Buoyancy stabilized pier structure and method for installing same

Abstract

A bridge pier structure is disclosed having a downwardly open footing chamber, an upper buoyant chamber, an upright member that mechanically connects these chambers, and that defines a fluid channel to the footing chamber. A valve is disposed in an upper portion of the fluid channel and configured to attach to a water ejection pump and a vacuum source. The pressure in the footing chamber can be reduced, such that hydrostatic pressure and the atmospheric pressure aids in embedding the footing. Optionally, a vibrating apparatus attaches to the structure to facilitate embedding. The apparatus may also enable the structure to be dislodged after installation, by providing a high pressure air source to the valve. The structure may be installed by towing it to location, positioning it on the waterway bed, and applying a suction to the valve.

1 . A bridge pier comprising:
 a footing chamber that is open downwardly;   an upper chamber defining a buoyant volume;   an upright portion mechanically connecting the footing chamber and the upper chamber, the upright portion further comprising a fluid channel that extends from an upper end of the upright portion to the footing chamber;   a valve having an open position and a closed position, the valve disposed in an upper portion of the fluid channel and configured to attach to a vacuum source.   
     
     
         2 . The bridge pier of  claim 1 , further comprising a vibratory device attached to the bridge pier and configured to selectively vibrate the bridge pier. 
     
     
         3 . The bridge pier of  claim 2 , wherein the upper chamber comprises a plurality of separated volumes that are configured to selectively receive water to act as ballast tanks to facilitate installation of the bridge pier. 
     
     
         4 . The bridge pier of  claim 1 , wherein the upper chamber is filled with a polymeric foam. 
     
     
         5 . The bridge pier of  claim 1 , wherein the downwardly open footing chamber further comprises a chamfered lower edge. 
     
     
         6 . The bridge pier of  claim 1 , wherein the bridge pier has a nominal design load, and wherein the upper chamber is sized and configured such that during use the upper chamber produces a buoyancy force that is equal to at least eighty percent of the nominal design load. 
     
     
         7 . The bridge pier of  claim 1 , wherein the upright portion comprises a plurality of interconnected upright members. 
     
     
         8 . The bridge pier of  claim 7 , wherein the plurality of upright members are telescopically interconnected. 
     
     
         9 . The bridge pier of  claim 1 , wherein the footing chamber, the upper chamber, and the upright portion comprise a unitary structure. 
     
     
         10 . The bridge pier of  claim 1 , wherein the bridge pier further comprises a bridge tower structure. 
     
     
         11 . A method for installing a bridge pier comprising:
 fabricating a bridge pier having a buoyant upper chamber, a downwardly open footing chamber, and an upright portion defining a channel to the footing chamber;   transporting the bridge pier to an installation location;   sinking at least a portion of the bridge pier to position the footing chamber positioned on a waterbed;   applying a vacuum to the channel such that a pressure in the footing chamber is reduced sufficiently to cause the footing chamber to become embedded in the waterbed.   
     
     
         12 . The method of  claim 11 , wherein the bridge pier is fabricated at a location remote from the installation location. 
     
     
         13 . The method of  claim 11 , wherein the step of transporting the bridge pier comprises towing the bridge pier in a waterway. 
     
     
         14 . The method of  claim 13 , wherein the bridge pier is towed in a non-vertical orientation, and further comprising the step of reorienting the bridge pier to a vertical orientation prior to the step of sinking at least a portion of the bridge pier. 
     
     
         15 . The method of  claim 11 , further comprising the step of vibrating the bridge pier to facilitate embedding the footing chamber in the waterbed. 
     
     
         16 . The method of  claim 11 , wherein the upright portion of the bridge pier comprises at least two telescoping upright members. 
     
     
         17 . The method of  claim 16 , wherein prior to the step of transporting the bridge pier the footing chamber is moved towards the upper chamber by telescoping the two upright members. 
     
     
         18 . The method of  claim 11 , further comprising the step of injecting pressurized air into the footing chamber prior to the step of applying a vacuum to the channel. 
     
     
         19 . The method of  claim 11 , wherein the buoyant upper chamber comprises a polymeric foam. 
     
     
         20 . The method of  claim 11 , wherein the buoyant upper chamber comprises a plurality of ballast tanks, and further comprising the step of selectively adding water to at least one of the ballast tanks to facilitate orienting the bridge pier during installation.