3 - The Red Zone

Day 3
The Degenkolb Recon Team was afforded a very special opportunity on Day 3, due to the hard work of team member Silvia Mazzoni, to enter the 'Red Zone' in the historic center of L' Aquila.
The 'Red Zone', comprising a 1-mile square in the center of the historic city, has been closed to all but Civil Protection personnel since the earthquake. On the day of our visit, approximately 12 days after the event, residents were just being escorted in to retrieve belongings.
Early reports indicated that the historic center of L' Aquila was "destroyed," and therefore we were anxious to access the area. After clearing a number of administrative hurdles, including securing an escort, we quickly charted a course to visit the high-profile collapse sites.
One of the most interesting was the Hotel Duca Degli Abruzzi, shown below before and after the earthquake. The hotel was a classic 'soft-story' structure, which was apparently under renovation at the time of the earthquake and, therefore, (and fortunately) unoccupied. The collapse site remains relatively undisturbed, with broken concrete and stripped rebar resting in plain view, offering tantalizing clues to its unfortunate demise.














Though it is difficult to pinpoint the exact cause of the collapse (other than simply "soft story" p-delta collapse), it appears to have precipitated at the southwest corner (right side of the photos). We observed that the frame detailing appeared on-par with other structures we visited elsewhere (e.g. on days 1 and 2) and that some portions of the structure (further up the hill) remained standing.

We visited two additional high-profile collapses of 'engineered' structures, both of which were occupied at the time of the earthquake. Upon arrival, we quickly realized that the sites had been combed and sorted in search of survivors. The sites provided a sobering reminder of the grim reality of the structural failures and the horrors that occurred therin.















We continued our tour through the old city, focussing on engineered structures and large historic structures. The large churches all appeared to have sustained some level of significant damage, most notably partial roof and wall collapses.


Our preliminary understanding is that these churches have all experienced various levels of modification thoughout their history, either to repair/rebuild damage or to replace the roof structures, though some may actually have been retrofitted (termed 'interventions'). There are very interesting and valuable lessons to be learned from these structures, though time and complete information will be required to reach meaningful conclusions. Currently, much of the information is obscured by limited access, difficult sight lines, and hundreds of years of history.
There is one church that appears to be retrofitted on one side and partially collapsed on the other. We believe this structure may offer a wonderful juxtaposition of performance and plan to gather more information during our next visit on Day 5.

Aside from the high-profile collapses and major church damage, the overall performance of 'modern' structures in the city center appears (from the outside) to be within "Life-Safety" limits. In general the damage is limited to frame infills and partition walls, which appeared to perform well as structural fuses and damping mechanisms, except where collapsed into interior spaces. As such, as structural engineers, we find the characterization 'destroyed' to be grossly overstated.

As we walked the city, however, I believe our perspectives diverged, or at least evolved, into two separate perspectives -- (1) that of performance based seismic structural engineers and (2) that of the residents.
The engineering perspective was of general acceptance of the damage, believing it to be generally within the standards of our profession.

From the perspectives of the residents, however, the term 'destroyed' appears closer and closer to the reality. Though many of the structures are actually intact, their 'homes' are not, their spirits are not, and their livlihoods are not. As a person, a father, and a husband, I can only imagine the terror that occurred at 3:30am on the day of the event -- the sounds, the thoughts, the fears, the ensuing days of doubt and disruption. I cannot imagine these are terrors that will soon dissipate from memory or from the consciousness of this city.
As we continue to observe, continue to speak with residents, and continue to learn, it has become painfully clear that there is a gross disconnect between the performance we seek as engineers and the performance we expect as residents.
As we move forward with this trip and with this experience, we will undoubtedly be searching to understand this disconnect and to seek its resolution.




















2 comments:

  1. Wow Drew amazing stuff. Thanks for sharing.

    B

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  2. I, too, subscribe to the need for performance standards that are consistent with public needs and expectations; i.e. more "earthquake proof" and less "life safe." This will require a major shift in the process and attitudes of developing and enforcing building standards. The good news is that a major event like this can create the political will to enact such a shift. The caveat is that such momentum also needs to be accompanied by sufficient funding mechanisms to put new standards into action - to build and rebuild accordingly. The question I've been thinking about is the economic one - standards are essential but not sufficient for a safe built environment - the structures also have to get built. How do we mobilize sufficient money toward safe (re)construction? Food for thought.
    Responses welcome by personal email.
    Kate Stillwell

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