Slattery Skanska Rebuilds Critical BQE Expressway

Wed March 23, 2005 - Northeast Edition
David S. Chartock

Similar to arteries to and from a heart, arteries in and around New York City get clogged, too. The Brooklyn-Queens Expressway (BQE), from 25th Avenue to Broadway in Woodside, Queens, got more than clogged. And after serving New Yorkers for 50 years, the New York State Department of Transportation, Region 11, determined that a challenging “surgery” was required.

The highway is a critical artery that pumps life to a road system linking two of New York City’s boroughs, Brooklyn and Queens, and major arterial roadways including I-95, I-87 and I-495. It also links New York’s two major airports, JFK and La Guardia, and three major sports stadiums (Yankee Stadium, Shea Stadium and Arthur Ashe Stadium where the U.S. Open is held each year).

The “surgery” took the form of a $250-million, four-year rehabilitation effort to improve the highway for current vehicle speeds for 142,500 daily users. Designed by URS Corporation, the project would widen and realign the expressway to improve safety, correct deficiencies and rehabilitate or replace structures to create a stronger, healthier artery.

Within the project area are local streets, the CSX Railroad structure and Northern Boulevard, a main roadway that leads to Manhattan and Long Island.

Included in the project, which began in March 2000, are utility and local roadway relocations and profile changes; replacement or rehabilitation of seriously deteriorated pavement; reduction or elimination of safety deficiencies such as limited sight distance and lane merges; realignment of the BQE both vertically and horizontally; new CSX railroad bridges; replacement of several bridges along and over the BQE; new widened BQE bridges over various avenues; modernization of traffic guidance and control system; construction of new aesthetically pleasing retaining walls to retain the fill areas supporting the BQE; construction of granite art walls on Northern Boulevard to complement the new single-point urban interchange provided to ease traffic movement on both local streets and the BQE.

To date, the project, which had been extended past its March 2004 completion date to provide even greater enhancements, has required approximately 430,000 cu. yds. (328,758 cu m) of earth be moved, according to Michael Cobelli, a project manager of Whitestone, NY-based general contractor, Slattery Skanska USA Inc.

To move all of this earth required the use of Caterpillar excavators models 235s, 320s and 350s. The project, which had an original bid of $228.8 million, but grew as a result of additions and change orders, also required the use of Juntan pile rigs from subcontractor Underpinning & Foundations, of Maspeth, NY, a Skanska company.

According to Cobelli, “a traditional pile rig is a lattice boom crane with fixed leads. Those fixed leads hold the pile driving hammer. The Juntan is a hydraulic boom machine that holds the hammer. This allows for quicker mobilization and demobilization of the machines. Juntans also were designed for use in tight spaces such as those on this job. Juntans also allow movement under bridges.

“Underpinning also used Bauer drill rigs with segmental removable casings. These were used to install concrete socketed H-pile caissons,” Cobelli added. “In addition, another subcontractor, Trevi Icos, of Boston, used Soil Mech drill rigs to install 10-foot diameter, 100-foot deep caissons.”

Scope of Work

Correcting sight, road, bridge and safety deficiencies were among the project team’s general challenges. The total reconstruction effort called for the demolition of 19 bridges; construction of 13 new bridges running along or over the BQE and two rail structures; demolition and reconstruction of 3.5 mi. (5.6 km) of retaining walls; relocation of a 3,000-ft. (914.4 m) section of the CSX Railroad; reconstruction of 1.6 mi. (2.6 km) of highway; construction of 18 temporary ramps and 28 temporary walls to support the multiple staging and phasing required to maintain the existing traffic configuration; construction of noise walls and environmental shields; and installation of a new drainage system, utilities and signage, explained Dhiaa Shubber, a project manager and resident engineer of Parsons Brinckerhoff Quade & Douglas Inc., the project’s New York-based construction inspection consultant.

“All of this work not only had to be done while minimizing disruption to commuters, residences and businesses, but it had to be done under an A+B contract,” Shubber said. “Under the A+B contract, the project’s general contractor would receive a $10,000 per day bonus for every day the project is completed ahead of its 1,270-day schedule.”

