   # The member shown in Figure P6.6-7 has lateral support at points A , B , and C . Bending is about the strong axis. The loads are service loads, and the uniform load includes the weight of the member. A992 steel is used. Is the member adequate? a. Use LRFD. b. Use ASD. ### Steel Design (Activate Learning wi...

6th Edition
Segui + 1 other
Publisher: Cengage Learning
ISBN: 9781337094740

#### Solutions

Chapter
Section ### Steel Design (Activate Learning wi...

6th Edition
Segui + 1 other
Publisher: Cengage Learning
ISBN: 9781337094740
Chapter 6, Problem 6.6.7P
Textbook Problem
29 views

## The member shown in Figure P6.6-7 has lateral support at points A, B, and C. Bending is about the strong axis. The loads are service loads, and the uniform load includes the weight of the member. A992 steel is used. Is the member adequate?a. Use LRFD.b. Use ASD. To determine

(a)

If the member is adequate using LRFD method.

### Explanation of Solution

Given data:

Concept used:

Write the equation that satisfies AISC specification by using LRFD method.

PuϕbPn+89(MuxϕbMnx+MuyϕbMny)1.0

Here, the compressive design strength is ϕbPn, the factored axial load is Pu the flexural load about xaxis is Mux, the nominal flexural strength about xaxis is ϕbMnx, the flexural load about yaxis is Muy, and the nominal flexural strength about yaxis is ϕbMny.

Calculation:

Write the expression for axial factored load Pu on the member.

Pu=1.6PL+1.2PD (I)

Substitute 170k for PL and 70k for PD in Equation (I).

Pu=(1.6×170k)+(1.2×70k)=272k+84k=356k

Write the expression for transverse concentrated load Tu on the member.

Fu=1.6TL+1.2TD (II)

Substitute 18k for TL and 7k for TD in Equation (II).

Fu=(1.6×18k)+(1.2×7k)=28.8k+8.4k=37.2k

Write the expression for the uniformly factored load on the member.

Wu=1.6WL+1.2WD (III)

Here, the uniformly factored dead load is WD and the uniformly factored live load is WL and the uniformly factored load is Wu.

Substitute 1.5k/ft for WL and 3.5k/ft for WD in Equation (III).

Wu=(1.6×3.5k/ft)+(1.2×1.5k/ft)=5.6k/ft+1.8k/ft=7.4k/ft

Write the expression for the bending moment.

Mnt=WuL28+FuL4 (IV)

Here, the factored bending moment of the load is Fu, and the uniformly factored load is Wu, the length of the member is L, and the bending moment of the load is Mnt.

Substitute 7.4k/ft for Wu, 16ft for L and 37.2k for Fu in Equation (IV).

Mnt=7.4k/ft(16ft)28+37.2k(16ft)4=236.8k-ft+148.8k-ft=385.6k-ft

When the factor for non uniform bending within the unbraced length is Lb=8ft, then Cb=1.

If Lb=8ft and Cb=1 then,

ϕbMn=488k-ftϕbMp=488k-ft

Since the member is transversely loaded, then Cm=1.

Write the formula for calculating buckling stress.

Pe=π2EI(KL)2 (V)

Here, the steels elastic modulus is E, the sections moment of inertia about major principal axis is I, and the members effective length about is KL.

Substitute 29000ksi for E, 623in4 for I, 1.0 for K and 16ft in Equation (V).

Pe=π2(29000ksi)(623in4)(1.0×(16ft)(12inch1ft))2=178314142.7k-in236864in2=4837k

Write the expression for moment amplification factor

To determine

(b)

If the member is adequate using ASD method.

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Find more solutions based on key concepts
Present Example 11.5 in Chapter 11 using the format discussed in Section 4.2. Divide the example problem into G...

Engineering Fundamentals: An Introduction to Engineering (MindTap Course List)

Briefly define the term cutting speed.

Precision Machining Technology (MindTap Course List)

What is the difference between vulnerability and exposure?

Principles of Information Security (MindTap Course List)

What e user applications? Suggest three examples that could boost user productivity.

Systems Analysis and Design (Shelly Cashman Series) (MindTap Course List)

What is a subtype discriminator? Give an example of its use.

Database Systems: Design, Implementation, & Management

Define the term, data file. Identify what is involved in file maintenance.

Enhanced Discovering Computers 2017 (Shelly Cashman Series) (MindTap Course List)

What is a twist ratio, and why is it important?

Network+ Guide to Networks (MindTap Course List)

Why is it important to seek medical treatment for eye burns?

Welding: Principles and Applications (MindTap Course List)

If your motherboard supports ECC DDR3 memory, can you substitute non-ECC DDR3 memory?

A+ Guide to Hardware (Standalone Book) (MindTap Course List) 