Load Duration Factor

Подпись: Copyright © Marcel Dekker, Inc. All rights reserved.Wood has the property of carrying a substantially greater maxi­mum load for short duration than it can for long duration of load-

Load duration

Cd

Typical design load

Permanent

0.9

Dead load

10 years

1.0

Occupancy live load

2 months

1.15

Snow load

7 days

1.25

Construction load

10 minutes

1.6

Wind/earthquake load

Impact

2.0

Impact load

From National Design Specification for Wood Construction 1991

ing. The tabulated design values given by NDS apply to normal load duration. Normal load duration is defined as the application of the full design load that fully stresses a member to its allowable design value for a cumulative period of approximately 10 years. Values for load duration factors are given in Table 3.7.