Building Failures and Sports Bubbles

As our staff was researching the sports bubble collapses, we stumbled upon additional information regarding fixed structures with their roofs collapsing. One of the commonalities with these buildings and their collapses was that many of them employ a newer style of construction method called truss construction. As we delved into truss construction, the safety information we came upon was overwhelming. Trying to digest it all was a pretty good challenge.

Truss construction has been around for a good number of years. It has been seen by most people in bridge construction and in warehouse roof construction. Here’s a few picture examples of its usage in bridges.

Finally, here’s one we believe you will be most familiar with:

That’s right, its the Tappan Zee Bridge in the Hudson River. 

When truss construction is in the design phase of a project, its usually being considered for several reasons. Those reasons might be time-savings to construct the frame, lower costs than traditional methods and stronger ability of lesser materials. By this we mean if a traditional roof were to be constructed of 2x6’s or 2x8’s, a truss roof, which is considered an engineered roof, can be made from 2x4’s and rated to hold the same weight (and possibly more) due to its geometric triangular shape, which is inherently stable under ideal conditions. Others reasons to use truss construction is quality control. Like a manufactured home that is built in a warehouse (usually with a truss roof) the conditions are controlled and more precise. When you build outside in the elements, with what is called “stick” construction, many factors affecting the construction’s outcome can come in to play, such as weather, materials, labor, etc.

Since we are looking at all of the sports bubble collapses, however, we’d like to focus on roof structures, what they offer and their detriments. A roof must be rated to sustain a certain amount of weight and pressure, referred to as Loads. There are dead loads, live loads, impact loads, static and repeated loads, wind loads, concentrated loads, axial loads, eccentric loads and torsional loads. Even with conventional stick construction methods, we’ve seen an increase beyond using standard-sized wood from trees of many sizes and types. We’ve also evolved from very early building methods to newer and more engineered methods. So while many aspects of construction have remained the same, much as evolved and changed. But is it necessarily better or something we should allow or use?

Greenburgh used to have two bowling alleys. One was the Skytop Lanes on Knollwood Road and the other was the Elmsford Lanes on Saw Mill River Road. Both suffered from roof collapses many years ago from excessive weight from snow. Skytop was eventually torn down and replaced with an office building. Elmsford Lanes was repaired and eventually morphed into Sportime, which continues to operate today. Large expanses of indoor property have always posed a construction challenge, whether it be a gymnasium, bowling alley or warehouse. Go into Sam’s Club on Rt 9A and look up. What you will see is truss construction.

Truss construction has benefits and detriments. One of the benefits is a financially cheaper way to construct a commercial building as well as a residential one. The loss of attic space in a home is detrimental to some homeowners but of no concern to others. The open air feel for a warehouse is obvious. The open air feel in a home, while faster and cheaper with truss construction can be achieved with “stick” construction as well, albeit usually at an increased cost. One problem that exists with truss construction is that the 2x4's are joined together with metal plates with quarter inch deep "teeth" that are pressed in the wood to join the pieces together. The stability of these plates can vary from installation to installation. Another issue with truss construction is firefighting.

It is well known in the fire service that truss constructed roofs collapse mush sooner than traditionally constructed roofs. One reason is the failure of the aforementioned metal joiner plates. Another is the fact that each piece in the truss is dependent on the others for its strength and stability. Loss one piece of a truss affects the overall integrity of the entire structure. The numerous firefighter line-of-duty-deaths (LODD) due to truss construction has caused the fire service to research and change the way the fire service fights fires when truss construction is used. They will cautiously enter a building, if at all, because truss construction failures happen so quickly, giving firefighters little time to exit to safety. Traditionally constructed buildings often give warnings when structural failure is imminent.

Truss constructed buildings give little or any signals of impending failure when involved in fire. Their failure is swift, usually without warning and does not allow firefighters much time to exit. Installed fire sprinklers will help control the fire scene usually by controlling the spread of fire, even extinguishing it. At a truss construction fire, firefighters will often be forced to execute what’s know as a “surround and drown” operation, where they do not enter the building and pour water into the fire scene. You’ve probably seen this type of operation on large building fires on the news. Obviously, if there are lives at stake firefighters will attempt a rescue, however, not if truss construction poses too much of a risk to firefighter lives.

The reason we have touched on truss construction is with all of our engineering marvels on the one hand, there are engineering failures on the other. The sports bubble collapses throughout the sports bubble industry are happening frighteningly too often, too uncontrollably and are proving too risky given the lack of safety standards that do not exist with this industry. Just because someone is able to create an inflatable tent the size of the one proposed by GameOn 365, doesn’t mean the Town or its residents must approve it. If buildings with fix roofs collapse under the weight of snow and because of other weather events, we don’t need to see what will happen with a “temporary” structure. Its only when the Town’s leaders cease to entertain pipe dreams like this sports bubble in a residential neighborhood that will we get A Better Greenburgh.