Precast concrete bridge and headwall assembly and method of production

1. A precast concrete bridge and headwall assembly comprising a precast concrete bridge unit including a top wall connecting opposite side walls, an upwardly projecting, precast concrete headwall having a bottom surface engaging and mating with said top wall of said bridge unit, a series of precast concrete counterfort members spaced laterally at intervals along said top wall of said bridge unit, each of said counterfort members being rigidly connected to said headwall, and a releasable rigid connection of each of said counterfort members to said top wall of said bridge unit.

2. The assembly as defined in claim 1 wherein said top wall of said bridge unit is arcuate, and said counterfort members are spaced laterally along an arcuate top surface of said top wall and positioned in a side-by-side arrangement extending between opposite side walls of said precast concrete bridge unit.

3. The assembly as defined in claim 1 wherein each of said precast concrete counterfort members has reinforcing members projecting from said counterfort member into said headwall and forming a non-releasable rigid connection between said counterfort member and said headwall.

4. The assembly as defined in claim 1 wherein said releasable rigid connection of each of said counterfoil members to said top wall of said bridge unit includes an internally threaded tubular anchor member embedded in said top wall, and a threaded rod extending through a hole within said counterfoil member into said anchor.

5. The assembly as defined in claim 1 wherein each of said counterfort members is tapered and has a large end portion rigidly connected to said headwall and a small end portion releasably connected to said top wall of said bridge unit.

6. The assembly as defined in claim 1 , wherein said releasable rigid connection of each of said counterfort members comprises an anchor member that extends through said respective counterfort member and into said top wall such that said anchor member can be removed from said respective counterfort member and said top wall.

7. A precast concrete bridge and headwall assembly comprising a precast steel reinforced concrete bridge unit including an arcuate top wall connecting substantially vertical opposite side walls, a precast concrete headwall having an arcuate bottom surface mating with said top wall of said bridge unit, a series of precast concrete counterfort members spaced laterally at intervals along said top wall of said bridge unit, each of said counterfort members having steel reinforcing members embedded in said headwall and forming a headwall and counterfort unit, and a releasable rigid connection of each of said counterfort members to said top wall of said bridge unit.

8. The assembly as defined in claim 7 wherein said releasable rigid connection of each of said counterfort members to said top wall of said bridge unit includes an internally threaded tubular anchor member embedded in said top wall, and a threaded rod extending through a hole within said counterfort member into said anchor.

9. The assembly as defined in claim 8 wherein each of said counterfort members is tapered and has a large end portion rigidly connected to said headwall and a small end portion releasably connected by said threaded rod to said top wall of said bridge unit.

10. The assembly as defined in claim 9 wherein each of said counterfort members is generally triangular in configuration.

11. A method of producing a precast concrete bridge and headwall assembly, comprising the steps of:

casting a reinforced concrete bridge unit having a top wall connecting opposite side walls,

casting a series of separate concrete counterfort members each having an embedded reinforcing member with an end portion projecting from an end surface of each counterfort member,

releasably attaching the precast concrete counterfort members to the top wall of the bridge unit at laterally spaced intervals between the side walls,

positioning the bridge unit with an end surface of the bridge unit supported by a horizontal casting surface and with the end surfaces of the counterfort members spaced above the casting surface and with the end portions of the reinforcing members depending from the end surfaces of the counterfort members,

precasting a concrete headwall unit on the casting surface with the projecting end portions of the reinforcing members embedded in the concrete headwall unit, and

removing the headwall and the counterfort members as a unit from the bridge unit.

12. The method as defined in claim 11 wherein the bridge unit is cast with an arcuate top wall, and the counterfort members are spaced along the arcuate top wall.

13. The method as defined in claim 11 wherein each of the counterfort members is cast with a generally triangular configuration.

14. The method as defined in claim 13 wherein each of the counterfort members is cast with a tapered configuration with a large end portion and a small end portion, and forming a cross hole within said small end portion.

15. The method as defined in claim 11 wherein the bridge unit is cast with the top wall integrally connecting generally vertical side walls.

16. A precast concrete bridge and headwall assembly comprising:

a precast concrete bridge unit including a top wall connecting opposite side walls;

a precast concrete headwall having a bottom surface mating with said top wall of said bridge unit; and

a series of precast concrete counterfort members spaced laterally at intervals along said top wall of said bridge unit, each of said counterfort members being rigidly connected to said headwall, and a releasable rigid connection of each of said counterfort members to said top wall of said bridge unit, wherein each of said counterfort members is tapered and has a large end portion rigidly connected to said headwall and a small end portion releasably connected to said top wall of said bridge unit.