## Calculator Description

This online engineering calculator computes the actual bending and shear stresses and allowable bending and shear stresses for a wood glulam member in bending and shear according to the National Design Specification for Wood Construction 2015 (NDS 2015)

## Calculator Link

## Input Parameters

Bending Moment, M

Maximum Shear Load, V

Member Width, b

Member Depth, d

Load Duration Factor, C_{d} – NDS 2015, Section 5.3.2

Wet Service Condition Factor, C_{m} – NDS 2015, Section 5.3.3

Temperature Factor, C_{t} – NDS 2015, Section 5.3.4

Beam Stability Factor, C_{L} – NDS 2015, Section 5.3.5

Volume Factor, C_{v} – NDS 2015, Section 5.3.6

Flat Use Factor, C_{fu} – NDS 2015, Section 5.3.7

Curvature Factor, C_{c} – NDS 2015, Section 5.3.8

Stress Interaction Factor, C_{I} – NDS 2015, Section 5.3.9

Shear Reduction Factor, C_{vr} – NDS 2015, Section 5.3.10

Reference Bending Stress, F_{b} – NDS Supplement 2015

Reference Shear Stress Parallel to grain, F_{v} – NDS Supplement 2015

## Output Parameters

Cross-Sectional Area, A

Section Modulus, S

Actual Bending Stress, f_{b}

Actual Maximum Shear Stress, f_{v}

Allowable Bending Stress, F_{b}‘ – NDS 2015 Table 5.3.1

Allowable Shear Stress Parallel to Grain, F_{v}‘ – NDS 2015 Table 5.3.1

Bending Check

Shear Check

## Structural Engineering Calculator to Analyze Wood / Lumber Members in Bending and Shear per NDS 2015

## Calculator Description

This online engineering calculator computes the actual bending and shear stresses and allowable bending and shear stresses for a wood sawn lumber member in bending and shear according to the National Design Specification for Wood Construction 2015 (NDS 2015)

## Calculator Link

## Input Parameters

Bending Moment, M

Maximum Shear Load, V

Member Width, b

Member Depth, d

Load Duration Factor, C_{d} – NDS 2015, Section 4.3.2

Wet Service Condition Factor, C_{m} – NDS 2015, Section 4.3.3

Temperature Factor, C_{t} – NDS 2015, Section 4.3.4

Beam Stability Factor, C_{L} – NDS 2015, Section 4.3.5

Size Factor, C_{F} – NDS 2015, Section 4.3.6

Flat Use Factor, C_{fu} – NDS 2015, Section 4.3.7

Incising Factor, C_{i} – NDS 2015, Section 4.3.8

Repetitive Member Factor, C_{r} – NDS 2015, Section 4.3.9

Reference Bending Stress, F_{b} – NDS Supplement 2015

Reference Shear Stress Parallel to grain, F_{v} – NDS Supplement 2015

## Output Parameters

Cross-Sectional Area, A

Section Modulus, S_{x}

Actual Bending Stress, f_{b}

Actual Maximum Shear Stress, f_{v}

Allowable Bending Stress, F_{b}‘ – NDS 2015 Table 4.3.1

Allowable Shear Stress Parallel to Grain, F_{v}‘ – NDS 2015 Table 4.3.1

Bending Check

Shear Check

## Calculator Description

This online engineering calculator computes the actual tensile and bending stresses and allowable tensile and bending stresses for a wood glulam member in tension + bending according to the National Design Specification for Wood Construction 2015 (NDS 2015)

