Tecvac, Inc. Presented With NCC/ACI's First Concrete Repair Award In The New Millennium
the
Tecvac, Inc. Receives Award of Excellence For Concrete Repair
facility and is credited with resolving a host of difficult repair tasks…with ecvac, Inc. is the recipient a host of multiform techniques. Not of the National Capitol the least of which was Tecvac's Chapter of The American ability to perform structural repairs Concrete Institute's Year without surface destruction or 2000 Award of Excellence in marring. Concrete Repair for work it Tecvac, Inc. is an performed at the Herndon /Monroe internationally recognized leader in Park'N Ride Garage Facility in innovative repair techniques for Fairfax, Virginia.. concrete, masonry and stone using Tecvac applied its exclusive vacuum technologies. Call today for vacuum processes throughout the more information. four level precast concrete Tecvac, Inc.
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Office 703 742-9186
886 Rhonda Place, SE Leesburg, VA 20175 FAX 703 742-9231 toll free 800 847-9324
www.tecvacinc.com
Herndon/Monroe Park’N Ride Garage Facility Herndon, Virginia
Tecvac, Inc. 39482 Rickard Road Lovettsville, VA 20180 800 847-9324
Restoration of the Herndon/Monroe Park'N Ride Garage Facility
The Herndon/Monroe Park'N Ride Garage opened in July of 1999. The completion of the facility marked the inauguration of the Dulles Corridor Express Bus Service. This service is a part of Fairfax County Virginia's overall plan to relive traffic congestion within the region. Commuters parking in the garage are able to ride regularly schedule buses into and out of Washington, DC.. The precast concrete structure is situated next to the busy Dulles Airport thoroughfare in Herndon, Virginia and is designed to accommodate parking for over 800 vehicles.
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Soon after erection of the Herndon/Monroe Park'N Ride garage structure began in late 1996, cracks began to develop in several of the members. Nothing will erode public confidence faster than visible cracks, or the unpleasant effects of repairs, especially in a new structure. The precast manufacturer suggested repair with conventional epoxy pressure injection, but because of the number of cracks, and their prominent locations in full view of commuters, the Owner and Architect rejected the idea. The defacing involved with the pressure injection process would leave the structure with the tell-tale and unsightly marring where repairs were made on the architectural surfaces. Their suggestion, in the absences of some other solution, was to remove the members and replace them with new un-cracked members. To avoid this drastic measure, a number of methods were tested, including a sealer product that was touted to easily strip from the surface after the injection process. The material did strip from the surface, but it failed to hold the pressures applied during the injection process and left a dark penetrated stain where it was applied along the crack line. Not quite as unsettling as the grinder marks normally associated with the process but nevertheless, unacceptable as a finished surface. All the while, the erection of the garage continued. Early in 1997, the cracking issue and other controversy have associated with the work, caused the entire project to be shut down. Months of discussions ensued regarding the problems. To make matters worse, the precast manufacture declared bankruptcy during the ordeal and its surety assumed the responsibility for the completion of the project.
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It was beginning to look as though there was no alternative to tearing down and replacing the structure when a specialty restoration contractor was discovered by the Architect. Apparently, this contractor was claiming the ability to perform structural repairs with little residual evidence of the repair. Moreover, this proprietary method also claimed the ability to completely fill cracks below 0.001 inched in width using vacuum, rather than pressure, technology. Ironically, the contractor was based just miles from the garage and could easily perform a demonstration of its techniques. The County's inspectors were gathered for the first of several demonstrations. To demonstrate the ability of the method to provide an unblemished surface after injection, a column member located on the site was positioned for a demonstration. The column had been set for rejection because it contained numerous hairline cracks, some barely visible and measuring below 0.001inch. During the test, the thin acrylic repair material used by the restoration technicians seemed to fill the crack entirely, but more importantly, the repair left no indication that the repair had been performed. The Owner reported their acceptance of the surface finish to the Architect who set up another round of demonstrations with the Engineer. The second demonstration was performed on a different member that was similarly cracked. Again, the surface appearance of the finished repair was closely scrutinized and found more than acceptable. The apparent penetration of the repair material was promising, but a confirmation of the filling effect of the repair materials was required.