The penalty portion is a bit more complex. It contains three penalty portions. The first provides a $10,000 penalty per day for each day the project is past its schedule; the second portion of the ’B’ part of the contract covers the Broadway pavement area; and the third portion of the penalties covers access to a residential building on 69th Street.

In addition to the A+B contract, project challenges included realignment of the highway horizontally and vertically and widening three lanes of roadway in both directions to accommodate breakdown lanes.

Built in Stages

Staging played a large role in getting the enormous amount of work for this project done on schedule. The project was divided into four primary stages. The first stage entailed realignment of the railroad bridges, including the CSX over 34th and 35th avenues, eastern half and the CSX over Northern Boulevard, western half.

The second stage included continued realignment of the railroad bridges. Specifically, completing the eastern portion of the CSX over 35th Avenue, the BQE and 34th Avenue; construction of 35th Avenue, the western portion of 69th Street and the eastern portion of 61st Street.

It also involved construction of the Triborough Bridge leg of the BQE western portion and the ramps between 30th Avenue and 49th Street; construction of the BQE eastbound and westbound roadways for the leg to the Grand Central Parkway; construction of the eastern portion and ramps of the BQE between 32nd and 25th avenues; construction of both the eastbound and westbound BQE roadway and bridges including ramps between Broadway and Northern Boulevard; and construction of a new Northern Boulevard interchange as a single-point urban interchange.

The third stage encompassed realignment of the CSX railroad bridges over 35th Avenue, the BQE and the western half of 34th Avenue; realignment of the CSX railroad over the eastern half of Northern Boulevard; continuation of construction of 35th Avenue from the second stage of the project; and construction of the eastern portion of 69th Street and the western portion of 61st Street.

This stage also included construction of the middle portion of the BQE between 30th Avenue and 49th Street; construction of the eastbound and westbound Grand Central Parkway leg of the BQE and the ramps between 32nd and 25th avenues; continued construction of the BQE, eastbound and westbound roadway and bridges, including the ramps between Broadway and Northern Boulevard; continued construction of the Northern Boulevard interchange; and construction of a pumping station.

Included in the fourth stage of the project is the continuation and completion of construction of the eastbound and westbound roadway of the BQE and bridges, including the ramps between Broadway and Northern Boulevard; continued construction and completion of the Northern Boulevard Interchange and the pumping station; construction of the eastern portion of the BQE eastbound Grand Central Parkway leg and ramps between Northern Boulevard and 31st Avenue; and construction of the eastern portion of the Triborough Bridge leg between 30th Avenue and 49th Street.

The Biggest Challenge

One of the project’s most difficult challenges was building the project while maintaining traffic, according to Craig Ruyle, engineer-in-charge of the New York State Department of Transportation (NYSDOT).

“Keeping the required number of traffic lanes open at all times made construction phasing extremely difficult,” said Ruyle. “The solution was to build the bridges in phases.”

Cobelli agreed that the project’s biggest challenge was the reconstruction of the entire width of the road, three lanes in each direction, without disrupting or decreasing existing service. The solution to this challenge was the staged construction, which included 18 bridges, each of which was built in a four-stage construction process.

Furthermore, the CSX Railroad alignment had to be modified and 34th and 35th avenues had to be lowered by 6 to 10 ft. (1.8 to 3 m) and the railroad had to be moved east between Broadway and 34th Avenue and to the west between 34th and 32nd avenues. Further complicating this task is the fact that the roadway splits at Northern Boulevard with one leg leading to the Triborough Bridge and the other leading to the Grand Central Parkway toward New York City’s airports.

Four Stages, 30 Phases

The solution to building the roadway while maintaining traffic was to perform the work in four stages and 30 phases to maintain current lane configurations throughout the duration of the project. In addition, at any given time, there were five single-lane cattle chutes, which presented the project with another challenge: maintenance and traffic protection, especially during winter when snow removal became difficult. The solution was to clean and temporarily widen the lanes to remove the snow, which had to be done overnight, he added.

