Anchoring without stakes
Event professionals should think twice before agreeing to provide a tent that is not staked.
InTents | August 2007
By Ken Keberle
Tent installations are increasingly becoming dependent on alternative methods for anchoring a tent. These non-staking jobs are changing the way many companies do business. Regardless of your reason for considering a non-staking installation, the overwhelming consideration must always be safety. The safety of the public, the safety of your crew and the safety of your company should be your first priority. If you don’t do things right, the public is at risk from a blown-away tent. If you don’t pay attention to the project, your crew can get hurt installing the tent. And if you don’t do things by the book, your company can get involved in litigation that can shut your business down.
The continued evolution of non-staking tent installations is influenced by several factors. Municipalities are becoming increasingly resistant to allow tent renters to drive stakes into public parks. Many venues are trying to get tents installed on concrete or asphalt, where they do not want the surface punctured. Sometimes, the event designer simply does not want ropes and stakes as a matter of aesthetics.
Before you agree to do a non-staking job, ask yourself the following questions. Do customers’ needs or requests override state or local regulations? Do customers’ demands override your need to stay in business? Even simply agreeing to comply with your customer’s non-staking requirements can place your company in danger of legal action, should any structural failure, injuries or damages occur. Be aware of this risk and protect your interests contractually and legally.
Remember: Manufacturers’ recommendations are the final word in erecting any structure. Anything you make up on-site or in the office is a deviation from the manufacturer’s guidelines.
The four ways a building can fail catastrophically are by knocking down, rolling, shear failure and uplift failure. These are not technical descriptions, but they can help you understand the ways in which things can go very wrong. They are all the result of wind or storms.
Knocking down occurs when a downward force from the wind basically explodes or flattens the building. Rolling occurs when the wind gets under the building and one side of the anchoring fails. Rolling is a greater risk for narrower tents; wider tents are more stable.
When a tent is blown over sideways, it is referred to as shear failure. Uplift failure occurs when the tent lifts off its anchoring and “flies away.” Uplift failure is definitely an anchoring issue. Strangely, wider buildings are more at risk than narrower buildings, as they have a more aerodynamic side profile, although failure is less likely to occur since wider tents are generally heavier.
Shear failure may or may not be a failure of anchoring (ballast), but it can be the first step in a catastrophic chain of events. Shear forces can slide a base plate out from under a ballast unit. Structural movement can dislodge ballast units. At this point, you would have no ballast to count on. In some cases, the wind can be lifting one part of the structure and crushing another area. These are extremely complex forces to understand, and their analysis and reporting should be left to professionals.
Components of non-staking jobs
The components of a non-staking installation are the mass you are using to anchor the structure and the connections to that mass. The final piece of this puzzle is the approved information to guide you in the appropriate selection of these components.
The ballast or mass is where this whole process begins. Based on the manufacturer’s or engineer’s recommendations on the required mass for a particular tent, you must decide which ballast to use. There are many different types of ballast. Water barrels are the most common and easily managed form of ballast, and they usually take the form of 55-gallon plastic drums. Water barrels generally weigh around 450 pounds when filled. Sandbags of varying weight and sizes are also very common.
Concrete barrels usually weigh 1,000 pounds each and are created by filling 55-gallon steel barrels with concrete. Concrete highway barriers, which are often referred to as Jersey barriers or K-rail, typically weigh 400 to 450 pounds per linear foot. Also available are large ballast blocks of concrete or water-filled highway barriers. Pre-cast blocks of concrete can weigh up to 4,000 pounds per unit.
Once you decide which type of ballast to use, determine how the mass will be attached to the tent or structure. The most common types of attachments are straps and ropes. Keep in mind that all connectors must be at least as strong as the ballast load, and they all must be in good condition. If an engineering team requires special base plates for the legs, then those engineers must specify all bolts and hardware in that system—no substitutions should be allowed.
Working with professionals
It’s crucial to have good working relationships with professionals who can certify your non-staking installation. Use your knowledge and experience to teach these professionals what tools or components you have to work with.
One way to meet all the requirements of your state and local authorities is to have your installation “engineered.” That’s the process where you present all the manufacturer’s specifications to engineers, who will then give you specific guidelines for your non-staking installation. You may also be required to supply a detailed site survey that includes surrounding buildings, soil information, surface details, dates of installation to determine likelihood of weather incidents, and anything else that could affect the performance of the installation.
This is an extremely tedious process that may require several attempts in order to complete all the specifications of the engineers. There is also no guarantee that you can indeed meet all the requirements of the professional engineers (PEs) to get your installation permitted. And in addition to the labor involved in this process, there will be considerable expense in getting the approval of the engineers and authorities. This can easily reach several thousand dollars. These reports are generally site-specific, so a new report may be required for each individual installation.
City or state authorities may require the project specification to be signed off by a PE. Many authorities require a “wet stamp,” or an engineer’s seal, before accepting a project report. A PE is a recognized engineer who has met all the requirements of his or her state in terms of educational and professional certification. Not all engineers are PEs. In addition, a state may not accept a project specification signed by a PE certified in another state.
In the case of non-staking installations, having your plans certified by an engineer can protect you in case any legal action arises from injuries or damages associated with a structural failure. A signed and sealed report detailing the actions you took to ensure a safe installation will probably be your best defense. An engineer who is recognized by his or her state as an authority in the field will be the first line of indemnification for you and your company.
There are many engineering firms that can advise you on having your installation engineered. Some of these are listed on the IFAI Web site at www.ifai.com/tent/engineerlist.cfm.
If your sales team closes the deal and the customer tells you after the bid is accepted that the installation will be non-staking, then you have every right to renegotiate the contract. There are so many other issues associated with non-staking installs that the cost can easily erode a significant amount of your profit.
If you do take on a non-staking job, your crew must be familiar with or trained in non-staking procedures. Don’t forget that there can be an increased danger to employees due to the crushing hazard of large pieces of concrete.
When constructing the layout for a tented event, keep in mind that ballast occupies more space and cannot block the exits. In addition, large concrete blocks or Jersey barriers require better site access for trucks. During the planning stage, factor in the need for extra personnel and equipment. If you are just adding ballast to your product offerings, think about storage. What will happen to the anchoring materials once you’re finished with them? Also, if you’re setting up a tent for a long-term installation, consider using ballast other than water barrels, as the plastic can crack and cause leakage.
Again, manufacturers’ recommendations are the final word in erecting any structure. Anything you make up on-site or in the office is therefore a deviation from the manufacturer’s guidelines. But what if the manufacturer does not have ballast guidelines? Many manufacturers will not commit to any specific amount of ballast.
If there aren’t any manufacturers’ guidelines to work with, your option as a tent renter is to create as many layers of liability protection as possible. Enlist as many professionals as you can to ensure the safety of the public, the safety of your personnel and the safety of your business. Mistakes or shortcuts at any step of this process can result in injury or death, and the resulting litigation can mean an end to your business.
Ballast is not an answer for every situation. Every non-staking installation must be undertaken with all the seriousness of any other technical problem. Conduct your business and your contracts in the most professional manner possible. Be aware of the risks and take your responsibilities seriously.