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A third test was then performed where the member was situated so it mocked the in place position in the structure. At the conclusion of the vacuum injection process, the repaired cracks were cored and tested by an independent laboratory. The report provided confirmation of through filling of the fracture with repair material. Additionally, shear testing confirmed the structural rebonding of the fracture within the zone. The restoration contractor vacuum injected over 2500 lineal feet of cracks within the structure. Soon after the vacuum injection work was begun, a host of other problems were posed to, and solved by, the restoration contractor that saved numerous members from the fate of rejection by the Architect and the Engineer. Some of the members contained objectionable numbers of "bug holes" in the surfaces. The restoration contractor filled the cavities with a special blend of polymer-modified cements and coloring agents. The result was a finished surface that so closely matched the existing member it was undetectable. Imbed pockets, manufactured within the members and used to lift and place the member into the structure, were initially filled by others with non-shrink grout. The dark cementitious material contrasted sharply with the rose toned concrete and was found highly objectionable. The restoration contractor produced a number of polymer concrete color "muffins" that spanned a range of colors close to the existing color of the member. After just the right color was selected by the Architect, the restoration contractor replaced the previously installed materials and filled over 5,000 additional embed pockets.
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Caulking the joints of the drive deck double-tee members required at least 1/4" of space between the panels and a number of the members were found to be edge to edge. This condition required installing the joint by saw cutting. Special width concrete saw blades were acquired to accommodate the width of the joint. To complicate matters, each of the panels was connected along the joint line by ten welded connection plates. These connections could not be nicked by the operations and would be closely inspected. The restoration contractor carefully cut nearly 20,000 lineal feet of new joints. Finish elevations of the members were found to be out of acceptable tolerance. Where some of the members were connected, the sharp edges of the misaligned pieces created pedestrian tripping hazards. This matter was resolved by bush hammering the edges into tolerance. The restoration contractor performed over 3,000 lineal feet of this work throughout the complex. A number of fabricated drain holes, that were to receive drain bodies and piping, were not fabricated in the proper locations. In some cases, this required filling an existing hole and in other cases, it required cutting a new hole, some up to fourteen inches in diameter. Where new holes were cut, the member was x-rayed to avoid cutting reinforcing steel. The restoration contractor carefully coordinated this work with the plumbing contractor to confirm the sizes and locations required. Additionally, the restoration contractor manufactured and installed the watertight sleeves at each location of penetration. Many of the bearing pads between the members were found to be deficient and required adjustments. However, when an inspection found a missing bearing pad on an upper level spandrel beam, the restoration contractor was set with the formidable task of installation. This condition was resolved by jacking the member up and positioning a high-density polyethylene pad in the exposed
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space. The event was successful but was proceeded by the installation of complicated shoring and careful deflection monitoring during the operations.
This project produced a host of other deficiencies that were resolved by the restoration contractor prior to completion. Expansion joints were modified, failed pressure injection epoxy was removed, siloxane sealers were applied, rust and burn marks were cleaned, misplaced anchor bolts were installed, member connections were modified and a good deal was learned about the effects of poor quality controls. Yet, thanks to a knowledgeable and diligent restoration contractor, there was little sign of the mult itude of repairs that had been completed when the facility opened to the public.
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Herndon/Monroe Park'N Ride Parking Garage
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Vacuum Injection Repair Processes Leaves No Marred Surface
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Misaligned Elevations Were Bush Hammered Into Tolerance
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Deep Penetrations Were Required to Align Anchor Bolts For Light Poles
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Expansion Joints Were Modified To Accommodate Movement of the Structure
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Joints Were Saw Cut Between the Panels To Accommodate Sealant
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