Abstract:
A connection between a wall stud or post and an anchor bolt embedded in a concrete foundation, using a holdown connector that attaches to the anchor bolt and supports the wall stud or post above it. The holdown connector has a tapered bottom that allows it to rotate laterally, allowing the connection to act more purely in tension than is possible with a rigid connection.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a connector for anchoring a first building structural member to a second building structural member. The connector works in conjunction with a separate anchor member that is received or attached to the second building structural member and with fasteners for attaching the connector to the first building structural member. 
         [0002]    Earthquakes, hurricanes, tornadoes and floods all impose forces on a building that can cause structural failure. To counteract these forces, it has become common practice to add or strengthen ties between the structural members of a building in the area of the building where these cataclysmic forces may be concentrated. For example, framed walls can be connected to the foundation rather than merely rest on it. Connections between the framed walls of each floor can be strengthened. And joists can be connected to both their headers and the walls that support the headers. One of the most common connectors designed for these applications is commonly called a holdown. Holdowns are commonly used to anchor framed walls to the foundation. Holdowns restrain wall posts or studs against uplift, particularly uplift at the ends of shear walls that occurs as a result of lateral loads being applied to the top of the shear wall. When lateral loads, such as may be caused by earthquakes and high wind, are applied to the top of a shear wall, the shear wall tends to overturn rather than collapse, because it is reinforced against lateral shear loads. The overturning moment tends to lift the trailing side of the shear wall. 
         [0003]    Early holdowns were constructed from two or more separate pieces of metal that were welded together. Welded holdowns had to be painted to prevent rust. They were heavy and costly to produce, in particular because of the additional labor involved in welding and painting. 
         [0004]    State of the art holdowns are made from galvanized sheet metal formed on progressive die machines. Recently, strong and light cast materials such as aluminum have also been used. Ideally, state of the art holdowns require no welding or painting. These advances have reduced the cost of making holdowns while increasing their ability to withstand tension forces. Severe earthquakes in California and Japan demonstrated that holdowns that are capable of being mass-produced and installed inexpensively should be made even stronger for many connections. 
         [0005]    Typical holdowns work in conjunction with a separate anchor member and are attached to the side face of the first building structural member, which is generally a vertically-disposed wall stud. In these holdowns that attach to the side of a stud or post, the anchor member is attached at the seat of the connector. The seat is connected to a back member and the back member attaches to the side face of the stud or post. Often, these holdowns have one or more side members to increase the strength of the connector or to connect the seat member to the back member. 
         [0006]    Another style of holdown attaches to the bottom end of the stud or post. A patented example of this type of holdown is found in U.S. Pat. No. 6,513,290, granted to William F. Leek on Feb. 4, 2003. The advantage of a holdown that attaches to the bottom end of a post or stud is that it can remove any eccentricity from the connection. Eccentric connections introduce bending stresses into the post or stud. Thus, as a shear wall moves back and forth under shear loads, the post or stud attempts to rotate about its base. Prior art holdowns, as described above, do not allow post rotation at the bottom, and bending stresses are introduced into the post above the holdown during shear wall movement. Concentric holdowns tend to allow a degree of lateral rotation because the holdown and the supported post are in line with the anchor bolt and the axis of rotation is generally on that line. The point at which the holdown is restrained to the anchor bolt is where rotation will tend to occur, if rotation is possible. Prior art holdowns, however, have not allowed rotation to occur at that point, but have instead permitted bending in the wood post at the juncture of the top of the holdown and the supported post. Eccentric holdowns tend to resist rotation in one direction only because they are attached to one side of the post and therefore to one side of the natural axis of rotation. In the present invention, the axis of rotation is below the post or stud and immediately below the point at which the holdown is restrained to the anchor bolt. 
