Abstract: A construction method is disclosed. The method includes providing a bottom support between a plurality of structural members and using the bottom support to support a structural material in a plastic state. The method also includes using the bottom support to support the structural material as it hardens from a plastic state into a hardened state. The structural material remains attached to the bottom support after the structural material hardens. The bottom support is transparent or translucent.

Abstract: A construction method is disclosed. The method includes providing a bottom support between a plurality of structural members and using the bottom support to support a structural material in a plastic state. The method also includes using the bottom support to support the structural material as it hardens from a plastic state into a hardened state. The structural material remains attached to the bottom support after the structural material hardens. The bottom support is transparent or translucent.

Abstract: A one-piece open bottom fiber reinforced precast concrete arch unit is buried in compacted soil and has an arcuate top wall portion integrally connecting arcuate side wall portions. The fiber reinforced wall portions have a configuration which provides ductility and flexure strength for effectively utilizing the surrounding compacted soil to resist deflection of the unit in response to a load and to redistribute stresses in the unit. Each of the side wall portions of the unit has a reducing wall thickness towards its bottom and has a radius of curvature greater than the rise of the unit and at least twice the radius of curvature of the top wall portion. A fiber reinforced end arch unit includes an integrally precast and fiber reinforced vertical collar connected to fiber reinforced wing walls by bolts extending through the collar and into anchor nuts embedded in the wing walls.

Abstract: A one-piece open bottom fiber reinforced precast concrete arch unit is buried in compacted soil and has an arcuate top wall portion integrally connecting arcuate side wall portions. The fiber reinforced wall portions have a configuration which provides ductility and flexure strength for effectively utilizing the surrounding compacted soil to resist deflection of the unit in response to a load and to redistribute stresses in the unit. Each of the side wall portions of the unit has a reducing wall thickness towards its bottom and has a radius of curvature greater than the rise of the unit and at least twice the radius of curvature of the top wall portion. Bands of continuous fibers may be attached by adhesive resin to the outer surface of the arcuate side and top wall portions of the unit near opposite ends of the unit to increase the load carrying capacity of the unit.