The Creative Use of Precast (CUP) Awards recognize projects that promote the innovative and cost-saving advantages of precast concrete over other materials.
Project Name: Kingston Monorail Test Track Project for Bombardier Transportation Canada
Bombardier Transportation Systems, a world leader in high-speed mass transit, awarded a contract to Anchor Concrete to manufacture and supply beams for 1.125 miles of precast concrete monorail track. The project included 124 straight beams with lengths ranging from 22 ft to 38 ft, 19 transition beams 33 ft in length and 20 super-elevated curved beams also 33 ft in length.
To provide an exceptionally smooth ride, all beams had extremely tight tolerances of +/-0.08 in. in a 5 ft straight edge, +/-0.12 in. in width at any location and +0.16 to -0.31 in. in any 38 ft length. This was achieved by using in-house innovations such as:
• building two straight molds in tandem to resist deflections;
• creating jigs for accuracy and repeatability of rebar cages;
• producing very detailed drawings;
• implementing a procedure to flip and roll the units to eliminate surface damage;
• pouring the beams upside down to ensure consistent textured finish on the top surface;
• creating a method to position the beam end bearing connection plates which required a high degree of coordination with the rebar cage due to the quantity of Nelson studs.
It was uneconomical to build specific molds for each type of the 19 special beams, so Anchor Concrete designed a system of proprietary adjustable molds. Quality control included a targeting system for lasers, calibrated tape measures and laser measuring devices. Systems of go/no-go gauges and a custom-designed recording spreadsheet were used to show compliance with tolerances.
Installation of the monorail track onsite was planned for four beams per day, but due to the accuracy of both construction and the precast elements, 12 to 16 beams were installed some days, reaching as many as 18 installations on the final day.
If high-speed rail is the future of mass transit, this project demonstrates that precast concrete is well equipped to go along for the ride.
Project Name: Montclair University Parking Structure
Montclair State University is New Jersey’s second-largest university and is continually growing. One of its goals is to increase the student body to 18,000, but with that comes the need for investment in infrastructure to support the influx.
The University hired a team responsible for designing and constructing a new 71/2-level precast/prestressed concrete parking structure with 1,532 spaces. The resulting design replicates the Spanish mission-style architecture of the other campus structures and incorporates a walkway at the southern corner of the structure that connects the facility with the existing campus pedestrian circulation system.
A key innovation by Nitterhouse Concrete was the use of bolt-on precast concrete arches. The arches on the main facades were fabricated in individual pieces that were added after the installation of the spandrel panels. The bolt-on precast arches were easily shipped and saved money compared with rounded arch spandrels. The spandrels were designed with relieving angles to allow for the connections. The resulting aesthetic effect was that of a full-rounded arch spandrel at a fraction of the cost.
It was also important that the parking structure harmonize with the Spanish Colonial architecture of the rest of the campus. The precast concrete materials used proved to be the perfect material as the architects were able to create fluid rounded shapes at the tops of stair and elevator towers. Precast design flexibility allowed for the creation of detailed stepped forms and corbels in the spandrels, while insets and reveals provided a base for decorative tile that surrounds entry and exit points of the garage stair towers.
The precast/prestressed concrete components included 63 columns with a variety of architectural finishes, 68 beams, 600 double tees, 18 solid slabs, 6 precast panels and 169 prestressed panels with architectural finishes, and 99 horizontal light walls.
Project Name: Fort Rosecrans National Cemetery POW Sculpture Base
Universal Precast Inc. (UPC) was commissioned by a group of ex-POWs in the San Diego area to commemorate American POWs with a custom precast concrete decorative base for a POW sculpture at Fort Rosecrans, San Diego. It is located near the entrance to the Miramar Annex of the Fort Rosecrans National Cemetery.
UPC was hired by the sculptor, Richard Becker, to create the sculpture base. The project involved the fabrication of a large, one-piece decorative pedestal to hold up a bronze sculpture created by the artist. The base’s diameter is 7 ft and is 5 ft tall.
