Column holdown connection

Abstract

A connection between a metal column, in particular a vertical I-beam, and an underlying structural member, in particular a ferroconcrete foundation, using a connector that is fastened to the metal column using both bolts and screws.

1 . A column holdown connection ( 1 ) in a building ( 2 ), said connection ( 1 ) comprising:
 a. an underlying structural member ( 3 );   b. an anchor ( 4 ) restrained by said underlying structural member ( 3 ), said anchor ( 4 ) having an attachment end ( 5 ) protruding above said underlying structural member ( 3 );   c. a substantially vertical metal column ( 6 ) with a bottom end ( 7 ) supported by said underlying structural member ( 3 );   d. a holdown connector ( 8 ) having a back member ( 9 ) and a seat member ( 10 ), said back member ( 9 ) being fastened to said column ( 6 ) with a plurality of bolts ( 11 ) and a plurality of screws ( 12 ), and said seat member ( 10 ) being restrained by said attachment end ( 5 ) of said anchor ( 4 ).   
     
     
         2 . The connection ( 1 ) of  claim 1  wherein:
 a. said underlying structural member ( 3 ) is a foundation ( 3 ).   
     
     
         3 . The connection ( 1 ) of  claim 2  wherein:
 a. said foundation ( 3 ) is cementitous.   
     
     
         4 . The connection ( 1 ) of  claim 1  wherein:
 a. said anchor ( 4 ) is an anchor bolt ( 4 ).   
     
     
         5 . The connection ( 1 ) of  claim 4  wherein:
 a. said seat member ( 10 ) of said holdown connector ( 8 ) is formed with an anchor opening ( 13 ) through which said attachment end ( 5 ) of said anchor ( 4 ) passes; and   b. said attachment end ( 5 ) of said anchor ( 4 ) has helical threads ( 14 ) and a nut ( 15 ) is threaded onto said helical threads ( 14 ), thereby restraining said attachment end ( 5 ) against said seat member ( 10 ).   
     
     
         6 . The connection ( 1 ) of  claim 1  wherein:
 a. said column ( 6 ) is an I-beam ( 6 ) with a central, substantially planar web member ( 16 ) having a first side ( 17 ) and a second side ( 18 ), a first substantially planar side member ( 19 ) and a second substantially planar side member ( 20 ), said first side member ( 19 ) and said second side member ( 20 ) being generally perpendicular to said web member ( 16 ) and extending beyond both said first side ( 17 ) and said second side ( 18 ) of said web member ( 16 ) to create a pair of back-to-back channels ( 21 ).   
     
     
         7 . The connection ( 1 ) of  claim 6  wherein:
 a. said column ( 6 ) is formed with a plurality of bolt openings ( 22 ) in said web member ( 16 ) adjacent said bottom end ( 7 );   b. said holdown connector ( 8 ) is formed with a plurality of bolt openings ( 23 ) in said back member ( 9 ); and   c. said plurality of bolts ( 11 ) passes through said plurality of bolt openings ( 23 ) in said back member ( 9 ) of said holdown connector ( 8 ) and through said plurality of bolt openings ( 22 ) in said column ( 6 ).   
     
     
         8 . The connection ( 1 ) of  claim 7  wherein:
 a. said bolt openings ( 22 ) in said column ( 6 ) each have a horizontal diameter ( 33 ) and a vertical diameter ( 24 ).   
     
     
         9 . The connection ( 1 ) of  claim 8  wherein:
 a. said bolt openings ( 23 ) in said back member ( 9 ) of said holdown connector ( 8 ) are round.   
     
     
         10 . The connection ( 1 ) of  claim 7  wherein:
 a. said back member ( 9 ) of said holdown connector ( 8 ) is formed with a plurality of screw openings ( 25 ); and   b. said plurality of screws ( 12 ) passes through said plurality of screw openings ( 25 ) in said back member ( 9 ) of said holdown connector ( 8 ) and into said web member ( 16 ) of said column ( 6 ).   
     