         [0007]    The present invention improves on the prior art by lowering the axis of rotation below the top of the anchor member that connects the holdown to the second structural member, or foundation. It is advantageous to have the axis of rotation as low as possible. Under gravity loads, the post pushes down on the concentric holdown below it along a load line of action. When the post is perfectly vertical, the load line of action passes through the middle of the holdown. When the post is rotated and compressed, as under racking deformation during an earthquake, the load line of action follows the line of the post and the projection point at which it intersects the underlying structural member moves away from the center of the holdown base. The higher the axis of rotation, the further the line of action moves for any given degree of rotation. If the line of action moves beyond the holdown base, the holdown base will tend to be pushed over because the top of the holdown base will be pushed toward a point beyond the bottom of the holdown base. Although the holdown base will tend to be pushed over, it is restrained, primarily by the anchor bolt. As the load line of action moves away from the center of the holdown, the compression stresses on the underlying structural member become increasingly non-uniform. This is undesirable because it tends to rupture the progressively bending upright post member and to damage the underlying structural member, usually a concrete foundation, which both supports and anchors the structure above it. The present invention lowers the axis of rotation so that the load line of action passes through the holdown base substantially away from its edges, keeping the bearing stresses on the underlying structural member as uniform as possible. 
         [0008]    Recently, it has become apparent that simply increasing the strength of holdowns does not necessarily result in the best connection for the most common installation, between a frame wall reinforced for shear resistance and a concrete foundation. The greater the simple strength of the holdown, the more rigid its connection. It is possible to design and manufacture holdowns that are so strong and rigid that failure is bound to occur elsewhere in the connected structure, such as in the load bearing wood member above the holdown. By transferring failure entirely out of the holdowns, the risk of catastrophic failure of the connected structure is increased. It has therefore become desirable to design holdowns that maximize resistance to uplift forces, but which allow a small amount of rotation to occur at the connection to the second structural member or foundation. 
         [0009]    The present invention improves on the prior art by allowing for rotation as close as possible to the point of attachment to the underlying structure. This means that there will be very little bending in the post or stud to which the holdown of the present invention is attached. This allows the post or stud to be smaller and of a lower stress grade. Because the post or stud bends very little, the attachment of the post or stud to a shear-resisting member, particularly to a panel by many small fasteners such as nails, works better, distributing and dissipating shear forces more evenly and effectively throughout the panel. This results in more gradual and predicable failure. The holdown of the present invention provides a hinge joint at the base of the holdown that improves on prior art rigid holdowns that raised the axis of rotation and tended to transmit additional tension forces into the anchor bolt when the shear panels levered up on their lateral corners. Without the hinge of the present invention, the tension forces acting on the anchor bolt and the prior art holdown are greater than the uplift force of the post or stud alone when the post is subject to an overturning moment. When prior art eccentric or concentric rigid holdowns resist post or stud rotation, additional tension forces are created in the anchor bolt. 
         [0010]    The most preferred form of the present invention is superior to prior art rotating concentric holdowns because the present invention does not rely on a relatively weak horizontal pin connection for both rotation and the transfer of both post uplift forces (by shear) and compression forces (due to gravity or overturning moment) between vertical plates embedded in the post or stud and a base that is connected to the anchor bolt. The present invention transfers compression forces by direct bearing of one contact surface on another, as in the most preferred embodiment in which a standoff base and channel slide between the bottom surface of a floating washer and the upper surface of a support base, from post to standoff base to strap to support base to foundation. The present invention transfers uplift forces directly to the anchor bolt in tension (aside from the post to strap connection). In its most preferred embodiment, the present invention achieves rotation with sliding surfaces rather than a pin connection that, if damaged or bent, could lead to failure of the gravity load system or rotation system. 
         [0011]    The holdown connector of the present invention improves on the prior art by providing a holdown that withstands very high tension loads with minimal deflection, while allowing for rotation about an axis lower than the top of the anchor member, and being economical to produce. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention is a connection between a wall stud or post and an anchor bolt embedded in a concrete foundation, using a holdown connector that attaches to the anchor bolt and supports the wall stud or post above it. The holdown connector has a tapered bottom that allows it to rotate laterally, allowing the connection to act more purely in tension than is possible with a rigid connection. 
         [0013]    An object of the present invention is to reduce bending moments in the wood wall stud or post at the juncture of the top of the holdown connector and the wall stud or post. 
