Protection of metallic structural elements against corrosion

Claim 1

Apparatus for protectively encasing an installed metallic columnar structural element of irregular horizontal cross-section against corrosion from water, air or a combination of water and air, comprising: top and bottom filler block assemblies secured to vertically spaced portions of said structural element to fill the cavities thereof; a split cylindrical back-up sheet means encircling said structural element in abutment with the exterior surface of said filler block assemblies and covering the edges of said elements, said back-up sheet means bring formulated so as to have a relaxed diameter less than the diameter defined by the outer diameter of said filler block assemblies; a generally rectangular, synthetic plastic, pliable water and airtight encasement sheet of a length at least as great as the length of the portion of said structural element to be protected, said encasement sheet being wrapped about said back-up sheet means with its edges overlapping; a pair of vertically extending, abutting pole pieces secured to the edges of said encasement sheet in a rolled-together water and airtight relationship with respect to the edges of said encasement sheet whereby said sheet is held against said back-up sheet means; upper and lower sealing bands of compressible foam interposed between the outer edges of said filler block assemblies, the upper and lower ends of said back-up sheet means, and the upper and lower portions of said encasement sheet, with the upper and lower ends of said pole pieces terminating below and above said upper and lower sealing bands, respectively; and upper and lower wrapping bands extending around the upper and lower portions of said encasement sheet and said pole pieces to compress said sealing bands into a water and airtight sealing relationship with the upper and lower ends of said encasement sheet, the upper and lower ends of said back-up sheet means, and said filler block assemblies, said wrapping bands also retaining said encasement sheet and said pole pieces firmly upon said structural element, with said sealing bands and rolled-together pole pieces cooperating with said encasement sheet, said back-up sheet means and said filler block assemblies to prevent the entry of air and water into the space between said sheet and the portion of said structural element to be protected.