Universal Framed Cofferdam

Abstract

Universal Framed Cofferdam has prefabricated skeletal steel space framing formed from multiple steel vertical pipes and two levels of horizontal diaphragm trusses rigidly connected to pipe columns. Beams of each diaphragm truss are attached to vertical pipes of the framing with rigid moment connections creating a rigid space frame of the perfectly round form that is used as a false work of the Cofferdam. Wales of the Cofferdam and short pieces of the flat sheet piling are attached to the vertical pipes forming a skeleton of the Cellular structure. The Skeleton of the Universal Framed Cofferdam is prefabricated in the convenience of the Dry Dock and than floated to the site. Buoyancy of the framing allows Cofferdam skeleton transportation without using the barge or otherwise necessary floating devices. Once brought to the site of installation Cofferdam skeleton is installed vertically in position and leveled on the bottom of the river bed. If necessary river silt can be jetted and pumped out of pipe annular space and pipe columns of framing can be simultaneously lowered in position by using vibro—hummer. After space framing installation, rock sockets are predrilled through the annular space of vertical pipes and rock anchors installed. Sheet pile skin of the Cofferdam installed between pipe columns concludes Cofferdam Can erection. Universal Framed Cofferdam Can than filled with compacted gravel and becomes a Hybrid Gravity Caisson/Columnar water front or marine structure that has the best features of the Conventional Cellular Cofferdam and of Columnar Dolphin structure. It has enhanced sliding and overturning stability provided by Rock anchors preloaded by Cofferdam granular fill and has effective mechanism that prevents concave or convex surface of rupture failure that may be suffered by conventional Cellular Cofferdams, and has mechanism that more effectively resists deep surface sliding failure of the Cofferdam base.

1 . Prefabricated rigid Cofferdam framing that is floated to the site of construction and positioned in place to complete and aid in Cofferdam construction. Prefabricated Cofferdam framing that comprises:
 a) a skeletal frame that is formed from multiple tubular columns.   b) at least two horizontal Diaphragms rigidly connected to columns and forming rigid space framing of Universal Cofferdam.   c) perimeter wale system attached to tubular columns to form perfect circular false work for the Cellular Cofferdam Can sheet piling.   
   
   
       2 . six end Star Truss that serves as a horizontal diaphragm and is formed from two equal sided triangles intersecting in two levels and connected together to form a rigid diaphragm structure or a truss that is formed in plan as a single piece element.
 Other horizontal truss diaphragm configurations that can be used for that purpose and do not violate the concept of present invention.   
   
   
       3 . Final Universal Framed Cofferdam product that comprises:
 a) Rock or soil anchors consisting of structural steel HP sections or round reinforced concrete section.   b) Sheet pile perimeter skin connected to the tubular columns of Prefabricated Cofferdam Cell framing that forms Hybrid Gravity Caisson/Columnar Framed Space Structure.   
   
   
       4 . Universal Framed Cofferdam as recited in  claim 3 a, where rock or soil anchors prevent undesired effects of Cofferdam Block Rotational movement, resist Sliding forces, prevent forming of Concave or Convex surface of rupture failures through the granular fill of Cofferdam or through the foundation base and prevent Deep Surface rotational sliding failure as shown in Failure Mechanism Diagram of Prior Art (FIG. D 3 )