## Calculator Link

## Input Parameters

Tensile Force, P

Bending Moment, M

Member Width, b

Member Depth, d

Net Cross-Sectional Area, An

Load Duration Factor, C_{d} – NDS 2015, Section 5.3.2

Wet Service Condition Factor, C_{m} – NDS 2015, Section 5.3.3

Temperature Factor, C_{t} – NDS 2015, Section 5.3.4

Beam Stability Factor, C_{L} – NDS 2015, Section 5.3.5

Volume Factor, C_{v} – NDS 2015, Section 5.3.6

Flat Use Factor, C_{fu} – NDS 2015, Section 5.3.7

Curvature Factor, C_{c} – NDS 2015, Section 5.3.8

Stress Interaction Factor, C_{I} – NDS 2015, Section 5.3.9

Reference Tension Stress Parallel to Grain, F_{t} – NDS Supplement 2015

Reference Bending Stress, F_{b} – NDS Supplement 2015

## Output Parameters

Section Modulus, Sx

Actual Tensile Stress, f_{t}

Actual Bending Stress, fb

Allowable Tension Stress Parallel to Grain, F’_{t }– NDS 2015, Table 5.3.1

Allowable Bending Stress without Stability Factor, F_{b}* – NDS 2015, Section 3.9.1

Allowable Bending Stress withthout Volume Factor, F_{b}** – NDS 2015, Section 3.9.1

Combined Tension and Bending Check – NDS 2015, Equation 3.9-1

Buckling on the Compression Face Check – NDS 2015, Equation 3.9-2

## Structural Engineering Calculator to Analyze Wood / Lumber Members in Tension + Bending per NDS 2015

## Calculator Description

This online engineering calculator computes the actual tensile and bending stresses and allowable tensile and bending stresses for a wood sawn lumber member in tension + bending according to the National Design Specification for Wood Construction 2015 (NDS 2015)

## Calculator Link

## Input Parameters

Tensile Force, P

Bending Moment, M

Member Width, b

Member Depth, d

Net Cross-Sectional Area, An

Load Duration Factor, C_{d} – NDS 2015, Section 4.3.2

Wet Service Condition Factor, C_{m} – NDS 2015, Section 4.3.3

Temperature Factor, C_{t} – NDS 2015, Section 4.3.4

Beam Stability Factor, C_{L} – NDS 2015, Section 4.3.5

Size Factor, C_{F} – NDS 2015, Section 4.3.6

Flat Use Factor, C_{fu} – NDS 2015, Section 4.3.7

Incising Factor, C_{i} – NDS 2015, Section 4.3.8

Repetitive Member Factor, C_{r} – NDS 2015, Section 4.3.9

Reference Tension Stress Parallel to Grain, F_{t} – NDS Supplement 2015

Reference Bending Stress, F_{b} – NDS Supplement 2015

## Output Parameters

Section Modulus, Sx

Actual Tensile Stress, f_{t}

Actual Bending Stress, fb

Allowable Tension Stress Parallel to Grain, F’_{t }– NDS 2015, Table 4.3.1

Allowable Bending Stress without Stability Factor, F_{b}* – NDS 2015, Section 3.9.1

Allowable Bending Stress with Stability Factor, F_{b}** – NDS 2015, Section 3.9.1

Combined Tension and Bending Check – NDS 2015, Equation 3.9-1

Buckling on the Compression Face Check – NDS 2015, Equation 3.9-2

In this post, I will provide a brief overview of determining thermal factors, C_{t}, for calculating flat roof snow loads on structures per ASCE 7-10, Table 7-3. The thermal factors are based on the thermal condition of the roof.

## Thermal Factors for Structures Based on Thermal Conditions

Structures kept just above freezing and other with cold, ventilated roofs in which the thermal resistance (R-value) between the ventilated space and the heated space exceeds 25 °F x h x ft^{2}/Btu (4.4 K x m^{2}/W), C_{t} = 1.1

Unheated and open air structures, C_{t} = 1.2

Structures intentionally kept below freezing, C_{t} = 1.3

Continuously heated greenhouses with a roof having a thermal resistance (R-value) less than 2.0 °F x h x ft^{2}/Btu (0.4 K x m^{2}/W), C_{t} = 0.85

All other structures, C_{t} = 1.0

## ASCE 7-10, Table 7-3