Drain Pan Void Fill Structural Support CDOT Region 1

A drain pan structure running adjacent to US-287 near Broomfield Colorado had experienced significant voids of varying severity beneath the structure. The drain pan was designed to move water away from the roadway during water events and run off; however, due to issues with the design of this particular structure, water was running beneath the concrete and eroding areas beneath the pan. The integrity of the structure was compro-mised due to the weakened and eroded supporting soil.

CDOT needed an effective solution to treat and repair the almost 800 foot long problem section of drain pan that would not only fill the voided areas, but also protect it against additional damage and structural failure that may also effect the safety of the adjacent highway.

A thorough evaluation of the site was conducted prior to design of the repair plan for the drain pan. It was determined that the more severe voids were located on the uphill slope area of the structure. Alternate solutions, including a flowable fill, were taken into account while determining the most effective way to treat the area. However, due to the advanced features of CST’s proprie-tary injection process, and the unique characteristics of the specialized expanding structural polymer, it was determined that filling the voided areas using this process would most effectively and most efficiently solve the problem. Injections were made directly through the drain pan, filling voids, and strengthening the supporting soils.

The entire stretch of affected drain pan was void filled and stabilized in four days without any disruption to traffic flow along the adjacent highway.

The treatment method allowed CDOT to extend the use life of the structure and avoid the expense of tearing out and replacing the structure.

The specifically designed repair not only eliminated the void space beneath the pan and strengthened the soils, but also provided protection to the structure against future erosion.

Repair costs came in under budget for this project.

Wyoming Manhole REpair

Rafter J Wyoming Manhole Repair

35 manholes/vaults and 4 transfer stations in this Wyoming manhole repair project at the Rafter-J Ranch Subdivision Improvement and Service District, located 5 miles south of Jackson Wyoming.

Critical Elements of this project included a very high sewer treatment costs due to excess water infiltration into its collection system. System was kept online during repair work. The savings in treatment costs paid for the repairs in less than one month.

Culvert Annular Void Fill

Utah DOT Culvert Annular Void Fill

Objective of this project was to fill annulus between culvert and surrounding embankment. The outer pipe was rusted out at the bottom and water was leaking in between the two pipes and coming out bottom of joint. Goal was to seal leaks in an outer pipe, surrounding smaller pipe and fill voids.

Critical elements of this project were dealing with the rusted out bottom of the outer surrounding pipe. Large amounts of water needed to be pushed out and fill resultant voids to assure pipe support and stability.

Inflow and Infiltration

Cokeville Wyoming Manhole Rehabilitation

As a result of successfully completing the manhole rehabilitation project for the Town of Big Piney, Concrete Stabilization Technologies was contacted by Cokeville Wyoming’s Assistant Public Works Director Mike Duran concerning infiltration in the town’ sewer system due to cracks and leaks in the town’s sanitary sewer lines.

Concrete Stabilization Technologies worked with Mr. Duran and a plan and proposal was developed to re-pair the leaking lines and prevent any future infiltration in to the sewer system.
Twin D Inc. Environmental Services was contracted to camera the lines and determine the exact location of each leak. They were also kept on stand- by with cleaner/cutter equipment in case any polyurethane made its way into the sewer system.

Strategically placed 5/8” holes were drilled through the overlying roadway, down to the connections in question between existing manholes. ½” probes were then inserted into the drilled holes to reach the infiltrating connections and cracked pipe. Using CST technologies, expanding structural polymer was injected through the probes, sealing cracks, gaps, and leaks in the -lines and joints.

CST crews began working on the project at 10:00 a.m. Each injection was precisely directed 1” to 2” from the joint/crack on top of the sewer pipe, the polymer followed the water trench around -the sewer pipe and into the crack or joint, sealing off where water was infiltrating.

The series of repairs were completed at each location, working a series of injections around each of the leaking lines and joints until all leaks were sealed. All work was completed by 6:30 p.m. Work was completed in situ and without taking any of the lines out of service during repairs.

Douglas County Sheriff MSE Wall Repair – Highlands Ranch, CO

Douglas County Sheriff MSE Wall Repair – Highlands Ranch, CO

Concrete Stabilization Technologies, Inc. partnered with the Douglas County Facilities Management division of Douglas County, CO to stabilize the MSE walls at the Douglas County Sheriff Sub-Station in Highlands Ranch, CO.

CST was referred by a geotechnical engineering firm to provide a solution to stabilize portions of distressed MSE wall. The geotechnical report indicates low density soils between base of wall and top of storm sewer pipe installed approximately 16’ prior to MSE wall. A section of the MSE wall was slated to be rebuilt after soil stabilization project was completed.

