Is Grout Helping or Harming Your Lighting and Utility Poles?
If you look at older steel lighting and utility poles that are anchored to pier foundations, you will probably find that grout has been applied underneath the base plate or flange. Most asset owners don’t see this as a problem. However, as these assets have aged, Exo has found that grouting baseplated connections actually does more harm than good.
The space between the baseplate and the top of the foundation was grouted which encased the exposed portion of anchor bolts. Why?
It was common practice in civil engineering and building construction to grout the baseplates of structural columns to disperse loads. This was a proven and effective design for those types of structural connections.
In the 1970’s when tubular steel poles started to become popular, those same design standards and construction practices were carried over to steel utility poles and lighting poles. If grout provides structural benefit to interior building columns, the same benefit must apply to exterior poles.
There’s a big difference, however, in the operating environment of building columns and utility and lighting poles. Electric transmission and lighting infrastructure is exposed to the elements (moisture from rain, snow, and humidity, temperature fluctuations, and so on). Structural columns inside a building are not exposed to these elements, with any changes in temperature or humidity being insignificant by comparison.
How to Determine if Grout is Helping or Hurting
Grout Contributes to Corrosion
While grout on poles does disperse loads at the base or flange connection, it does not protect anchor bolts from moisture and corrosion. In fact, it has the opposite effect.
Grout is not a total barrier. It not only allows moisture to enter the foundation, but it traps the moisture around those critical anchor bolts and flanges of utility and lighting assets. If left unchecked, this corrosion could impact the structural integrity of the foundation connection and even the shaft wall of the pole itself.
Older structures with grouted foundations and grouted baseplates are therefore at heightened risk for shortened asset lifecycle, and have an increased potential for unplanned, catastrophic failure, This
increases cost of repair and maintenance, and could lead to downtime or service interruption.
Inspect and Correct Grout Damage
Because the grout covers the anchor bolts and the baseplates, you can’t see the corrosion damage as it spreads and worsens. Therefore, the following steps are necessary to protect your lighting systems and preserve your system infrastructure:
- Determine if your system has grouted baseplates and foundations.
- If you do have grouted assets, you need an inspection and remediation program.
- For a successful program, we recommend immediate grout removal, followed by a qualified structural inspection of the anchor bolts, foundation, and pole shaft to determine if there has been any weakening or deterioration due to corrosion.
- If the qualified inspection shows degradation, you need a team to design and implement a solution that either restores or replaces your assets as needed.
Expert Support for Stronger Lighting Structures
If you are faced with the prospect of grout removal, corrosion remediation, and asset repair and maintenance, Exo offers a turnkey solution to asset management. Our expertise includes inspection, remediation, engineering evaluation, and data management.
Partnering with us means you have ongoing insights into asset performance, and plans for repair and replacement that are efficient, cost effective, and innovative.