Abstract:
A connection made with a multi-purpose connector that can act as a holdown or tension tie and transfer tension, uplift, or lateral load, between a minimum nominal 2×4″ wood framing member and a ½″ diameter anchor. The anchor may be tied to a concrete foundation, another connector of the same type, a wood framing member, or other supporting members.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to a sheet metal connector for anchoring an anchored structural member to an anchoring structural member. The connector works in conjunction with a separate anchor member that is received by or is attached to the anchoring structural member and with fasteners for attaching the connector to the anchored structural member. 
         [0002]    Earthquake, hurricanes, tornadoes and floods impose forces on a building that can cause structural failure. To counteract these forces, it has become common practice to strengthen or add ties between the structural members of a building in areas where such cataclysmic forces may be imposed. For example: framed walls can be attached to the foundation rather than merely rest upon 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 this application is called a holdown by the inventor. Holdowns are commonly used to anchor framed walls to the foundation. 
         [0003]    Early holdowns were formed from two or more separate pieces of metal welded together. These holdowns had to be painted to prevent rusting. They were heavy and costly to produce. 
         [0004]    State of the art holdowns are made from galvanized sheet metal formed on progressive die machines that require no welding or painting. See U.S. Pat. No. 4,665,672 granted May 19, 1987 to Commins, Gilb and Littleton; U.S. Pat. No. 5,092,097 granted Mar. 3, 1992 to Young; U.S. Pat. No. 5,249,404 granted Oct. 5, 1993 to Leek and Commins; and U.S. Pat. No. 6,327,831 granted Dec. 11, 2001 to Leek. These advancements have reduced to cost of making holdowns while increasing their ability to withstand tension forces. However, recent severe earthquakes in San Francisco, Los Angeles and Kobe, Japan demonstrate that holdowns capable of being mass produced and installed inexpensively should be made even stronger for many connections. 
         [0005]    Generally, holdown connectors that work in conjunction with a separate anchor member and attach to only one face of the anchored structural member—generally a vertically-disposed stud—work in a common fashion. The anchor member attaches at the seat of the connector. This seat is connected to a pair of side members that are, in turn, connected to a pair of back members. The back members attach to the anchored structural member. Most holdown connectors have side members to increase the strength of the connector or to connect the seat member to the back member. 
         [0006]    The connector of the present invention works in a similar fashion to most of the prior art holdowns, such that it is amenable to standard installation practices. The connector of the present invention improves on the prior art by incorporating a number of design features that make it lighter and cheaper to produce while withstanding high tension loads. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is a connection made with a multi-purpose connector that can act as a holdown or tension tie and transfer tension, uplift, or lateral load, between a minimum nominal 2×4″ wood framing member and a ½″ diameter anchor. The anchor may be tied to a concrete foundation, another connector of the same type, a wood framing member, or other supporting members. 
         [0008]    The connector of the present invention improves on the prior art by combining a set of design features to achieve loads comparable to connectors made from much heavier sheet metal. Connectors made from much heavier sheet metal are several times more expensive to make and are also more expensive to ship, not to mention relatively wasteful of both sheet metal in manufacturing and fuel in shipping. 
         [0009]    The connector of the present invention can be fastened to a single nominal 2×4″ or larger joist, which makes it ideal as a tension tie in a floor system or as a connector in a guardrail assembly. The connector is preferably fastened with self-drilling wood screws and connects to a ½″ diameter bolt, a foundation anchor, or a heavy duty screw anchor for concrete and masonry. 
         [0010]    The connector of the present invention is preferably made from 14 gauge ASTM A653 GR33, G90 sheet steel. It is preferably fastened to the anchored structural member with 8 Simpson Strong-Drive ¼″×1½″ self-drilling wood screws (preferably installed with a low speed high torque drill with a ⅜″ hex head driver). The anchor member is preferably a ½″ diameter steel threaded rod, ASTM A307 or A36 minimum. Preferably, a standard, cut washer (1 ⅜″ outside diameter) is installed between the anchor member and the seat member. 
         [0011]    In one preferred embodiment, the connector of the present invention is installed horizontally, with the seat member perpendicular to the ground. The anchored structural member is a wood deck joist and the anchoring structural member is a nominal 4×4″ deck guardrail post. The anchor member preferably is a ½″ diameter HDG (hot dip galvanized) machine bolt or threaded rod. 
