Automated Concrete Removal (ACR™) Saves the Day on a High-Profile Project in Salt Lake City
By now, it is commonly known and agreed among industry stakeholders that the $11 trillion dollar construction business needs to grow bigger and more productive, and quickly. To support expected economic growth, experts predict that $69.4 trillion in global infrastructure investment will be needed between 2017 to 2035, almost double the historical average.[1]
But will the necessary labor force be available to turn these infrastructure investments into functioning assets? According to the construction consulting group, McKinsey & Co., “41 percent of the current US construction workforce is expected to retire by 2031,” while at the same time the world will need “up to 200 million additional [construction] jobs by 2030 if countries fill global infrastructure gaps and boost affordable housing supply.”[2]
Clearly, there is a need for automation that can maximize the productivity of the scarce labor supply, particularly when it comes to construction projects involving the world’s vital civil infrastructure. Fortunately, innovative equipment manufacturers, such as Conjet AB, and their customers are working hard to solve the world’s infrastructure challenges. An ongoing parking deck rehabilitation project in Salt Lake City, Utah, provides an excellent case study on this subject.
The plaza area of Temple Square is being renovated as part of a larger, four year project to enhance, refresh, and beautify the historic Salt Lake Temple and its surrounding grounds. Photo: Intellectual Reserve, Inc.
A High-Profile Renovation Project with Unanticipated Challenges
In December 2019, the Church of Jesus Christ of the Latter-day Saints (the “Church”) began a large renovation project on the Church Office Building plaza, situated in the heart of downtown Salt Lake City, Utah. The plaza sits between the Church’s administrative buildings and consists of an impressive landscape of fountains, flower gardens, grass and other vegetation. Its location, 200,000 square feet in the middle of the Church’s senior administrative offices, means that the asset owners have a front row seat to the progress of construction each day!
The Church hired General Contractor, Jacobsen Construction, to serve as general contractor in charge of the overall renovation of the Salt Lake Temple and Temple Square. Jacobsen has been in business over 99 years performing large commercial construction projects in Utah and other states around the country. Paul Shingleton serves as Project Manager for Jacobsen on this Church project. Mr. Shingleton has been in the construction industry for 19 years and a member of the Jacobsen team for 16 years.
The unanticipated amount of delamination found on the parking deck roof presented a major risk of project delays. Photo: Intellectual Reserve, Inc.
Below the plaza sits an underground, three-story parking deck built in 1962. The parking deck had been experiencing some observed leakage from the water circulation system and landscape directly above. To clear the landscape area for renovations and address the leakage, the entire plaza of landscaping and concrete architecture would have to be removed along with the waterproofing layer on the parking deck’s concrete roof. Complicating matters, the waterproofing layer contains asbestos from the original construction. As structural engineers developed the scope of work and renovation timeline for the plaza, they estimated that excavation would reveal two to five percent delamination of the concrete roof (4,000 – 10,000 square feet).
In March 2020, the renovation work began and the site was excavated down to the parking deck, where it was discovered that there was a shocking 70-90% delamination across the entire 200,000 square foot roof area. This unknown, unanticipated condition presented a major risk of significant project delays. Jacobsen quickly called in a demolition subcontractor to start removing the top layer of damaged concrete, totaling between 140,000 to 180,000 square feet!
The subcontractor immediately got to work with a crew of 12 laborers operating 6 large jackhammers. However, even with this large amount of manpower using some of the most powerful jackhammers available, it became clear that the project would be delayed by an additional two years, minimum, due to the massive amount of concrete to be removed.
At this point, Jacobsen’s culture of resourceful creativity came into play as they searched for innovative technologies that could automate and increase efficiency compared to the manual jackhammer removal process. Fortunately, it did not take them long to discover the Automated Concrete Removal (ACRTM) robots manufactured by Conjet AB.
Jacobsen and TID Demolition Adopt ACRTM for Increased Efficiency
The Conjet ACRTM Robot 557, with just two TID field personnel, was able to drastically outperform a crew of twelve workers with jackhammers. Photo: Conjet Inc.
Conjet, headquartered just outside of Stockholm, Sweden, with additional offices in Charlotte, North Carolina, is the global leader in the design and manufacture of ACRTM robots. Conjet was established in 1990 by a small group that had developed the hydrodemolition technology as a division of a larger company in the mid-80’s. (Hydrodemolition was invented in response to a request from the Swedish National Road Authority to make bridge maintenance more efficient.) For the past 35+ years, Team Conjet has been focused exclusively on making the hydrodemolition process easier, more precise and more productive. Collectively, this 35+ years of technology development is known as “Automated Concrete Removal” (ACRTM) technology and is embedded into every Conjet robot.
After discovering the ACRTM robots through online searches, Mr. Shingleton reached out to Conjet’s North American team to investigate its potential utility on the plaza renovation. Mr. Shingleton and the Conjet team had a detailed educational meeting where Conjet explained the efficiency, safety, and quality advantages of ACRTM and hydrodemolition. Mr. Shingleton then connected Conjet with one of its most capable subcontractors, TID Demolition, who could further investigate the application and advantages of ACRTM for the renovation.
TID Demolition, based in North Salt Lake, Utah, has over 25 years of experience in retail spaces, office towers, medical facilities, government projects, manufacturing and residential work. Through a combination of experienced, skilled personnel and specialized equipment, TID is able to successfully execute complex and challenging demolition projects while providing a safe, clean and productive job for its customers.