According to Shubber, “one of the project’s more difficult tasks was combining the three structures that carry the CSX Railroad into a single structure with nine spans The original structure pre-dates the construction of the BQE. It is a complicated structure because its foundations vary and include 1-foot cast-in-place concrete piles, 1-foot mini-piles and 3-foot, 6-foot and 10-foot diameter concrete shafts.”

The cast-in-place concrete piles, mini-piles and 1-yd. (.9 m) shafts were used to support the abutment while the two-yard shafts supported cap beams and spans 1, 2, 4 and 8. The 10-ft.-diameter shafts supported rigid-framed structures at spans 4, 5, 6 and 7.

The original configuration of the bridge, Shubber explained, is a single structure running over the local streets with built-up embankment in between. The new nine-span bridge consists of I-girders framed into box cap beams, some resting on 2-yd. diameter (1.8 m) concrete columns while others connect to box columns extending halfway down into 3-yd. (2.7 m) shafts.

Plans called for the construction of 3-yd. reinforced concrete shafts that extend approximately 90 ft. (27.4 m) into the ground. An integral steel box extends an average of 38 ft. (11.6 m) into the ground inside the shaft outside a reinforcement cage. The column then extends above the ground, connecting with the pier cap beam where I-girders supporting the deck are framed in.

There also is a reinforcement cage inside the integral steel box that extends 2 yds. below and above the bottom and top elevations of the steel box. The tolerances for the shafts are 3 in. (7.6 cm) off the center at the top and two percent off the vertical at the bottom. The integral steel box columns have zero tolerance all around, which must be met in order for the superstructure to be constructed.

To meet this contract requirement a mechanism was devised that would hold the outside cage, the steel column and the inside cage in position, within tolerance before the concrete was placed. The weight of the components made this a difficult task. The outside cage weighed 42 tons (38.1 t), the rigging 4 tons (3.6 t), steel box column 81 tons (73.5 t), and the inner cage 9 tons (8.2 t).

“The construction of this entire system was further complicated by the hiring of different subcontractors to perform the work and the tight schedule under which the project was being built,” Shubber said.

A detailed construction plan was developed in the field. It required the shaft to be constructed with a tolerance equal to the one associated with the construction of the integral steel box column — one-sixteenth inch.

It also called for the different components to be installed in a sequence that would allow adherence to the specified tolerance. In addition, the solution called for the installation by vibration of 10.5-ft. to 11-ft. diameter (3.2 to 3.3 m), half-in. thick (1.3 cm) and 50-ft. long (15.2 m) steel casing. The casing helped in supporting the excavation and in controlling the shaft tolerance at the top.

Once the casing was in the ground, the shaft drilling began until tip elevation was reached. Slurry was used to stabilize the excavation below the casing and allow placement of the class G concrete. The outer reinforcement cage was lowered into the hole and concrete was placed up to 2 yds. above the bottom elevation of the casing. After placing the concrete, the slurry mix was removed and the inner reinforcement cage was installed.

Next, concrete was placed up to the bottom elevation for the steel box column. Once the concrete was cured, the lower portion of the steel box column was installed, Shubber pointed out.

To control horizontal movement of the lower column, a system consisting of eight 50-ton (45.3 t) jacks was installed at the bottom. The jacks were anchored into the concrete base to restrain displacement. Later, a concrete collar was installed at the top of the casing to receive another set of eight 50-ton jacks that were installed to control the horizontal movement of the top portion of the column, which would be spliced in.

Once the jacking systems and the two column pieces were in position, the cap beam was spliced to the columns and the I-girders to support the deck were erected. As the erection process took place, adjustments in the column positions were made at all four corners of the span using the jacks, Shubber said, adding that “sometimes adjustments had to be made on two adjacent spans to fit the different components of the structural steel. The adjustment was so finite, they were likened to the movement of a fine Swiss watch.”

Three-Truss Span Structure

The other CSX structure goes over Northern Boulevard. This is a three-span structure with a truss system in the middle span. The size and weight of the truss forced the contractor to utilize barges to deliver the steel to the Brooklyn yard. Heavy 500- and 600-ton (453.6 and 544.3 t) cranes were utilized to erect the structure.

