Fracture Mechanics Models for Brittle Failure of Bottom Rails due to Uplift in Timber Frame Shear Walls

Table 5

Measured failure loads and horizontal crack lengths for failure mode 2 for specimens with the pith oriented downwards (PD) for single- and double-sided sheathing. is the length of the horizontal crack before it changes direction. End 1 and End 2 indicate the two bottom rail ends.

(a) Study A

⁢Series 1						⁢Series 2						⁢Series 3
Set 3			Set 4			Set 2			Set 3			Set 1			Set 2
Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]
	End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2
⁢Single-sided
—	—	—	—	—	—	23.6	20	—	31.4	22	—	20.5	11	—	33.4	18	—
—	—	—	—	—	—	—	—	—	27.1	13	—	—	—	—	29.5	10	—
—	—	—	—	—	—	—	—	—	27.8	17	—	—	—	—	29.4	17	—
—	—	—	—	—	—	—	—	—	25.6	31	—	—	—	—	—	—	—
⁢Double-sided
—	—	—	43.4	17	18	⁢—

(b) Study B

⁢Series 1						⁢Series 2						⁢Series 3
Set 3			Set 4			Set 2			Set 3			Set 1			Set 2
Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]		Failure load [kN]	[mm]
	End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2		End 1	End 2
⁢Single-sided
—	—	—	20.7	21	—	7.70	—	21	24.5	—	39	—	—	—	—	—	—
—	—	—	—	—	—	—	—	—	28.8	22	—	—	—	—	—	—	—
—	—	—	—	—	—	—	—	—	27.5	18	—	—	—	—	—	—	—
—	—	—	—	—	—	—	—	—	21.5	—	37	—	—	—	—	—	—
⁢Double-sided
2/31.5	24–13	25	47.4	—	20	⁢—
44.5	15-16	—	46.1	20	—
—	—	—	48.0	10	—
—	—	—	47.2	—	15

Horizontal crack on both edges of the bottom rail.