Untangling the Triangle

Feb. 21, 2003

If it's a weekday you can bet there are over 150,000 people in Kansas City, Mo., barely moving on a couch.

If it's a weekday you can bet there are over 150,000 people in Kansas City, Mo., barely moving on a couch.

The Grandview Triangle Interchange, where I-435, I-470 and Highway 71 meet in a tangled mess, is perhaps the most outdated of its kind. Containing three merging freeways and as many as 64 movements, the thoroughfare is struggling to move its daily numbers, which could reach as high as a quarter of a million in 10 years. The Missouri Department of Transportation recently decided to give the Triangle a shapelier figure, but there was little room to expand the waistline.

"One MoDOT official said the work involved is kind of like somebody redoing your sofa and nobody has to get up," Bill Clarkson Sr., president of Clarkson Construction, told Roads & Bridges.

Still, the mid-20th century look had to go, and in May of 2001 Clarkson Construction Co., Kansas City, Mo., started the first of a four-phased job. Work began, but the traffic continued. The prime contractor could only close lanes during predetermined off-peak hours or face up to a $6,000-an-hour fine. If certain milestones weren't met by a certain date, the charge was $8,000 a day.

"In this area you can't slow down traffic, especially during rush hour," Rich Markey, chief bridge engineer at Clarkson Construction, told Roads & Bridges. "They wanted to maintain traffic flow as best as they could."

"The reason why the Triangle is so extensively complicated is because we have to find a way to keep functioning out there," Steve Porter, senior public information specialist for MoDOT, told Roads & Bridges.

There's also run-ins with the past, most of which have been dug and cleaned up--some required an excavator, others a handshake.

It's their way--or no highway

Over 50 years ago, MoDOT thought it had the upper hand. The Kansas City Planning Commission developed a concept to connect the south with the north along 71 Highway. The South Midtown Freeway was a major element in the city's highway master plan, and in the mid-60s Kansas City officials gained support for the project and received approval of a corridor plan.

By 1970, properties on the south side of the project, from Bannister Road to 63rd Street, were being acquired. Property owners in the path of the project, however, soon followed with a lawsuit, and work was stalled for more than a decade. Officials eventually went another way with the design, and changed the corridor--now called the Bruce R. Watkins Drive--to a trafficway with signalized intersections at several key points. Work was completed in 2001.

"We learned the hard way. When we had an alternative we thought it was the best alternative and said, ?This is the way we're going to do it,'" Steve Hamadi, MoDOT transportation proj-ect manager, told Roads & Bridges. "That's the way highway departments used to operate."

Traffic has been known to function unpredictably, and during the time of the Watkins debate congestion was starting to move in the wrong direction. In the 1960s, city planners thought the growth pattern would go south along 71 Highway and I-35. The Watkins was supposed to solve this problem, but during the delay life and development began sprouting up in other places. The Grandview Triangle Interchange was taking the brunt of the traffic strike. Overland Park has turned into the fastest growing business district in the state, and Lee's Summit is the fastest growing community.

"You draw a line between Lee's Summit and Overland Park and it's basically I-435 and I-470 going through the Triangle," said Porter. "When we designed the Triangle back in the early 70s we did not figure on it being the main line through that section, but we designed the movement as a ramp or two. The mainline traffic cannot handle just two lanes of traffic."

The original design concept called for a series of collector ramps and some added lanes. Politicians heavily opposed the idea, which was immediately scratched.

MoDOT then conducted a value engineering study. Officials had a one-week meeting with community leaders and outside engineers and came up with the following alternatives:

* Repairing and adding lanes;

* Adding a couple of collector ramps; and

* Grand redesign and rebuild.

It was decided to take the second alternative to the public, which gave it lukewarm support at best (40% was in favor of the design). Still not satisfied, MoDOT formed a Triangle Advisory Board, which contained some of the harshest of critics, and hired a consulting firm, HNTB Corp., Kansas City. After additional input, HNTB had six months to come up with a fourth design option.

HNTB was able to combine strong elements of all three of the original alternatives, and public support shot from 40% to 97%.

"Their roadway design probably took well over 100,000 man-hours," added Hamadi.

Fast-acting medicine

MoDOT didn't want to see any more travel time go to waste and immediately did some patch work--$5 million worth--on the Triangle to loosen the flow.