In order to create this design, UPC made a highly custom multi-piece mold after many rendering sessions with the architect and the local POW organization. The base was then made in a single, monolithic pour with tan integral concrete color.
This process was made a little more difficult by the design requirements of a recessed time capsule, and five round recesses needed to hold bronze seals for each of the five military branches. Cast-in letters on the front spell “LIBERATION,” which is the name of the memorial statue.
The design includes fluted vertical sides, and the top surface of the base was polished to give it a marble-like finish. The end result was a very artistic and visually appealing base design.
By producing the pedestal in precast concrete rather than granite or marble, the manufacturing time was cut to about two weeks, as opposed to many months of hand sculpting out of other materials. The estimated total cost savings for using precast concrete was between $10,000 and $20,000.
The finished sculpture and base received a lot of publicity when it was revealed at a grand opening ceremony at the Fort Rosecrans National Cemetery.
Project Name: Magnetometer Stabilization Caissons
When the military needed to stabilize sensitive military equipment 60 ft deep in the Pacific Ocean due to the tidal action creating interference, it was precast concrete that delivered the best solution to a touchy problem.
Because of severely tight parameters for the stabilization of this equipment, precast concrete was the only viable material of choice. Steel would rust and composites could not handle the tidal action or pressure from the water. Precast concrete covered all of the parameters. The tight time span required that forming be completed in a matter of three weeks, start to finish.
Eight 36-in. diameter cylindrical tubes rising 22 ft out of the ocean floor contained the magnetometer equipment for the U.S. Navy’s minesweeper range. Precast concrete round piles were designed to slip over the tubes, and caissons were designed to slip over the round piles/tubes. The caissons were filled with 6-in., low-iron stone, capped with a precast top and grouted in place. Precast scour mats were used around the structure to prevent erosion.
In addition to severely tight parameters, U.S. Concrete Precast Group-Southern California needed to adapt its production to the extremely sensitive nature of the equipment. There could be no ferrous or steel content, so all reinforcement had to be fiberglass and zip-tied. The aggregates also had to have low iron content, and the cement could not be supplied by any plant that uses steel-belted radials for heating its kilns. The precast scour mats, normally attached and tethered with steel cable, had to be connected with graphite composite rope.
Since no molds existed, a precast concrete inner core was formed and the exterior was created from steel mold outer jackets. The caisson shell was also cast from that formwork. The structure was then lifted to a casting location that contained the outer formwork with the perimeter of the caisson base. The fiberglass bar reinforcing for the base was then tied to the protruding fiberglass bar reinforcing from the caisson shell.
Each base is 20 ft x 28 ft 6 in. x 12 ft, weighing in at a whopping 279,600 lbs. Each cap is 14 ft 3 in. x 9 ft 5 in. x 4 ft 6 in., and weighs 65,280 lbs. The structures were loaded at the plant and shipped at night with California Highway Patrol escorts. At the harbor, they were loaded onto a heavy cargo barge with a 500-ton crane. The units were barged to the site about a mile from the San Diego coast and set into place with the 700-ton barge crane. By using a precast solution to stabilize the existing magnetometers, the project saved the military $1.7 million.
Project Name: Georgia Street Pedestrian Promenade
There are few annual events that draw the level of attention the Super Bowl garners. The city of Indianapolis spent the last two years preparing for the spotlight, including the complete renovation of a three-block stretch of Georgia Street that served as an entertainment focal point outside the stadium. Bookended by the Indianapolis Convention Center on the west and Bankers Life Fieldhouse (formerly Conseco Fieldhouse) on the east, the street was transformed into Super Bowl Village and was visited by more than 150,000 people during the run-up to the big game.
