Final Presentation for

CE 331 Introduction to Structural Engineering

Your Assignment for Project 2 was to:

Visit a construction site

Photograph structural components, copy structural drawings

Calculate structural adequacy

Describes your structure

Summarizes your structural analysis

Create an interesting presentation that:

n

u

P

PUC

Pu

Pn

The following slides are examples.Feel free to use copy and paste any sketches into your own presentation.

Gravity Load Analysis for Sears

Tower

for

CE 331, Spring 2007

Project 2

byMatt Damon andJennifer Lopez

The Sears Tower is a 108-story steel-frame office building in downtown Chicago Illinois.

(Original) Owner: Sears & Roebuck Co.

Contractor: Morse-Diesel Inc.

Structural Engineer: Skidmore, Owings, and Merrill

The Sears Tower is constructed of nine steel “tubes”, each 75 feet across.

Insert several slides using your own photos here.

We analyzed a typical interior column and spread footing.

Elevation View

- steel tube column

- reinforced concrete foundation

- steel roof deck- bar joist

- joist girder

Roof dead load = 14 psf

waterproof membrane 4 psf

steel deck 4 psf

purlins 3 psf

suspended ceiling 2 psf

sprinklers 1 psf

14 psf

Section of Roof

We checked the design of an interior column for axial buckling.

Pu

Pn

Column live load = 15 psf

Specified live load = 20 psf

Interior Column

Column live load = 15 psf

specified live load = 20 psf

tributary area = 525 sf

live load reduction factor = 0.75

reduced live load = 15 psf

Factored load to column (Pu) = 30.6k

Pu = [ 1.2 (14psf) + 1.6 (15psf) ] (30ft)(25ft) = 30.6k

Pu

Column capacity (Pn) = 44k

failure mode: axial buckling

grade 50 steel E = 29,000ksi

fy = 50ksi

slenderness (kLu/r) r = 23.4in

k = 1.0

Lu = 10.5ft

AISC Table Pn = 44k

HSS 3x4x3/16

Design check shows column design is OK

82.0)44)(85.0(

6.30

k

k

n

u

P

PUC

Pu

Pn

We checked the design of a typical reinforced concrete spread footing for flexure failure.

Flexure failure occurs when demand (Mu) exceeds capacity ( Mn).

location of flexure failure

factored soil pressure, qu

Pu, factored axial force from column

qu

C

T

Mn Mu