         [0012]    In another preferred embodiment, the connector of the present invention is installed vertically, with the seat member parallel to the ground. The anchored structural member is a double nominal 2×4″ wood wall post and the anchoring structural member is a concrete foundation that supports the wall post, either directly or with an intervening mudsill. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of the sheet metal connector of the present invention. 
           [0014]      FIG. 2  is a top plan view of the sheet metal connector of the present invention. 
           [0015]      FIG. 3  is a front elevation view of the sheet metal connector of the present invention. 
           [0016]      FIG. 4  is a bottom plan view of the sheet metal connector of the present invention. 
           [0017]      FIG. 5  is a rear elevation view of the sheet metal connector of the present invention. 
           [0018]      FIG. 6  is a left side elevation view of the sheet metal connector of the present invention. The right side of the sheet metal connector of the present invention is a mirror-image of the left side. 
           [0019]      FIG. 7  is a is a perspective view of the holdown building connection of the present invention. 
           [0020]      FIG. 8  is a sectional front elevation view of the tension tie building connection of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    As shown in  FIG. 8 , the present invention is a building connection  1  that comprises an anchored structural member  2  attached to a sheet metal connector  4 , an anchoring structural member  3  that hold an anchor member  5 , the sheet metal connector  4  and the anchor member  5 . The sheet metal connector  4  is fastened to the anchored structural member  2  and is anchored to the anchoring structural member  3  by the anchor member  5 . The anchor member  5  is restrained by the anchoring structural member  3 . The sheet metal connector  4  comprises a first back member  6 , a first side member  11 , a seat member  18 , a second side member  26 , and a second back member  34 . The terminology “anchored” and “anchoring” for the structural members  2  and  3  is not intended to exclude the possibility of connecting a pair of the sheet metal connectors  4  of the present invention with an anchor member  5  that is held in tension between the paired sheet metal connectors  4 , as in a floor-to-floor or purlin-to-purlin connection. 
         [0022]    As shown in  FIGS. 1 ,  2 ,  3 ,  4  and  7 , the first back member  6  has an inner side edge  7 , an outer side edge  8 , an inner surface  9  and an outer surface  10 . The first side member  11  has a stiffening embossment  12 , an inner surface  13 , an outer surface  14 , a back edge  15  and a bottom edge  16 . As shown in  FIGS. 1 ,  3  and  7 , the back edge  15  of the first side member  11  is integrally connected to the outer side edge  8  of the first back member  6  at an angle  17  less than 180 degrees between the inner surface  13  of the first side member  11  and the inner surface  9  of the first back member  6 . As shown in  FIGS. 1 ,  2  and  4 , the seat member  18  has an anchor member receiving opening  19  reinforced by a circumferential embossment  20 , an upper surface  21 , a lower surface  22 , a first side edge  23  and a second side edge  24 . As shown in  FIGS. 2 and 3 , the first side edge  23  of the seat member  18  is integrally connected to the bottom edge  16  of the first side member  11  at a first juncture  25  greater than 90 degrees between the upper surface  21  of the seat member  18  and said inner surface  13  of the first side member  11 . The first juncture  25  is reinforced with a first gusset  33 . The second side member  26  has a stiffening embossment  27 , an inner surface  28  facing the inner surface  13  of the first side member  11 , an outer surface  29 , a back edge  30  and a bottom edge  31 . The bottom edge  31  of the second side member  26  is integrally connected to the second side edge  24  of the seat member  18  opposite the first side member  11  at a second juncture  32  greater than 90 degrees between the upper surface  21  of the seat member  18  and the inner surface  28  of the second side member  26 . The second juncture  32  is reinforced with a first gusset  33 . As shown in  FIGS. 1 and 5 , the second back member  34  has an inner side edge  35 , an outer side edge  36 , an inner surface  37  and an outer surface  38 . The outer side edge  36  of the second back member  34  is integrally connected to the back edge  30  of the second side member  26  at an angle  40  less than 180 degrees between the inner surface  28  of the second side member  26  and the inner surface  37  of the second back member  34 . The outer side edge  36  of the second back member  34  faces away from the outer side edge  8  of the first back member  6 . 
         [0023]    The sheet metal connector  4  is preferably made from cold-formed  14  gauge galvanized sheet steel. 