         [0014]    The present invention is a connection with a support base that provides a bearing surface that the bottom of the connector can move against instead of the underlying foundation. 
         [0015]    The present invention is a connector with substantially arcuate, or curvilinear, tapering portions which allow the connector to rotate more smoothly than with angularly tapering portions. 
         [0016]    The present invention is a connection in which the tapered support surface of the support base conforms to the registering tapered portions of the connector, allowing the connector to rotate smoothly against the support base. 
         [0017]    The present invention is a connection in which the connector slides smoothly on the support base below it, accommodating rotating through matched slip surfaces rather than a pin connection or deformation of the holdown connector. 
         [0018]    The present invention is a connector with a channel that encloses and supports a standoff base that, in turn, supports the wall stud or post. 
         [0019]    The present invention is a connection in which the wall stud or post is inserted between the upright arm of the channel and stands on the upper surface of the standoff base. The sides of the channel are connected to the wall stud or post with fasteners such as nails, screws or bolts. The sides of the channel include fastener openings. 
         [0020]    The present invention is a connector in which the support base is a flat-bottomed plate than rests on the planar concrete foundation surface. 
         [0021]    The present invention is a connector that has a standoff base that is made with an upper portion, an open portion and a lower portion, the upper portion being open to permit access to the top of the anchor bolt, which comes up through the bottom and terminates in the open portion below the supported wall stud or post, which stands on the upper portion. The open portion has two sides that connect the top and bottom portions and elevate and support the wall stud or post. 
         [0022]    The present invention is a connector with a channel that has a back member, so that the supported wall stud or post is enclosed on three sides. The back member is then connected to the wall stud or post with fasteners. 
         [0023]    The present invention is a connector with a floating washer that rests on the inner bottom surface of the standoff base and remains level when the rest of the connector and the wall stud or post rotate. The floating washer slides, but remains in full bearing contact with the inner bottom surface of the standoff base. The anchor bolt comes up through the channel, the standoff base and the floating washer, and is restrained on top of the floating washer. 
         [0024]    The floating washer has a substantially arcuate bottom that matches the substantially arcuate bottoms of both the standoff base and the channel, providing surfaces that ideally are sections of circles around the axis of rotation. 
         [0025]    The anchor bolt openings in the standoff base and the channel are laterally oversized to allow the standoff base and channel to rotate, sliding relative the support base and the floating washer while the support base and floating washer remain level and relatively static. 
         [0026]    Thus, as the wood post or stud rotates, only a minimal bending force in transmitted to the vertical anchor bolt in the concrete foundation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1A  is a perspective view the connection of the present invention. 
           [0028]      FIG. 1B  is a partial cross-section and front elevation view of the connection of the present invention showing rotation of the connector of the present invention about an axis due to the imposition of lateral forces on the connector. 
           [0029]      FIG. 10  is a perspective view of the connection of the present invention showing the axis of rotation. 
           [0030]      FIG. 2  is an exploded perspective view of a connector constructed in accordance with the present invention. 
           [0031]      FIG. 3  is a top plan view of the support base of the connector of the present invention. 
           [0032]      FIG. 4  is a front elevation view of the support base of the connector of the present invention. 
           [0033]      FIG. 5  is a side elevation view of the support base of the connector of the present invention. 
           [0034]      FIG. 6  is a bottom plan view of the support base of the connector of the present invention. 
           [0035]      FIG. 7  is a top plan view of the channel of the connector of the present invention. 
           [0036]      FIG. 8  is a bottom plan view of the channel of the connector of the present invention. 
           [0037]      FIG. 9  is a front elevation view of the channel of the connector of the present invention. 
           [0038]      FIG. 10  is a perspective view of the connection of the present invention showing the axis of rotation. 
           [0039]      FIG. 11  is a top plan view of the standoff base of the connector of the present invention. 
           [0040]      FIG. 12  is a front elevation view of the standoff base of the connector of the present invention. 
           [0041]      FIG. 13  is a side elevation view of the standoff base of the connector of the present invention. 
           [0042]      FIG. 14  is a bottom plan view of the standoff base of the connector of the present invention. 
