Method to Compress Prefabricated Deck Units by Tensioning Elements at Intermediate Supports

Abstract

A structural system comprised of prefabricated deck units spaced along longitudinal load-carrying members which produces longitudinal axial compression in deck units. During construction, prefabricated deck units are erected on top of and supported by the longitudinal load-carrying members via leveling devices, which also permit relative motion between the longitudinal load-carrying members and the prefabricated deck units. Anchor assemblies are affixed to the longitudinal load-carrying members near intermediate supports. Tensioned structural elements are installed in the anchor assemblies between spans and stressed to induce tension in the longitudinal load-carrying members and subsequently produce deck compression.

1 . A structural system, comprising:
 a. a plurality of longitudinal load-carrying members,   b. a plurality of prefabricated deck units spaced longitudinally along a structure, wherein said prefabricated deck units are supported by said longitudinal load-carrying members,   c. one or more intermediate supports upon which said longitudinal load-carrying members are partially supported, whereby a plurality of longitudinal load carrying member spans are defined,   d. one or more anchor assemblies affixed to said longitudinal load-carrying members in a region in proximity to said intermediate supports,   e. one or more tensioned structural elements installed into said anchor assemblies to introduce longitudinal axial compression to a plurality of said prefabricated deck units, wherein said axial compression is a result of the application of longitudinal axial tension to said longitudinal load-carrying members, wherein no separate longitudinal post-tensioning elements are required in the deck, and wherein no direct jacking of said prefabricated deck units is required to introduce said longitudinal axial compression,   f. means to allow for relative movement between a plurality of said longitudinal load-carrying members at a time at which tensioning is applied to said tensioned structural element or elements,   g. means to transfer said longitudinal axial tension in said longitudinal load-carrying members to axial compression to a plurality of said prefabricated deck units.   
     
     
         2 . The means to allow for relative movement of  claim 1  (f) is comprised of a physical gap of predetermined width between the longitudinal load-carrying members of  claim 1  that lie along the same longitudinal line but in different spans, wherein said spans are as defined in  claim 1  (c). 
     
     
         3 . The means to transfer axial tension of  claim 1  (g) is comprised of a plurality of mounted elements affixed to the longitudinal load-carrying members of  claim 1  in-between which are located a plurality of prefabricated deck units of claim  1  that are non-composite with the longitudinal bad-carrying members of  claim 1  at the time of the tensioning of  claim 1  (f). 
     
     
         4 . The mounted elements of  claim 3  are comprised of a plurality of prefabricated deck units of  claim 1  that are composite with the longitudinal bad-carrying members of  claim 1 , whereby said composite prefabricated deck units act as deck connection units. 
     
     
         5 . The structure of cairn  1  is comprised of one or more structural units, wherein the longitudinal axial compression of  claim 1  may be introduced into the prefabricated deck units of  claim 1  in any one of said structural units independent of any other one or more of said structural units. 
     
     
         6 . The longitudinal load-carrying members of  claim 1  are comprised of any one member or any combination of members selected from the group consisting of steel, concrete, wood, and composite materials. 
     
     
         7 . The longitudinal load-carrying members of  claim 1  are comprised of any one member or any combination of members selected from the group consisting of I-girders, I-beams, box girders, and trusses. 
     
     
         8 . The tensioned structural element or elements of  claim 1  are comprised of any one member or any combination of members selected from the group consisting of high strength bars, post-tensioning rods, steel plates and post-tensioning tendons. 
     
     
         9 . A method for constructing one or more structural units wherein no separate longitudinal post-tensioning elements are required in the deck, comprising the steps of:
 a. constructing a plurality of prefabricated deck units, a plurality of supports for the structure, a plurality of longitudinal bad-carrying members, a plurality of anchor assemblies, wherein said assemblies are affixed to said longitudinal bad-carrying members in regions to be in proximity with intermediate instances of said supports, a plurality of mounted elements, and a plurality of tensioned structural elements,   b. installing said longitudinal load-carrying member or members, wherein said longitudinal load-carrying members are supported by said supports,   c. installing said tensioned structural elements into said anchor assemblies   d. installing a plurality of said prefabricated deck units, wherein said prefabricated deck units are supported by said longitudinal load-carrying members and rest on devices that permit relative motion between said prefabricated deck units and said longitudinal load-carrying members, wherein said prefabricated deck units are non-composite with said longitudinal load-carrying members,   e. installing a plurality of mounted elements, wherein a plurality of said prefabricated units are located in-between said mounted elements,   f. stressing said tensioned structural elements to introduce axial compression in said prefabricated deck units, wherein said axial compression is a result of the application of longitudinal axial tension to said longitudinal load-carrying member or members,   g. making said non-composite prefabricated deck units composite with said longitudinal load-carrying members.   
     
     
         10 . The longitudinal load-carrying members of  claim 9  are comprised of any one member or any combination of members selected from the group consisting of steel, concrete, wood, and composite materials. 
     
     
         11 . The longitudinal load-carrying members of  claim 9  are comprised of any one member or any combination of members selected from the group consisting of I-girders, I-beams, box girders, and trusses.