Renovating a Historic Bridge While Keeping Citizens Online
Built in 1912, the historic Eighth Street Bridge in Sioux Falls, South Dakota is a concrete deck bridge that commuters, pedestrians, cyclists and joggers alike use to cross over the Big Sioux River. The beautiful 243-foot long triple-arch concrete deck bridge was added to the National Register of Historic Places in 1993 and has not seen renovation since the 1970s. In March of 2020, Sioux Falls began a planned reconstruction of the unique soil-filled bridge that they planned would take about a year and a half. General Contractor Journey Construction was awarded the rebuilding of the bridge in the 1970s and again in 2020. When Journey Construction realized that they would need access to the entire bridge, including the areas holding the high-speed cable, they reached out to internet, phone and cable company CenturyLink.
CenturyLink quickly realized this job was going to require out-of-the-box ideas if they planned to renovate this bridge and keep the entire South Dakota city online during the construction. CenturyLink reached out to Midwest consulting firm Terra Technologies, Inc., based out of Denver, Colorado, to find a way that work could progress in a manner that would not interrupt any communications to Sioux Falls. Local to Sioux Falls, CSDA member Northwest Concrete Cutting and Crane Service was contacted by Terra Technologies, Inc. in February 2020 regarding some simple flat sawing along the historic Eighth Street Bridge. Their goal was to erect a temporary cable suspension bridge in order to raise the existing fiberoptics and communication lines that ran 8-feet beneath the pavement so Journey Construction would have working room to complete the remainder of the project and the citizens of Sioux Falls would not have any interrupted communication.
As the project progressed, Terra Technologies realized that they needed more than just concrete cutting. They reached out looking for contacts for other aspects of the project, including certified welding services, crane services as well as additional concrete cutting. It was at this time that Northwest Concrete Cutting and Crane Service became a turnkey subcontractor for Terra Technologies and was now responsible for the initial slab sawing to prepare for the demolition and removal of the existing pavement that ran across the bridge. The pavement had to be cut and completely removed to prepare for the proper installation of new concrete. Each slab measured 30 feet long by 15 feet and 8 inches thick. Two slabs were removed, totaling 90 feet of total cutting and 45,000 pounds of concrete. After the existing pavement was removed, Northwest then formed and poured the two suspension tower footings that were 14 feet by 14 feet and 30 inches thick.
Once the tower footings were completed, Northwest had to pour the “deadman” weights for the suspension bridge. These weights were located at opposing ends of the bridge and were 7 feet thick by 27 feet long and a total of 14 feet wide. Each individual weight weighed about 400,000 pounds and all of these structures were temporary, needing to be removed once the backfill for the bridge was completed. The preparation alone was already turning out to be quite the undertaking.
Northwest supplied four certified welders who assembled two 35-foot tall by 10-foot wide towers made of hollow structural section (HSS) steel. After the towers were assembled, they then became in charge of the delivery and erection of the towers. Northwest Concrete Cutting and Crane Service supplied semitrucks and trailers, a 90T mobile hydraulic crane, certified riggers/signalmen and certified welders to haul and erect each tower. After the towers had been erected, it was business-as-usual for Terra Technologies’ responsibilities on the project. As soon as the cables were suspended, Journey Construction could continue working on the underground and structure work that needed to be completed.
As exciting as it was to finalize all the groundwork for this project, completion meant that it was time to bring everything back down from the suspension bridge — communication lines had to come down, as well as the suspension bridge, towers, tower footings and the massive 400,000 pound deadman weights. Northwest once again brought their 90T mobile crane onsite, as well as certified riggers and signalmen to help dismantle and load the towers onto Terra Technologies’ semitrucks and trailers. As a safety precaution, Terra Technologies was adamant about not allowing more than 60,000-pounds on the bridge deck in any one area.
After the towers were disassembled, Northwest was responsible for removing each of the 400,000-pound deadman weights. Hydraulic hammers could not be used because of the sensitivity of the fiber optic cables and the condition of the bridge itself. After some major planning, it was decided to lay 2-inch PVC pipe every 2-foot 8-inches on the bottom of the anchors to create 40,000 pound pieces once cut with the wire saw. Imbed lifting points were designed so that once cuts were made, they could be lifted from the top of the deadman. A Diamond Products WS25 Hydraulic Wire Saw and a Husqvarna CS10 High Cycle Wire Saw were used to cut the two deadman weights into twenty equal sections, upon which the sections were loaded onto a 110T mobile hydraulic crane and disposed of at the recycler where the pieces were unloaded with a 55T mobile crane.
Standard PPE was used during this bridge renovation, including steel toe boots, high-visibility clothing, gloves, hearing protection, safety glasses and hard hats. Landon Lueders of Northwest Concrete Cutting and Crane service said about this job, “As a company, I am proud of the fact that we are able to be of such value to our customers. The original inquiry started as a simple flat sawing project and then grew into something much more. It is a testament to our ability to service customers from start to finish, from concrete sawing and demolition to pouring footings, foundations, certified welding, crane service, steel erection and trucking. At Northwest, we are truly the definition of team players. Everyone is working towards the same goal of finishing a safe, on budget and on schedule project that not only we can be proud of, but our city can be proud of as well.”
Lueders says he believes Northwest was chosen for their impressive track record with other projects, as well as their extensive list of services they offer. For this restoration, forward thinking and planning increased the productivity and allowed the team to finish within budget. Having placed the PVC pipe and pick points before the deadman were poured prevented the need for any core drilling to run the wire saw through, which saved the project time and money. Northwest had the right equipment, manpower and expertise to help bring the historic Eighth Street Bridge project to fruition while also keeping the citizens of Sioux Falls connected.
Northwest Concrete Cutting & Crane Service is a family owned and operated business based out of Sioux Falls, South Dakota. They service a 400-mile radius of the Sioux Falls market, but will travel anywhere in the country if their customers need their experience and expertise. They have been in business for 31 years and currently employ roughly 40 people. They have 15 full-service concrete cutting service trucks, three mobile hydraulic cranes ranging from a 55-ton all the way up to a 300-ton, semi-trucks and trailers, dump trucks, high cycle wire saws and medium to heavy excavating equipment. Their broad range of services include, but are not limited to: concrete cutting/sawing, concrete coring, concrete grinding, shot blasting, wire sawing, wall sawing, flat sawing, engineered demolition, selective demolition, concrete pouring, pre-cast erection, steel erection, certified welding, crane service, rigging service, trucking and select general contracting jobs. Northwest Concrete Cutting & Crane Service is here to help everyone achieve the same goal of a safe and successful project. They have been a CSDA member since 2015.
Terra Technologies, Inc.
Concrete Cutting Contractor
Northwest Concrete Cutting and Crane Service
Slab Sawing, Wire Sawing