QuakeWrap, Inc., an Arizona
Corporation, has successfully completed the strengthening of a cell phone tower
using a patent-pending system that utilizes Fiber Reinforced Polymer (FRP)
products. The repaired tower is located in a congested site in Los Angeles, CA
and is one of many such towers worldwide that could benefit from this
technology.
With the increased use of
mobile communication worldwide, existing cell phone towers must be structurally
upgraded to accommodate loads from additional antennas. In many cases,
these towers are located in congested urban areas where zoning restrictions
limit the number of towers being built, and the use of guy wires is not an
acceptable option. For these types of self-supported structures, cell tower
owners and carriers must find a compact strengthening system that can be used
in tight spaces, and is non-disruptive to service. QuakeWrap Inc. provides just
such a solution.
The first application of this
technology was recently
completed for Crown Castle International, the largest provider of shared
wireless infrastructure in the United States. A 55 foot (17 meter) high cell
tower located in a high seismic zone in southern California was strengthened to
increase its load-carrying capacity. The monopole structure is made of a hollow
spun precast concrete tube with a thickness of less than 2 inches (or 50
mm). In a technique developed by the QuakeWrap engineering team, the
tower was modeled and analyzed to determine the strengthening required at
various elevations along the height of the tower. It was determined the lower
two thirds of the tower required tension reinforcement; this was achieved by
bonding Carbon Fiber Reinforced Polymer (CFRP) sheets saturated with epoxy
resin to the surface of the tower.
In addition, about half of the
tower was too thin, and required a thicker concrete to resist the increased
load safely. According to Dr. Mo Ehsani, President of QuakeWrap, Inc. and
Professor Emeritus of Civil Engineering at the University of Arizona who has
invented this system, “the challenge in this case was that we had to make the
wall of the concrete tower thicker; our patented PileMedic® laminates allow us
to easily make a shell of any size around the tower. The annular space
between this shell and the tower can be filled with grout.”
The high structural performance
of QuakeWrap® Fiber Reinforced Polymers (FRPs) combined with their low profile
and flexible application made an ideal solution for the strengthening of the
tower. Layers of carbon and glass fabrics, in combination with QuakeWrap’s
patented PileMedic® jacket strengthening system, and proprietary epoxies and
resins provided a fast and economical solution as demonstrated in a
video posted to QuakeWrap’s YouTube channel.
QuakeWrap, Inc.
2055 E. 17th Street
Tucson, AZ 85719
(520) 791-7000
www.QuakeWrap.com