GPRS utility site maps helped Teichert Solar to successfully install a solar carport system at the Gateway Seminary in Ontario, California. The structural integrity of a solar carport relies on a proper foundation, and that requires accurate underground utility and sewer locations to be cleared before selecting and placing concrete piers.
The seminary planned to construct a solar parking structure enabled with electric vehicle charging on an existing parking lot. Teichert Solar, a division of Teichert Construction, was contracted to design and engineer the carport system.
A solar carport is designed to hold overhanging solar panels and serves the dual purpose of providing shelter and generating electricity from the sun to charge electric vehicles (EV).
Installing solar carports is a technically challenging project that requires careful engineering and a proper foundation to support the weight of the steel structure and solar panels. For ground-mounted carport system installation, such as the application for the seminary, concrete piers are poured into a cored hole around rebar, with the footing extending above ground level to support the solar parking structure and withstand vehicle collision. Installers then place and anchor the racking portion and solar panels on top of the concrete piers.
GPRS was called out to scan, locate, mark, and map utility and sewer locations: information that was critical to correctly plot and place the solar carport foundations to avoid clashes or utility strikes.
Utility Mapping the Seven-Acre Site
In one day on site, Project Managers Vincent Lopez, Dillon Malang, and James Petersen, used GPR technology and EM locators to mark the precise locations of all underground utilities, collect GPS coordinates, and deliver a CAD utility site plan showing accurate vertical and horizontal positions.
For the seven-acre site, all subsurface electric, communication, water, storm sewer, sanitary sewer, and irrigation lines were located and marked with depths. In addition to the utility locate, the team was required to account for any individual objects that may also be underground, such as a concrete pad or UST.
Equipment Utilized to Locate Utilities
Ground penetrating radar (GPR) technology helped the team identify all underground utilities at the site. This technology is mounted on a stroller frame that rolls over the surface and features an antenna that uses frequencies ranging from 250 MHz to 450 MHz. Subsurface data is displayed on the screen and marked on the surface in real time. The total effective scan depth of GPR can be as much as eight feet and will vary throughout a site depending on factors such as surface type, surface conditions, soil type, and moisture content.
An electromagnetic (EM) locator was used to detect the electromagnetic signals from pipes and cables at the site. EM locators were used to actively trace conductive pipes and tracer wires, and passively detect power and radio signals traveling along conductive pipes and utilities. An electromagnetic radio frequency transmitter sends out a signal in a specific frequency, which transmits through the conductive material in an underground pipe or other piece of infrastructure.
A high-end GPS unit provided geospatial accuracy down to four inches using the satellite environment at the time of collection. GPS locations can be collected as points, lines, or areas and then exported as a KML/KMZ or overlaid on a CAD drawing.
After scanning was complete, Teichert Solar was able to quickly access 99.8% accurate field-verified GPS-enabled CAD utility site maps in PDF, KMZ, and SHP file format via SiteMap®, GPRS’ cloud-based infrastructure visualization software.
GPRS Project Manager Vincent Lopez said, “There were so many utilities on this site. We scanned over 300,000 square feet in one day. With GPR and EM locators, we could see every utility line and sewer location.”
Planning the Layout of Concrete Piers
When plotting and placing the concrete piers on site, the seminary did not want to disrupt the flow of traffic or eliminate any parking spaces. With a subsurface infrastructure map, Teichert Solar could design the layout and placement of the concrete pier foundation plan prior to construction, and securely share it with the solar canopy subcontractors and engineers to collaborate on installation and avoid utility strikes.
Accurate subsurface as-builts helped Teichart Solar identify the required excavation clearance before coring holes in the parking surface for the concrete foundation. GPRS experts recommend potholing or hand digging around marks, or to stay clear of marks by two feet when coring. GPRS subsurface data helped to avoid utility strikes and unexpected obstacles during placement of the concrete piers, minimizing delays, and reducing the need for project redesigns, ultimately leading to more efficient and cost-effective project management.
Engineering of the Solar Carports
Solar carports must be designed to withstand environmental factors such as wind, snow, floods, storms, hurricanes, earthquakes, and other natural disasters. The design requires foundations that include ground mounting concrete piers at varying depths to hold heavy steel structures.
