04/14/2018

Importance Factors by Risk Category of Buildings and Other Structures for Snow, Ice, and Earthquake Load per ASCE 7-10, Section 1.5

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

04/13/2018

Nominal Load Combinations for Allowable Stress Design in ASCE 7-10

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.

 

Parameter Definitions

D = Dead Load

E = Earthquake Load

L =Live Load

Lr = Roof Live Load

R = Rain Load

S = Snow Load

W = Wind Load

 

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

  1. Dead load
  2. Dead load + Live load
  3. Dead load + the maximum of (roof live load or snow load or rain load)
  4. Dead load + 0.75 times live load + 0.75 times the maximum of (roof live load or snow load or rain load) 
  5. Dead load + the maximum of (0.6 times wind load or 0.7 times earthquake load)
  6. Dead load + 0.75 times live load + 0.75 times 0.6 times wind load + 0.75 times the maximum of (roof live load or snow load or rain load)
  7. Dead load + 0.75 times live load + 0.75 times 0.7 times earthquake load + 0.75 times snow load
  8. 0.6 times dead load + 0.6 times wind load
  9. 0.6 times dead load + 0.7 times earthquake load
04/13/2018

Factored Load Combination for Strength Design in ASCE 7-10

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.

 

Parameter Definitions

D = Dead Load

E = Earthquake Load

L =Live Load

Lr = Roof Live Load

R = Rain Load

S = Snow Load

W = Wind Load

 

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

 

Load Combinations for Strength Design, Text

  1. 1.4 times dead load
  2. 1.2 times dead load + 1.6 times live load + 0.5 times the maximum of (roof Live Load or snow load or rain load)
  3. 1.2 times dead load + 1.6 times the maximum of (roof Live Load or snow load or rain load) + maximum of (live load or 0.5 times wind load)
  4. 1.2 times dead load + 1.0 times wind load + live load + 0.5 times the maximum of (roof Live Load or snow load or rain load)
  5. 1.2 times dead load + 1.0 times earthquake load + live load + 0.2 times snow load
  6. 0.9 times dead load + 1.0 times wind load
  7. 0.9 times dead load + 1.0 times earthquake load
04/12/2018

Structural Engineering Calculator to Analyze Wood Glulam Members in Tension per NDS

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

Calculator Link

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

Load Duration Factor, CD

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

04/10/2018

Structural Engineering Calculator to Analyze Wood / Lumber Members in Tension per NDS

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

Calculator Link

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

Load Duration Factor, Cd

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