Patented processes were used to increase bearing capacity and stabilize the West and East MSE wall in the sewer trench area of the facility for an area of approximately 60 LF. CST’s deep injection method was performed to reinforce low density soils between top of storm sewer pipe and bottom of MSE wall. The distressed MSE wall was monitored with laser levels during the injection of expanding structural polymer into the underlying soils. Injections were also performed around a manhole to void fill and seal joints.

Video camera inspections were done before and after injection to verify pipe condition. The patented injection processes used in this stabilization project saved the customer from excavating and possibly replacing the pipe.

This project was completed on time and on budget!

CDOT HWY 52 CMP Rhabilitation – Hudson, CO

The Problem

The deterioration of Corrugated Metal Pipe, (CMP) at the flow line is a result of exposure to oxygen and moisture mixed with metal, which causes rust. Other factors such as soil conditions and the acidity of the water flow will also affect the rate of deterioration.

When CMP deteriorates, water runs under the pipe instead of through and undermining of the structure occurs. Sink holes above the structure will begin as the soil collapses. The underlying bedding material or support fill is then exposed to water flow, and begins to erode away, causing voids and loss of structural support. This creates a potentially dangerous situation with the possibility for failure of the entire structure and collapse of the overlying roadway.

Concrete Stabilization Technologies, Inc.’s Field Consultant, Richard Hess was contacted by Colorado Department of Transportation Maintenance Department representative for Region 4, Zach Junk, concerning a deteriorated culvert beneath Colorado State highway 52 near Hudson, Colorado. The traditional method of tearing out and replacing eroded culvert pipe had proven to be a time consuming and disruptive process which had lead CDOT to seek a less disruptive solution.

The Solution

CST met on site with Mr. Junk and after reviewing the area, determined that our CMP repair process was an ideal fix for this particular culvert and overlying roadway. Subgrade stabilization injections from the roadway surface were included in the repair plan where exfiltration of soils through the rusted out pipe had caused variable settlement in the road surface above the culvert, requiring steel plates as a temporary fix against further damage to the road surface and vehicles. Thus, part of the CST complete solution was to not only secure the metal sheets to the old CMP but to also inject from the road surface above to 3′ to 4′ to reinforce the subgrade while replacing soil lost to exfiltration.

CDOT maintenance representative Zach Junk stated that he, “liked the fact that they didn’t have to close the road or detour traffic like they normally do when having to replace pipe.”

Structural integrity of the existing pipe was a concern and it was discussed that not only would the structural integrity of the pipe be restored, but also restoration of correct flow into the repaired pipe.

The ditch company expressed concern of subsequent debris buildup such as weeds and silt that may disturb the water flow. The repair design and installation is such that this concern is positively addressed and re-establishes water flow with no added obstruction.

After an in depth investigation and review of the site, it was assured that this would be an ideal repair process for the deteriorated culvert and CST was given the approval to begin the project.

Crews arrived on the job site around 10:00 a.m. to begin repairs. A significant amount of water was running in the ditch containing the culvert. While water was shut down, crews began deep injection to stabilize the sub-grade on the overlying roadway. Injections were made from the surface at a depth of approximately 3 ½ feet on 5 foot centers, while monitoring at the surface for move-ment. After the subgrade stabilization was complete, it was determined that one of the two overlying road lanes was in good shape and the other lane would only require select asphalt patching once repairs were complete.

The Results

Neither lane required any excavation during repair, due to CST’s unique in situ polymer injection process. Once stabilization of the roadway was complete, the crew began repairing the corrugated metal pipe. Repairs and cleanup were completed in one working shift. The Frico Ditch Company representative confirmed that “the ditch is flowing well”.

Benefits of CMP Repair

The patented CMP repair process is quick and non-disruptive. The pipe is first cleaned of any sticks, rocks, and other debris. Repairs begin on the outlet-side of the pipe where the new sheets of specially coated metal are laid, ensuring the corroded water line is covered. The metal sheets are then attached to the ribs of the pipe with corrosion resistant fasteners. Overlapping sheets are then continuously added and secured in place until the length of the pipe is completely reinforced. In this case, the culvert being repaired was approximately 50 feet long and 5 feet in diameter with the corrosion/water line reaching approximately one third of the way up the side wall of the culvert. Once the new metal sheets are all placed, and secured, expanding structural polymer is injected beneath the metal sheets, to fill any voids beneath the pipe. Excess material is removed and a tar coating is applied to the top edge of the new metal sheeting as an extra protective measure to deter rusting and to ensure longevity.  The benefits include:

  • No-excavation
  • Less disruptive
  • Reduces costs
  • No road or rail closure or downtime
  • Repair equipment & material are easily mobilized
  • Extends lifetime of invert
  • No loss of flow
  • Environmentally inert materials
  • Completely restores structural integrity