In response to a fatal 2006 concrete roof collapse at the Boston Big Dig, ACI, in partnership with the Concrete Reinforcing Steel Institute, has developed a new ACI Adhesive Anchor Installation Program.
In the summer of 2006, a portion of the concrete roof of the Central Artery/Tunnel Project in Boston, Mass., also known unofficially as the "Big Dig," collapsed, killing a motorist and injuring another. The National Transportation Safety Board (NTSB) released its accident report soon after and made recommendations to several parties, including the American Concrete Institute. The recommendation to ACI was to use its "building codes, forums, educational materials, and publications to inform design and construction agencies of the potential for gradual deformation in anchor adhesives under sustained tensile-load applications."
As part of the overall response to the recommendations of the NTSB, ACI has partnered with CRSI to develop a certification program for Adhesive Anchor Installers. Adhesive anchors are recognized by the structural design profession as an important structural connection in many applications. Adhesive anchor effectiveness is measured by the bond strength achieved between the adhesive and concrete, and adhesive and anchor. Adhesive anchor manufacturers have developed installation procedures for their specific products that when followed, are intended to provide the proper conditions for the anchor system to achieve that required bond strength.
ACI and CRSI assembled a group of Subject Matter Experts (SMEs) who identified the criteria candidates must meet for certification as ACI/CRSI Adhesive Anchor Installers. Candidates are required to be able to read, comprehend, and execute instructions to properly install adhesive anchors as are typically provided by adhesive anchor manufacturers. In addition, candidates must possess the knowledge to properly assess ambient conditions, the condition of the concrete, materials, equipment, and tools for installing adhesive anchors and determine when it is appropriate to proceed with an installation or when additional guidance from a supervisor/foreman/project engineer is needed.
"There are many different variables to consider when installing adhesive anchors," said John W. Nehasil, managing director of certification programs at ACI. "From understanding jobsite conditions and manufacturers' instructions to recognizing time limits of the adhesive and proper selection and assembly of equipment, installing adhesive anchors properly involves awareness of the variables and skill in executing instructions. The ACI/CRSI Adhesive Anchor Installer Certification program is designed to verify that candidates possess these qualities." Knowing that Adhesive Anchor Installer Certification will be required in this summer's 2011 update of ACI 318, Building Code Requirements for Structural Concrete and Commentary, ACI and CRSI have completed the following:
- Development of a 75 question written examination - The exam covers information on adhesive concrete anchor installation in regards to preparing for installation, drilling anchor holes, cleaning anchor holes, injecting adhesive using cartridge systems, installing adhesive capsule systems, and installing anchors. The exam was vetted in December 2010, under the direction of Professional Testing Services of Orlando, Fla.
- Creation of a "Generic Manufacturers Printed Installation Instructions" (MPII) - In working with the Concrete Anchor Manufacturers Association (CAMA), a generic set of installation instructions was developed for use the performance portion of the certification program.
- Development of the performance exam portion of the program - Candidates must be able to read, comprehend, and execute the Generic Manufacturers Printed Installation Instructions for:
- the installation of an anchor in a vertical-down position, and
- the ability to inject adhesive to the proper depth into simulated holes in an overhead (vertical-up) position with both a rigid applicator tip and flexible stinger end with piston plug in a manner that produces results meeting program requirements.
ACI and CRSI completed two pilot programs earlier this year with a total of 35 participants taking both the written and performance examinations.
The ACI/CRSI Adhesive Anchor Installer Certification program is planned to go to market in early summer of 2011, before the release of ACI 318-11. In the meantime, ACI and CRSI are working on the completion of a study package and all documents and assisting Local Sponsoring Groups that offer ACI certifications around the world with program start-up. Additionally, ACI and CRSI plan to start the development of a training program to accompany the examination program.