# BCN 4431 Structural Design II Homework 2

BCN 4431 Structural Design II

Spring 2019

Homework 2

Design the beam and column system shown in the figure below (NOTE: The support conditions

are not realistic and are only used for class purpose to simplify structural analysis and design

process). Check for flexure, shear and deflection in beam. Whenever you use code, please also

report the page number that you referred to and the values that you are looking into. Units should

be mentioned wherever applicable. All intermediate steps should be shown for partial credit.

Legend:

Symbol Meaning

Beam section

Column section

Bracing at center of the beam span

Concentrated load

Uniformly distributed load

Hinge support

Roller support

Fixed support

(20+x) k

(10+x) k

DL: (20 + x) k

LL: (10 + x) k

(30 + x) ft Span = (30 + x) ft long

Your Panther ID governs the value of x. If your PID is 3456789 then, x = 3.45. x is a number

less than 10 with two decimal places.

i.e. x = <first digit of PID>.<second digit><third digit>

Use steel with Fy = 50 ksi. Allowable deflection is 1/360 of the span of the beam.

Assume that the sections W 21 x 62 are available to you for no cost.

Assume the cost of steel for any other sections = $ 4.2/lb. (finished).

In case you do not find a relevant constant for a loading condition (Cb, Cv or C1), use the constant

that corresponds to the worst case scenario. (NOTE: The only intent of this instruction is to

simplify the problem. Calculated values of the constants MUST be used in real design.)

Please calculate,

i) Minimum cost of the beam system (when W 21 x 62 is free)

ii) Most economic cost of the beam system if the sections W 21 x 62 were not freely available

iii) Most economical cost of column system.

OPTIONAL: The concentrated load provided on top of UDL in mid-span of beam CD is

optional. You will get extra 10% points if you consider it in design. Hint: See Example 9-10.

The homework is due at 5:00 PM on March 01, 2019 through canvas as a single pdf file.