Soldier piles and wood lagging systems are commonly used and are extremely cost efficient. Soldier piles are driven or predrilled at intervals along the wall’s baseline. If a predrilled approach is used, holes are drilled, grout is placed, and an H-pile is installed in the hole, thereby providing a vibration-free installation. As the excavation in front of the wall proceeds, wood lagging is installed between the soldier piles in lifts. Tieback anchors may be installed and stressed to provide lateral restraint.
Featured Project
US 31
Petoskey, MI
Little Caesars Arena
Detroit, MI
5th Avenue Parking Structure
Ann Arbor, MI
Project Details
Team Hardman Construction opened up the year 2019 with a precise and detailed undertaking. Located along US-31 on the north side of Petoskey, Michigan, Hardman Construction was hired by DJ McQuestion to install a retaining wall approximately 450 feet in length with a maximum height of nearly 22 feet at its highest point. There were many aspects to this job, including but not limited to the following key items:
- 57 drilled shafts at 17.5’ deep
- HP14x117 H-piles up to 22’ above top of drilled shaft
- 56 earth anchors with a capacity of 113 kips each
- Waler system which demanded a tolerance between installed H-piles of less than one half inch
- Timber lagging structure to retain backfill/subgrade and expedite the road building process
- Permanent reinforced 16” thick concrete wall
- Simulated stone masonry finish
It was clear from the beginning that this job would require adherence to a tight schedule and having multiple crews working on the wall at the same time while performing different tasks would be the way to accomplish that goal. At the beginning of the job, Hardman worked closely with Rohrscheib Son’s Caissons to get the shafts drilled. Rohrscheib would drill all the shafts, and Hardman would follow behind setting cages and beams in the shafts, verifying the tight tolerances were met by bracing the steel in place, and then tremie pouring the shaft with a crane, concrete pump and a tremie pipe.
Following behind the shaft crew was the anchor crew. Hardman installed one anchor between each pair of H-piles. Since the ground elevation on site was approximately 590’ and anchor elevations went up as high as 601.5’, Hardman construction had to work off of an elevated dirt work platform for the middle 80% of the wall. This provided many logistical challenges with so much moving equipment around a narrow jobsite. Good communication was required to ensure there was enough sand moved in front of the anchor crew for them to work, Rohrscheib had to continually move their drill spoils, and several concrete trucks moved in and out of the site every day for the drilled shaft pours.
Behind the anchor crew was the anchor testing crew to perform verification proof tests on every anchor before they are tied into the wall. At this point we were ready to install wood lagging and begin backfill behind the wall. For this application Hardman chose to band the 8’x6”x10” (LxWxH) wood lagging together and set the boards as 2 to 6 board panels. This method saved a lot of time and allowed Hardman to begin installing the wale system almost one week ahead of schedule. With a crew following the lagging crew mag drilling holes for the walers and bolting them in place, all that was left for the main structure was to set the final lagging panel on top of the waler to bring the wall to design height and lock off all of the anchors to complete the structure.
At this point DJ McQuestion could begin grading on top of the wall, and Hardman could put finishing touches on the wall, and began tying and hanging resteel for the concrete pour. Steel forms had to be put together, and all of the simulated stone texturing had to be fixed to the forms before they were stood up against the wall. A single pour could be up to almost 22 feet high and would be either 48 or 72 feet in length along the wall. Once all of the texturing was in place and pouring concrete commenced, it was our goal to pour 48 to 72 feet of wall every 3 days. We achieved this goal and placed the last concrete on May 15, 2019.
Hardman Construction managed to finish the project ahead of schedule and ended with a structurally sound and aesthetically pleasing product, making an iconic land mark for the City of Petoskey to enjoy for years to come.
The Joe Louis Arena located along the banks of the Detroit River has been the home of the 11-time Stanley Cup Champion Detroit Red Wings since 1979. The “Joe” replaced the Olympia Arena where the Detroit Red Wings had played since 1927. Just as the Olympia Arena was replaced by the Joe, the time had come for the Joe to be replaced by the new Little Caesars Arena. Located in downtown Detroit, this multi-purpose building has become the new home for the Detroit Red Wings (NHL), the Detroit Pistons (NBA), as well as a facility for hosting special events. Construction began in April 2015 and the 785,000 square-foot development which seats approximately 20,000, opened its doors September 5, 2017. As a geotechnical construction contractor, Hardman Construction was tasked with building the temporary earth retaining system around the main and practice ice arenas. The earth retention system was composed of four 40′ tall retaining walls which spans more than 1,700′. The ERS design combines augercast piles, tiebacks, and lagging. The augercast piles are installed a set distance apart, and lagging boards are used to span the space between piles. Each augercast pile is constructed by drilling a large diameter vertical hole. The hole is then filled with grout, and a steel H-beam is installed in the hole. After a short period of time, the grout is removed from the face of the beams so the lagging can be installed. The ERS achieves its retaining strength by the use of tiebacks, which are a type of earth anchoring system. Although the schedule was tight and the construction process complex, the project was completed on schedule.
The $50 million dollar 5th Avenue parking structure required the installation of a temporary Earth Retention System consisting of a tangential auger cast pile wall & soldier pile & lagging system. Augercast tangential walls were selected over secant walls for the tangential pile areas, and the soldier pile & lagging system was per the original scope of services. The primary reason for the augercast wall was the economics and schedule constraints that the secant wall presented. The project was set up as a secant wall design, however when the final bids were received, the project team decided to use the tangential auger cast pile wall as it was a substantial saving to the project. The scope of services was the construction of the new parking garage adjacent to the existing downtown buildings. The site was extremely congested, and deliveries had to be scheduled days in advance because of this. The existing buildings were still in service and our work could not affect these operations. The project required an ERS system to support the existing residential, & commercial building that were on site, numerous utilities that serviced the existing buildings, and tower cranes. The ERS system had to be vibration free, due to the sensitive nature of the existing operations, which were directly adjacent to our work. Due to the site conditions, weekly meeting with project managers were held throughout the project. Daily activity meeting with the site superintendent and look-ahead schedules were required. The settlement of the existing structures were monitored by settlement points. These points were checked throughout the project’s duration and to date there has been no settlement of any adjacent structures or utilities. The project included 1,510 lineal foot of tangential auger cast pile wall (855’) & soldier piles & lagging (656’). The excavation depths were up to 71’ deep. There were over 40,000 lineal foot of augercast pile drilling installed, 1,130,000 lbs. of reinforcing steel installed, and over 6,000 cubic yards of grout used for the project. To our knowledge, this is one of the deepest excavation depths which utilized this type of system. The tangential auger cast pile wall utilized earth anchors which were installed using duplex drilling and self-drilling/grouted anchors. Over 700 earth anchors were installed. All of the anchors were tested and locked at their required loads. The duplex drilled earth anchors were tested to maximum of 235 Kips and the self-drilling anchors were tested to 144 Kip. The duplex-drilled anchors were installed using water, grout, and air as the drilling mediums.