Method for externally reinforcing girders

A method of externally reinforcing a continuous beam having one support at each end and a plurality of intermediate supports forming corresponding beam spans therebetween, each of said beam spans comprising first and second ends, a web, an upper or compression flange, and a lower or tension flange, each of said web and said flanges having first and second opposing faces such that each of said beam spans has first and second opposing faces, said method comprising the steps of:

• attaching exclusively by friction forces to each of said faces of said webs at said first end of each of said beam spans a first upper friction connector below said upper flange and extending in a downward direction towards a center of the length of the beam span,
• attaching exclusively by friction forces to each of said faces of said webs at said second end of each of said beam spans a second upper friction connector below said upper flange and extending in a downward direction towards the center of the length of the beam span;
• attaching exclusively by friction forces to each one of said faces of said lower flanges of each of said beam spans first and second lower friction connectors, said first lower friction connector of each respective beam span being collinearly arranged with respect to said first upper friction connector of said beam span, said second lower friction connector of each respective beam span being collinearly arranged with respect to said second upper friction connector of said respective beam span, and said first and second lower friction connectors being collinearly arranged with and spaced apart from each other;
• passing a first tension member through said first upper friction connector, said first lower friction connector, said second lower friction connector, and said second upper friction connector on each face of each of said beam spans, thereby forming a first tension member stretch extending in a downwardly inclined direction between said first upper friction connector and said first lower friction connector, a second tension member stretch extending in a horizontal direction between said first and second lower friction connectors, and a third tension member stretch extending in an upwardly inclined direction between said second lower friction connector and said second upper friction connector;
• tensioning at least one of said first, second, and third tension member stretches sufficiently to transmit, exclusively by means of friction forces, the required forces to said continuous beam in order to increase the load bearing capacity thereof;
• attaching exclusively by friction forces to each one of said faces of each of said beam spans having the second end adjacent said first end of the another beam span a first horizontal friction connector adjacent said upper flange and at a predetermined distance from said second end of said beam span;
• attaching exclusively by friction forces to each one of said faces of each of said beam spans having the first end adjacent said second end of the another beam span a second horizontal friction connector adjacent said upper flange and at a predetermined distance from said first end of said beam span;
• passing a second tension member through adjacent first and second horizontal friction connectors of adjacent beam spans such that each intermediate support of said continuous beam is located at the midpoint of said second tension member;
• and
• tensioning said second tension member with a stress sufficient to compensate for negative bending stresses applied to said continuous beam by said intermediate supports;
• wherein said steps of attaching exclusively by friction forces to each one of said faces of said web first and second upper friction connectors, first and second lower friction connectors, and said first and second horizontal friction connectors include the steps of sufficiently pressing said friction connectors on said first face of each said beam span against said first face of each said beam span and sufficiently pressing said friction connectors on said second face of each said beam span against said second face of each said beam span to cause the vertical forces maintaining said friction connectors in place against said faces of said beam span to be provided exclusively by friction.

A method of externally reinforcing a girder for increasing the load bearing capacity thereof, said girder comprising first and second ends, a web, an upper or compression flange, and a lower or tension flange, each of said web and said flanges having substantially parallel first and second opposing substantially vertical faces such that said girder has first and second opposing faces, said method comprising the steps of:

• attaching exclusively by friction forces to each one of said faces of said lower flange at said first end of said girder a first lower friction connector;
• attaching exclusively by friction forces to each one of said faces of said lower flange at said second end of said girder a second lower friction connector, said first and second lower friction connectors being collinearly arranged with and spaced apart from each other;
• passing a tension member extending horizontally through said first and second lower friction connectors on each face of said girder;
• and
• tensioning said tension members sufficiently to transmit, exclusively by means of friction forces, the required forces to said girder in order to increase the load bearing capacity thereof;
• wherein said steps of attaching exclusively by friction forces to each one of said faces of said girder first and second lower friction connectors include the steps of sufficiently pressing said friction connectors on said first face of said girder against said first face of said girder and sufficiently pressing said friction connectors on said second face of said girder against said second face of said girder to cause the forces maintaining said friction connectors in place against said faces of said girder to be provided exclusively by friction.

A method of externally reinforcing a girder for increasing the load bearing capacity thereof, said girder comprising first and second ends, a web, an upper or compression flange, and a lower or tension flange, each of said web and said flanges having first and second opposing faces such that said girder has first and second opposing faces, said method comprising the steps of:

• attaching exclusively by friction forces to each one of said faces of said web at said first end of said girder a first upper friction connector below said upper flange and extending in a downward direction towards a center of the length of the girder;
• attaching exclusively by friction forces to each one of said faces of said web at said second end of said girder a second upper friction connector below said upper flange and extending in a downward direction towards the center of the length of the girder;
• attaching exclusively by friction forces, to each one of said faces of said lower flange, first and second lower friction connectors, said first lower friction connector being collinearly arranged with respect to said first upper friction connector, said second lower friction connector being collinearly arranged with respect to said second upper friction connector, and said first and second lower friction connectors being spaced apart from each other;
• passing a first tension member through said first upper friction connector and said first lower friction connector on each face of said girder, and passing a second tension member through said second upper friction connector and said second lower friction connector on each face of said girder, thereby forming a first tension member stretch extending in a downwardly inclined direction between said first upper friction connector and said first lower friction connector, and a second tension member stretch extending in a downwardly inclined direction between said second upper friction connector and said second lower friction connector;
• and
• tensioning at least one of said tension member stretches sufficiently to transmit, exclusively by means of friction forces, the required forces to said girder in order to increase the load bearing capacity thereof;
• wherein said steps of attaching exclusively by friction forces to each one of said faces of said girder first and second upper friction connectors and first and second lower friction connectors include the steps of sufficiently pressing said friction connectors on said first face of said girder against said first face of said girder and sufficiently pressing said friction connectors on said second face of said girder against said second face of said girder to cause the forces maintaining said friction connectors in place against said faces of said girder to be provided exclusively by friction.