Precast Arch-Shaped Overfilled Structure

Abstract

An arch structure for use in forming an overfilled structure includes at least one footing and at least one precast concrete bridge element forming an open bottom arch structure that is supported on the at least one footing. The arch structure has an upper portion, that may be formed by a first half-ellipse shape, and a lower portion, that may be formed by part of a second half-ellipse shape. The upper portion and lower portion meet at an elevation along the rise of the arch structure, and such elevation defines the largest span of the arch structure. The arch structure includes lower ends that come back inward toward each other, such that the span at the bottom of the arch structure is less than the largest span.

1 . An overfilled structure, comprising:
 a footing;   first and second precast concrete bridge elements that have upper ends connected by a crown joint,   the precast concrete bridge elements form an open bottom arch structure that is supported on the footing;   the footing extends an entirety of a lower end span of the arch structure and includes spaced apart upwardly facing recesses to receive lower ends of the precast concrete bridge elements;   the precast bridge elements sized and shaped such that the arch structure has an upper portion that is formed by a first half-ellipse shape and a lower portion that is formed by part of a second half-ellipse shape;   the two half-ellipse shapes meet at an elevation along a rise of the arch structure, and such elevation defines a largest span of the arch structure;   the arch structure includes lower ends that come back inward toward each other, such that the lower end span is less than the largest span.   
     
     
         2 . The overfilled structure of  claim 1  wherein:
 the largest span is between 18 and 24 feet, the rise is between 25 and 30 feet and the lower end span is between 15 and 18 feet;   the elevation of the largest span is between 9 and 13 feet from the lower end of the arch structure.   
     
     
         3 . The overfilled structure of  claim 1  wherein:
 a ratio of the largest span to the rise is about 75-85%;   a ratio of the elevation of the largest span to the rise is about 35 to 45%.   
     
     
         4 . The overfilled structure of  claim 1  wherein the upper end of one of the precast bridge elements includes a rib that is received in a groove of the upper end of the other precast bridge element. 
     
     
         5 . An arch system, comprising:
 at least one footing;   at least one precast concrete bridge element forming an open bottom arch structure that is supported on the at least one footing, the arch structure has an upper portion and a lower portion that meet at an elevation along a rise of the arch structure, and such elevation defines a largest span of the arch structure, the arch structure includes lower ends that come back inward toward each other, such that a lower end span of the arch structure is less than the largest span.   
     
     
         6 . The arch system of  claim 5  wherein:
 the largest span is between 18 and 24 feet, the rise is between 25 and 30 feet and the lower end span is between 15 and 18 feet;   the elevation of the largest span is between 9 and 13 feet from the lower end of the arch structure.   
     
     
         7 . The arch system of  claim 5  wherein:
 a ratio of the largest span to the rise is about 75-85%;   a ratio of the height of the largest span to the rise is about 35 to 45%.   
     
     
         8 . The arch structure of  claim 5  wherein the footing extends an entirety of the lower end span and includes spaced apart upwardly facing recesses that receive lower side ends of the arch structure. 
     
     
         9 . The arch structure of  claim 8  wherein the footing include a middle segment that is substantially parallel and end segments extending upward and outward from the middle segment, each recesses located on a respective one of the end segments. 
     
     
         10 . The arch structure of  claim 5  wherein the upper portion is formed by a first half-ellipse shape and the lower portion is formed by part of a second half-ellipse shape. 
     
     
         11 . A method of forming an overfilled structure, the method comprising:
 precasting first and second concrete bridge elements;   moving the precast first and second concrete bridge elements to a site;   placing lower ends of the precast first and second concrete bridge elements in spaced apart, upwardly facing recesses in a footing such that the first and second precast bridge elements form an arch structure having an open bottom that is spanned by and supported on the footing;   joining the precast first and second concrete bridge elements at their upper ends;   the precast first and second concrete bridge elements sized and shaped such that the arch structure has an upper portion that is formed by a first half-ellipse and a lower portion, the upper and lower portions meet at an elevation along a rise of the arch structure, and such elevation defines a largest span of the arch structure;   the resulting arch structure includes the lower ends that come back inward toward each other, such that a lower end span of the arch structure is less than the largest span.   
     
     
         12 . The method of  claim 11  wherein:
 the largest span is between 18 and 24 feet, the rise is between 25 and 30 feet and the lower end span is between 15 and 18 feet;   wall thickness is between 1.1 and 1.5 feet;   the elevation of the largest span is between 9 and 13 feet from the lower end of the structure.   
     
     
         13 . The method of  claim 11  wherein:
 a ratio of the largest span to the rise is about 75-85%;   a ratio of the height of the largest span to the rise is about 35 to 45%.   
     
     
         14 . The method of  claim 11  wherein the upper end of one of the precast first and second bridge elements includes a rib that is received in a groove of the upper end of the other precast first and second bridge element. 
     
     
         15 . The method of  claim 11  further comprising aligning multiple arch structures forming a tunnel. 
     
     
         16 . The method of  claim 11  further comprising precasting the footing and locating the footing at the site. 
     
     
         17 . The method of  claim 11  further comprising casting the footing in place at the site.