In this post, I will provide a brief overview of the importance factors by risk category of buildings and other structures for snow, ice, and earthquake loads that are specified in ASCE 7-10, Section 1.5.

## Risk Category I

Snow Importance Factor, Is = 0.80

Ice Importance Factor – Thickness, Ii = 0.80

Ice Importance Factor – Wind, Iw = 1.00

Seismic Importance Factor, Ie = 0.80

## Risk Category II

Snow Importance Factor, Is = 1.00

Ice Importance Factor – Thickness, Ii = 1.00

Ice Importance Factor – Wind, Iw = 1.00

Seismic Importance Factor, Ie = 1.00

## Risk Category III

Snow Importance Factor, Is = 1.10

Ice Importance Factor – Thickness, Ii = 1.25

Ice Importance Factor – Wind, Iw = 1.00

Seismic Importance Factor, Ie = 1.25

## Risk Category IV

Snow Importance Factor, Is = 1.20

Ice Importance Factor – Thickness, Ii = 1.25

Ice Importance Factor – Wind, Iw = 1.00

Seismic Importance Factor, Ie = 1.50

In this post, I will provide a brief overview of the nominal load combinations for allowable stress design that are specified in ASCE 7-10, Section 2.4. Before identifying the load combinations, it’s a good idea to review the definitions of parameters used in these allowable stress design load combination formulas.

## Load Combinations for Allowable Stress Design, Formulas

1. D
2. D + L
3. D + (Lr or S or R)
4. D + 0.75L + 0.75(Lr or S or R)
5. D + (0.6W or 0.7E)
6. D + 0.75L + 0.75(0.6W) + 0.75(Lr or S or R)
7. D + 0.75L + 0.75(0.7E) + 0.75S
8. 0.6D + 0.6W
9. 0.6D + 0.7E

## Load Combinations for Allowable Design, Text

In this post, I will provide a brief overview of the factored load combinations for strength design that are specified in ASCE 7-10, Section 2.3. Before identifying the load combinations, it’s a good idea to review the definitions of parameters used in these strength design load combination formulas.

## Load Combinations for Strength Design, Formulas

1. 1.4D
2. 1.2D + 1.6L + 0.5(Lr or S or R)
3. 1.2D + 1.6(Lr or S or R) + (L or 0.5W)
4. 1.2D + 1.0W + L + 0.5(Lr or S or R)
5. 1.2D + 1.0E + L + 0.2S
6. 0.9D + 1.0W
7. 0.9D + 1.0E

## Calculator Description

This online engineering calculator computes the actual tensile stress and allowable tensile stress for a wood glulam member in tension according to the National Design Specification for Wood Construction

https://www.engineeringexamples.net/engineering-calculator-for-analysis-of-wood-glulam-member-in-tension-per-nds/

## Input Parameters

Member Width, b

Member Depth, d

Number of Bolt Holes, n

Bolt Hole Diameter, dh

Tensile Force, P

Wet Service Condition Factor, CM

Temperature Factor, Ct

Reference Tension Stress Parallel to Grain, Ft

## Output Parameters

Net Cross Sectional Area, An

Actual Tensile Stress, ft

Allowable Tension Stress Parallel to Grain, Ft

Final Check

## Reference Formulas

An = b*(d-n*dh)

ft = P / An

Ft‘ = Ft*CD*CM*Ct

## Calculator Description

This online engineering calculator computes the actual tensile stress and allowable tensile stress for a wood / lumber member in tension according to the National Design Specification for Wood Construction

https://www.engineeringexamples.net/engineering-calculator-for-analysis-of-wood-member-in-tension-nds/

## Input Parameters

Member Width, b

Member Depth, d

Number of Bolt Holes, n

Bolt Hole Diameter, dh

Tensile Force, P

Wet Service Condition Factor, Cm

Temperature Factor, Ct

Size Factor, CF

Incising Factor, Ci

Reference Tension Stress Parallel to Grain, Ft

## Output Parameters

Net Cross Sectional Area, An

Actual Tensile Stress, ft

Allowable Tension Stress Parallel to Grain, F’t

Final Check

## Reference Formulas

An = b*(d-n*dh)

ft = P / An

F’t = Ft*Cd*Cm*Ct*CF*Ci