Movable brace frame for self-installing platform

Abstract

Pre-assembled self installing platforms with improved performance due to additional rotational restraint to supporting legs and methods of installation. The platform includes a hull, legs movable relative to the hull, at least one brace frame movably connected to at least two of the legs. Upon installation, the brace frame may be positioned at a desired elevation and rigidly secured to the legs, providing rotational restraint to significantly reduce leg stress and increase rigidity of the legs. With the increased rigidity, it becomes possible to install platforms in relatively deep waters and harsh environments, and yet preventing large overall platform sway induced by adverse weather or sea conditions. As the brace frame is securable to the legs after the legs or footings are penetrated into or supported on the sea bed, differential penetration of legs or footings into the seabed becomes possible without risking large structural loads in the brace frame.

1 . A pre-assembled self-installing platform comprising:
 a hull;   a plurality of legs movable relative to the hull; and   at least one brace frame movably connected to at least two of the plurality of legs, wherein the at least one brace frame is securable to the at least two of the plurality of legs for providing rotational restraint thereto.   
     
     
         2 . The pre-assembled self-installing platform of  claim 1 , wherein the at least one brace frame further includes:
 a plurality of sleeves fitted around the at least two of the plurality of legs; and   at least one brace member connecting the plurality of sleeves.   
     
     
         3 . The pre-assembled self-installing platform of  claim 1 , wherein the at least one brace frame includes a truss structure. 
     
     
         4 . The pre-assembled self-installing platform of  claim 1 , wherein the at least one brace frame is securable to the at least two of the plurality of legs by one of a filler joining material and a clamp. 
     
     
         5 . The pre-assembled self-installing platform of  claim 1 , further comprising: a plurality of guides interposed between the plurality of sleeves and the at least two of the plurality of legs for preventing scratching on the at least two of the plurality of legs. 
     
     
         6 . The pre-assembled self-installing platform of  claim 1 , further comprising:
 a rack and pinion system for movably connecting the at least one brace frame with the at least two of the plurality of legs; and   a plurality of clamps for securing the brace frame to the at least two of the plurality of legs at a desired elevation.   
     
     
         7 . A method for installing a platform, comprising:
 transporting a pre-assembled self-installing platform to an offshore site, the pre-assembled self-installing platform comprising:
 a hull; 
 a plurality of legs movable relative to the hull, and 
 at least one brace frame movably connected to at least two of the plurality of legs, wherein the at least one brace frame is securable to the at least two of the plurality of legs for providing rotational restraint thereto; 
   lowering the plurality of legs into a seabed;   positioning the at least one brace member at a desired elevation along the at least two of the plurality of legs; and   securing the at least one brace member to the at least two of the plurality of legs.   
     
     
         8 . The method of  claim 7 , wherein transporting a pre-assembled self-installing platform further includes transporting by a barge supporting the pre-assembled self-installing platform. 
     
     
         9 . The method of  claim 7 , wherein transporting a pre-assembled self-installing platform further includes floating the pre-assembled self-installing platform. 
     
     
         10 . The method of  claim 7 , wherein positioning the at least one brace member further includes lowering the at least one brace member using one of a cable system and a rack and pinion system. 
     
     
         11 . The method of  claim 7 , wherein securing the at least one brace member to the at least two of the plurality of legs further includes securing using one of a filler joining material and a clamp.