The Florida Condo Collapse

It will be some time before forensic engineering teams determine the cause of the failure of the Champlain Towers in Surfside, Florida, but speculation is rife that the building was not constructed according to specifications and contained less than the required amount of rebar. If true, there will be a major shift in the way construction projects are inspected and in the way that older structures are maintained and recertified. Costs will be significant, and which stakeholders will bear that expense has yet to be determined. One solution may be highly penetrating extreme nuclear inspection technologies look inside reinforced concrete for flaws, but these technologies are too expensive for routine use. Development of lower cost, highly portable systems could save many lives as American infrastructure ages in the 21st century.

Access all episodes of End of the Line on Engineering TV along with all of our other series.

To see any graphs, charts, graphics, images, and/or videos to which the transcript may be referring, watch the above video.

The tragic collapse of the Champlain Towers in Surfside, Florida last week took the lives of some 160 people and destroyed a 13 story 135-unit condominium structure in a matter of seconds. The collapse of buildings with loss of life is common in regions hit by earthquakes or tsunamis but this collapse was sudden, unprovoked by mother nature and totally unexpected. But should we have expected it? This kind of collapse is extraordinarily rare in the Western world, for a reason. Civil engineers work with safety factors far beyond anything we see in manufacturing industries like consumer goods or automotive, and it’s very common to see designs that are an order of magnitude stronger than the minimum necessary for support. 

There are several reasons for this. One is that buildings have exceedingly long lifespans, and they can be incredibly difficult to repair or remediate once built. Another is that it can be difficult or impossible to inspect critical areas in the structure after the building is complete. In the automotive industry, used to physically chisel apart automobile bodies to check weld integrity. You can’t do that with a skyscraper. The other major reason for extreme conservatism in civil engineering is the inability to predict the overall environment decades into the future. 

That’s especially true of coastal areas like Florida, were notoriously porous rock, fluctuating sea levels and hurricanes all play a part in taking down what humans try to put up. With recovery operations still ongoing, and the recent demolition of the remaining portion of the Champlain Towers, it’s too early for the forensic engineering teams to draw conclusions about the cause of the collapse. There are unconfirmed reports that columns contained less than the specified amount of rebar. If true, this collapse may trigger a widespread and expensive re-examination of any structures built by any firm connected with the concrete work on this project. 

It also exposes two fundamental flaws in the way buildings are built and operated the United States: one is that projects are routinely built by corporations that are temporary legal structures formed specifically for the project, effectively eliminating liability. Another is that condominiums are managed by boards composed of stakeholders, and although municipalities enforce inspection routines, in most jurisdictions there is no legal requirement for condo board to actually implement the fixes noted in an engineer’s report. Reinforced concrete structures in America frequently require expensive remediation due to water intrusion and corrosion of the steel reinforcement. Most people have been to an American city and seen the most visible effect of this, the spalling of concrete from columns and beams in bridges and elevated freeways. In a way, the spalling is a good thing because it makes the need for remedial action readily apparent. 

As I tell you this, there been no reports of phenomena like widespread spalling in the reinforced concrete structures of the Champlain Towers pre-collapse. There have been reports of the failure of an underground membrane beneath the swimming pool designed to move water away from the structure. That may be critical. And that illustrates another problem for civil engineers: later renovations and even landscaping can alter the way water flows in and around the structure, potentially causing damage invisible to the human eye. Can this kind of thing be stopped? More frequent inspections can help, as well as a closer look at what damage is defined as safety critical in municipal building codes, but I think the technology that’s really needed is widespread adoption of high-energy, penetrating concrete inspection systems that would allow engineers to see inside reinforced concrete. Technology similar to CAT scans can see inside 6 feet of concrete, but it’s expensive, so much so that they’re commonly used after damage is apparent, to determine how extensive it is and to calculate a sensible remediation strategy. 

In a well-designed building, something is very wrong if a structure showing minimal or cosmetic damage to structural members fails suddenly and catastrophically without warning. If the Champlain Towers were not built to the structural engineer’s specifications, no amount of routine inspection could’ve stopped this tragedy. The question then becomes, who inspected the rebar before concrete was poured? I think we need to look more closely at how incentives drive behaviour over the entire lifecycle of a building, from architect, structural engineer, project manager, construction trades and finally active management of the structure as it ages. Our tendency is to attempt to assign blame to a single party, but as the old saying goes, success has many fathers, but failure is an orphan.