WOOD - Materials for Civil and Construction Engineers - page 443

Table P10.22

Observation P (lb) ¢L (in.) s (psi) e (in./in.) u i (psi)

No.
0 0 0 N/A

1 720 0.020

2 1720 0.048

3 2750 0.076

4 3790 0.108

5 4606 0.140

6 5338 0.164

7 6170 0.200

8 6480 0.224

9 5400 0.253

u t =

stress s and engineering strain e . Determine the toughness of

1 2 1 2

the material u t by calculating the area under the stress-strain

1 2

curve, namely,

e f

u t = L s de

0

where is the strain at fracture. This integral can be approximated
numerically using a trapezoidal integration technique:

e f

n n

1
2

u t = a u i = a 1 s i + s i - 1 21 e i - e i - 1 2

i = 1 i = 1

10.23 A short rounded wood column with a diameter of 10 inches is to be
constructed. If the failure stress is 7.3 ksi, what is the maximum load
that can be applied to this column, using a factor of safety of 1.3?
10.24 For the purpose of designing wood structures, laboratory-measured
strength properties are adjusted for application conditions. State
five different application conditions that are used to adjust the
strength properties.
10.25 What are the five types of organisms that attack wood?
10.26 What are the two types of preservatives that can be used to protect
wood from decay? How are these preservatives applied?
10.27 What are the main types of engineered wood products?
10.28 What are the main advantages of engineered wood products over
natural-timber members?