           [0043]      FIG. 15A  is an enlarged front elevation view of the connector of the present invention showing the standoff base inserted into the strap without any rotation. 
           [0044]      FIG. 15B  is an enlarged front elevation view of the connector of the present invention showing rotation about an axis. 
           [0045]      FIG. 16  is an enlarged front elevation view of the connector of the present invention showing the standoff base inserted into the strap without any rotation. 
           [0046]      FIG. 17  is an enlarged front elevation view of the connector of the present invention showing the standoff base inserted into the strap without any rotation. 
           [0047]      FIG. 18  is an enlarged front elevation view of the connector of the present invention showing the standoff base inserted into the strap without any rotation. 
           [0048]      FIG. 19  is an enlarged front elevation view of the connector of the present invention showing the standoff base inserted into the strap without any rotation. 
           [0049]      FIG. 20  is a top plan view of the channel of the connector of the present invention having a back member. 
           [0050]      FIG. 21  is a bottom plan view of the channel of the connector of the present invention having a back member 
           [0051]      FIG. 22  is a front elevation view of the channel of the connector of the present invention having a back member. 
           [0052]      FIG. 23  is a top plan view of the channel of the connector of the present invention having an integral standoff member. 
           [0053]      FIG. 24  is a bottom plan view of the channel of the connector of the present invention having an integral standoff member 
           [0054]      FIG. 25  is a front elevation view of the channel of the connector of the present invention having an integral standoff member. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0055]    As shown in  FIGS. 1A ,  1 B,  10  and  15 A- 19 , the present invention is a building connection  1  including a first building structural member  2 , a second building structural member  3 , a first anchor member  4 , and a connector  7  that receives the first end portion  5  of the first anchor member  4 . As shown in  FIGS. 1B ,  10  and  15 B, the connection  1  has an axis of rotation  12  and the axis of rotation  12  is below the first end  6  of the first anchor member  4 . 
         [0056]    The first building structural member  2  includes a first side face  43  and a bottom end  44 , the bottom end  44  having a width  45 , as shown in  FIG. 19 . The second building structural member  3  includes an upper surface  46  that supports the first building structural member  2 . The first anchor member  4  is restrained by the second building structural member  3 ; the first anchor member  4  further includes a first end portion  5  extending from the second building structural member  3  and a first end  6 . 
         [0057]    The connector  7  includes an upper portion  47  and a lower portion  48 , at least partially located between the bottom end  44  of the first building structural member  2  and the upper surface  46  of the second building structural member  3 . 
         [0058]    The upper portion  47  includes a first structural attachment member  8 , the first structural attachment member  8  including a first side  15  that is attached to the first side face  43  of the first building structural member  2 . 
         [0059]    The lower portion  48  further includes a first standoff member  49 , a first anchor attachment member  11 , and a bottom portion  51  located between the bottom end  44  of the first building structural member  2  and the upper surface  46  of the second building structural member  3  and not extending beyond the width  45  of the bottom end  44  of the first building structural member  2 . As shown in  FIGS. 23 and 25 , the first standoff member  49  can an integral support. 
         [0060]    The first standoff member  49  includes a first bearing surface  50  that supports the first building structural member  2  above the second building structural member  3 . The first anchor attachment member  11  interfaces with the first anchor member  4  and restrains the first anchor member  4  from withdrawing from the connector  7 . The bottom portion  51  includes a first anchor member opening  52 , as shown in  FIG. 14 , through which the first end portion  5  of the first anchor member  4  passes, and first and second tapered portions  53  that narrow the connector  7  toward the first anchor member opening  52 , the first and second tapered portions  53  together tapering at least one quarter the width  45  of the bottom end  44  of the first building structural member  2  such that the bottom portion  51  of the connector  7  can rotate relative to the second building structural member  3 . The bottom portion  51  must be sufficiently tapered to allow rotation. If the bottom portion  51  has less taper, the bottom portion  51  will resist rotation too much and the bottom portion  51  will pry up against the lower corners that will be formed if the taper is lessened or absent; the corners will in turn push down on the underlying second building structural member  3  and will tend to crack or break it, in particular if it is a concrete foundation  3  as preferred. 
