Anchorage Design for Petrochemical and Other Industrial Facilities

This introductory chapter presents an overview of use extrapolations and interpretations of the code provisions provided by the American Concrete Institute, American Institute of Steel Construction, ASCE, and other standards development organizations as the basis for the design of anchorage systems commonly used by petrochemical and other industrial engineering firms and owner companies. The continuing need to establish a uniform anchorage design methodology that is acceptable for use throughout petrochemical and other industrial facilities is explored. The Concrete Capacity Design Method is introduced as a simple approach to the calculation of concrete breakout strength that is readily adaptable to groups and near-edge conditions.

Post-installed anchors are manufactured using a variety of materials. Responsible engineers must therefore select the most appropriate materials for anchors and their environment, considering such properties as grade, yield strength, tensile strength, and weldability, and providing for corrosion resistance so that the anchorage will perform as required and intended. This chapter identifies basic materials, properties, and corrosion protection recommendations for anchor bolt and rod assemblies, headed studs, post-installed anchors, and shear lugs. Also examined are the main design concerns associated with exposure of anchors to extreme low temperatures: brittleness and failure that is premature or at a strength level that is less than its design load.

The Concrete Capacity Design (CCD) Method uses a pyramid failure surface with a slope of 1.5 to 1 (approximately 35 degrees) for both tensile and shear loading. This chapter details how testing has revealed that the CCD Method is a more accurate predictor of concrete capacity for various anchorages than methods using bond strength of anchors to concrete. Design of foundations in petrochemical and other industrial facilities often requires the anchorage of tall vessels and structures subject to large wind and seismic forces, which in turn results in large diameter anchors. Recommendations are included on the implementation of design practices to facilitate constructability and minimize future anchor repair or replacement.

The term post-installed anchor is used to describe devices installed in holes drilled in hardened concrete for the purpose of transferring loads into the concrete. Post-installed anchor types explored in this chapter include expansion anchors, undercut anchors, and screw anchors, as well as grouted and bonded (adhesive) anchors. Qualification requirements for post-installed anchors to be used to resist seismic loads in a structure assigned to Seismic Design Category C, D, E, or F are discussed. These involve the performance of specific tests and application of acceptance criteria for qualification and determination of relevant design parameters. Applications of post-installed reinforcing bar connections that are common in construction are explored including column and slab extensions, foundation augmentation, wall thickening, and slab-to-wall connections.

This chapter provides basic information regarding installation of anchors. Both cast-in-place and post-installed anchors are discussed. Anchor constructability considerations that address and detail quality control, inspection, design, and construction practices, which will help ensure constructible and structurally effective anchor installations are then outlined. Finally, anchor repair procedures are presented, with specific recommendations to address common anchor installation problems, such as misalignment and erroneous projections. Discussions and recommendations are provided for successful installation of post-installed anchors, as well as for successful application of quality control, inspection, design, and construction practices to ensure constructible, structurally effective anchor installation.