We have developed proprietary solutions for repair and strengthening of deteriorated H piles that have been tested by independent agencies. Our structural engineers will provide designs that enhance axial, flexural and shear capacity of the steel H-piles, regardless of the extent of corrosion on these piles. Client will also receive sealed engineering drawings and calculations for their projects.
In some cases, the corrosion is similar to an extensive pitting as shown here. While there may not be a major concentrated loss of cross section in these H-piles, nevertheless, the steel H-piles shown here have lost significant axial and bending capacity and must be repaired and strengthened to restore the original strength of the steel H-pile. However, such restoration to original capacity is not an easy task.
Welding as a solution
One approach to repair and strengthen steel H piles is by welding additional steel plates or shapes such as C Channels or steel angles to the deteriorated pile. Such repairs have their own problems. First, welding of new steel sections underwater to corrosion-damaged piles is a difficult and expensive task. Secondly, the difference in metals between the original steel H-pile, the new steel sections and the weld material can lead to galvanic corrosion. Such repairs are not a permanent fix.
Texas DOT research on steel H-piles repaired with PileMedic®
In August 2011, Texas DOT initiated a research study (Project:0-6731- Repair Systems for Deteriorated Bridge Piles) to evaluate some of the techniques for strengthening of corroded steel H piles. The 3-year study consisted of two parts. Structural performance of the jackets for both reduced- and full-scale piles was given to the University of Houston. Texas Tech University was given the task of evaluating the durability of the system.
To simulate corrosion, different percentage of cross sections from the webs and flanges of these seven H-piles were removed. In some cases, as much as 80% of the wall thickness was removed to represent excessive loss of capacity due to corrosion. The researchers wanted to perform the repairs in conditions closely resembling field conditions. The steel H-piles were placed inside a large steel tank that was filled with water. The damaged portion of the H-piles were wrapped in PileMedic® to create a solid seamless shell. Next, the portion of the H-pile that was wrapped was filled with PileMedic® underwater grout. The pile was allowed to remain in that position while the grout cured. In some cases, steel reinforcing bars were also included in the grouted space.
Testing of steel H-Piles repaired with PileMedic®Testing of the large-scale H piles consisted of placing the specimens inside the red color test frame. For safety and ease of operation, the specimens were positioned horizontally in the test frame. Concentric axial load was applied to the repaired piles.
The test had to stop after the jack applied a load of 658,400 pounds (2,930 kN) because the jack had reached its limit and could not provide any additional load! Nevertheless, the research team leader, Prof. Dawood, concluded that "at a minimum, the PileMedic® system restored the capacity of the deteriorated pile to its initial undamaged capacity." The final report on this study is available in pdf format here and the video can be viewed below.
Transfer of forces between steel and concrete (or grout) is a design concern to many engineers. Traditionally, welded shear connectors have been used for such load transfer. But underwater welding is not easy and on some jobsites that handle flammable materials, welding may not be allowed. That is why we have recently developed a patent-pending system similar to those shown here that allows transfer of loads through a friction mechanism. Our engineering design package submitted to the clients provide design details and calculations for ShearClamp™.
While there are a number of our patents that address repair of piles and columns, below are a sampling of some of the pertinent issued patents:
U.S. Patent No. 10,808,412. Spacers for repair of columns and piles
U.S. Patent No. 9,890,546. Reinforcement and repair of structural columns
U.S. Patent No. 9,376,782. Repair and strengthening of piles and pipes with FRP laminates
U.S. Patent No. 8,650,831. Reconstruction methods for structural elements
Using a combination of unidirectional and/or biaxial fabrics, PileMedic® laminates provide strength in both longitudinal and transverse directions.
PileMedic® is very thin; with a thickness as small as 0.01 inch, it is flexible enough to be wrapped around corners of square columns
PileMedic® laminates are manufactured in plants under high quality control standards; this improves the quality of the finished construction.
The repairs can be completed much faster in the field.
The strength of the laminates can be tested prior to installation.
The number and pattern of the layers of fabrics in PileMedic® laminates can be changed to produce an endless array of customized products providing different strength values along the height of the pile or in the hoop direction.
Additional coatings to the surface of the laminate can be added for abrasion and UV protection.
"In a business where compliments are few and far between, I would like to assign credit to a few good men. I would like to thank your exemplary employees, as they championed this project from start to finish with enthusiasm unknown to most construction work. ” — Inspector Salt Lake City Department of Public Utilities
"Piles are now being repaired in an hour compared to a day." Navy Commander