Portal frame

Abstract

A portal frame is disclosed for use around portals in, for example, a light-framed construction. The portal frame includes a pair of vertically-oriented shearwalls, and a header extending between and connected to the shearwalls. The portal frame may be used around a variety of portals formed in a construction, including for example doors, garage doors and windows. By forming a portal frame using a pair of shearwalls connected to a header, the portal frame in embodiments of the present invention is able to effectively reduce the loads exerted on a foundation by the shearwalls in comparison to a shearwall acting alone (i.e., one that is not part of a portal frame).

1 . A portal frame, comprising:
 a pair of shearwalls, each shearwall including:
 a top edge and a bottom edge generally defining a height of the shearwall, 
 first and second ends, extending between the top and bottom edges, generally defining a width of the shearwall, and 
 a corrugated section extending at least partially between said top edge and said bottom edge in between said first and second ends, said corrugated section forming at least one corrugation; and 
   a header extending between and mounted to top edges of the pair of shearwalls, the pair of shearwalls and header together defining a frame for a portal of a construction.   
   
   
       2 . A portal frame as recited in  claim 1 , further comprising a sill plate affixed at the top edge of each shearwall and having a footprint at least as large as the footprint of each shearwall. 
   
   
       3 . A portal frame as recited in  claim 1 , further comprising a bottom plate affixed at the bottom edge of each shearwall and having a footprint at least as large as the footprint of each shearwall, the bottom plates affixing the shearwalls to a surface on which the portal frame is supported. 
   
   
       4 . A portal frame as recited in  claim 3 , wherein a lateral load on the portal frame results in negligible forces between the bottom plates and support surface. 
   
   
       5 . A portal frame as recited in  claim 1 , further comprising a sill plate at the top edge of each shearwall and a bottom plate at the bottom edge of each shearwall, the header affixed to the sill plates and the bottom plates affixed to a surface on which the portal frame is supported, wherein a lateral load on the portal results in substantially equal forces between the sill plates and header on the one hand, and between the bottom plates and support surface on the other hand. 
   
   
       6 . A portal frame as recited in  claim 1 , wherein the header is formed of tube steel. 
   
   
       7 . A portal frame as recited in  claim 1 , further comprising bolts for bolting the header to the shearwalls. 
   
   
       8 . A portal frame as recited in  claim 1 , wherein the header is formed of engineered lumber. 
   
   
       9 . A portal frame as recited in  claim 8 , wherein the engineered lumber is glulam. 
   
   
       10 . A portal frame as recited in  claim 8 , further comprising bolts for bolting the header to the shearwalls, the bolts fitting within recessed holes in the engineered lumber. 
   
   
       11 . A portal frame as recited in  claim 1 , further comprising yield links at the joints between the header and shearwalls. 
   
   
       12 . A portal frame as recited in  claim 1 , further comprising first and second chords affixed one each to said first and second ends of each shearwall. 
   
   
       13 . A portal frame as recited in  claim 1 , wherein said shearwalls are formed of 7-gauge steel. 
   
   
       14 . A portal frame, comprising:
 a pair of shearwalls, each shearwall including:
 a top edge and a bottom edge generally defining a height of the shearwall, 
 first and second ends, extending between the top and bottom edges, generally defining a width of the shearwall, and 
 a corrugated section extending at least partially between said top edge and said bottom edge in between said first and second ends, said corrugated section forming at least one corrugation; 
   sill plates affixed at the top edges of the shearwalls;   a header extending between and mounted on top of the sill plates, the pair of shearwalls and header together defining a frame for a portal of a construction; and   base plates affixed at bottom edges of the shearwalls, the base plates affixing the portal frame to a surface on which the portal frame is supported,   wherein a lateral load on the portal frame results in negligible forces between the bottom plates and support surface.   
   
   
       15 . A portal frame as recited in  claim 14 , wherein the header is formed of tube steel. 
   
   
       16 . A portal frame as recited in  claim 14 , wherein the header is formed of engineered lumber. 
   
   
       17 . A portal frame as recited in  claim 16 , wherein the engineered lumber is glulam. 
   
   
       18 . A portal frame as recited in  claim 16 , further comprising bolts for bolting the header to the shearwalls, the bolts fitting within recessed holes in the engineered lumber. 
   
   
       19 . A portal frame as recited in  claim 14 , further comprising yield links at the joints between the header and shearwalls. 
   
   
       20 . A portal frame, comprising:
 a pair of shearwalls, each shearwall including:
 a top edge and a bottom edge generally defining a height of the shearwall, 
 first and second ends, extending between the top and bottom edges, generally defining a width of the shearwall, and 
 a corrugated section extending at least partially between said top edge and said bottom edge in between said first and second ends, said corrugated section forming at least one corrugation; 
   sill plates affixed at the top edges of the shearwalls;   a header extending between and mounted on top of the sill plates, the pair of shearwalls and header together defining a frame for a portal of a construction; and   one of a first and second pair of base plates affixed at bottom edges of the shearwalls, the base plates affixing the portal frame to a surface on which the portal frame is supported, the first pair of base plates capable of bearing less load than the second pair of base plates,   wherein a lateral load on the portal frame results in negligible forces between the bottom plates and support surface when the first pair of base plates are affixed to the bottom edges of the shearwalls, and   wherein a lateral load on the portal results in substantially equal forces between the sill plates and header on the one hand, and between the bottom plates and support surface on the other hand, when the second pair of base plates are affixed to the bottom edges of the shearwalls.   
   
   
       21 . A portal frame as recited in  claim 20 , further comprising a first pair of anchors for anchoring the portal frame to the support surface when the first pair of base plates are affixed to the bottom edges of the shearwalls. 
   
   
       22 . A portal frame as recited in  claim 21 , further comprising a second pair of anchors for anchoring the portal frame to the support surface when the second pair of base plates are affixed to the bottom edges of the shearwalls, the second pair of anchors capable of supporting a larger load than the first pair of anchors. 
   
   
       23 . A portal frame as recited in  claim 20 , wherein the header is formed of tube steel. 
   
   
       24 . A portal frame as recited in  claim 20 , wherein the header is formed of glulam. 
   
   
       25 . A portal frame as recited in  claim 20 , further comprising yield links at the joints between the header and shearwalls.