Redi-Rock International, producer of precast, large-block retaining wall systems that stack using a knob and groove design, announced the winners of its 2015 Rocky Awards. The awards honor the best Redi-Rock walls built in the categories of Commercial, Water Application, Freestanding, Residential, and People’s Choice Award, which is chosen by the public in an online vote. More than 130 Redi-Rock manufacturers across the world competed for these awards.
Commercial Wall of the Year
Redi-Rock of Kentuckiana, Mount Washington, Ky., was honored for the gravity and reinforced retaining walls installed at the Louisville International Airport in Louisville, Ky. The airport wanted to extend a runway to put in an Engineered Materials Arresting System (EMAS), but a security access road ran through the location where they needed to make the extension, and there wasn’t any space to move the road or utilities.
HNTB engineers decided that the best solution would be to build a tunnel so the security access road could run under the runway, which gave room for the expansion. To do this, they designed four retaining walls that lead up to the tunnel, with each wall posing its own challenges. HNTB originally specified a pile and lagging wall, or an option for small segmental blocks. Mike Mattingly, P.E., from Mattingly Engineers, said that Redi-Rock was the final choice because the price was significantly less, it would take less time for the installation, and because of the versatility of the Redi-Rock system.
According to Mattingly, sloping bedrock, utility duct banks, a utility manhole, and a tight construction schedule were all challenges they had to work through as the project progressed. Redi-Rock of Kentuckiana completed the walls in 23 days. The biggest problem faced was with a duct bank that was in the backfill area, which couldn’t be disturbed because it helped run United Parcel Service’s ground operations. Since the duct bank was in the way of the excavation area for the geogrid, they decided to put up a temporary shoring wall, but it ended up being a permanent wall because of complications that pushed into the area where they could put reinforcement.
The project included four gravity and positive connection walls, which equaled approximately 20,943 square feet of wall face, and 385 Redi-Rock caps to give the walls a more finished look. The walls each led up to the tunnel that runs under the area where the EMAS blocks were installed. The wall engineer incorporated multiple types of Redi-Rock blocks throughout the project design, all in the Limestone face texture, which gave the walls a beautiful, cohesive look.
“In the end, to accommodate all of the various site and project constraints, six different typical sections were developed and used. These included a gravity system… in a soil retained zone; a gravity system using 28-inch blocks and cast-in-place concrete backfill; a gravity system in front of a (sheet piling to protect the manhole) per AASHTO; a reinforced system with a soil retained zone; a reinforced system with a soil and rock retained zone; and a reinforced system with a rock retained zone and a (sheet pile),” Mattingly said.
According to Mattingly, all of the walls were designed in accordance with AASHTO LRFD 2012, and the gravity sections were analyzed with the Redi-Rock Wall Analysis Software; reinforced sections were analyzed with MSEW software.
Water Application Wall of the Year
Wilbert Vaults of Houston was awarded for the Pecan Lakes subdivision project. Jones Creek runs adjacent to this high-end housing development and due to the development’s close proximity to the Brazos River, water from the Brazos River inundates Jones Creek and poses a significant flooding threat to the neighborhood. In 2007, the Federal Emergency Management Agency began remapping the area to update the flood insurance rate maps. As a result of the remap, all 325 residents of Pecan Lakes subdivision would be without flood protection.
Searching for a solution to reinforce the creek banks and protect the neighborhood, the Pecan Grove Municipal Utility District partnered with District Engineer Jones|Carter to find a solution to reinforce the creek channel and provide flood protection that would be on par with the rest of the district.
Initially, officials thought that the project could not be successful or cost effective without acquiring approximately 26 homes, due to unstable soil conditions and the limited right of way along Jones Creek. However, Jones|Carter’s design allowed the district to provide a solution that negated the need to acquire the homes saving $1 million. The overall solution included a multi-component system consisting of an earthen levee, a structural floodwall, and a pump station.
For the structural floodwall, Jones|Carter devised a solution that included a gravity retaining wall system coupled with a complex dual-level subsurface sheet piling wall for soil stabilization. It proved the best solution to minimize short- and long-term impacts to residents.
“In 2013 when this project started construction, Texas had been in a drought for several years. Vegetation was dying and engineers were concerned that if a large storm event came through, you’d see massive said Jamie Johnson, P.E., of Redi-Rock International. of the poor soil conditions, there was a significant concern that flooding events would saturate the bank and as floodwaters receded, you’d have an unstable slope condition.”
