A flat roof is subject to the following uniformly distributed loads: a dead load of 21 psf (pounds per square foot of roof surface), a roof live load of 12 psf, a snow load of 13.5 psf, and a wind load of 22 psf upward. (Although the wind itself is in a horizontal direction, the force that it exerts on this roof is upward. It will be upward regardless of wind direction. The dead, live, and snow loads are gravity loads and act downward.). If load and resistance factor design is used, compute the factored load (required strength) in pounds per square foot. Which AISC load com­bination controls? There are 5 load combinations below: Combination 1: 1.4DCombination 2: 1.2D+1.6L+0.5(Lr or S or R)Combination 3: 1.2D+1.6(Lr or S or R) +(0.5L or 0.5W)Combination 4: 1.2D+1.0W+0.5(Lr or S or R)Combination 5: 0.9D+1.0W How to deal with the wind load? If the wind load W=-22 psf, then the result of combination 5 will be -3.1 psf, which is negative.  And the tensile strength of materials and compressive strength is not the same. How to answer this question?

Steel Design (Activate Learning with these NEW titles from Engineering!)
6th Edition
ISBN:9781337094740
Author:Segui, William T.
Publisher:Segui, William T.
Chapter2: Concepts In Structural Steel Design
Section: Chapter Questions
Problem 2.5P
icon
Related questions
Question
  • A flat roof is subject to the following uniformly distributed loads: a dead load of 21 psf (pounds per square foot of roof surface), a roof live load of 12 psf, a snow load of 13.5 psf, and a wind load of 22 psf upward. (Although the wind itself is in a horizontal direction, the force that it exerts on this roof is upward. It will be upward regardless of wind direction. The dead, live, and snow loads are gravity loads and act downward.). If load and resistance factor design is used, compute the factored load (required strength) in pounds per square foot. Which AISC load com­bination controls?
  • There are 5 load combinations below:
  • Combination 1: 1.4D
    Combination 2: 1.2D+1.6L+0.5(Lr or S or R)
    Combination 3: 1.2D+1.6(Lr or S or R) +(0.5L or 0.5W)
    Combination 4: 1.2D+1.0W+0.5(Lr or S or R)
    Combination 5: 0.9D+1.0W
  • How to deal with the wind load? If the wind load W=-22 psf, then the result of combination 5 will be -3.1 psf, which is negative.  And the tensile strength of materials and compressive strength is not the same. How to answer this question?
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 9 steps with 5 images

Blurred answer
Knowledge Booster
Roofing elements and materials
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Steel Design (Activate Learning with these NEW ti…
Steel Design (Activate Learning with these NEW ti…
Civil Engineering
ISBN:
9781337094740
Author:
Segui, William T.
Publisher:
Cengage Learning