         [0061]    In contrast, the axis of rotation  12  of a prior art holdown connector  7  would occur at some point above the bearing surface  50 , even in prior art holdown connectors  7  that are designed to permit rotation, and above the structural attachment member  8  in prior art concentric holdown connectors  7  that are not designed to permit rotation. 
         [0062]    As shown in  FIGS. 1A ,  1 B,  10  and  15 A- 19 , in preferred embodiments, the connection  1  preferably further includes a support base  10  including a first support surface  22 , located between the connector  7  and the second building structural member  3  and which supports the connector  7 , and an anchor member opening  21  through which the first end portion  5  of the anchor member  4  passes. The support base  10  is best shown in  FIGS. 3-6 . 
         [0063]    Preferably, the first and second tapered portions  53  of the connector  7  are substantially arcuate. Preferably the first support surface  22  of the support base  10  conforms to the first and second tapered portions  53  of the connector  7 . Preferably, the bottom portion  51  of the connector  7  slides on the first support surface  22  of the support base  10  when the connector  7  rotates relative to the second building structural member  3 . 
         [0064]    As shown in  FIGS. 1A ,  1 B,  10  and  15 A- 19 , preferably, the first structural attachment member  8  and the bottom portion  51  of the connector  7  are parts of a channel  13  including a base  14 , with an anchor opening  16 , and two sides  15 , the channel  13  additionally including a second structural attachment member  8 , the first and second structural attachment members  8  being the two sides  15  of the channel  13  and the bottom portion  51  of the connector  7  being the base  14  of the channel  13 . 
         [0065]    Preferably, the first standoff member  49  is part of a separate standoff base  17 , further including a substantially arcuate bottom  18 , the bottom  18  of the standoff base  17  being formed to be received between the sides  15  of the channel  13  and resting on the base  14  of the channel  13 , the standoff base  17  being formed with an opening  19  for receiving the first anchor member  4 , the standoff base  17  being connected to the anchor member  4  by the first anchor attachment member  11 . The standoff base is best shown in  FIGS. 11-14 . 
         [0066]    Preferably, the first building structural member  2  is received between the sides  15  of the channel  13  and the bottom end  44  of the first building structural member  2  rests on the first bearing surface  50  of the standoff base  49 . Preferably, fasteners  28  connect the two sides  15  of the channel  13  to the first building structural member  2 . Preferably, the support base  10  is a plate  10  additionally including a flat bottom  23  that rests on the upper surface  46  of the second building structural member  3 . 
         [0067]    Preferably, the channel  13  is a strap  13  and the sides  15  of the channel  13  each additionally includes an end  26  and a plurality of fastener openings  27 . Preferably, the standoff base  17  additionally includes a lower portion  29 , an upper portion  30 , and an open portion  31  between the lower portion  29  and the upper portion  30 . Preferably, the open portion  31  of the standoff base  17  includes two sides  32  that connect the lower portion  29  and the upper portion  30 . The channel  13  is best shown in  FIGS. 7-9  and  20 - 25 . 
         [0068]    Preferably, the first building structural member  2  is a wall stud  2 . Preferably, the second building structural member  3  is a concrete foundation  3 . 
         [0069]    As best shown in  FIGS. 20-22 , in an alternate embodiment, the channel  13  preferably further includes a back member  37  joining the two sides  15 , and the first building structural member  2  interfaces with the back member  37 . Preferably, fasteners  28  connect the back member  37  to the first building structural member  2 . 
         [0070]    As in the other preferred embodiments, in the most preferred embodiment the first and second tapered portions  53  of the connector  7  are substantially arcuate. 
         [0071]    Preferably, the first structural attachment member  8  and the bottom portion  51  of the connector  7  are parts of a channel  13  including a base  14 , with an anchor opening  16 , and two sides  15 , the channel  13  additionally including a second structural attachment member  8 , the first and second structural attachment members  8  being the two sides  15  of the channel and the bottom portion  51  of the connector  7  being the base  14  of the channel  13 . 