“Putting solar carports on proper footing is the first piece in the construction process, and it’s arguably the most important,” said Billy Ludt, Senior Editor of Solar Power World. According to his recent article in Solar Power World, a typical carport has foundations about every 30 ft., with holes dug between 10 ft. and 14 ft. deep, in average soil conditions.
The equipment contractors use to core holes for foundations varies depending on the surface conditions. Concrete saws can be used to cut through parking surfaces. A pressure digger or truck-mounted auger can be used for normal soil conditions. For sandy or loose soils, a temporary casing can be used to retain the sides of the borehole long enough for the concrete to be placed. Hammer drills can break up any rocks present in soil. Sump, suction, or additional pumps can be used to de-water water tables.
RBI Solar designs, engineers, manufactures and installs solar mounting systems for commercial and utility scale solar projects. Brad Fey, Senior Project Manager at RBI Solar, said in a recent Solar Power World article, “Foundations are the key to any canopy project, so there’s a lot of nuances to put them in there. It’s also making sure that you’re laid out correctly, making sure you have the right spacing, because all of your steel comes pre-punched. If you have a foundation that’s out of place, if it’s off by two inches or it’s moved in the wrong direction, you don’t have anchor rods that are in correctly, now you’re slowing down the steel install process too.”
“Once you get out of the ground, carports are easy,” Fey added. “It’s basically a giant erector set. You’re putting steel together, it’s all pre-punched, and everything bolts together. It’s the foundations that are the hardest part of any carport project.”
Why GPRS? The GPRS Difference.
GPRS Intelligently Visualizes The Built World® for customers in almost every industry in the U.S. Our subsurface damage prevention and existing conditions documentation allows Project Managers to deliver the accurate locations of underground utilities so you can better plan and execute excavation and construction projects. GPRS is an industry leader with a proven 99.8%+ accuracy rate when locating utilities, scanning concrete and inspecting sewer and water pipes. We provide the highest level of information for underground facilities and pipelines during all phases of the construction process.
GPRS has built upon the foundation of consistency and excellence in the Renewable Energy sector. We have completed hundreds of wind (utility-scale) and solar projects in all stages of project development and construction.
With the recent expansion of the EV-charging network, we’ve worked with major companies such as Tesla, ChargePoint, EVgo, and Electrify America to provide underground utility locates using the most reliable scanning technology available. Every renewable energy project allows us to offer a comprehensive range of reporting options, from marks on the ground, to a basic field sketch, satellite image overlays, or an AutoCAD report that pinpoints buried electrical, water, gas, communication, sewer and storm drain lines.
SiteMap® (patent pending) digitally stores your GPRS site & project data in a secure cloud-based software, accessible and shareable 24/7 from any laptop or mobile device. SiteMap® is an invaluable tool for construction projects, providing precise location data that enhances safety, efficiency, cost management, accuracy and overall project coordination.
What can we help you visualize?
Frequently Asked Questions
What is SiteMap?
SiteMap®, powered by GPRS, enables users to interact with high-resolution, layered digital maps of underground utilities, leveraging GIS tools to accurately depict the location, depth, and type of utility lines. If GPRS collected the data, you’ll find it in SiteMap®, backed by the 99.8% accurate hard data collected by our Project Managers. Detailed subsurface utility mapping helps stakeholders avoid conflicts, plan excavation activities, and reduce the risk of damage to underground infrastructure. SiteMap® keeps an accurate record of utilities’ locations for future construction work.
Who is Teichert Solar?
Teichert Solar’s in-house design/build team has engineered and installed over 365 megawatt (MW) of solar in California, including solar carport canopies, garage tops, ground fixed tilt, single-axis trackers, and utility-scale energy storage projects. Teichert Construction, its' parent company, is headquartered in Sacramento, California and has been providing civil infrastructure since 1887.
Who is RBI Solar?
RBI Solar designs, engineers, manufactures and installs solar mounting systems for large commercial and utility scale projects in the United States. RBI Solar offers a broad range of solar racking systems, ground mount, roof mount, and specialty solar structures to support every PV module manufacturer. A PV module manufacturer, also known as a solar module manufacturer, makes and assembles photovoltaic (PV) panels and other components of solar energy systems.