         [0024]    Preferably, the first side edge  23  of the seat member  18  is integrally connected to the bottom edge  16  of the first side member  11  at a first juncture  25  of between 95 and 110 degrees between the upper surface  21  of the seat member  18  and the inner surface  13  of the first side member  11 . Preferably, the bottom edge  31  of the second side member  26  is integrally connected to the second side edge  24  of the seat member  18  opposite the first side member  11  at second juncture  32  of between 95 and 110 degrees between the upper surface  21  of the seat member  18  and the inner surface  28  of the second side member  26 . 
         [0025]    Preferably, the first side edge  23  of the seat member  18  is integrally connected to the bottom edge  16  of the first side member  11  at a first juncture  25  of 103 degrees between the upper surface  21  of the seat member  18  and the inner surface  13  of the first side member  11 . Preferably, the bottom edge  31  of the second side member  26  is integrally connected to the second side edge  24  of the seat member  18  opposite the first side member  11  at second juncture  32  of 103 degrees between the upper surface  21  of the seat member  18  and the inner surface  28  of the second side member  26 . 
         [0026]    The stiffening embossment  12  in the first side member  11  preferably is elongated and embossed into the inner surface  13  of the first side member  11  to a depth equal to the thickness of the first side member. The stiffening embossment  27  in the second side member  26  preferably is elongated and embossed into the inner surface  28  of the second side member  26  to a depth equal to the thickness of the first side member. 
         [0027]    As shown in  FIGS. 1 and 6 , the stiffening embossment  12  is the first side member  11  preferably has two straight, angularly-related linear segments  43 . The stiffening embossment  27  in the second side member  26  also preferably has two straight, angularly-related linear segments  43 . 
         [0028]    Preferably, the circumferential embossment  20  in the seat member  18  is circular and embossed into the upper surface of  21  of the seat member  18  to a depth equal to thickness of the seat member  18 . 
         [0029]    As shown in  FIG. 4 , the first juncture  24  preferably is reinforced by a first gusset  33  and a second gusset  39 , and the second juncture  32  preferably is also reinforced by a first gusset  33  and a second gusset  39 . 
         [0030]    Preferably, the first back member  6  has four fastener openings  41  arranged in a zig-zag pattern; and the second back member  34  has four fastener openings  41  arranged in a zig-zag pattern. Preferably, the fastener openings  41  are each 0.265 inches in diameter. 
         [0031]    The seat member  18  is preferably 1⅝ inches wide from the first side member  11  to the second side member  26 . Preferably, the anchor member receiving opening  19  is 0.612 inches in diameter. 
         [0032]    When the anchored structural member  2  is a single wood nominal 2×4″, the building connection  1  preferably achieves a tension load of 1850 pounds before failing. When the anchored structural member  2  is a double wood nominal 2×4″, the building connection  1  preferably achieves a tension load of 2000 pounds before failing. 
         [0033]    When the connector  4  of the present invention is a holdown  4 , the anchored structural member  2  is vertically-oriented. Preferably, the anchored structural member  2  is a wall stud  2 . The anchoring structural member  3  preferably is a concrete foundation  3  if the connector  4  is being used on the ground floor of a building. If the connector  4  is being used on an upper level of a building, the anchoring structural member  3  preferably is part of an upper floor structure. As shown in  FIG. 7 , the anchor member  5  may pass through a mudsill  44 . The anchor member  5  preferably is restrained against the seat member  18  by a nut  46  and is reinforced by a washer  45 . Preferably, a plurality of fasteners  47  secure the holdown  4  to the wall stud  2 . 
         [0034]    When the connector  4  of the present invention is a tension tie  4 , the anchored structural member  2  is horizontally-oriented. Preferably, the anchored structural member  2  is a floor beam  2 . The anchored structural member  2  preferably is a deck floor beam  2 . Preferably, the anchoring structural member  3  is a deck post  3 . Alternatively, the anchored structural member  2  is a roof beam  2  and the anchoring structural member  3  is a wall  3 , not shown in the drawings. As shown in  FIG. 8 , the anchor member  5  may pass through a rim joist  49 . The rim joist  49  is partially fastened to the floor beam  2  with a plurality of nails  50 . The anchor member  5  preferably is restrained against the seat member  18  by a nut  46  and is reinforced by a washer  45 . Preferably, a plurality of fasteners  47  secure the tension tie  4  to the deck floor beam  2  which is surmounted by a plurality of deck boards  48 . 
       Testing of the Present Invention 
       [0035]    The connector  4  of the present invention was tested for the applicant by Testing Engineers, Inc. (TEI) in two rounds of testing. The test data is summarized below: 
         [0000]    
       
