Precast concrete bridge unit and headwall assembly and method of production

Abstract

A method of producing a precast concrete bridge and headwall assembly, includes the steps of casting a reinforced concrete bridge unit having a top wall connecting opposite side walls, releasably attaching a series of counterfort forms to the top wall of the bridge unit at laterally spaced intervals between the side walls, and positioning the bridge unit with a first side supported by a horizontal casting surface, wherein the top wall is positioned adjacent a casting framework and a bottom edge of the counterfort forms is located adjacent the casting framework. The method further includes precasting a concrete headwall unit onto the casting surface, precasting a series of counterfort members into the counterfort forms before the headwall has completely hardened, removing the series of counterfort forms from the top wall of the bridge unit; and removing the headwall and counterfort members as a unit from the bridge unit.

What is claimed is: 
     
         1 . 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;   releasably attaching a series of counterfort forms to the top wall of the bridge unit at laterally spaced intervals between the side walls;   positioning the bridge unit with a first side supported by a horizontal casting surface, wherein the top wall is positioned adjacent a casting framework and a bottom edge of the counterfort forms is located adjacent the casting framework;   precasting a concrete headwall unit onto the casting surface;   precasting a series of counterfort members into the counterfort forms before the headwall has completely hardened;   removing the series of counterfort forms from the top wall of the bridge unit; and   removing the headwall and counterfort members as a unit from the bridge unit.   
     
     
         2 . The method of  claim 1 , wherein the precasting of the headwall and the series of counterfort members is simultaneous, forming an integral unit made up of the counterfort members and the headwall. 
     
     
         3 . The method of  claim 1 , wherein the casting of the bridge unit includes positioning a series of anchor members in the top wall at laterally spaced intervals between the side walls. 
     
     
         4 . The method of  claim 1 , wherein a cross-hole is created in each of the counterfort members during the casting of the series of counterfort members. 
     
     
         5 . The method of  claim 1 , wherein the precasting of the headwall includes positioning at least one primary bracket at least partially in the casting framework, such that the at least one primary bracket is integrally formed with the headwall once the headwall has hardened, and including at least one secondary bracket attached to the top wall of the bridge unit, such that the at least one primary bracket formed in the headwall and the at least one secondary bracket attached to the top wall of the bridge unit are positioned between adjacent anchor members. 
     
     
         6 . The method of  claim 5 , wherein the at least one primary bracket includes studs extending into the casting framework. 
     
     
         7 . The method of  claim 5 , wherein, prior to precasting of the headwall a first end of at least one rod is releasably coupled to the at least one primary bracket in the casting framework and a second end of the at least one rod is releasably coupled to the at least one secondary bracket attached to the top wall of the bridge unit. 
     
     
         8 . The method of  claim 1 , wherein the series of counterfort forms includes at least two different sizes of forms. 
     
     
         9 . The method of  claim 8 , wherein a first size of the counterfort members has a releasable connection to the top wall of the bridge unit, and a second size of the counterfort members has a releasable connection to the top wall of the bridge unit. 
     
     
         10 . The method of  claim 1 , wherein releasably attaching the series of counterfort forms includes side plates of the counterfort forms having forward edges adjacent the top wall of the bridge unit and a lateral plate, which extends between the side plates, being spaced from the top wall of the bridge unit. 
     
     
         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;   releasably attaching a series of counterfort forms to the top wall of the bridge unit at laterally spaced intervals between the side walls;   positioning the bridge unit with a first side supported by a horizontal casting surface, wherein the top wall is positioned adjacent a casting framework and a bottom edge of the counterfort forms is located adjacent the casting framework;   positioning at least one primary bracket at least partially in the casting framework;   releasably attaching a first end of at least one rod to the at least one primary bracket in the casting framework and attaching a second end of the at least one rod to at least one secondary bracket attached to the top wall of the bridge unit;   precasting a concrete headwall unit onto the casting surface;   precasting a series of counterfort members into the counterfort forms before the headwall has completely hardened;   removing the series of counterfort forms from the top wall of the bridge unit;   detaching the first end of the at least one rod from the at least one primary bracket and detaching the second end of the at least one rod from the at least one secondary bracket; and   removing the headwall and counterfort members as a unit from the bridge unit.   
     
     
         12 . The method of  claim 11 , wherein the precasting of the headwall and the series of counterfort members is simultaneous, forming an integral unit made up of the counterfort members and the headwall. 
     
     
         13 . The method of  claim 11 , wherein the casting of the bridge unit includes positioning a series of anchor members in the top wall at laterally spaced intervals between the side walls. 
     
     
         14 . The method of  claim 13 , wherein a shaft is anchored within each of the anchor members and extends outwardly from the top wall and through each of the counterfort forms, wherein a cross-hole is created in each of the counterfort members during the casting of the series of counterfort members. 
     
     
         15 . The method of  claim 14 , wherein a tubular member is positioned over the anchored shaft and is integrally formed within the counterfort member such that the diameter of the cross-hole generally corresponds to the diameter of the tubular member. 
     
     
         16 . The method of  claim 11 , wherein the series of counterfort forms includes at least two different sizes of forms. 
     
     
         17 . A precast concrete bridge and headwall assembly comprising:
 a precast concrete bridge unit including a top wall connecting opposite side walls; and   a precast concrete headwall having a bottom surface mating with the top wall of the bridge unit and a series of counterfort members at laterally spaced intervals between the side walls, the counterfort members being integrally formed with the headwall such that no seam is present between the headwall and the counterfort members.   
     
     
         18 . The assembly of  claim 17 , wherein the series of counterfort members includes at least two different sizes of members. 
     
     
         19 . The assembly of  claim 18 , wherein the counterfort members of a first size have a releasable connection to the top wall of the bridge unit, and the counterfort members of a second size have a releasable connection to the top wall of the bridge unit. 
     
     
         20 . The assembly of  claim 17 , further comprising:
 at least one primary bracket integrally formed with the headwall;   at least one secondary bracket attached to the top wall of the bridge unit such that the at least one primary bracket formed in the headwall and the at least one secondary bracket attached to the top wall of the bridge unit are positioned between adjacent anchor members; and   at least one rod having a first end releasably coupled to the at least one primary bracket and a second end releasably coupled to the at least one secondary bracket.