Jones|Carter specified Redi-Rock as the gravity retaining wall system for the project. was able to give us an alternative so that we could build the flood wall behind the homes with enough space to allow annual maintenance and operations. We also had room to transition the walls back down to the bottom of the existing said Craig Kalkomey, P.E., of Jones|Carter. gravity walls allowed us to avoid using soil anchors, which would have had to extend into private property and beneath existing
The soil along the creek is a mixture of heavy clay with high plasticity index, mixed with pockets of very poor sand and gravel. The sheet pile component of the bank stabilization was required to cut off these sand and gravel seams. Kalkomey explained that as water rises in the channel, designers wanted to avoid water passing through the walls and underneath homes because that could lead to material washing out from underneath residences. A 20-foot sheet pile cutoff wall was designed to increase overall global stability.
“It was really designed as a full system — the wall and sheet piles were designed to function together,” Johnson said.
Above the sheet pile walls, Redi-Rock walls were set on a gravel underdrain system and backfilled with gravel. Essentially we did the two-tiered wall to make the design a little safer. We still have the vertical drops, but instead of having one big vertical drop this allowed us to tier it, giving an amenity look with intermediate Kalkomey said.
The design team utilized Redi-Rock 9-inch setback blocks to increase the batter of the walls. felt that the 9-inch setback would help give a better aesthetic rather than two completely vertical walls. It also provides flexibility and stability during ingress and egress for cleaning and maintenance purposes. It helps us better inspect the system because it actually serves as mini stairs to safely access the Kalkomey said.
These walls, all of which feature the Limestone face texture, stretch over a quarter mile along the edge of the housing development and encompass a total of 38,525 square feet of retaining walls. The lower wall stands 13.5 feet tall and the upper wall as tall as 6 feet. The 9-inch setback walls give the channel a trapezoidal shape, which creates an efficient hydraulic radius that leads to improved open channel flow rates.
The system is designed based on a 100-year storm level, which was tested when a storm hit the area in May 2015, shortly after the project was completed. Based on the effective information on the flood, experts classified the storm between a 50-year and 75-year event.
“Parts of the wall were underwater for nearly a month,” Kalkomey said. “Since the May event, we’ve had multiple successive events and the system has been soundly tested. Fortunately, everything worked out very well. For the portion ultimately supplemented with the Redi-Rock, we could not take a chance. We had to stabilize it; we had to make sure movement would not occur.”
The project also received a Silver Award from the American Council of Engineering Companies – Houston in the water resources category.
Freestanding Wall of the Year
Mid-Hudson Concrete Products Inc., Cold Springs, N.Y., was honored for the freestanding walls supplied for the Mount Kisco Medical Center in Yorktown, N.Y. In 2012, Lake Osceola Realty Corp submitted a proposal for development of a new 27,000-square-foot medical office building and parking area in Yorktown. The proposed development was going to be built behind existing office buildings on a site surrounded by low-lying wetlands. The significant grade change from the entrance of the development leading down to the office building and parking areas posed a challenge to the design and construction of the site. To make construction possible and the new offices accessible, developers needed a way to accommodate grade-change requirements for the roadways leading to the building site while minimizing disturbances to the adjacent wetlands.
Engineers from Civil Design Professionals and Site Design Consultants came up with a design that incorporated a combination of retaining and freestanding walls to support the roadway and parking areas. They selected Redi-Rock because of speed of installation, aesthetics, and sensitivity to work adjacent to said Matt Moran, representative for Lake Osceola Realty Corp.
Minimal excavation is required to install Redi-Rock, making it possible for this project to be built quickly without encroaching on the wetlands surrounding the site. Plus, Redi-Rock was able to achieve the height requirements called for in the design of the walls.
“The benefit of using Redi-Rock blocks on this site was the efficiency of both excavating for the walls and installation of square footage per said Matthew Dubray, working foreman for WD Excavation & Contracting Inc., the installer of the project. was not required on this, which would have been necessary for most smaller modular block systems. Not having to over-excavate areas behind the walls allowed us to keep the site functional during installation by not having massive cuts and stockpiles of fill.”
Local Redi-Rock producer Mid Hudson Concrete Products supplied a combination of 60-inch, 41-inch, and 28-inch Redi-Rock gravity blocks in the Limestone texture to complete the gravity walls, which were 12 feet tall in the highest spot.
Redi-Rock Limestone freestanding walls were built on top of the gravity walls to act as a guardrail along the roadway. The curved design of some of the freestanding walls presented a slight challenge to the installers; however, they were able to do some custom work on the blocks to achieve the radiuses necessary to complete the walls. The use of freestanding walls as an extension of the gravity walls provided the force protection needed, while giving a seamless, high-end look to the development. Finally, Redi-Rock caps were added to the top of the walls to complete the project.
In total, 12,340 square feet of Redi-Rock was used on the project, which was completed in 2014.
Residential Wall of the Year
North Coast Marine Construction Inc. (NCMC), Avon Lake, Ohio, supplied Ledgestone texture gravity walls installed at a private residence on Lake Erie. After purchasing a home in Bay Village, Ohio, situated on the shores of Lake Erie, the owners intended to take full advantage of their new lakefront property. However, the steep slope of their backyard made accessing the lake area incredibly difficult. With big plans for several upgrades for the lakefront area, including a boat garage, beach house, pier, and marine elevator, the homeowners needed a way to make it easier to access.
