Structural Preservation Systems (SPS) — a specialty-contracting firm focusing on the repair, protection and strengthening of structures — recently received seven project awards from the International Concrete Repair Institute (ICRI), including four “Awards of Excellence” and three “Awards of Merit.”
In its 14th year, ICRI sponsors the annual awards program to recognize outstanding projects in the concrete repair industry. As the only organization dedicated to improving the quality of repair, restoration and protection of concrete and other structures, ICRI receives submittals for the competition from around the world. This year’s awards were presented at a banquet held in conjunction with the ICRI Fall Convention in St. Louis, Mo. SPS was honored for:
• structural concrete repairs and cathodic protection system installation at an 18-story apartment building near the campus of Johns Hopkins University in Baltimore,
• strengthening of overloaded prestressed concrete beams that were structurally damaged due to an overload by snow at a government parking structure in Washington, D.C.,
• concrete repair and cathodic protection at a nuclear power plant in Lusby, Md., to remedy eventual structural deficiencies,
• balcony removal and replacement for a high-rise condominium building due to structural deterioration in South Palm Beach, Fla.,
• structural strengthening of the State University of New York (SUNY) Health Science Center Parking Structure using carbon fiber technology similar to aerospace materials
• concrete repair on a 3,000-ft.-long (914 m) dock in the Gulf of Mexico, and
• concrete strengthening on the famous ring walls of Frank Lloyd Wright’s Guggenheim Museum in New York City.
“We are honored that seven of our diverse projects were highlighted by ICRI this year,” said Brian Gallagher, vice president of Structural Preservation Systems. “The ICRI awards are well-known for recognizing the industry’s most challenging projects, which makes this achievement extremely gratifying for our team.”
Concrete Repairs and Protection Systems Installation at Hopkins House
Built in 1968 near the campus of Johns Hopkins University in Baltimore, Md., the Hopkins House Apartment Building is an 18-story apartment complex. Designed to have balcony access from all 271 units, this building overlooks much of the campus with skyline views of downtown Baltimore.
Since the building’s original construction, minor repairs had been performed on the high-rise and parking garage structures. Because of damaging environmental conditions including multiple freeze-thaw cycles and harsh winters requiring corrosive de-icing salts, rebar corrosion and concrete spalling were prevalent throughout the high-rise balcony and parking garage structures.
In 2004, the owner undertook a large rehabilitation project that included installation of new windows, balcony handrails and divider panels, interior apartment renovations and renovation of the building entrance.
The owner hired SPS to perform concrete spall and crack repairs for both the balconies and the parking garage. The balconies were repaired in six phases with each phase strategically composed of multiple vertical tiers around the structure. A unique formwork design was developed for the parking garage waffle slab repairs. This unique design consisted of customized wood forms and prefabricated fiberglass forms designed to match the dimensions of the existing waffle pan and rib sizes. In addition to the repairs, SPS also installed a cathodic protection system, protective coating systems and new drains to protect the structure from future corrosion.
A team approach by SPS, other contractors, the engineer and the owner helped facilitate a successful repair project that was completed several months ahead of schedule.
Calvert Cliffs Nuclear Power Plant Concrete Repair and Cathodic Protection
Built by Baltimore Gas & Electric in the 1970s, the Calvert Cliffs Nuclear Power Plant (CCNPP) and its associated high power electric lines is a Calvert County landmark. When deterioration of the reinforcing steel in the intake floor, circular water pump bowels (CWB) and salt-water pits (SWP) became severe, CCNPP contacted SPS for assistance. The owner wanted to repair the concrete surfaces with a bonded concrete overlay that would help prevent corrosion and last for a period of approximately 20 years to reduce plant maintenance costs.
For the $3.25 million project, the scope of work encompassed three main areas: the intake floor, CWB and SWP. In order to achieve the owner’s goal, the team utilized an impressed current cathodic protection (ICCP) system to help prevent corrosion of the new and existing reinforcing steel in the floor.
On all horizontal surfaces, concrete was removed an average of 6.5 in. (16.5 cm) with high-chloride and severely corroded reinforcing was replaced. This also enabled the ICCP ribbon to be installed within 1-in. (2.5 cm) of the top mat of reinforcing steel, prior to placing the new overlay.
