It’s time to step away from the past when considering the future of your anti-buoyancy solution

Burying cables and pipes is by far the most practical solution when it comes to supplying buildings with basic amenities, as there are millions upon millions of miles of cable globally which would take up a vast area of space and cause countless hazards if left above ground. The provision of electricity, gas and water, as well as connections such as telephone and internet services, are all reliant on underground cables. Underground duct banks are often used to ensure that these essential utilities are protected from any external factors and can continue to run smoothly.

The cost of installing underground services can vary massively from state-to-state due to things such as regulation, ground conditions, population density and labor costs. This fluctuation can be as high as $200/ft on the West Coast to as low as $20/ft in South-Eastern states. Due to the unpredictability of installation costs, it is absolutely essential that damaged cables, and the subsequent callouts for repairs, are avoided.

The high cost of labor and materials have caused manufacturers and installers to reconsider their construction process, introducing innovative methods such as pre-assembled duct banks which are easily lowered into the trench as one whole unit. The necessity to ‘think outside of the box’, and consider new and innovative approaches, is born primarily out of a desire to minimize overall project costs.

Conduit buoyancy’ occurs when the total downward force is lesser than the resulting upwards force which is acting on the conduit. This is often an issue when installing conduit banks for electrical services due to the increased area of empty space within the conduits – especially when using concrete casing, due to its rotatory nature. This can lead to catastrophic damage, particularly when considering the cost of the service being down and the time needed to replace the damaged line.

The trouble with tradition…

Despite the common nature of flotation issues, until now there hasn’t been a specifically engineered solution for the problem on the market. While conducting an installation which uses concrete pour, installers will often use rebar as a tie-down method – either driving the rebar into the ground before manipulating it at a 90 degree angle in an attempt to secure the conduit bank, or driving the rebar into either side of the trench wall as a reinforcement method. While traditional anti-buoyancy techniques have managed to develop widespread adoption, they are certainly not without their problems.

As the current anti-buoyancy methods aren’t specifically engineered for the application, it is impossible to guarantee that the approach will be successful in allowing the system to avoid flotation. This is worsened by the fact that any issues will only be discovered once a failure occurs, which inevitably leads to time consuming operations in order to locate the failure and begin repairs. Any level of flotation at all in conduit banks is usually nothing less?than catastrophic, as a full conduit bank floating upwards at different rates will often render a full system useless once concrete has entered the broken conduit – meaning a full, time-consuming removal and replace operation.

The interaction of traditional methods with the soil which surrounds the trench walls increases the likelihood of trench collapse. While steps have been taken to improve the health and safety of workers in trenches, 2019 and 2020 were the second-deadliest years for trench-collapse deaths since 2010 according to the CPWR Center for Construction Research and Training Study 2019. This number of trench-collapse fatalities meant that employers accumulated financial penalties of over $1.1 million in 2020 alone. Minimizing the amount of time which is spent working in trenches and avoiding disturbance to trench walls are two of the ways which employers are attempting to reduce the above figures. Many traditional solutions for counteracting the uplift of conduit banks require both long periods of time spent working in trenches and interaction with the trench walls, increasing the risk of potentially fatal accidents.

As conduit banks are almost always installed in trenches, this means that installers are often carrying out their work in potentially dangerous environments for long periods of time. This inevitably leads to high labor costs which further increases the importance of choosing the most efficient installation methods. Traditional anti-buoyancy techniques are notoriously time-consuming and often require numerous installers at each installation point. One of the main priorities for any company which is undertaking an installation will always be to minimize installation times – allowing them to reduce labor costs and, as an outcome, avoid any unnecessary further health and safety risks.?

Conduit banks which supply electrical services are frequently installed to connect several locations. This means that installations often take place in fairly remote locations, which aren’t always guaranteed to have suitable infrastructure to make them easily accessible. The cumbersome nature of traditional anti-buoyancy techniques only increases the logistical issues that?will be faced while trying to access project sites.

