19 minute read

17 Feet Under the Sea: Building a Foundation Below Sea Level

Ekedal Concrete

17 FEET

UNDER THE SEA: Building a Foundation Below Sea Level Below Sea Level

California-based Ekedal Concrete takes on jobs others shy away from—the type of projects that require years of experience and sophisticated skills. The company received the Concrete Foundation Association’s 2020 Overall Grand Project of the Year Award for Single Family Homes Over 5,000 Square Feet for just such a project. Ekedal constructed a 9,000-sq.-ft. basement foundation, with the bottom of the slab sitting at -17 ft. below sea level along the bayfront in Newport Beach, Calif.

“It's a pretty unique project and it gets very complicated,” says Ryan Ekedal, president of Ekedal Concrete. “If you don't know what you're doing, you can be in a world of trouble.”

DRILLING THE CAISSONS

Ekedal was hired to complete the entire structural concrete package, from planning to steel framing, shoring, de-watering, and building the foundation. Building along the water required advanced shoring and de-watering systems.

The crew drilled 109 caissons, which are used for retaining water to allow for the construction of bridges, dams, and similar structures. Each of the caissons was 30 in. in diameter and in all, the total drilling depth was 6,000 ft. The Bauer BG 15H rotary drilling rig was an Italian model that used a continuous flight auger to drill the caisson and pour the concrete through the auger.

The interlocking design provided a faster construction timeframe because it eliminated the need for the casing of holes and lagging. The interlocking caissons were made up of hard and soft piles of slurry and concrete. “One (secant pile) would be full of a slurry, like a two-sack slurry, the one next to it, which would basically butt into that caisson a little bit, would be full concrete,” Ekedal says.

The crew brought the water table below the mat slab to ensure a dry working environment. Ekedal Concrete

The exact location of each caisson was critical for the project to be effective, he says. A civil engineer gave them the center location for each caisson, but the blueprint doesn’t always match the reality of the construction site. Ekedal crews thoroughly verified each location.

“When we go in and double check things, we make sure that we lay out the center caissons exactly where they needed to go, and the entire time the drilling process is going, we're making sure that the drilling is plumb and vertical and not at an angle,” he says. “Because that's where you're going to end up having problems, where you might be an inch out of plumb at the very top, but 50-ft. down…you're going to be a foot off. So, it was making sure they're perfectly set and poured, in the way that they need to be, to make everything work when we get to the bottom of grade.”

There were several factors to watch when lowering the water table, he says. As part of the dewatering process, 17 well points at 18-in. were drilled 50 ft. deep.

Using a filter fabric pipe with rock, Ekedal pumped all the water back into the bay. “But it's slow and methodical because there's a high possibility you'd be pulling fines (fine ash and other materials) and sands and different material from the adjacent properties," explains Ekedal. "If you do that, you're creating voids under those homes, which would lead to the foundation starting to settle. And then you have all sorts of other issues.” It’s important to watch how quickly the water table is being lowered. “From the point when we turn on the pumps, we give it a couple of weeks, typically, before we do anything,” he says. “We slowly, slowly bring the water table down to a point where we know it's below our working environment, which would be the bottom of the mat slab. Then, when we know it's to that point and it's dry enough, nothing's moving. The surveyors are there daily checking, taking shots, checking the adjacent properties, checking our property lines, making sure nothing's moving. When we know everything is stabilized and good, then we can start actually excavating in 3-ft. lifts.” The shoring wall was 20-ft. tall and tapered from 12 in. to 15 in. and was shotcreted into place. Several of the other walls needed to be cast in place due to a large amount of hardware on the tops of the walls. Once the shoring and dewatering was complete, excavation began on the basement and the foundation could be started. Instead of traditional footings, the project has a 15,000-sq.-ft., 30-in. thick mat slab with two layers of epoxy-coated No. 6 rebar at 9-in. spacing.

Overall, the project involved nearly 1 million lbs. of steel when you consider the reinforcing cages in the caissons and slabs. In addition, Ekedal explains that they had to do two concrete on pan decks above the first four.

Building along the water required advanced shoring and de-watering systems.

Ekedal Concrete

Ekedal Concrete

‘LIKE A BATH TUB’

While shoring and dewatering were big jobs, waterproofing the foundation also took considerable time and work. “We had to make sure that the thing was basically like a bathtub, just 100% sealed if the water table goes up,” Ekedal says. “We can’t have any leaks because it only takes a little pin size hole and you're going to have problems.” Ekedal says they used effective waterproofing means and methods. “The big key is aligning yourself with the right waterproofing manufacturers and installers who warranty their products,” he says.

Double and triple layers of hydrostatic waterproofing were used to prevent leaking.

“I believe the corners were at three layers because that's where you're likely to have issues with leaking,” he says. “We were being really cognizant before we backfilled, to make sure there were no punctures in the membrane and no issues with air bubbles or different

As part of the dewatering process, 17 well points at 18-in. were drilled 50 ft. deep.