A left-hand lane was installed on a previous project with the idea that lanes would eventually be added to I-435. What it turned into was a left-hand drop, where vehicles had to make a forced merge. Crews went in and modified the configuration so the left-hand lane was continuous instead of ending at the Triangle.

"That lane-drop configuration really helps the traffic flow quite a bit," said Hamadi. "It didn't increase the capacity of the roadways, but it decreased the number of lane changes, and lane changes could have a bigger impact than the number of lanes that are built."

MoDOT also decided to resurface 71 Highway and conduct some bridge repairs. The 71 Highway was in such bad shape maintenance was being conducted on a daily basis. As soon as Triangle work is complete, MoDOT will tear up and apply a more permanent surface.

"We needed to get 71 Highway in good enough condition so it would last five or seven years and take our maintenance crews off of it," said Hamadi.

A motorist assist program was put in place, and emergency zoning signs were installed. Each zone now carries a number a driver can use to report accidents. Officials say the system has taken 15 minutes off emergency response time.

"The police came to us and said they were having a hard time locating incidents in the interchange and they came up with the idea of dividing the Triangle up into zones," said Hamadi. "Emergency services now has a chart that tells them not only where the incident is at but the best way to get there."

A release valve to the south is being reconstructed. The two-lane 150 Highway has expanded to a four-lane divided one.

"We've had people who have used the Triangle regularly for a number of years and they come up to us and say, ?Is the Triangle working better today than three or four years ago?'" said Porter. "The fact is, it is operating better than before."

History hit MoDOT again during the early stages of the Triangle. A creek that parallels 71 Highway between Red Bridge Road and I-470 had to be relocated 150 ft to the east so that additional ramps could be installed. The creek rests on a flood plain, which for years was used as a dump site.

"When we went out there it looked like these tires were just growing out of the stream bank, and you could see other construction materials like brick and shingles," said Hamadi.

Fuel tanks and contaminated soil had to be removed, as well as almost 200 tons of tires, some still attached to axles.

The landfill also was the resting place of two demolished bridges. Several asbestos-contaminated buildings had to be torn down, and PCB had to be removed along an old railroad route.

When the final truckload of garbage was removed, cleanup costs ranged between $1-2 million.

Where's the money from?

Once preliminary work was complete, MoDOT rolled in for the big show.

As mentioned before, the project has been cut into four stages. Phase 1--the area carrying the highest risk for accidents--involved building a two-lane, south-to-west mainline on I-435; reconfiguring south I-435 ramps to south 71 Highway and east I-470 to create a separation from express traffic; adding lanes to north I-435 and replacing bridges. There was an $8,000-a-day incentive/disincentive, with the maximum award working out to 5%--or about $2.5 million--of the $48 million job. Clarkson completed work on Dec. 23, 2002, 10 months ahead of schedule, to receive full benefits.

Work on Phase 2 ($65 million) began in July 2002. Here the focus is on west I-470 and ramps from north 71 Highway to I-470. The ramps will allow merging traffic to join mainline traffic on parallel lanes, no longer forcing motorists to immediately merge with high-speed traffic. The redesign also shifts west I-470 to the right side of 71 Highway. The plan, when completed, will more than triple capacity.

The third phase includes east I-435 to I-470, a section of 71 Highway and most of its ramps north of Red Bridge Road and ramps from south I-435 to south 71 Highway and east I-470.

The final upgrade will consist of 71 Highway; its ramps and collector roads south of Red Bridge Road; the relocation and reconstruction of a new Red Bridge Road bridge; replacement of the Longview Road underpass with a bridge over 71 Highway; and replacement of the Kansas City Southern railroad bridge over 71 Highway just north of Blue Ridge Blvd.

Funding, however, could keep all work locked up in Phase 2. Unlike other states, Missouri does not fund road and bridge work through a sales or gas tax. A four-cent-per-gallon gas tax increase was on the ballot this past November, but voters rejected it by a 71% margin.

Due to the lack of financial support, MoDOT has to rely on bond financing. Between 2001-2006, MoDOT is allowed to issue up to $2 billion in bond financing, but the downswing in the economy cut from what was originally planned. So far almost $110 million in bonds has been used for Triangle work.

"The last $30-50 million is probably up in the air right now, but we'll get funded eventually," said Hamadi.

But if the cash flow is reduced to a trickle, MoDOT may have to break the project up into smaller pieces. The original timetable called for all work to be completed in 71?2 years. A lack of funding could stretch it out to 12 years.

