Abstract: A precast reinforced concrete base mat element, a base mat assembly and method for constructing a base mat assembly from a plurality of the base mat elements are described. The base mat element comprises a concrete body having first and second conduits extending there through in first and second generally perpendicular directions and a liner plate anchored in the concrete body. Preferably the concrete bodies have interlocking surfaces formed there on. A plurality of the base mat elements may be juxtaposed together with the interlocking surfaces interlocking with one another and with the tensile members extending through the first and second tensile conduits and being post-tensioned and anchored about the base mat elements to clamp the base mat elements together. The liner plates may then be welded together to form a generally planar membrane.

Abstract: A ring beam element, a ring beam and a method of constructing a ring beam from a plurality of ring beam elements is disclosed. The ring beam can support a shell or wall of a tank. The ring beam element comprises a reinforced concrete body, preferably having a metal base plate anchored therein, and a plurality of tensile conduits extending circumferentially there through. Ideally, the reinforced concrete body will have interlocking surfaces such that the ring beam elements interlock with one another when circumferentially juxtaposed. Tensile members can be placed through the plurality of tensile conduits and tensioned and anchored by anchors to clamp a plurality of juxtaposed ring beam elements together. Ideally, the base plates of a plurality of the ring beam elements can be connected or welded together to form an annular ring of base plates.

Abstract: A method for constructing a composite concrete roof on an outer LNG containment tank is disclosed. The roof includes a roof assembly and a plurality of precast reinforced concrete roof elements. The roof assembly is mounted on a tank shell. At least some of the roof elements including a concrete body and embedded metal plates adapted to be welded to the roof assembly. The roof elements are welded to the roof assembly to provide additional strength and stiffness to the roof assembly. Preferably, no or minimal cast in place concrete structural joints are needed to join the roof elements to the roof assembly and or top of the shell. Ideally, the roof assembly includes a membrane and mounting beams connected to the membrane. The embedded plates of the roof assemblies are welded to the mounting beams on the roof assembly. The method may further include mounting or welding the roof elements to the roof assembly while workers access the interior of the shell to perform work therein.

Abstract: A precast reinforced concrete base mat element, a base mat assembly and method for constructing a base mat assembly from a plurality of the base mat elements are described. The base mat element comprises a concrete body having first and second conduits extending there through in first and second generally perpendicular directions and a liner plate anchored in the concrete body. Preferably the concrete bodies have interlocking surfaces formed there on. A plurality of the base mat elements may be juxtaposed together with the interlocking surfaces interlocking with one another and with the tensile members extending through the first and second tensile conduits and being post-tensioned and anchored about the base mat elements to clamp the base mat elements together. The liner plates may then be welded together to form a a generally planar membrane.

Abstract: A shell for an outer LNG containment tank and a method of making the shell from a plurality of precast reinforced concrete shell elements are described. The shell elements having a precast concrete body to which are anchored a radially inwardly facing liner plate and a pair of circumferentially spaced apart side plates which depend radially outwardly from the liner plate. The shell elements can be arranged upon a ring beam with side plates abutting one another. The side plates are welded together to form radially and vertically extending stiffener ribs which are circumferentially spaced around the shell. As these stiffener ribs provide great structural support, the shell can be constructed with minimal or no cast in place structural joints being needed to construct the shell. Ideally, the shell elements have bottom base plates welded to a ring beam or foundation and top end plates that are welded together to form an annular ring thus enhancing the structural strength of the shell.