Ekedal Concrete

things that could lead to problems down the road. We were being extremely, extremely thorough. It's critical.”

A MASSIVE PROJECT

The sheer size of the project made it challenging, Ekedal says.

“It was just big in stature and the mat slab was big; it was a 2 1/2 ft. of actual foundation slab,” he says. “It had two No. 6 rebar layers and the spacing was pretty tight; 9 in. each direction. The other thing was that all the rebar in the entire project was epoxy coated because of the correlation to where it is near the ocean, obviously.”

The project, including pre-planning, took about 18 months, he says.

“This job takes a lot of planning from all different parties. This is a long process because, for instance, the de-watering portion was seven or eight months of continuously, 24 hours a day, the pumps were on, pushing water out of there,” he says. “We can't turn those off until that basement is backfilled.”

Ekedal says his company has more than 40 years of experience working on these types of difficult projects, such as installing below sea level foundations, and has a deep bench of talent on his team.

“We’re definitely not just cutting our teeth on it,” he says. “We know how to do it and do it right. The probability of getting in a position where you're having all sorts of problems is extremely high if you don't know what you're doing.”

Even with the industry-wide worker shortage, Ekedal has been able to build a team of highly skilled contractors and subcontractors.

“That's kind of what we've been building for all these years, we’ve had a lot of talented people at work here at Ekedal and have for a long time,” he says. “We’re always trying to keep that kind of culture evolving and broadening and getting larger and larger, so we can continue to keep these sorts of projects in our wheelhouse.”

Watch a video of this project at

ForConstructionPros.com/ 21576799.

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WORLD OF CONCRETE 2021 PRODUCT WRAP-UP

BOSCH PROFACTOR 18V Cordless Rotary Hammers

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Husqvarna's K1 PACE Battery-Powered Cut-Off Saw

The first product to be launched on Husqvarna's battery system, PACE, the K1 PACE high-power battery cutter was designed to handle heavy-duty jobs. Husqvarna tells contractors to expect power and performance equivalent to gasoline-powered cutters, with the additional benefits battery powered equipment brings to both operators and the environment.

The PACE battery system can be utilized for more machines as the battery-powered family expands. In addition to the power cutters and battery system, diamond blades in 12 in. and 14 in./300 and 350 mm have been optimized for battery operation. The machine is also equipped with X-Halt brake function capable of stopping the rotation of a blade in a fraction of a second for enhanced safety.

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Pioneer Cloud Batch Sysdyne Technologies

Sysdyne Technologies' Pioneer Cloud Batch brought the batch software online and made it visible and accessible by multiple users. By logging onto ConcreteGO.com, plant managers, IT support staff, quality control managers and regional executives can access batch controls anywhere at any time using any device to monitor the batch cycles, make mix design changes as needed and address loading issues without interfering with the actual concrete loading cycle. It helps speed up the batch process, make sure the mixes are properly adjusted as needed and reduce the material cost by tightly controlling the material usages.

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The CoreHub In-Vehicle IoT Platform by Coretex

Coretex's CoreHub integrated IoT solution connects an in-vehicle IoT hub with selfinstalled wireless drum rotation, hydraulic temperature, water add meter sensors, and cameras throughout the vehicle to collect and present information about the driver, asset and load—providing contextualization of what is happening on the load and full digital view of supply chain operations.

At the show, Coretex also announced its partnership and integration with CiDRA Concrete, an IoT-based business that provides real time data that continuously measure the concrete quality, air, slump, and temperature of the mix from the batch plant to the job site via concrete Ready-Mix trucks.

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Vanguard's 400 EFI ETC Single-Cylinder Engine

The Vanguard 400 EFI ETC single-cylinder horizontal shaft commercial gasoline engine is the latest addition to the Vanguard product lineup. The electronic fuel injection (EFI) system provides better fuel efficiency, improved overall performance and quick load acceptance and offers easy all weather choke-less starting. The addition of the electronic throttle control (ETC) system means that operators can count on smooth and consistent power with any load size or type of terrain they encounter. Like its predecessors, the engine features a fully integrated cyclonic air cleaner with advanced AutoShed technology, extending service internals. The single-cylinder Vanguard 400 EFI ETC 14.0 Gross HP engine will be available for purchase in March 2022.

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Miller Formless WB-3200 Work Bridge

With the WB-3200 slipform paving machine work bridge, contractors can utilize fully functional texture/cure abilities. Its compact design allows a working height as low as 18 in. from grade and the adaptive frame design allows for any attachments to be mounted on either side. The tethered electronic control console is mounted the same way as the operator seat, allowing the operator to be on the left or right side with a quick-change feature. A quick selection in the control system allows for all controls to be reversed, with no electrical or hydraulic connections needing to be removed. The unit has a 12-ft. minimum paving width and is available with optional frame extensions up to 32 ft. Power is provided by a 25-hp Caterpillar 1.1 diesel engine.

