Hometown Team Tackles The New Vikings Stadium
A hometown team is building the new Vikings stadium with Golden Valley, Minnesota based general contractors Mortenson Construction leading the construction effort. Ready mixed concrete is supplied by Cemstone, a St. Paul based producer who also owns a fleet of concrete pumps. Even the pumping equipment is home grown with Schwing America’s factory just 18-miles from the Minneapolis stadium site. The billion-dollar project is proceeding at a rapid pace because Minneapolis won the bid to host the 52nd Super Bowl in 2018. NFL rules state a stadium must be fully operational for two seasons before it can stage a Super Bowl. This is the first fixed-roof stadium built since 2002 and the height of the structure is requiring long booms and innovative methods to pump the concrete.
The new stadium will seat approximately 65,000 fans, but at 1,750,000 square feet it is nearly double the old stadium size due to wider concourses and plentiful common areas that are so popular with new sports venues. Cemstone’s advantage in scheduling the ready mixed concrete delivery from nearby plants and providing placing equipment made them the logical choice for the pumping, “Our ability to provide boom lengths from 17 to 61-meters on short notice, along with engineered mix designs and having plants within 10 minutes from the site made us the logical choice,” explains John Dickey, Vice President of Operations, “Plus we enjoy a great relationship with Mortenson.” Cemstone has used every boom pump in their fleet on the project.
With the different mix designs used on the project by Mortenson, it helps to have the expertise of Cemstone’s Operations and Engineering Services Group on the project team. Lars Anderson, Cemstone’s Quality Control and Assurance Manager states, “Based on the order, Central dispatch tickets the correct mix design to the ready-mix concrete plants that service the project. The load is checked for batching accuracy and quality control tests are performed to ensure project performance. We have had no lost loads for quality reasons.” He describes the majority of the mixes as 5,000 to 7,000 psi.
The schedule of construction and the fact that the new stadium occupies the site of the Metrodome meant that before its demolition was completed, foundation work on the new facility began in early 2014. “We put our Schwing 47-meter pumps on the early subgrade work and walls because it had the reach for multiple pours from one set-up,” according to Dickey. The company enjoyed relative freedom to move throughout the site early on. “We progressed from foundations to slab on grade and upper concourses pumping from inside the bowl using our 47, 55 and 61-meter pumps that moved around the site with ease.”
At nearly 30-stories tall, the new Stadium had extensive steelwork to support the roof’s translucent panels. The roof and windows will allow natural light to enter the stadium, as well as giving fans a view of downtown Minneapolis. “The steelwork is monumental,” Dickey states, “Today there are five tower cranes and an equal number of crawler cranes on-site to keep up with the iron workers that are erecting steel in two shifts.” The concentration of cranes has relegated concrete pumping to the outside of the stadium bowl.
“With our Schwing 31XT’s low 18’8” unfolding height, we are able to place slabs under the decks,” Dickey notes. The unique truck-mounted pump has a five-section, modified Z boom with a telescopic main section that offers 15’3” of horizontal movement with total horizontal reach of 87-feet. He adds, “Our 55 and 61-meter booms poured the ring beams up to 200-feet high.” Concrete construction has kept Cemstone’s pumps on the job every day for more than a year. Once the concrete placement exceeded 200-feet, the plan was to crane and bucket the concrete for raker beams, columns and stairwells. Unfortunately, steel placement for the roof structure continues to occupy crane time.
Cemstone suggested an alternative delivery system utilizing a Schwing 750-18 trailer pump placed 200-feet up in the stadium’s superstructure. The Cemstone S 61 SX at maximum reach was able to reach the trailer pump’s hopper and targeted pumping volume was maintained at the required distances.
In the land of the Vikings, cold doesn’t stop the construction crews until wind chill temperatures reach -40 degrees. “That happened once, otherwise the work goes on,” John notes, “In order to keep the pumps at peak performance in the cold, we run multi-viscosity hydraulic oil, insulate the boom pipe and keep the pumps indoors at night.” Concrete temperatures must be 70-degrees in the pipeline which requires batching with hot water and/or heated aggregates in the winter months. The short 10-minute haul to the job site helps keep the concrete flowing. Cemstone keeps the job “green and clean” by cleaning out mixers and pumps back at their shop.
And concrete must keep flowing – 75,000 plus cubic yards of it – to meet the fall 2016 deadline.
Owner: Minnesota Vikings
Architect: HKS Architects, Dallas, Texas
General Contractor: Mortenson Construction, Golden Valley, Minnesota
Ready Mixed Concrete Supplier: Cemstone, Mendota Heights, Minnesota
Pumping Equipment: Schwing S17, S31XT, S34 X, S39X, S47 SX, S55 SX and S61 SX truck-mounted concrete pumps with placing booms and SP 750-18 stationary pump.