A u-bolt is a u-shaped curved bolt having threads on each end used as supports in the piping and pipeline industry. U-Bolts are one of the simplest and widely used types of piping support. They work mainly as Rest+Guide+Hold down support; though with a little installation change can be made to work as line stops as well. U-bolts with their curved shape fit nicely around the pipes which are then secured with a secondary member using nuts. They are easily available in various sizes and thicknesses. The important dimensions of a u-bolt are shown in Fig. 1 below:\n\n\n\nFig. 1: Major dimensions of a u-bolt\n\n\n\nApplications of U-bolts\n\n\n\nU-bolts have an extended range of applications. They are widely used as piping support solutions. The common uses of u-bolts in piping solutions are:\n\n\n\nUse of u-bolt as pipe supports: They are used to provide lateral restraints to pipes. For small bote piping systems, u-bolts are the most simplest and widely used type of piping supports. In any plant, for supporting bare pipes lesser than 8-inch size, u-bolts are extensively used. As already stated they function as rest+guide+hold down. U-bolts are capable to suppress line vibrations by providing rigidity to the system. For supporting vertical elevated runs of pipe, U-bolts are a good choice.\n\n\n\nUses of u-bolts for pipe shipping: In the pipe and pipeline shipping industry, u-bolts are used to avoid pipe movement and breakage. U-bolts prevent haphazard pipe movements due to transportation loads.\n\n\n\nMaterials of U-bolts\n\n\n\nEven though u-bolts can be manufactured from any type of strong and durable materials; in the piping industry, the following materials are widely used.\n\n\n\nPlain Carbon Steel, andStainless steel.\n\n\n\nSometimes, protective coatings are added to prevent corrosion. Some of the usual u-bolt coatings are:\n\n\n\nZinc PlatingHot-Dip GalvanizationThermoplastic coatingFluoropolymer coating\n\n\n\nTypes of U-bolts: Gripped vs Non-gripped U-bolts\n\n\n\nIn general, u-bolts are used as guide+hold down. However, they can be used to work like anchors as well. Depending on these u-bolt functions, they are classified into two groups; Gripped u-bolt and non-gripped u-bolt.\n\n\n\nNon-gripped U-bolt: U-bolt as Guide\n\n\n\nNon-gripped u-bolt is the most common and simple installation to work as the pipe guide. It does not restrict axial movement. In non-gripped pipe u-bolt installation, one nut is placed on the top and the other on the bottom of the support beam. Both nuts are fixed, keeping a gap in between the pipe and u-bolt surface.\n\n\n\nGripped U-bolt: U-bolt as Anchor\n\n\n\nIn gripped u-bolt configuration, the u-bolt work as an anchor and stop pipe movement at the support location. To work the pipe u-bolt as an anchor, the u-bolt needs to be installed such that there is no space in between the pipe and u-bolt. Both the bolts are placed at the bottom of the secondary support structure and tightened to snug against the pipe. The friction force in between the clamp and pipe surfaces restricts the pipe movement in the axial direction to work as a directional anchor. However, with an increase in line stop axial forces, the frictional force may not be able to withstand the axial force may slip. This is the reason the use of u-bolt as anchors are limited to lower size pipes; usually up to 6-inch pipes.\n\n\n\nFig. 2: Gripped vs Non-gripped U-bolt\n\n\n\nInstallation of U-bolts\n\n\n\nInstalling a pipe U-bolt is very easy. The size of u-bolts is decided based on the pipe OD. All properly sized u-bolts come with threads and nuts. The only job is to drill the hole in the support beam, properly align the bolt through those holes, and tighten the nuts depending on the support type (anchor type or guide type).