         
               
             
               
               
               
               
             
               
             
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
             
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
             
             
               
                 Simpson Test # P525 - Connector 
               
             
          
           
               
                   
                 Measured Value 
                 Measure or Witnessed by 
                 How sample was obtained 
               
               
                   
               
               
                 Model: MPHD 
                 — 
                 — 
                 Fabricated by Simpson 
               
               
                 Drawing No. 
                 Conforms to 
                 Vertified by TEI 
                 Strong-Tie at the 
               
               
                 PROTOTYPE 5 Rev: B 
                 drawing 
                   
                 manufacturing plant 
               
               
                 Date: Jun. 10, 2008 
                   
                   
                 located in Stockton, CA, 
               
               
                 Connector Material: ASTM 
                 Fyact = 38.2 ksi 
                 Worthington Steel 
                 USA 
               
               
                 A653 GR33 
                 Fu act  = 50.8 ksi 
               
               
                 (Fy min  = 33 ksi ksi Fu min  = 
               
               
                 45 ksi) 
               
               
                 Thickness: 14 Ga. 
                 0.072″ 
                 Base Metal Thickness TEI Lab# 
               
               
                   
                   
                 X110 
               
               
                 Finish: G90 
                 0.075″ 
                 Overall Thickness measured by 
               
               
                   
                   
                 TEI 
               
               
                   
               
             
          
           
               
                 Simpson Test # P525 - Fastener 
               
             
          
           
               
                   
                   
                 Measured 
                 Measured 
                 Lot # &amp; Fyb 
                 Measured or 
                 How sample 
               
               
                 Location 
                 Quantity &amp; Type 
                 Diameter (in.) 
                 Length (in.) 
                 (psi) 
                 Witnessed by 
                 was obtained 
               
               
                   
               
               
                 Face 
                 (8) SDS ¼″ × 1½″ 
                 0.2455 
                 1.522 
                   
                 Witnessed by 
                 Stock at R&amp;D 
               
               
                   
                   
                   
                   
                   
                 TEI 
                 Lab 
               
               
                 Anchor 
                 (1) ½″ Dia. HS 
                 0.4905 
                 8 
                 — 
                 Witnessed by 
               
               
                   
                 ATR w/ ½″ cut 
                   
                   
                   
                 TEI 
               
               
                   
                 washer 
               
               
                   
               
             
          
           
               
                 Simpson Test # P525 - Members 
               
             
          
           
               
                   
                 Species and 
                 Size 
                 Measured Moisture Content 
                 Measured or 
                 How sample was 
               
               
                 Member 
                 Grade 
                 (in.) 
                 (average %) 
                 Witnessed by 
                 obtained 
               
               
                   
               
               
                 Post 
                 DFL 
                 2 × 4 
                 11.1 
                 Witnessed by TEI 
                 Stock at R&amp;D 
               
               
                 Foundation 
                 Steel N.A. 
                 2 × 3 × 18 
                 — 
                 Witnessed by TEI 
                 Lab 
               
               
                   
               
             
          
           
               
                 Simpson Test # P525 - Test Data 
               
               
                   
               
             
          
           
               
                   
                 Load (lbs.) 
               