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Curb Roller Lynx Modular Roller Screed

The Lynx Screed has a modular design featuring a series of linkable screed pipes that can accommodate concrete pours in varying widths from 3 to 22 ft. • Available in a package consisting of three 7-ft. pipes, or a package containing a 5-, 7- and 9-ft. pipe • Can be customized to include any 3-, 5-, 7- and 9-ft. length combination up to 22 ft. • Pipes aligned and connected with three separate bolts and a centering ring for quick, easy installation • Setup completed by bolting drive and static heads to the assembled pipe’s ends and connecting to the electric Eel Screed or battery-powered Batt Screed

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GOMACO CC-1200e Battery-powered Curb Machine

The CC-1200e is equipped with a 48VDC lithium-ion battery pack that provides enough power for a full day of paving. Charging options include the standard eight to 10-hour normal charge rate or an optional two-hour fast charge system. The G+ control system with full-function radio remote control puts all machine operations in the hands of the operator. Rotary-sensored slew drive steering on the front wheel assemblies allows smoother paving, easier control, and maximum turning capability with the ability to slipform a 24-in. (radius, depending on mold profile. The compact unit has a 19-cu.-ft. hopper capacity with up to 15 in. of horizontal sliding capabilities for easy alignment with ready-mix trucks. Curb molds can be interchanged easily and can be positioned on either side for right-side or left-side paving.

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Cemen Tech Featured its Volumetric Concrete Mixer Tech

There is nothing like testing out the real thing. Cemen Tech allowed attendees to put their hands on some of the most intuitive, user-friendly technology applications available for volumetric concrete mixers. Throughout the event, Cemen Tech will be offering demonstrations and hands-on testing of Cemen Tech CONNECT and ACCU-POUR software platforms.

“Downtime and waste are killers for most businesses. That is why we offer technology to help reduce both—less downtime with your equipment and more accurate tracking of your concrete,” says Connor Deering, Cemen Tech President and CEO. “Our technology products surround you and your fleet of volumetric mixers with vital resources and tools to keep you moving.”

More about the technology at World of Concrete 2021:

CONNECT: This video support platform is your best tool for quick problem solving. With your smart phone, desktop or tablet hold a live video conversation with a Cemen Tech service technician. That person will help you inspect your volumetric equipment, identify problems and design solutions in real time. They will even help you order replacement parts immediately. ACCU-POUR: Cemen Tech’s suite of proprietary productivity tools includes both Office and Mobile versions and is compatible with any brand volumetric mixer. Connect your office, dispatch, and fleet in real-time. This next generation technology has over 300,000 yards of concrete poured through it in the last 24 months by ACCU-POUR users around the world. Utilize GPS fleet tracking, electronic scheduling, batch ticketing and up-to-the minute reporting on completed jobs and material usage from a single platform.

“Adopting new technology can come with some hurdles—like figuring out what’s the best solution for you or even finding time to learn the tools. We’re taking these barriers away by hosting one-on-one demos and helping customers compare products,” says Deering.

ForConstructionPros.com/21485459

Pettibone Adds T1056X to Traverse Lineup

Pettibone introduced the Traverse T1056X telehandler, the first 10,000-lb. capacity Traverse model in its X-Series lineup. The Traverse is telehandler product line featuring a traversing boom carriage with the capability to move loads by traveling horizontally, allowing operators to safely place loads at full lift height without needing to coordinate multiple boom functions. • Specifi ed lift height of 56 ft., 6 in., identical landing height • Traversing boom provides up to 70 in. of horizontal boom transfer, extending its maximum forward reach to 45 ft., 10 in. • Powered by a 117-hp Cummins

QSF 3.8 Tier 4 Final diesel engine mounted on a side pod for easy service access • Engineered on Pettibone’s next gen X-Series platform with full-time four-wheel-drive with limited-slip front axle differential • Turning radius of 14 ft., 4 in. • Featuring formed boom plates and less welding, the machine’s four-section boom offers greater strength while reducing weight. • Boom overlap has been nearly doubled from previous models to provide smoother operation and reduce contact forces on wear pads.

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APOC Weather Armor Air & Weather Barriers by ICP Building Solutions Group

Achieve comprehensive protection against the elements with APOC’s Weather Armor air and weather barriers, available in a variety of formulations suitable for a range of abovegrade wall applications.

Weather Armor air and weather barriers are liquid-applied, one-component solutions that protect against unwanted or uncontrolled air and moisture in a variety of climates. By eliminating air infiltration, Weather Armor helps ensure long-term structural durability while contributing to higher levels of building energy efficiency and air quality. • Monolithic protection against air infi ltration • Available in acrylic, STPE or silicone formulations • Available in impermeable and permeable options • Easy to spray, brush or roller apply • Rain-safe in 30-90 minutes, depending on technology • Can be exposed for up to a year for fl exibility in construction phasing

ForConstructionPros.com/21508933

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