Pumps on the Edge
Pumps on the EdgeConcrete Placement Challenges Abound on Colorado River Bridge Project
STURTEVANT, Wisconsin (October 10, 2005) - Positioned mere inches from the edge of a mountainous cliff near the Hoover Dam, a Putzmeister BSF 58-Meter boom pump stretched its long 188 ft. boom to its fullest extension to pump concrete into the hopper of another boom pump situated in a gorge below.
Ironically, the unit underneath - a Putzmeister BSF 42X-Meter - was also set up on the edge of yet another cliff, overlooking a river 900 ft. below. Its boom was also extended to its longest reach at 138 ft. to pump concrete to its final destination.
Together, these “pumps on the edge” were deemed the only way to effectively place concrete for construction of a large bridge pier. Not just any bridge pier. This one will provide the foundation for vertical columns needed to support the special arch of the new Colorado River Bridge. The 2,000-foot-long, cast-in-place bridge is being built to reduce traffic on U.S. Highway 93, which crosses over Hoover Dam.
Quinn Concrete Pumping of Las Vegas provided the equipment, expertise and creativity to conceptualize and mastermind this challenging concrete placement feat. Executed with great ingenuity in mid September of this year, it proved successful.
Before the 'pump to pump' pour could commence, a temporary road was specifically built for the BSF 42X-Meter so it could travel down the steep and rocky slope. In addition, a 35 ft. by 50 ft. platform was specially graded flat to ensure a structurally sound base for unit setup below.
Steve Heimark, Operations Manager at Quinn Concrete Pumping says, “Originally, we considered a 36-Meter for its lighter weight. However, we had to upsize to a 42X-Meter for greater reach.”
“It was nerve racking,” Heimark adds, “when this larger boom pump had to travel down an almost 45-degree slope while connected to the cable of a track-hoe excavator. All the time, we were relying on the cable's strength not to let the pump escape, which would have sent it plummeting over the edge and almost a quarter mile down before crashing into the waters below.”
Fortunately, the unit stayed its course. The crew worked at night to take advantage of lower summer temperatures and less traffic congestion. However, due to the nature of the pour itself, it still took seven hours to place 380 cubic yards of concrete.
Casino Ready Mix, Inc. supplied the well-known harsh Vegas mix from a batch plant specifically set up about three miles from the project. Obviously, as ready-mix trucks could not traverse down the extreme slope, they would discharge into the hopper of the BSF 58.20H pump situated atop the upper edge, which in turn, pumped to the other boom pump's hopper below.
With established concrete pumping services since 1998 and an ever-expanding fleet of Putzmeister equipment, Quinn Concrete Pumping was selected exclusively to pump all aspects of this high profile project. Heimark says, “On other jobs related to the Hoover Dam project, the general contractor had witnessed our Big Mouth S-Valve handle extremely harsh mixes that others just couldn't pump. As a result, our equipment's performance was a major factor in being selected.”
Although this was a challenging pour on the bridge's structure, it will not be the most difficult or most unique as the three-and-a-half-year project progresses. Quinn, the pumping company's owner says, “Throughout various stages, we will be attempting some of the most unusual and innovative concrete placement techniques ever imagined. Visitors to the Hoover Dam should also be focusing their cameras at this construction site.”
“We handle so much residential, casino and other commercial work,” Heimark adds, “that it's definitely a change of pace to handle such a prominent civil project, especially one that will require so many unique concrete placing strategies.”
The $114 million Colorado River Bridge project was awarded to the joint venture partnership of Obayashi Corporation and PSM Construction USA, Inc. Construction started in January 2005 with completion scheduled for June 2008.
General contractor: Joint venture of Obayashi Corporation and PSM Construction USA, Inc.
Ready mix supplier: Casino Ready Mix, Inc. - Las Vegas, NV
Pumping contractors: Quinn Concrete Pumping - Las Vegas, NV
Equipment: Putzmeister BSF 58-Meter and BSF 42X-Meter concrete boom pumps