Wood Connection Results

 

Results

plate-connector joints

speed:  0.1 in/min

Specimen Maximum Load (lb) Number
of Teeth		 Load per
Tooth (lb)		 Plate
Cost* ($)		 Load per
Dollar (lb/$)
Test 1 Test 2 Test 3 Average
1"x2" pine blocks with Simpson  
MP14 mending plates 		 1179 763 1019 987 48 21 0.82 1204
1"x3" pine blocks with Simpson  
MP24 mending plates 		 3383 2520 2532 2812 112 25 1.02 2757
* total for two plates

Reference values:  none; these connectors are not load rated (source)

 

dowel bearing

Load
Direction		 Test
Number		 Yield
Load (lb)		 Block
Width (in)		 Experimental
Bearing
Strength (psi)		 Average Exp.
Bearing
Strength (psi)		 Reference
Bearing
Strength (psi)		 Percent
Error
axial

(parallel
to grain)		 1 5665 1.500 5036 4993 4015  24%
2 6049 1.530 5271
3 5799 1.521 5083
4 5075 1.530 4423
5 5900 1.527 5152
transverse

(perpendicular
to grain)		 1 2520 1.500 2240 1877 2966 37% 
2 2821 1.543 2438
3 1422 1.480 1281
4 1645 1.490 1472
5 2308 1.573 1956

 
Reference values  (source)
Wood Load Direction
Relative to Grain		 Bearing
Strength (psi)
spruce-pine-fir parallel 4015
perpendicular 2966
southern pine parallel 6757
perpendicular 5813

 

fastener withdrawal

Fastener Max. Withdrawal
Force (lb)		 Surface
Area* (in2)		 Force per
Area* (psi)		 Cost per
Fastener ($)		 Force per
Dollar (lb/$)
nail 6d bright common, plain
shank (0.114"-dia. x 2.0")		 49 0.358 137 0.0108 4540
8d bright common, plain 
shank (0.131"-dia. x 2.5") 		 65 0.412 158 0.0178 3650
10d bright common, plain 
shank (0.150"-dia. x 3.0") 		 103 0.471 219 0.0273 3770
16d common, plain 
shank (0.162"-dia. x 3.5")		 125 0.509 246 0.0383 3260
screw #8 x 1.75" wood screw,
flat Phillips (0.164"-dia.)		 457 0.0568 8050
#10 x 1.75" wood screw,
flat Phillips (0.190"-dia.)		 483 0.0588 8210
#12 x 1.75" wood screw,
flat Phillips (0.216"-dia.)		 555 0.0962 5770
* surface area in contact with wood

Reference values  (source)
Wood Withdrawal force
for cut nails (psi)		 Safe load for wood screws (lb/in)
4 8 12 16 20 24 28 30
white pine 167 50 70 90 100 120 140 150 160
yellow pine 318 70 90 120 140 150 160 180 190
white oak 940 80 100 130 150 170 180 190 200

 

Janka hardness

speed:  0.25 in/min

 Wood Janka Hardness (lb) Reference
Value (lb)		 Percent
Error
Test 1 Test 2 Test 3 Test 4 Average
2"x2" clear western red cedar 313 322 334 292 315 360  13% 
2"x2" poplar 607 551 800 696 664 600 11%
2"x2" southern yellow pine 738 753 683 706 720 690 4%
2"x2" red oak  1737 1628 1650 1666 1670 1260 33%
2"x2" ChoiceDek composite decking
(51% wood waste, 49% recycled plastic)		 1400 1312 1172 1117 1250 1326  6% 

 Reference value sources: 1, 2, 3, 4, 5

 

planar shear

Instron Output

shear stress = 33 x 315 lb / (64 x 4.75 in. x 0.5 in.) = 68 psi

bending stress = 9 x 315 lb x 8 in. / (16 x 4.75 in. x (0.5 in.)^2) = 1200 psi

 

 

Discussion Questions

  1. Which mending plate is most effective, most efficient?
  2. Which direction offers the best bearing resistant?
  3. How did the nails compare to the reference values?
  4. Were these screws safe to use?
  5. Which fastener is most effective, most efficient?
  6. Which wood type offered the best resistance to indentation?
  7. How did the wood types compare to the reference values?