On all vertical surfaces and areas where the concrete was still sound, slots were cut to install the ICCP ribbon. With impressed current cathodic protection systems, a small, direct current passes from a permanent anode to the reinforcing steel. An external power supply connects between the anode and the steel with the appropriate polarity and voltage to prevent the reinforcing steel from giving up electrons. This system repels chloride ions away from the reinforcing steel toward the installed anode and provides flexibility in corrections since the current or output easily adjusts.
Concrete Dock Repair — Removal and Replacement of Concrete Slab
Commissioned in 1901, the southern refinery of a major oil and gas company has undergone several upgrades. However, one area that had not been significantly upgraded was the concrete dock located outside the refinery. Constructed in 1910, the 3,000-ft. (914.4 m) long dock is connected to an intercostal waterway leading to the Gulf of Mexico. This cast-in-place concrete dock serves as the off-load for crude oil and the on-load of petroleum products. The facility has a throughput capacity of approximately 325,000 barrels per day. The dock is crucial to maintaining operations at the facility; every day ships are loaded or unloaded at the dock.
An investigation of the dock’s structural integrity revealed substantial erosion on the bottom-side of the dock. In particular, the concrete beams that supported the dock were in poor condition and had visible damage, including rebar that was hanging in the water. While other contractors suggested using a barge and crane from the water for the repair, Structural Preservation Systems recommended performing the repairs from the dock. This approach was attractive to the owner because, with the other repair method, each time a ship would come to the dock, the barge would have had to be moved. This would have led to a tremendous amount of downtime, greatly lengthening the project schedule. By completing repairs from above, the dock was removed in small, manageable pieces, and work never had to stop for deliveries.
Even with the significant amount of repair work done by hand, including removing more than 2,500-lb. (1,134 kg) pieces of concrete near an open hole, there were no workplace incidents. Crews worked around the clock, seven days a week to complete the project in a mere two-and-a-half weeks. The owner was so pleased with the results that the SPS team began repairing another dock section one week later.
State University of New York (SUNY) Health & Science Center
Located in Brooklyn, the State University of New York (SUNY) Health Science Center parking structure serves as the main parking facility for the adjacent medical complex. Constructed in 1967, the 360,000-sq.-ft. (33,445 sq m) structure has 10 levels — three below grade and seven above — and has space for approximately 933 vehicles. Built using a cast-in-place reinforced concrete moment frame, the floor was designed showing a one-way joist/slab supported by beams having the same depth. However, during construction, a dome pan was used that created a waffle floor slab appearance.
Immediately following the completion of construction, a structural crack developed perpendicular to the one-way joists. The crack occurred on all supported levels of the structure. An investigation revealed that a major structural error had occurred and a substantial amount of the negative bending reinforcing steel was not developed sufficiently past the column supports. Upon realization of the error, the garage was shored full height and a corrective solution was implemented.
However, over time, the parking structure condition deteriorated due to corrosion damage from deicing salts. Much of the waterproofing system and expansion joints began to fail and many beams and columns were spalled from corrosion damage. Further, the structural concrete topping debonded in large areas. It was not in the university’s best interest to continue repairing the concrete overlay, and the original defect still needed to be addressed to maintain the safety of the structure.
In response to these challenges, Structural Preservation Systems used Carbon Fiber Reinforced Polymers (CFRP) for strengthening the structure. CFRP is similar to material used to build the stealth bomber as well as the next generation of Boeing and Airbus jumbo jets.
The use of Carbon FRP on this project is perhaps one of the largest top-side FRP strengthening applications in the United States. Not only did CFRP prove to be a cost-effective repair method that eliminated a serious trip hazard liability, but it also increased the headroom in a low clearance structure as well as eliminated the risk of future repair costs on a chloride-filled concrete overlay.
Although the project was complicated by the fact that the structure remained open, SPS managed the project in 11 phases, which allowed for the removal of only 100 spaces at any one time.
Strengthening of Snow Overloaded Prestressed Concrete Beams
During the summer of 2007, SPS completed a unique prestressed beam repair project at a government parking structure in the Washington, D.C. area. The project required the repair of two post-tensioned beams damaged after being overloaded by a concentration of snow debris.
The beam failure was first noted in December 2006 by an employee who noticed concrete spall debris on the deck. She looked up, saw the cracked beams and exposed prestressing strands, and immediately called 911. For this project, SPS developed an alternate, in-place repair solution as compared to complete removal that involved enlarging the damaged beams using self consolidating concrete (SCC) and post-tensioning with mild steel reinforcement to add strength.