Gripple’s Solution:

While conducting a conduit bank installation using concrete pour as an encasement, the chosen anti-buoyancy technique can make a huge difference to the speed and safety levels of an installation, and the overall reliability of a system once a project is complete. Failing to consider the overall performance of anti-buoyancy techniques will lead to a less efficient installation while also increasing the likelihood of even more serious consequences such as cable failures. These issues can be avoided with the adoption of a specifically-engineered, fully-tested anti-buoyancy system which is designed especially to be compatible with conduit banks.

Gripple has used its vast experience and knowledge of uplift prevention, gained whilst working in the civil construction and solar industries, to develop an innovative method of counteracting the flotation of conduit banks. The system can be used to reduce installation times, minimize health and safety concerns and avoid unnecessary risks.

Gripple’s Underground Buoyancy Anchoring kits are the perfect solution to prevent all uplift of any underground MEP services which are at risk of flotation. The kits consist of an Underground Buoyancy Anchor connected to a pre-cut length of 1/8 inch cable, driven into the ground, and then secured to the conduit bank with a D3 Lockable Plus fastener.

The system has been developed while working alongside contractors and installers, to maximize the product’s ability to solve everyday problems that are faced on-site. The anchor’s narrow frontal profile ensures that it can be driven into all soil types using only basic, hand-held tools. Once the anchor has been driven into the ground, it is ‘flipped’ so that its wider top profile can ‘load-lock’ into the soil’s engineering properties. This creates a truncated cone of soil which maximizes the anchor’s uplift capabilities. Once the anchor is fully set, it can be attached directly to all styles of duct bank before using the D3 Lockable Plus as a termination and tensioning mechanism. This allows the system to have complete control over any upwards forces despite using considerably less materials than traditional anti-buoyancy techniques.

Initial feedback indicates that, while still offering a considerable amount of protection against uplift, Gripple’s UBA kits can be installed around five times as quickly as traditional methods. All kits have been designed to be installed while working individually and are supplied in ready to use, ‘out-of-the-box’ kits to simplify handling and organization while on site. The kits can even be attached to the conduit bank prior to the bank being lowered into the trench, further reducing the time spent working in difficult and potentially dangerous conditions.

As well as vastly improving the time which is needed for an installation, the kits ensure that each installation provides full ‘peace of mind’. While traditional techniques could be considered to be ‘tried and tested’, they cannot provide the engineering calculations to guarantee that all uplift will be avoided. This could be considered risky as any faults with the system will only be discovered following the installation. Provided with each unique project’s details (conduit area, conduit length and soil type), Gripple engineers can use the Underground Buoyancy calculator to recommend the specific number of anchors that would be needed to allow the full conduit bank to counteract all upward forces.

Considering the future:

Underground conduit banks are key components to the avoidance of downtime within essential and ever-expanding facilities such as data banks, manufacturing locations and hospitals. The protection of any buried conduits should therefore be a high priority throughout the installation process. Concrete pour is a tried and tested method of securing any buried conduit banks, protecting electrical cables from extreme weather conditions, seismic stress, corrosion and even vandalism.?

While concrete pour is the most commonly chosen method of conduit bank encasement, the increased chances of flotation due to the natural ‘churn’ of the concrete means that the risk of damaged conduits grows. This only serves to highlight the importance of promoting the choice of anti-buoyancy technique from an after-thought to a serious consideration for all project stakeholders. Installation times can be minimized meaning more competitive bidding rates for Electrical Contractors, less time can be spent working in dangerous conditions for Installers meaning less health and safety risks for Employers, and improvements in reliability mean reductions can be made in downtime and maintenance checks for Engineers.?

With the ever-growing importance of conduit bank protection, comes the increasing importance of trusting new innovation. It’s time for the market to step away from the past when considering the future of their preferred anti-buoyancy solution.?