         [0072]    Preferably, the first standoff member  49  is part of a separate standoff base  17 , further including a substantially arcuate bottom  18  and a substantially arcuate inner bottom surface  42 , the bottom  18  of the standoff base  17  being formed to be received between the sides  15  of the channel  13  and resting on the base  14  of the channel  13 , the standoff base  17  being formed with an opening  19  for receiving the anchor member  4 , the standoff base  17  being connected to the anchor member  4  by the first anchor attachment member  11 . 
         [0073]    As shown in  FIGS. 1A ,  1 B,  10 ,  15 A- 15 B and  18 - 19 , preferably, the connector  7  further includes a floating washer member  38  that rests on the substantially arcuate inner bottom surface  42  of the standoff base  17  above the opening  19  in the standoff base  17 , the floating washer member  38  including a top surface  39  and a bore  41 . The anchor member  4  preferably passes through the opening  19  in the standoff base  17  and the bore  41  in the floating washer member  38 . As shown in  FIGS. 17 and 18 , the less preferred embodiments do not have a floating washer  38 . 
         [0074]    Preferably, the connection  1  further includes a support base  10  including a first support surface  22  that supports the connector  7  and an anchor member opening  21  through which the first end portion  5  of the anchor member  4  passes. 
         [0075]    Preferably, the first support surface  22  of the support base  10  conforms to the first and second tapered portions  53  of the connector  7 . Preferably, the bottom portion  51  of the connector  7  slides on the first support surface  22  of the support base  10  when the connector  7  rotates relative to the second building structural member  3 . 
         [0076]    As shown in  FIGS. 1A ,  1 B,  10 ,  15 A- 15 B and  18 - 19 , preferably, the floating washer member  38  additionally includes a substantially arcuate bottom surface  40  that interfaces with and rests on the substantially arcuate inner bottom surface  42  of the standoff base  17 , and the bore  41  in the floating washer member  38  joins the top surface  39  and the bottom surface  40  of the floating washer member  38 . 
         [0077]    Preferably, the opening  19  in the standoff base  17  and the opening  16  in the channel  13  are larger than the anchor member  4 , allowing the standoff base  17 , the channel  13  and the first building structural member  2  to rotate relative the second building structural member  3  while the floating washer member  38  remains level. 
         [0078]    Preferably, the first building structural member  2  is received between the sides  15  of the channel  13  and the bottom end  44  of the first building structural member  2  rests on the first bearing surface  50  of the standoff base  17 . 
         [0079]    Preferably, fasteners  28  connect the two sides  15  of the channel  13  to the first building structural member  2 . Preferably, the support base  10  is a plate  10  additionally including a bottom  23  that rests on the upper surface  46  of the second building structural member  3 . Preferably, the channel  13  is a strap  13  and the sides  15  of the channel  13  each additionally include an end  26  and a plurality of fastener openings  27 . 
         [0080]    Preferably, the standoff base  17  additionally includes a lower portion  29  occupied by the floating washer  38 , an upper portion  30 , and an open portion  31  between the lower portion  29  and the upper portion  30 . Preferably, the open portion  31  of the standoff base  17  includes two sides  32  that connect the lower portion  29  and the upper portion  30 . 
         [0081]    Preferably, the first building structural member  2  is a wall stud  2 . Preferably, the second building structural member  3  is a concrete foundation  3 . 
         [0082]    In an alternate embodiment, the channel  13  preferably further includes a back member  37  joining the two sides  15 , and the first building structural member  2  interfaces with the back member  37 . Preferably, fasteners  28  connect the back member  37  to the first building structural member  2 . 
         [0083]    Preferably, the first support surface  22  of said support base  10  conforms to the bottom portion  51  of the connector  7 . If the bottom portion  51  is curved, the support surface  22  will have a matching curvature. If the bottom portion  51  has flat portions, the support surface will have matching flat portions. Preferably, the first support surface  22  of the support base  10  forms a concavity  24  that cradles the bottom portion  51  of the connector  7 . 
