There really is a difference. This category of piers goes by a dozen names, each with a very narrow and specific design, but is also used in a broader sense for general foundation support and repair.

Let’s narrow it down a bit and define the differences and applications.

A helical abutment is a square bar or tube that has helices on it (much like a post hole digger). A hydraulic motor spins the pipe causing it to be bolted into the ground. The direction could be vertical or angled (mass degree) as required by the design. The stiffer the soil, the greater the load capacity. It has the unique characteristic of having the same capacity in compression (vertical load) as in traction (fastening to a wall).

It can be installed to its capacity with the installation kit, excluding any building, foundation, or other mass.

It is ideal for new construction, light loads, fractured footings, tie downs, tension loads, temporary applications (easily removed) and generally has a maximum actual capacity of 156 kips (1 kip = 1,000 lbs.) although there are some sources with higher capacities.

What about pillars of push (also called pillars of resistance)? These are open-ended tubes that are pushed vertically into the ground until they terminate in soil that is determined to be strong enough to support the load they are required to carry. A hydraulic ram is used to insert the pillars and then anchor them to the structure. The weight of the structure becomes a resisting mass to push against, hence the name thrust pillars. Capacity is limited to the direct load provided by the building. It is a one-to-one capability with no factor of safety (FS). FS comes with multiple thrust pillars that, when designed correctly, share the load. Full capacity can only be reached if the reaction load is heavy enough to withstand it.

A push spring is a strong spring, albeit a very simple one. It is stable and ideal for heavy loads. It can be installed in a very small area and can shore up an existing footing that could be undermined by adjacent excavation. Typical maximum capacity is 90 Kips.

There are overlaps in some applications such as nominal to fairly heavy duty shoring and remediation projects. A thrust pillar or lashing cannot be removed because its sections only compression fit. It also can’t be a newly built pier because it needs the reaction mass in place to push. It should not be used under light load (because of the minimum weight) or with cracked or broken shoes.

Helical piers can do most remediation jobs because they create their own unique capacity from the weight of the structure and not “load-release-load-release-load” the foundation like thrust piers. It is not as good as a thrust column for shoring because it cannot be sleeved to reduce buckling. Helical pillars are more expensive but go in faster. Most of the time, they use the same foot supports.

Both are vibration-free, cost-effective, long-lasting, approved by building engineers and inspectors, and have 30+ years of design, field testing, and actual field use. Installed correctly, the failure rate is so small that it is practically non-existent. Most failures are related to other factors. All springs can be easily reloaded for proper performance.

Whether your installer chooses a helical or thrust abutment, you can be sure it will be a rewarding decision and a great solution to your problem.