The first stage involved the installation of the first two trusses and related bracings. The second stage consisted of installing the third truss, while mating the loaded first stage. This complicated the construction process, which necessitated mating an undeflected truss to a fully deflected structure. To solve this problem, the third truss was constructed to meet its mate at the middle point and was hydraulically jacked at its ends and at intermediate predetermined points to connect the remaining panel points. A total of 16 panel points had to be connected to the 220-ft.-long (67 m) structure, Shubber explained.

The remaining structures carry the BQE over local streets. One of them had to be built in several stages because of the difference in deflection and structure types. These issues were addressed by closely monitoring structure behavior using periodic surveys of the deflection of the concrete decks as the curing process progressed, he added.

Retaining Walls

The retaining walls also were a challenge because some were as high as a three-story building. They supported the highway or other railroad structures. The walls supporting the railroad were difficult to construct because of the staging sequence and the steel ties required at their tops to minimize deflection. In addition, temporary walls of heavy gauge steel sheeting tied at three different levels, further complicated the installation of these walls, Shubber said.

Another set of walls running along the Triborough Bridge link had to be repaired and refaced with an aesthetically pleasing look. The difficulty was finding a way to accomplish the task within a limited space. The contractor needed special forms as large as 21-ft. (6.4 m) high by 40-ft. (12.2 m) long to install a single panel. This was accomplished by using cranes positioned on the service road, running along the highway, and single lane closures applied to the expressway.

Once the form was in position and the reinforcement adjusted to meet the tolerance requirements, the concrete was placed. Vibrating the concrete 20 ft. (6.1 m) down to occupy every corner in the wall was a tall order since there was only 8 in. (20.3 cm) of space between the existing wall and the construction form.

These forms contained a “simulated Ashlar Stone finish, which required form liners to give the appearance of natural stone,” Cobelli said, noting that this task was performed along 6 mi. of retaining wall.

The staging on the airport link also was challenging because the width of this work area was just 12 ft. (3.6 m) and large machines had to be operated in that small area. This included innovative, high-tech machines used to drill the required shafts for the 5.5 mi. (8.8 km) of permanent and temporary edge piles.

Lowering 34th and 35th Avenues

The work also called for lowering 34th and 35th avenues from 6 to 10 ft. (1.8 to 3 m). In turn, this required all utilities to be lowered, including 48-in. (121.9 cm) and 72-in. (182.8 cm) water mains, 12- and 20-in. (30.5 and 50.8 cm) gas mains, and all sewer lines and electrical ducts.

The challenge here, according to Cobelli and Shubber, was lowering all of these utilities while maintaining local street traffic. The task at 34th Avenue was accomplished by building a temporary retaining wall to support existing traffic on one side and a bridge abutment for the existing BQE traffic on the other side.

This schedule allowed the 72-in. water main to be installed in segments and within a tight workspace. Each segment of the main was lowered into a specific open hole and dragged backward or forward to mate with the next piece. The 72-in. water main was coupled with an 84-in. (208.3 cm) sleeve.

Lowering the 72-in. water main under 34th Avenue had to be done during specified time periods in which the impact on local residents was minimized. This meant doing the work from October through April and it meant at least one water main had to remain operational at all times. This task was achieved through the implementation of a phased work schedule, Shubber added.

Another challenge was the drilling and installation of 10-ft. deep (3 m), 10-ft. diameter caissons. This work had to be performed in active traffic with nighttime lane closures from midnight to 5 a.m., Cobelli noted.

Both Cobelli and Shubber agreed that a key to the success of the project was its outreach program. The program conveyed news of project progress to government agencies, team members, residents and business owners. It included weekly meetings of the project team and government agencies, and briefings and monthly updates to Community Boards 1, 2, 3 and 4.

The BQE project is on schedule. It had been scheduled for completion by March 2004, but $40 million of additional work extended the project to its current $250 million value and a new completion date of June 2005. CEG