Las Vegas, Nev., sees a lot of traffic, with tourists flocking there for the night life, the gambling and the sun. Las Vegas’ airport, McCarran International, saw 48 million arriving and departing passengers go through its terminals in 2007, and was the sixth busiest commercial airport in the United States in 2006.
To deal with this volume of traffic, McCarran is undertaking a $1.85 billion dollar expansion project that will include a new three-story, 1.9 million-sq.-ft. (176,500 sq m) terminal with ticket counters, baggage claim, shops, restaurants, security checkpoints and 14 aircraft gates, including six configured for international service. The project also includes new roadways, a 6,000-space parking garage and an underground tram system that will connect the new Terminal 3 to the existing D Concourse by 2012.
The land that will house Terminal 3 was bisected by a busy thoroughfare called Russell Road. The United States Department of Aviation has spent nearly $62 million to relocate Russell Road a few hundred feet to the north in order to create a larger contiguous parcel for Terminal 3. Once that road was moved, the next task was clearing the site to begin the early stages of Terminal 3’s construction. There wasn’t much to remove beyond the old roadway, a parking lot and a few small buildings here and there.
However, the existing aircraft movement area, or ramp, is located at a higher elevation than the area where Russell Road used to run. The new ramp supporting Terminal 3’s gates must be built at the same elevation as the existing ramp space to the south. Work is underway to raise the ground level near the eventual Terminal 3 site.
Southern Nevada Paving Inc. received the contract to do all the mass grading, structural excavation, building the Type 2 base and paving. Southern Nevada Paving is owned by Holcim Ltd., a global company with locations in more than 70 countries. Holcim is one of the largest suppliers of Portland and blended cements and related mineral components in the United States.
The McCarran International Airport job immediately presented a daunting problem in sheer size — 74,000 cu. ft. (56,600 cu m) of rock needed to be removed on the 54-acre (21.8 ha) site. Southern Nevada Paving subcontracted Flippin’s Trenching of Las Vegas to handle the site excavation work with soil conditions on the job site ranging from caliche rock to wet clay at the water table.
Flippin’s Trenching is a privately owned family business that has been doing business in southern Nevada since 1956. In those 50 years, the company has grown from a one-trencher operation run by T.O. Flippin to more than 100 pieces of equipment. The company specializes in the installation of wet and dry utilities, demolition, grading, paving, mass excavation and rock removal.
Caliche, a calcium carbonate, is a special concern for Flippin’s Trenching as it’s almost impossible to work with.
“When you mill this stuff, you can turn it into aggregate-based material, but getting it out is the problem,” said Ken Flippin Jr., commercial operations manager of Flippin’s. “It was formed as underground water ran through the valley. As the water ran from high to low, it built up these layered deposits and sealed itself off so no more water would run. In most areas of town, it trapped boulders and stones to create a cemented conglomerate, but here at the airport, think of it as only the super-hard glue that holds regular cement conglomerate together.”
Flippin said traditional blasting creates a two-fold problem: getting rid of truck-sized boulders and getting a good quality material to use elsewhere on the job. Other methods used by Flippin have included balling. This involved taking a heavy steel ball and pulverizing the rock. However the process is difficult and slow. He also used a hoe-ram in the past, but this method was not effective for large-scale projects. According to Flippin, a contractor cannot always obtain the desired results with these two methods.
Flippin said that a Vermeer Terrain Leveler Surface Excavation unit was going to be the best option.
“Milling is more manageable and there are fewer safety concerns,” Flippin said. “Because of regulatory and environmental concerns, blasting really isn’t an option and milling is becoming the way to go.”
Designed specifically for site preparation and excavation, surface mining, road construction and soil remediation, the Terrain Leveler unit was the ideal solution for Flippin. The T1255 Terrain Leveler attachment has a patented tilting head with top-down cutting action for efficiency and deeper tooth penetration. With a 600 hp (447 kW) engine, the unit can dig up to 27 in. (69 cm) deep and 12 ft. (3.7 m) wide in one pass. The unit’s top-down technique is powered by a large direct drive hydrostatic transmission that provides greater speed control for the cutting section.
Flippin’s Trenching owns one Vermeer T1255 Commander 3 Terrain Leveler unit but rented three others to help on this job. At one time, Flippin’s had five Terrain Leveler machines on the job at once. The sheer number put a huge strain on the whole operation as they had to support the machines with five service trucks on hand.
“We just couldn’t do all of that in-house,” said Flippin. “So we called Vermeer and they sent their staff out to help.”
Before the rock excavation process began, 26 dewatering wells were installed on the 54-acre site to dry out the subterranean area. John Jennings, project manager of Southern Nevada Paving, said that prior to excavating, crews drilled down far below the water level and installed pumps.
“This way we lowered the water level so when excavation got to that level, you don’t have water intruding in the excavation,” he said. “The process included drilling 3-foot diameter holes 25 to 40 feet down with a pipe put in place to pump the water out, similar to having a sump pump in one’s basement. The water is pumped into a pipe system above ground and drained off-site.”
Progress each day varied according to the hardness of the rock, which ranges from 8,000 to 10,000 psi.
“It went from 300 to 1,200 cubic yards per eight-hour machine day,” Flippin said. “This was some of the hardest stuff we’ve seen in a long time.” The excavation part of the project began in May 2007 and is on schedule to be completed in October 2009.
The caliche was being removed from the site and not being re-used on the job.
“We just turned it into something that can be picked up and hauled off to the rock crusher and re-sold as usable material,” Flippin said. Another problem posed by the site was dust control. “We had water tanks on the machines, and given the proximity to airport traffic, that alone wasn’t going to satisfy the airport officials,” Flippin said. “It became one man with a water tank and a hose on each machine.”
Jennings said all the milestone deadlines have been met. “When you’ve got a project this big, there are lots of smaller scheduling deadlines put in the various phases of the work, and those can be tight to meet,” he said. “We’ve hit them all within reason.”