             
          
           
               
                   
                 Applied Load 
                 TEST A 
                 TEST B 
                 TEST C 
               
               
                   
                   
               
               
                   
                 PRELOAD 
                 — 
                 — 
                 — 
               
               
                   
                 LOAD AT AVERAGE ¼″ DEFLECTION 
                 2666 
                 2823 
                 3362 
               
               
                   
                 ULTIMATE LOAD 
                 5168 
                 5349 
                 7583 
               
               
                   
                 FAILURE MODE 
                 Wood Split Screws 
                 Wood Split Screws 
                 Part 
               
               
                   
                   
                 Withdrawal 
                 Withdrawal 
                 Tore 
               
               
                   
                 TOTAL ELAPSED TIME TO ULTIMATE 
                 5.80 
                 4.16 
                 5.21 
               
               
                   
                 (min) 
               
               
                   
                   
               
             
          
           
               
                   
                 Load (lbs.) 
               
             
          
           
               
                   
                 Applied Load 
                 TEST D 
                 TEST E 
                 TEST F 
               
               
                   
                   
               
               
                   
                 PRELOAD 
                 — 
                 — 
                 — 
               
               
                   
                 LOAD AT AVERAGE ¼″ DEFLECTION 
                 3457 
                 3046 
                 2999 
               
               
                   
                 ULTIMATE LOAD 
                 6648 
                 7035 
                 6796 
               
               
                   
                 FAILURE MODE 
                 Part Tore 
                 Part Tore 
                 Part 
               
               
                   
                   
                   
                   
                 Tore 
               
               
                   
                 TOTAL ELAPSED TIME TO ULTIMATE 
                 4.17 
                 5.08 
                 4.60 
               
               
                   
                 (min) 
               
               
                   
                   
               
             
          
           
               
                 Simpson Test # P525 - Test Limit 
               
             
          
           
               
                   
                 ALLOWABLE STRESS 
                 Lbs. 
               
               
                   
                   
               
               
                   
                 Average value at ¼″ deflection of 6 tests/1.4 
                 2185 
               
               
                   
                 Average ultimate of 6 tests/3 - Safety Factor 
                 2143 
               
               
                   
                 Average ultimate load of 6 tests 
                 6430 
               
               
                   
                 Test Procedure: 
                 ICC AC155 &amp; TEI SOP 20.160 
               
               
                   
                 Test Machine: 
                 MTS200 
               
               
                   
                 Load Cell: 
                 25K-186583A 
               
               
                   
                 Load Rate: 
                 0.200 in/min 
               
               
                   
                 Measuring Devices: 
                 LVDTs: #1013 &amp; #1014 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
               
             
               
             
               
               
               
               
               
               
               
             
               
             
               
               
               
               
               
               
             
               
             
               
               
             
               
               
               
               
               
             
               
               
             
               
               
               
               
               
             
               
             
               
               
               
             
           
               
                   
               
             
             
               
                 Simpson Test # P648 - Connector 
               
             
          
           
               
                   
                 Measured Value 
                 Measure or Witnessed by 
                 How sample was obtained 
               
               
                   
               
               
                 Model: MPHD 
                 — 
                 — 
                 Fabricated by Simpson 
               
               
                 Drawing No. 
                 Conforms to 
                 Vertified by TEI 
                 Strong-Tie at the 
               
               
                 PROTOTYPE 5 Rev: B 
                 drawing 
                   
                 manufacturing plant 
               
               
                 Date: Jun. 10, 2008 
                   
                   
                 located in Stockton, CA, 
               
               
                 Connector Material: ASTM 
                 Fyact = 38.2 ksi 
                 Worthington Steel 
                 USA 
               
               
                 A653 GR33 
                 Fu act  = 50.8 ksi 
               
               
                 (Fy min  = 33 ksi ksi Fu min  = 
               
               
                 45 ksi) 
               
               
                 Thickness: 14 Ga. 
                 0.072″ 
                 Base Metal Thickness TEI Lab# 
               
               
                   
                   
                 X110 
               
               
                 Finish: G90 
                 0.0795″ 
                 Not verified by TEI 
               
               
                   
               
             
          
           
               
                 Simpson Test # P648 - Fastener 
               
             
          
           
               