     
         11 . The connection ( 1 ) of  claim 10  wherein:
 a. said screws ( 12 ) of said plurality of screws ( 12 ) are self-drilling screws ( 12 ).   
     
     
         12 . The connection ( 1 ) of  claim 11  wherein:
 a. said screws ( 12 ) of said plurality of screws ( 12 ) are self-tapping screws ( 12 ).   
     
     
         13 . The connection ( 1 ) of  claim 1  wherein:
 a. said bottom end ( 7 ) rests on a substantially horizontal bottom plate ( 26 ), and said bottom plate ( 26 ) rests on said underlying structural member ( 3 ).   
     
     
         14 . The connection ( 1 ) of  claim 13  wherein:
 a. said bottom plate ( 26 ) is a channel ( 26 ) having two side members ( 27 ) and a bottom member ( 28 ), said two side members ( 27 ) embracing said bottom end ( 7 ) of said column ( 6 ).   
     
     
         15 . The connection ( 1 ) of  claim 1  wherein:
 a. said back member ( 9 ) of said holdown connector ( 8 ) is substantially planar. and substantially vertical;   b. said seat member ( 10 ) of said holdown connector ( 8 ) is substantially planar and substantially horizontal.   
     
     
         16 . The connection ( 1 ) of  claim 15  wherein:
 a. said back member ( 9 ) and said seat member ( 10 ) are integrally joined.   
     
     
         17 . The connection ( 1 ) of  claim 16  wherein:
 a. said back member ( 9 ) and said seat member ( 10 ) are joined by a first side member ( 29 ) substantially orthogonal to both said back member ( 9 ) and said seat member ( 10 ).   
     
     
         18 . The connection ( 1 ) of. claim 17  wherein:
 a. said back member ( 9 ) and said seat member ( 10 ) are joined by a second side member ( 30 ), said second side member ( 30 ) being substantially orthogonal to both said back member ( 9 ) and said seat member ( 10 ).   
     
     
         19 . The connection ( 1 ) of  claim 18  wherein:
 a. said first side member ( 29 ) and said second side member ( 30 ) are substantially planar.   
     
     
         20 . The connection ( 1 ) of  claim 19  wherein:
 a. said back member ( 9 ) and said seat member ( 10 ) are generally rectangular.   
     
     
         21 . The connection ( 1 ) of  claim 21  wherein:
 a. said first side member ( 29 ) and said second side member ( 30 ) are substantially triangular.   
     
     
         22 . The connection ( 1 ) of  claim 6  wherein:
 a. said back member ( 9 ) of said holdown connector ( 8 ) fits entirely between said first side member ( 19 ) and said second side member ( 20 ) of said column ( 6 ).   
     
     
         23 . The connection ( 1 ) of  claim 1  wherein:
 a. said column ( 6 ) is a wall stud ( 6 ).   
     
     
         24 . The connection ( 1 ) of  claim 7  wherein:
 a. said bolt openings ( 22 ) in said web member ( 16 ) of said column ( 6 ) are substantially vertically aligned.   
     
     
         25 . The connection ( 1 ) of  claim 24  wherein:
 a. said plurality of screws ( 12 ) are horizontally spaced to either side of said bolt openings ( 22 ) in said web member ( 16 ) of said column ( 6 ), in order to resist deflection and rotation.   
     
     
         26 . The connection ( 1 ) of  claim 1  wherein:
 a. said column ( 6 ) is formed from steel.   
     
     
         27 . The connection ( 1 ) of  claim 1  wherein:
 a. said holdown connector ( 8 ) is formed at least in part by cutting sheet steel.   
     
     
         28 . The connection ( 1 ) of  claim 1  wherein:
 a. said holdown connector ( 8 ) is formed at least in part by casting metal.   
     
     
         29 . The connection ( 1 ) of  claim 1  wherein:
 a. said holdown connector ( 8 ) is formed with planar metal members ( 31 ) and said column ( 6 ) is formed with planar metal members ( 32 ) and said planar metal members ( 32 ) of said column ( 6 ) are thicker than said planar metal members ( 31 ) of said holdown connector ( 8 ).