A manhole cover assembly comprises a base frame, the base frame comprising a base body and a base flange extending laterally outward from the base body. The assembly further comprises a top frame, the top frame comprising a top body disposed annularly about at least a portion of the base body, a top flange extending laterally outward from the top body, and a lip extending laterally inward from the top body.

Extensible shells and related methods for constructing a support pier are disclosed. An extensible shell can define an interior for holding granular construction material and define a first opening at a first end for receiving the granular construction material into the interior and a second opening at a second end. The extensible shell can be flexible such that the shell expands when granular construction material is compacted in the interior of the shell. A method may include positioning the extensible shell in the ground and filling at least a portion of the interior of the shell with the granular construction material. The granular construction material may be compacted in the interior of the extensible shell to form a support pier.

A system for building a wall includes a plurality of blocks and a plurality of connectors for aligning the blocks in successive courses. Each block has opposing first and second surfaces bounded by opposing front and rear faces and opposing end faces, the first and second surfaces being profiled with respective first and second rectilinear channels extending parallel to the front and rear faces. Each connector has first and second portions profiled for reception in respective first and second channels, the first portion being profiled to slide but not rotate in the first channel, the second portion being profiled to slide and rotate in the second channel. The second portion is offset from the first portion so that two different orientations of two blocks placed against each other are possible. The blocks preferably have a trapezoidal shape cut with only straight cuts to facilitate using natural stone.

A manhole cover assembly comprises a base frame, the base frame comprising a base body and a base flange extending laterally outward from the base body. The assembly further comprises a top frame, the top frame comprising a top body disposed annularly about at least a portion of the base body, a top flange extending laterally outward from the top body, and a lip extending laterally inward from the top body.

A manhole cover assembly comprises a base frame, the base frame comprising a base body and a base flange extending laterally outward from the base body. The assembly further comprises a top frame, the top frame comprising a top body disposed annularly about at least a portion of the base body, a top flange extending laterally outward from the top body, and a lip extending laterally inward from the top body.

Extensible shells and related methods for constructing a support pier are disclosed. An extensible shell can define an interior for holding granular construction material and define a first opening at a first end for receiving the granular construction material into the interior and a second opening at a second end. The extensible shell can be flexible such that the shell expands when granular construction material is compacted in the interior of the shell. A method may include positioning the extensible shell in the ground and filling at least a portion of the interior of the shell with the granular construction material. The granular construction material may be compacted in the interior of the extensible shell to form a support pier.

A passive annular grout seal assembly is disclosed for sealing an annular opening between a driven pile and a skirt pile sleeve for an offshore platform. The annular seals are located at the bottom of the pile sleeves near sea floor and automatically activated when piles are inserted and driven through the pile sleeves without any active operational procedure during offshore piling. The seal configuration fully utilizes the seal height, the grout column height and the density difference between grout and sea water to produce enhanced sealing capacity against the column of grout above.

A system for building a wall includes a plurality of blocks and a plurality of connectors for aligning the blocks in successive courses. Each block has opposing first and second surfaces bounded by opposing front and rear faces and opposing end faces, the first and second surfaces being profiled with respective first and second rectilinear channels extending parallel to the front and rear faces. Each connector has first and second portions profiled for reception in respective first and second channels, the first portion being profiled to slide but not rotate in the first channel, the second portion being profiled to slide and rotate in the second channel. The second portion is offset from the first portion so that two different orientations of two blocks placed against each other are possible. The blocks preferably have a trapezoidal shape cut with only straight cuts to facilitate using natural stone.

Extensible shells and related methods for constructing a support pier are disclosed. An extensible shell can define an interior for holding granular construction material and define a first opening at a first end for receiving the granular construction material into the interior and a second opening at a second end. The extensible shell can be flexible such that the shell expands when granular construction material is compacted in the interior of the shell. A method may include positioning the extensible shell in the ground and filling at least a portion of the interior of the shell with the granular construction material. The granular construction material may be compacted in the interior of the extensible shell to form a support pier.

A trenchless method of installing a new poured-in-place manhole liner provides structural rehabilitation to an existing buried manhole, and is extended above the existing manhole to a higher pre-determined elevation to match the finished grade of a raised levee design. The new liner can be formed in a single or double stage process, which substantially eliminates trenching and excavation of soil, so that new levee soil is not disturbed. The process is faster and less expensive than building a totally new manhole, and maintains the structural integrity of the levee.