Underneath this newly constructed pedestrian promenade sits an innovative precast concrete water-recycling stormwater sluiceway, but it wasn’t originally planned that way. Norwalk Concrete Industries was initially contracted only for load-bearing grade beams, but after looking at the initial design, the precaster convinced the contractor that a custom all-precast solution would provide many benefits over the originally specified cast-in-place structures.
More than 700 precast components were cast, including U-shaped sections using continuous precast elements and segmental L-shaped walls about 4-ft-by-4-in. high on each side of the trench. The design also included vaults cast in two pieces at 52,000 lb per half, with H20-rated aluminum hatches and a fiberglass-grated partial false floor for drainage.
The precast option meant less digging, which can cause major headaches on busy downtown streets. The precast structures also fit neatly into the small footprint, with pieces delivered as needed, ready for rapid assembly. With the Super Bowl deadline looming, the precast option was not dependent on weather and also provided greater on-site safety, less site disruption, and reduced interference to street-front businesses. The original 12-in.-thick Cast-in-place (CIP) footing was also reduced to 7 in., providing a considerable cost savings.
The precast design allowed the contractor to avoid heavy cranes on site, make site elevation adjustments to match precast components and reinforce embedment for CIP closure points and jobsite sequencing. In addition, casting continued off-site at a time when site conditions would have prevented any cast-in-place work. The precast option reduced the contractor’s jobsite labor crew, and enabled the contractor to leapfrog down the project as needed. In other words, the contractor was able to take advantage of the many benefits of precast over cast-in-place construction.
This project provides the perfect example of how the natural advantages of precast concrete can cause contractors to rethink traditional CIP designs.
Project Name: Bronx River CSO
Management of wastewater is a vital part of our society, and often precast is called upon to complete the job. The Bronx River Combined Sewer Overflow (CSO) project, a successful partnership between Northeast Remsco and Garden State Precast, is a perfect example of why precast is often the material of choice.
The Bronx River CSO Netting Facility consists of 23 precast concrete sections. These sections form a three-chamber, post-tensioned unit for removal of solids from the combined sewer outfall.
The Netting Chamber is the first unit and measures approximately 18 ft 8 in. x 41 ft x 20 ft 4 in. The bar screens and net mountings are installed within this chamber. The second chamber is the tidegate chamber. A large 7 ft x 7 ft cast steel tidegate is mounted within this section. The final chamber is the turning chamber. This chamber is used to reduce the flow back to the size of the outfall box culvert, and to provide an angled deflection in the box culvert. A precast concrete gravity retaining wall then encloses the facility on three sides.
The use of precast concrete reduced the cost by allowing the pumps to be shut off and the excavation flooded after installation, eliminating the need for an overnight pump tender. The contractor was also able to use shoring from another project due to the reduced installation envelope.
The as-needed delivery of the precast pieces allowed the contractor to fill holes in his schedule with the precast installations, thus rainy days became profitable and labor could be redirected as needed. The project is located adjacent to a school, so savings were also realized by a reduction in required traffic diversions.
The use of precast also allowed for watertight joints in three directions through the use of two different sealing methods, and match casting was accomplished with a variance of less than 1 in. in 43.75 ft. The design required the unit to be modeled in engineering software to check not only design loads but handling and rotational stresses, and the facility submittal was reviewed by nine agencies for approval. All approvals were acquired, and the casting and installation went smoothly.
ABOVE GROUND HONORABLE MENTION
Company: ARTO Brick and California Pavers,
Project Name: Mariachi Plaza
For more information, see Precast Solutions Winter 2011.
Company: Nitterhouse Concrete Products Inc.,
Project Name: Riddle Memorial Hospital West Parking Garage and Pedestrian Bridge
Company: Smith-Midland Corp., Midland, Va.
Project Name: Camp Lejeune Mock Afghan Village
UNDERGROUND HONORABLE MENTION
Company: Gillespie Precast, Chestertown, Md.
Project Name: Camp Pecometh Centralized Wastewater Treatment Plant