         [0084]    Preferably, if the supported post  2  is a double 2×4 stud, the support base  10  is a metal plate that has a flat bottom  23  and a substantially arcuate first support surface  22  that is ¾″ thick at a minimum, forming a concavity  24 . The concavity  24  is an arc preferably with a radius of 1¾″. Preferably, the support base  10  is 3½″ long and 3″ wide and has an anchor member opening  21  that is 15/16″ in diameter and centered in the concavity  24 . Preferably, there are two flat portions  25  on either side of the concavity  24  and these are preferably ¼″ wide. The support base  10  is preferably steel or cast aluminum. 
         [0085]    Preferably, if the supported post  2  is a double 2×4 stud  2 , the channel  13  is a U-shaped strap  13  with a base  14  that fits snugly between the concavity  24  of the support base  10  and the substantially arcuate bottom  18  of the standoff base  17 . The channel  13  is preferably a length of 3-gauge sheet steel with two sides  15  that stand 18¼″ tall from the lowest point of the substantially arcuate bottom  18  to the ends  26  of the sides  15  of the channel  13 . Preferably, it is 3″ wide and its sides  15  are spaced 3″ apart. Preferably, its substantially arcuate bottom  18  has an outside radius of 1¾″. Preferably, both of the sides  15  of the channel  13  have a plurality of fastener openings  27 , preferably beginning 7⅛″ from the lowest point of the channel  13  and continuing substantially all the way up the sides  15 . The sides  15  are preferably attached to the first structural member  2  with a plurality of mechanical fasteners  28 , preferably self-drilling wood screws, but also possibly other types of screw, nails or bolts. The sides  15  might also be attached to the first structural member  2  using chemical bonds or adhesives. 
         [0086]    As shown in  FIGS. 1A ,  1 B,  10 ,  15 A- 15 B and  18 - 19 , in the most preferred form of the invention, if the supported post  2  is a double 2×4 stud  2 , the standoff base  17  is preferably a single piece of cast aluminum, although it can also be made of other metals or composites, and can be a multipart component. The standoff base  17  is preferably 3″ long and 3″ wide, with a lower portion  29  that has a substantially arcuate bottom  18  and a centered vertical opening  19  for receiving the first anchor member  4 . The curve of the substantially arcuate bottom  18  preferably has a radius of 1½″. The opening  19  for receiving the first anchor member  4  is preferably slotted, the slot being 1 3/16″ long and 15/16″ wide. Preferably, the standoff base  17  has an upper portion  30  separated from the lower portion  29  by an open portion  31  that has two sides  32  that connect the lower portion  29  and the upper portion  30 . The open portion  31  is preferably 2½″ tall and has upper rounded corners  34  with radii of ½″. The upper portion  30  is preferably ⅜″ thick. Preferably, the standoff base  17  has a top surface  35  that has two rounded side edges  36  with radii of ¼″. Preferably, the standoff base  17  has a substantially arcuate inner bottom surface  42  with a radius of ¼″. Preferably, the lower portion  29  of the standoff base  17  is occupied by a floating washer member  38  which has a top surface  39  that is 2¼″ wide, a bottom surface  40  with a radius of ¼″ that matches the radius of the substantially arcuate inner bottom surface  42  on which it rests. The floating washer member  38  preferably has a bore  41  that connects the top surface  39  and the bottom surface  40 ; the bore  41  preferably has a diameter of 15/16″ to accommodate a first anchor member  4  of matching diameter. 
         [0087]    Alternate preferred embodiments are shown in  FIGS. 16 and 17 . In the alternate preferred embodiments, there is no floating washer member  38  but rotation is still possible. In the alternate preferred embodiment shown in  FIG. 16 , the standoff base  17  is a square tube section and an underlying solid half cylinder, both steel, although it can also be made of other metals or composites, and can be a single piece or a multipart component. The standoff base  17  is preferably 3″ long and 3″ wide, with a lower portion  29  that has a substantially arcuate bottom  18  and a centered vertical opening  19  for receiving the first anchor member  4 . The curve of the substantially arcuate bottom  18  preferably has a radius of 1½″. The opening  19  for receiving the first anchor member  4  is preferably 5/16″ in diameter. Preferably, the standoff base  17  has an upper portion  30  separated from the lower portion  29  by an open portion  31  that has two sides  32  that connect the lower portion  29  and the upper portion  30 . The open portion  31  is preferably 2½″ tall, has lower rounded corners  33  with radii of ¼″ as shown in  FIG. 16 , and has upper rounded corners  34  with radii of ½″. The upper portion  30  is preferably ⅜″ thick. Preferably, the standoff base  17  has a top surface  35  that has two rounded side edges  36  with radii of ¼″. 
