The plastic cribbing blocks are useful in their stacked configuration for supporting a structure during a leveling procedure on an uneven ground surface. The tops and bottoms of the cribbing blocks include interlocking mechanisms or texturing to prevent lateral movement between adjacent blocks when they are in their stacked configuration. A plurality of the plastic cribbing blocks can be placed in their nesting configuration, such that the tops of lower blocks are nested within the bottoms of upper blocks. This configuration may be used for transporting or storing the blocks. The blocks are generally rectangular with a top central horizontal panel, a bottom perimeter horizontal panel and four sides extending between the top central horizontal panel and the bottom perimeter horizontal panel. The block includes interior and exterior ribs or structures.

A building foundation structure includes a ground improved body obtained by improving a surface layer ground, and foundation concrete placed on the ground improved body on site. The foundation concrete located below a building pillar has an upper part and a lower part having different shapes. The lower part has a reverse trapezoidal sectional shape in a cross section taken along a vertical plane including a horizontal direction perpendicular to a horizontal line connecting building pillars adjacent to each other. The upper part has a brim portion protruding in the first horizontal direction from a side edge at an upper end in the sectional shape of the lower part.

A building foundation structure includes a ground improved body obtained by improving a surface layer ground, and foundation concrete placed on the ground improved body on site. The foundation concrete located below a building pillar has an upper part and a lower part having different shapes. The lower part has a reverse trapezoidal sectional shape in a cross section taken along a vertical plane including a horizontal direction perpendicular to a horizontal line connecting building pillars adjacent to each other. The upper part has a brim portion protruding in the first horizontal direction from a side edge at an upper end in the sectional shape of the lower part.

A prefabricated formwork is disclosed. The prefabricated formwork of the present disclosure comprises at least one bracket comprising a first slot and a second slot, at least one first wall configured to be inserted into the first slot of the at least one bracket, and at least one second wall configured to be inserted into the second slot of the at least one bracket. The prefabricated framework may further comprise at least one support having at least one groove configured to receive the at least one bracket.

A concrete chair elevates rebar above an underlying surface. The chair includes a rectilinear rim having a length, width and height of different distance. The rim may be oriented so each side abuts the underlying surface so rebar can be supported at three different heights above the underlying surface. In a foundation pour, the chair supports rebar at three different elevations. In a tilt wall pour, the chair supports rebar at three different elevations and produces a mark on the cured wall of considerably reduced extent.

A drainage and ventilation system includes a plurality of drainage cores. Each core includes a sheet having a first and a second end, a first and a second side, and a plurality of dimples disposed between the ends and the sides. The dimples extend outwardly from the sheet and define a plurality of passages. The passages include passages extending from end to end and passages extending from side to side. The system also includes a fabric attached to each core. The passages of the cores receive and convey a flow of at least one of liquid, air and gas through the drainage cores. In one embodiment, the cores are disposed in soil, and the dimples are filled with an adhesive to enhance the shock absorbing properties of the soil. In another embodiment, the dimples are filled a cement-based material for adhering a finish material to the cores.

A drainage and ventilation system includes a plurality of drainage cores. Each core includes a sheet having a first and a second end, a first and a second side, and a plurality of dimples disposed between the ends and the sides. The dimples extend outwardly from the sheet and define a plurality of passages. The passages include passages extending from end to end and passages extending from side to side. The system also includes a fabric attached to each core. The passages of the cores receive and convey a flow of at least one of liquid, air and gas through the drainage cores. In one embodiment, the cores are disposed in soil, and the dimples are filled with an adhesive to enhance the shock absorbing properties of the soil. In another embodiment, the dimples are filled a cement-based material for adhering a finish material to the cores.

A building foundation structure includes a ground improved body obtained by improving a surface layer ground, and foundation concrete placed on the ground improved body on site. The foundation concrete located below a building pillar has an upper part and a lower part having different shapes. The lower part has a reverse trapezoidal sectional shape in a cross section taken along a vertical plane including a horizontal direction perpendicular to a horizontal line connecting building pillars adjacent to each other. The upper part has a brim portion protruding in the first horizontal direction from a side edge at an upper end in the sectional shape of the lower part.

A building foundation structure includes a ground improved body obtained by improving a surface layer ground, and foundation concrete placed on the ground improved body on site. The foundation concrete located below a building pillar has an upper part and a lower part having different shapes. The lower part has a reverse trapezoidal sectional shape in a cross section taken along a vertical plane including a horizontal direction perpendicular to a horizontal line connecting building pillars adjacent to each other. The upper part has a brim portion protruding in the first horizontal direction from a side edge at an upper end in the sectional shape of the lower part.

A prefabricated formwork is disclosed. The prefabricated formwork of the present disclosure comprises at least one bracket comprising a first slot and a second slot, at least one first wall configured to be inserted into the first slot of the at least one bracket, and at least one second wall configured to be inserted into the second slot of the at least one bracket. The prefabricated framework may further comprise at least one support having at least one groove configured to receive the at least one bracket.