Although TID had no prior experience with hydrodemolition, Conjet’s team was able to explain the process and answer all of TID’s questions, such as the key factors to consider when performing hydrodemolition, the ACRTM robots’ operation, productivity capabilities, and how to handle water containment and treatment. In addition to the clear productivity advantages of ACRTM, Conjet was also able to educate both Jacobsen and TID on its other benefits. For example, worker safety is improved due to the elimination of silica dust and vibrations, along with drastically reduced noise. Also, the useful life of the structure is extended significantly because the hydrodemolition process results in a 2.5X stronger bond between residual concrete and the new overlay.[3]
After multiple meetings with Conjet, Jacobsen and TID decided to try out the ACRTM technology for improved efficiency as well as its other advantages. In June 2021, TID purchased a Conjet ACRTM Robot 557 Standard model and began work on the Temple Square renovation.
TID Uses Automation to Preserve the Project Timeline
As the Robot 557 was delivered to TID, Conjet provided a startup training using the Conjet University (“ConjetU”) curriculum. Tim Best, Conjet’s Customer Success Manager for North America, led the ConjetU training. He has over 20 years’ experience operating hydrodemolition equipment in the field, as well as planning, estimating, and managing the execution of complex and challenging projects all across the U.S. and Canada.
Conjet’s ACRTM robots have been designed with ease of use, precision and productivity as the primary objectives, and the 557 lived up to its design intentions on this project: Within a couple of days, Mr. Best had trained TID’s primary operator on how to properly use the Robot 557, the accompanying Hammelmann high pressure pump, and manage wastewater runoff. In the first week of operations, TID’s main operator became comfortable using the Robot 557. By the second week, the productivity advantages of ACRTM became clear: The Robot 557 along with two TID employees was removing, on average per hour, the same amount of concrete that required the previous contractor to spend three full days with twelve employees using jackhammers.
TID’s early productivity results caused project engineers to re-evaluate the timeline once again. The initial phase of work involved a 65,000 square foot removal area. Using jackhammers, it was estimated to take until February 2022 to complete this initial phase. However, with the ACRTM Robot 557 TID finished this removal in September 2021. In fact, due to sequencing conflicts with the garage below, TID has begun moving the 557 for work on other jobsites in between work sprints on the plaza project.
The hydrodemolition process preserves and cleans the underlying rebar, leaving a residual surface that is free of microcracks and ideal for bonding to the new concrete overlay. This results in a 2.5X increase in the strength of the structure compared to jackhammer removal methods. Photo: Conjet Inc.
In addition to the productivity gains experienced with ACRTM compared to jackhammers, there have been other, more qualitative benefits. Because the plaza is surrounded by offices, Jacobsen was receiving many complaints about the loud noise created by jackhammering. In contrast, the Robot 557 and pump are relatively quiet and have drastically reduced the number of noise complaints from surrounding office workers.
Travis Keenan, TID’s Project Manager overseeing the Temple Square work, stated, “We have been extremely impressed with both the ease of use and the productivity of the 557. With the Conjet ONE operating system and just a couple days of training from Mr. Best, our field employees were able to quickly become comfortable and adept at the ACRTM process. And the productivity has absolutely blown us away. When we first were brought into the Temple Square project, the general contractor set what we thought was an aggressive target for concrete removal per day. However, with Conjet’s ACRTM technology we have been able to actually exceed that target. We could not be more pleased with our decision to bring the ACRTM Robot 557 into our arsenal of tools at TID Demolition.”
Mr. Shingleton commented, “The amount of time that will be saved based on the jackhammer process will completely save the project. This was my first experience with Conjet’s ACRTM technology and hydrodemolition. In the future when we have jobs with concrete removal required, we will most definitely be consulting with TID and Conjet to find the most efficient, effective ACRTM solution.”
Bridging the Infrastructure and Labor Gaps
When the unexpected bad news first came to Jacobsen – that the amount of delaminated concrete in the plaza was in the range of 140,000 to 180,000 square feet compared to the original estimate of 4,000 to 10,000 square feet – the timeline for completion was pushed back two years to July 2023. However, after TID brought in the Conjet ACRTM Robot 557 and quickly learned this innovative technology for performing hydrodemolition, the completion date for removal of all delaminated concrete was moved up to July 2022, a full year earlier than would have been possible with the manual jackhammer process. In addition, TID estimates that the automation and productivity of the 557 has reduced the amount of labor needed by 30,000 to 40,000 man hours.
The plaza renovation project is a microcosm of both the infrastructure challenges that face our planet, as well as the power of innovation to solve these challenges. There is a massive inventory of aging concrete infrastructure in need of repair, coupled with the aggravating factor of a declining construction work force. Yet, innovative technologies such as Conjet’s ACRTM robots give us a viable path forward that is more sustainable, safe, and efficient than the old ways of doing things, providing hope that the world will be a place where future generations will have adequate infrastructure to not only survive, but thrive.
[1] McKinsey Global Institute, Bridging infrastructure gaps: Has the world made progress?, Oct. 2017
[2] McKinsey & Co., The impact and opportunities of automation in construction, Dec. 2019
[3] Silfwerbrand, Improving Concrete Bond in Repaired Bridge Decks, 1990