SPS addressed the customer’s need for a sound, cost-efficient repair with minimal downtime. They facilitated detailed analysis of structural elements with review and approval by the engineer-of-record (as well as two additional structural engineer peer reviews), and then safely and successfully completed the repair to the satisfaction of the general contractor, architect, engineer and owner.
Full Balcony Replacement for Le Chateau Condominiums
Located directly on the Atlantic coast in South Palm Beach, Fla., Le Chateau Condominiums has two high-rise buildings and a parking garage. The east building has eight floors consisting of 64 units. The west building has nine floors consisting of 72 units and a four-story post-tensioned parking garage centered between the two buildings. Constructed in 1973, the facility was subject to the harsh coastal elements and had never had any formal restoration. Because of the corrosive environment caused by the ocean, the east building structural columns were deteriorated beyond 50 percent of the column dimension. In addition, the lack of any maintenance over the life of the building contributed to the deterioration of the structure.
The work included full balcony removal and replacement, waterproofing, railing removal and replacement, post-tension cable repairs, columns repairs and a cathodic protection system on two columns. For the balcony removal, two different methods were used. For the east building, SPS opted to remove and replace the balconies with a conventional method that involved using the two lower balconies to support the weight of the shoring and new concrete. For the west building, SPS developed an innovative approach to reduce the project duration for the owner — all of the balconies were demolished at one time. Shoring towers were installed from the ground up and new concrete was placed in two pours.
By using two different methods for the balcony repair, SPS was able to increase production by 21 percent. This led to a six-week reduction, which provided the owner with cost savings. Further, the use of cathodic protection will ensure the longevity of the repairs and provide a beautiful and structurally sound building for many years.
Concrete Strengthening at the Guggenheim Museum
One of the premier destinations in New York City is the Solomon R. Guggenheim Museum located in Manhattan. Designed by world-renowned architect, Frank Lloyd Wright, the Guggenheim opened in 1959. In 2004, a comprehensive investigation was prompted by signs of distress. It was not known if cracking was related to structural issues or possible corrosion of the reinforcement. As such, the museum’s management team embarked on a comprehensive investigation and assessment of the facility. Eventually, this investigation would lead them to structural strengthening and repair of this distinctive landmark.
Keeping with the vision to preserve the exact appearance of the exterior form line texture, it was determined that all repair strategies would need to be performed to the interior side of the wall. FRP and CFRP sheets were the final choice of the team. The museum remained open during the entire repair. Also, one of the hottest summers ever in NYC created challenges related to the resin pot life and rapid cure times. The museum’s location in the city also offered unique obstacles for getting materials and employees to the site. Despite the complexities, the repair project was a success. Each step faced strict scrutiny by the restoration team and needed to address structural, architectural and constructability perspectives. Clearly demonstrating the success of early collaboration between team members, the Guggenheim restoration and strengthening project was completed by summer 2007.
With roots dating back to a meeting held in conjunction with the World of Concrete in 1988, the original organizing members sought an organization dedicated to improving the quality of concrete restoration, repair and protection, through education of, and communication among, the members and those who use their services. The philosophy of the group was that if the quality of work improved, and purchasers of repair services felt that they were obtaining a durable product, the demand for their products and services would increase and the image of the concrete repair industry would be elevated.
Initially it was to have been an organization for contractors, however, the immediate interest of engineers, manufacturers and others in its formation and success made it obvious that it should be open to all. Today, ICRI publishes a bimonthly magazine and technical guidelines for concrete repair, as well as co-sponsors the World of Concrete. Local chapters provide regional networking opportunities.
About Structural Preservation Systems, A Member of Structural Group
Structural Preservation Systems (www.spsrepair.com) is a division of Structural Group, one of the nation’s leading specialty contractors. Structural Group’s four companies include Structural Preservation Systems, VSL, Pullman Power and Electro Tech CP. Structural Preservation Systems is the largest specialty contractor focusing on structural repair, masonry, wood and concrete restoration, strengthening, and protection services for both historic and contemporary structures. VSL is the technical leader in post-tensioning and specialty reinforcement. Pullman Power leads the industry in chimney, silo and stack construction, maintenance and repair.
Electro Tech CP is a specialty provider of corrosion control services, and technology that protects infrastructure, buildings, and investments worldwide. From operating centers across the United States, Structural Group businesses perform a wide range of projects involving industrial facilities, commercial properties, public infrastructure and municipal buildings.