The general contractor building the lakefront beach house had originally planned to construct a ramp leading down to the lake, but after taking a closer look at the sheer hillside, he realized he would need a better solution. The general contractor turned to landscape designer Doug Baldi, owner of Baldi Design Solutions Inc. for help. After viewing the property himself, Baldi realized they were going to, a lot more than straight walls and terraces.
“One of the challenges is they had a hillside that was basically a 1-to-1 slope that you could hardly walk up and down,” Baldi said. “The homeowner had some very definitive requirements for this project, one being he wanted to have a ramp that you could actually drive a vehicle down. The second requirement was he really wanted usable space as he went down, and he envisioned a [miniature] golf course.”
To accommodate the homeowner’s requests and contend with the challenges of the sloping property, Baldi came up with a design that would incorporate curved walls, terraced levels, ramps, and stairs built with Redi-Rock retaining wall system
“In the Cleveland area, we have a lot of shale cliffs. You want to build in front of the shale and protect it, but you have to anchor those walls back into the shale somehow because you can only go so high with segmental block. With Redi-Rock, we can go so much higher with the walls and we can get good foundations on the shale without having to excavate for geogrid or try to do some type of drill and pin anchoring for the walls,” Baldi said.
Baldi worked with Stephen Jones and his team from local Redi-Rock producer and installer NCMC to complete the project. They began by creating I-beam pilings on the hillside driven down to the point of refusal which, for most of the hillside, was the shale cliff. Rebar reinforcement was added then concrete was poured on top to create concrete footers on which the retaining walls were built.
Redi-Rock blocks in the Ledgestone texture were used on the walls of the project, which span from the backyard of the home all the way down the hillside to the lake area. The design incorporated multiple terraced levels, each one with a landscaped miniature golf hole and connected to the next level by both a ramp and a set of stairs.
Most of the walls were designed to increase in size with the slope of each ramp. Starting out around 0 to 2 feet high, the walls rise up to 10 feet to 12 feet high at the far end of the ramps. There’s also one massive wall more than 20 feet tall at one end of the project where there’s a curved staircase.
According to Baldi, of the design challenge was to get big enough radiuses so you could maneuver down the ramps with a trailer and a
NCMC installers were able to customize the wall blocks to achieve the radiuses needed to accommodate the design of the curved walls. In fact, once the ramps were in place, the installers took advantage of the ramps by taking their skid steer loaders and other equipment up and down them to perform maintenance work and install the mini golf course areas.
Redi-Rock gravity blocks in 60-inch, 41-inch, and 28-inch sizes were used to build the retaining walls on this project. As the gravity walls rose above the ramp level, they transitioned into Redi-Rock freestanding blocks to form the guardrail for the ramps. A combination of ramps and Redi-Rock steps were used to connect one level to the next, with a putting green added to each level and custom work done by NCMC to create curved steps to follow the curve of the walls. Columns in the Ledgestone texture and caps were added throughout the project to pull the design together for a cohesive look throughout.
In total, 9,000 square feet of Redi-Rock was used to complete this project, which was finished in 2015. Additional custom work was done to provide heating for the ramps leading down to the lake. There are also multiple gas lines that run through the walls to power 12, 35,000-BTU lamps incorporated within the design to light the walls at night.
People’s Choice Rocky Award
Wilbert Precast of Spokane, Wash., received the People’s Choice Award for a beautiful residential landscape upgrade project. Mark Hattenburg wanted to add a terrace and pool to the backyard of his home near Spokane but he had no design plan and wasn’t quite sure where to begin. He knew he would need to do something about the 8-foot grade change on the property. While driving down Little Spokane Drive one day, Rick Lindberg, from local Redi-Rock manufacturer Wilbert Precast, noticed an excavator in the field behind Hattenburg’s house. Curious about the project and knowing it would require a retaining wall, he spoke to Hattenburg about his plans.
“He knew he needed a wall, but he just didn’t know what he was going to do,” said Lindberg. Lindberg’s background is in landscape design, so he offered to help Hattenburg by designing the backyard landscape using Redi-Rock. Hattenburg owns a construction company called Hattenburg Excavation. Having installed Redi-Rock walls in the past, he knew Redi-Rock would be a good fit on this project too.
The final design included Redi-Rock gravity retaining and freestanding walls, plus coordinating columns, steps, and caps, all in the Cobblestone texture. A waterfall feature was incorporated into the design to conceal the utilities for the pool. More than 500 Redi-Rock blocks were used to complete the beautiful yard and pool area with walls that extended as high as 10 feet at the tallest point.
Information provided by Redi-Rock International (redi-rock.com).