                   
                   
                 Measured 
                 Measured 
                 Lot # &amp; Fyb 
                 Measured or 
                 How sample 
               
               
                 Location 
                 Quantity &amp; Type 
                 Diameter (in.) 
                 Length (in.) 
                 (psi) 
                 Witnessed by 
                 was obtained 
               
               
                   
               
               
                 Face 
                 (8) SDS ¼″ × 1½″ 
                 0.2500 
                 1.510 
                   
                 Witnessed by 
                 Stock at R&amp;D 
               
               
                   
                   
                   
                   
                   
                 TEI 
                 Lab 
               
               
                 Anchor 
                 (1) ½″ Dia. HS 
                 0.5050 
                 8 
                 — 
                 Witnessed by 
               
               
                   
                 ATR w/ ½″ cut 
                   
                   
                   
                 TEI 
               
               
                   
                 washer 
               
               
                   
               
             
          
           
               
                 Simpson Test # P648 - Members 
               
             
          
           
               
                   
                 Species and 
                 Size 
                 Measured Moisture Content 
                 Measured or 
                 How sample was 
               
               
                 Member 
                 Grade 
                 (in.) 
                 (average %) 
                 Witnessed by 
                 obtained 
               
               
                   
               
               
                 Post 
                 DFL 
                 2 × 4 
                 13.3 
                 Witnessed by TEI 
                 Stock at R&amp;D 
               
               
                 Foundation 
                 Steel N.A. 
                 2 × 3 × 18 
                 — 
                 Witnessed by TEI 
                 Lab 
               
               
                   
               
             
          
           
               
                 Simpson Test # P648 - Test Data 
               
               
                   
               
             
          
           
               
                   
                 Load (lbs.) 
               
             
          
           
               
                   
                 Applied Load 
                 TEST A 
                 TEST B 
                 TEST C 
               
               
                   
                   
               
               
                   
                 PRELOAD 
                 — 
                 — 
                 — 
               
               
                   
                 LOAD AT AVERAGE ¼″ DEFLECTION 
                 2834 
                 3040 
                 3080 
               
               
                   
                 ULTIMATE LOAD 
                 5850 
                 6229 
                 4832 
               
               
                   
                 FAILURE MODE 
                 Post Split 
                 Post Split 
                 Post Split 
               
               
                   
                 TOTAL ELAPSED TIME TO ULTIMATE (min) 
                 4.10 
                 4.15 
                 4.12 
               
               
                   
                   
               
             
          
           
               
                   
                 Load (lbs.) 
               
             
          
           
               
                   
                 Applied Load 
                 TEST D 
                 TEST E 
                 TEST F 
               
               
                   
                   
               
               
                   
                 PRELOAD 
                 — 
                 — 
                 — 
               
               
                   
                 LOAD AT AVERAGE ¼″ DEFLECTION 
                 3152 
                 2998 
                 2863 
               
               
                   
                 ULTIMATE LOAD 
                 4740 
                 6442 
                 4782 
               
               
                   
                 FAILURE MODE 
                 Post Split 
                 Post Split 
                 Post Split 
               
               
                   
                 TOTAL ELAPSED TIME TO ULTIMATE (min) 
                 3.19 
                 4.63 
                 3.72 
               
               
                   
                   
               
             
          
           
               
                 Simpson Test # P648 - Test Limit 
               
             
          
           
               
                   
                 ALLOWABLE STRESS 
                 Lbs. 
               
               
                   
                   
               
               
                   
                 Average value at ¼″ deflection of 6 tests/1.4 
                 2139 
               
               
                   
                 Average ultimate of 6 tests/3 - Safety Factor 
                 1826 
               
               
                   
                 Average ultimate load of 6 tests 
                 5479 
               
               
                   
                 Test Procedure: 
                 ICC AC155 &amp; TEI SOP 20.155 
               
               
                   
                 Test Machine: 
                 MTS200 
               
               
                   
                 Load Cell: 
                 25K-186583A 
               
               
                   
                 Load Rate: 
                 0.200 in/min 
               
               
                   
                 Measuring Devices: 
                 LVDTs: #1013 &amp; #1014