"We have kept I-435 and all of mainline I-470 on schedule," said Hamadi. "That is probably about 65-70% of the traffic congestion and the worst accident location. The problem is 71 Highway has to be reconstructed last, and that has the biggest impact from the financial perspective."

Phasing right through

There are times when construction is the victim of delay. Clarkson's suffering came soon after Phase 1 received the go-ahead, in the late spring/early summer of 2001. The Kansas City area experienced one of its wettest seasons in recent memory, and two miles of permanent median barrier had to be installed along I-435. The Oct. 31 deadline for barrier work was closing in.

"We were running into late Oct., Nov. and early Dec. (2001) trying to get the concrete extruded there," said Clarkson. "If we got caught in the winter we were facing about a $250,000 a month penalty."

Throwing another twist into the deadline was the fact that Missouri does not allow Superpave to be placed on concrete after Oct. 1. So the completion date on the barrier job--which included a Superpave overlay--was pushed up 30 days.

Closing two lanes of traffic on I-435 during every dry night, Clarkson was able to meet the rush delivery. The median barrier construction included laying a 4-in. aggregate base, which was covered with 14 in. of concrete and a 5-in. Superpave overlay. Clarkson used a Rexcon Town & Country to pave the 14-in.-thick concrete section. Producing the overlay was a Blaw Knox 5510 asphalt paver (Circle 932). Three vibratory rollers--two Hypac 766s (Circle 933) and a Hypac 778 (Circle 934)--and a Bomag 180 pneumatic roller (Circle 935) handled compaction. A Gomaco 6400 (Circle 936) formed the 51-in. barrier wall.

Five structural-steel bridges were erected in phase 1, and most of the steel was set at night. A total of 42 bridge deck pours, with the assistance of a Gomaco C450 deck finisher (Circle 937), also were done during twilight hours. Two of the spans--one 781 ft long, one 1,199 ft long--stand on north I-435. South I-435 holds the other three, which measure 275, 1,781 and 2,452 ft long.

Drilled shafts 5 in. in diam. were placed 50 ft deep for the 120 bridge columns in Phase 1.

All new bridges in the Triangle are designed to have hammerhead-type caps. An ashler stone form liner is used when pouring the columns for aesthetic purposes.

Also unique to Missouri bridge building is the use of prestressed concrete panels in the bridge deck. Instead of wood forms, a pad of Styrofoam is placed on top of the girders. Then comes the 3-in. prestressed concrete panel, and a 51/2-in. full-depth riding surface is placed on top. A seven-day wet cure has produced strengths as high as 6,000-7,000 psi. The MoDOT requirement is 4,500 psi.

Clarkson also dropped 80,000 sq yd of pavement during phase 1, and most was of the 14-in.-thick concrete variety.

Plant location has played a key role in the quick production. LaFarge North America is the ready-mix supplier and has a plant located two miles from the center of the jobsite. Using a CS Johnson dual-drum wet batch plant set up adjacent to the Triangle, Clarkson has been able to batch its own product for the concrete paving portion of the job.

Mid America Precast, Jefferson City, Mo., supplied over 50,000 sq ft of mechanically stabilized earth (MSE) retaining walls in phase 1.

Work on I-470--Phase 2--has been in full swing for weeks. At press time, about 40 of the 64 bridge columns were in place and progress had been made on four bridges. All substructure work must be complete by July 4.

Two of the bridges, currently being worked on adjacent to existing traffic on I-470, are 2,000-ft-long overhead structures over Hickman Hills Drive and Hickman Hills Creek. A 500-ft-long temporary bridge is being installed to tie into west I-470, and the fourth span (300 ft) is an on-ramp, which will take traffic from Red Bridge Road to 71 Highway north.

When complete, Phase 2 will have eight new bridges. The drilled shafts--8-9 ft in diam., 40 ft deep--are the only real change in bridge construction specs from phase 1.

Phase 2 will contain over a million yd of embankment-in-place, which couldn't start until the massive environmental cleanup and the creek relocation were complete.

The design calls for over 90,000 sq ft of MSE retaining walls.

Clarkson expects to start concrete paving in the spring, and all traffic must be driving on the new west I-470 by March 24, 2004.

About The Author: Bill Wilson is editor of Roads & Bridges.

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