         [0088]    As shown in  FIGS. 1A ,  1 B,  10 ,  15 A- 15 B and  18 - 19 , in the most preferred embodiment, all of the connector  7 , other than the floating washer member  38 , and the first building structural member  2  are allowed to rotate while the floating washer member  38  remains level. This has substantial advantages over the alternate preferred embodiments that do not have the floating washer member  38  because it allows the connector  7  to rotate smoothly about an axis of rotation  12  approximately centered on the top surface  39  of the floating washer member  38 . In all embodiments of the present invention, the connector  7  rotates on an axis of rotation  12  that is below the first end  6  of the first anchor member  4 , approximately at the first anchor attachment member  11 . In prior art connections, a prying moment is imposed by uplift on the first anchor member  4 , elongating it by stretching and bending it when the connector  7  attempts to rotate. The present invention with its floating washer member  38  are preferable because, even if the first anchor member  4  is infinitely, and theoretically, ductile, the whole connection  1  will be loosened if the first anchor member  4  is stretched. 
         [0089]    In the preferred form, the connector  7  of the present invention is used to connect a first building structural member  2 , which can be a double wall stud or post  2  made from two nominal 2×4 lengths of lumber, to a second building structural member  3 , which is preferably a concrete foundation  3 . The first anchor member  4  is preferably a steel anchor bolt  4  embedded in the concrete foundation. Preferably, the first end portion  5  of the anchor bolt  4  is threaded. The anchor bolt  4  preferably passes through the anchor member opening  21  in the support base  10 , through the anchor opening  16  in the base  14  of the channel  13 , and through the opening  19  in the lower portion  29  of the standoff base  17 . In the preferred form, the anchor attachment member  11  is a nut  11  that is turned down over the threaded first end portion  5  of the anchor bolt  4 . The open portion  31  allows the nut  11  to be turned down and tightened on the threaded first end portion  5  of the anchor bolt  4 . Alternatively, the anchor attachment member  11  could be a pin  11  that passes through the anchor bolt  4  or the anchor attachment member  11  could be a weld  11  that either closes off the first end  6  of the anchor member  4  or that joins the first end portion  5  of the anchor member  4  to the connector  7 . 
         [0090]    As shown in  FIG. 16 , in a first alternate preferred embodiment the standoff base  17  is a two-piece steel member, in which the lower portion  29  is a half-cylinder washer plate and the open portion  31  and upper portion  30  are a tube section 4″ tall, 3″ wide, with ¼″ thick walls. 
         [0091]    As shown in  FIG. 17 , in a second alternate preferred embodiment the standoff base  17  is a two-piece steel member, in which the lower portion  29  is a half-cylinder washer plate and the open portion  31  and upper portion  30  are an inverted U cap, 5/16″ thick, welded to the sides  15  of the channel  13  just below the upper portion  30 . 
         [0092]    As shown in  FIG. 18 , in a third alternate preferred embodiment, the standoff base  17  is a 3-gauge U-plate that also forms the sides  32  of the open portion  31 . The sides  32  of the open portion  31  support a 5/16″ cap plate that forms the upper portion  30  of the standoff base  17 . A floating washer member  38  is held within the 3-gauge U-plate. 
         [0093]    In another alternate embodiment, shown in  FIGS. 20-22 , the sides  15  of the channel  13  are joined by a back member  37  and the back member  37  and the sides  15  interface with the first building structural member  2 . 
         [0094]    It may be desirable to coat the curved slip planes between the support base  10  and the channel  13  and between the standoff base  17  and the floating washer  38 , and the coating could be a dry or liquid lubricant, metal bearing liners, Teflon fabric bearing liners, or the like.