PEC PROVIDES COMPETITIVE APPROACH TO MANHOLE REHABILITATION DESIGNS By Michelle Coulter
Beginning in 1983, PEC has become renowned as sewer assessment, rehabilitation, and design experts. Oftentimes, clients return to our firm for our expertise and experience in various means of rehabilitating and repairing sewer structures. We work alongside various contractors to provide quality assessment and design plans and ensure our clients have sewer structures with long life expectancies.
As of late, PEC has been tasked with assessing and rehabilitating manholes and structures for several clients, including the cities of Phoenix, Mesa, and Glendale, as well as the Town of Paradise Valley and EPCOR Water. Prior to providing methods to rehabilitate or repair these sewer structures, the PEC team evaluates the viability of the sewer structures to ensure they are appropriately graded according to their existing condition.
Our team is certified with the National Association of Sewer Service Companies (NASSCO) in their Manhole Assessment and Certification Program (MACP), which allows us to properly grade manholes in a consistent and accurate manner so that we may propose effective means of rehabilitation and establish a baseline for future assessments. We also have engineers trained in the NASSCO Inspector Training Certification Program (ITCP) for pipeline and manhole rehabilitation.
PEC is currently working with the City of Phoenix on their Large Diameter Sanitary Sewer Rehabilitation program for grades 4 and 5 manholes. The project includes 200 precast concrete or brick manholes with varying interior finishes, including unlined concrete, coated concrete, and polyvinyl chloride lined concrete. PEC has prepared rehabilitation design plans for manholes and structures throughout the valley (i.e., for the cities of Glendale, Peoria, Mesa, as well as EPCOR Water). Due to our experience, the City of Phoenix recently selected us to prepare design plans and specifications for the repair of their sewer structures.
Tom Braatelien, PEC’s project manager, stated, “This is a great opportunity for us. PEC has gained the City’s trust through our familiarity with manhole assessments and background with gravity sewers. We’ve been able to effectively provide our expert knowledge of the City’s manholes and means of rehabilitating them.”
Our team has suggested various rehabilitation and repair methods for the City of Phoenix manholes, including inserts, coatings, liners, collar replacements, and even the use of polymer inserts. We have also had the opportunity to work with several contractors to explore additional cost-effective methods.
Braatelien continued, “PEC is working with the contractors to determine possible methods for rehabilitating the manhole invert channels. On larger diameter systems, these structures could cost $60,000 or more to bypass. Through these working relationships, we’re investigating flow-through plugs and other means of drying up the channels so as to save the City time and money.”
We have also discovered that bypassing may be the only option in certain scenarios. For the Town of Paradise Valley, we have found that flow diversion is the preferred option for the work on their system.
PEC’s project engineer, Levi Hawkins, stated, “Typically, we don’t prepare plans to divert flows in low flow sewers because of the impact it can have to residents. The Town prefers to do a simple bypass and avoid potential problems.”
By diverting flows, the contractor was able to successfully avoid sewer overflows and apply epoxy coating that would extend the life of the manholes in Sun City and Sun City West. There were also several older manholes that required removal of steps prior to cleaning and applying epoxy coating. These manholes were identified in an assessment previously completed for EPCOR Water, which allowed our team to gain a trusted relationship with the client.
PEC has also had the opportunity to develop a working relationship with the City of Mesa, a client that has repeatedly returned to our experts for sewer infrastructure assessment and design services. Tom Braatelien stated, “PEC has serviced the City for several years, having completed sewer design projects on various projects. We are currently awaiting a notice-to-proceed for another wastewater evaluation project that includes additional manholes throughout the City.”
During the Wastewater Manhole Evaluation Phase 13 project, PEC was tasked with tackling an aggressive schedule to assess and rehabilitate 850 manholes. PEC expedited our services by distributing work to additional team members.
PEC is efficient with mitigating challenges that surface during sewer design projects. Mark Lee, project manager for the City of Glendale Sewer and Manhole Rehabilitation, Phase V project, had recently discovered a sewer line in critical condition.
Lee claimed, “In the middle of the pre-design work on this project, our designers identified a collapsed sewer line that required an emergency repair. We were then contracted by the City to design a repair for this critical sewer line, which is now fully functional.”
The project also involved 43 manholes requiring various means of rehabilitation or repair. Depending on the severity of deterioration, the PEC team prepared plans for spot repairs, epoxy coatings, and frame and cover replacement.
As a result of our successful completion of this project and others similar to the services required, PEC was selected to design a structural solution for an existing manhole over which a BNSF heavy rail spur track will be located by a developer. We provided the design for a structural slab located over the manhole to transfer the train load away from the remaining structure and sewer pipe. In addition, we were selected to prepare abandonment plans for several nearby manholes along the Glendale Avenue railroad alignment.
As demonstrated in our background with sewer infrastructure projects, PEC is renowned for our sanitary sewer assessment and rehabilitation design of manhole structures. PEC maintains strong relationships with clients and contractors for our expertise and experience in sewer pipeline and manhole rehabilitation designs.