Download - Computer Associates International, Regional Office

SETH R. TAKOCH STRUCTURAL OPTION

Computer Associates International, Regional

Office Herndon, VA

Seth R. Takoch

AE Senior Thesis

Structural Option

April 15, 2003


Presentation Outline

Background InformationExisting Structural ConditionsDesign CriteriaRedesignConstruction ManagementLighting DesignConclusions and RecommendationAcknowledgements



Location

15min. Off Beltway 35mins. Outside D.C

Wood Oak Dr.

Baseball Field


Background Information

Function: Computer Associates Int. Regional Headquarters

Size: 233,000 sq. ft. – 6 floors

Rentable Office Space: 207,000 sq. ft.

Architectural Features:

•Precast Concrete Façade with Glass Curtain Wall

•Six Story Glass Enclosed Atrium

•Adjacent Day Care Facility


Project Team

Owner – Computer Associates International Arcitect – Davis, Carter, Scott Structural Engineer – Smislova, Kehnemui, & Associates. General Contractor – Clark Construction Developer – Tishman Speyer Properties Mechanical – GHT Limited Plumbing – GHT Limited


Existing Structure

Flat Slab ConstructionConcrete Structure

• 30’ x 30’ Bays• 9” Thick Slab Thickness• 10’ x 10’ x 5-1/2” Drop

Panels• 24” x 24” Conc. Columns


Existing Structure

Wind Loads are Transferred by Diaphragm Action of Façade

Transferred to Framing by Tributary Area• 8 Frames N-S and 9 Frames E-W

Concrete Frames Resist Lateral Forces • Short and Long Frames

Floor Slab Adds Resistance due to Diaphragm Action


Design Limitations

Old Code – BOCA 96 New Code – IBC 2000 Local Zoning Ordinances Similar Square Footage Minimal Architectural

Changes Floor-to-Floor Heights

LIVE LOADS PER IBC 2000

LOAD TYPE LOAD

ROOF ( RAIN ) 50 psf

ROOF ( SNOW ) HIGH ROOF 22 psf

ROOF (SNOW) LOW ROOF 30 psf

OFFICES, CUBICLES 50 psf

ASSEMBLY, STAIRS 100 psf

MECHANICAL 150 psf

CORRIDORS 80 psf


Proposal

To Redesign a Feasible and Desirable Alternative Structural System and to Incorporate Construction Costs and Schedule Length Into My Solution

Time = Money …

Money = Time

$$$$


Possible Faming Alternatives

Composite Steel Construction

Non-Composite Steel Construction


Steel Construction

Code – IBC2000LRFD Analysis

• Parameters• 30’ x30’ Typical Bays• Fy = 50ksi ASTM A992 Steel• F’c = 3ksi• Normal Weight Concrete• Shear Studs - 3-1/2”high, ¾” diameter

(composite)• 22 gage Metal Deck


Composite Steel Construction

Gravity Analysis – RAM • Determined Beam Sizes• Determined Column Sizes

2 Story Column Lengths 26’ – 28’ Tall• Ranging from W10’s to W12’s

Beam Sizes W12x14 Spaced at 6’ o.c.• Girders as Deep as a W21’s


Non-Composite Construction

Gravity Analysis – RAM • Determined Beam Sizes• Determined Column Sizes

2 Story Column Lengths 26’ – 28’ Tall• Using W12’s

Beam Sizes W12x14 Spaced at 6’ o.c.• Girders as Deep as a W24’s


Depth Comparison

Composite Steel

•Average – W12’s

•Critical Depth – W21

Non-Composite Steel

•Average – W12’s

•Critical Depth – W24

Advantage – Composite Steel Construction

Composite Saves 20 Tons

of Steel


Lateral System

Shear Wall to Resist Lateral LoadingBased on Critical Wind Loading and

Torsion2 – 60’ Long Shear Walls

• Reinforced to Resist Forces• Deflection of h/400

A trium

S hear Wall #2

Shear W

all #1

C enter of Rigidity

A trium


Design

Reinforcement Based on the Following Vn = (2f’c bd +

Avfyvd/s) Mn = Asfy (d-a/2)

Wall Floor ShearBendin

g

1#4 @ 12"

8 - #11

2#4 @ 12"

6 - #11

1 3#4 @ 12"

6 - #9

4#6 @ 12"

4 - #9

5#7 @ 12"

2 - #9

6#9 @ 12"

1 - #9

1#4 @ 12"

8 - #11

2#4 @ 12"

6 - #11

2 3#5 @ 12"

6 - #9

4#6 @ 12"

4 - #9

5#8 @ 12"

2 - #9

6#10 @

12"1 - #9


Construction Management`

Address Two Main Issues

•Cost Comparison

•Project Duration


Construction Management

Total Building Cost• D4 Cost

• Total = $27,678,667• 20-25% Accurate• Range of $34.6 million to $20.8 million • Not Very Accurate• $115.33 / sq. ft.

`



Total Building Cost• Means Building Construction Cost Data

• Separate Estimates for Steel and Concrete• 10 -15% Accurate• More Precise Than D4• Steel Framing = $96.74 / sq.ft.• Concrete Frame = $98.45 / sq.ft. • Difference = $1.71 / sq.ft. = $410,400

`



Cost Comparison• D4 Cost = $115.33/sq.ft. = $27,678,667• Means Steel = $96.74/sq.ft. = $23,217,600• Means Concrete = $98.45/sq.ft. =

$23,628,000• Percentage Savings Using Steel = 1.7%

Savings

`



Scheduling• Means Data to Calculate Duration • Primavera Utilized to Schedule Sequences• Total Duration Steel Erection = 376days• Total Duration Concrete Placement = 847

days

`


Construction Management`

After Scheduling Concrete – 260 Days


Construction ManagementAfter Scheduling – 150 Days

`



Savings• Advantage Composite Steel Construction

Time

• Advantage Composite Steel Construction

`

Composite Design is Considered One of the Most Economical Methods of Floor Construction for an Office Building



Crane Sizing• On Site 3-1/2 Months• Tower Crane

• Placed Through Atrium• Liebherr 200HC• Hook Radius – 197ft.• Capacity – 5,070#• Satisfies Critical Lift of 3,000# @160ft.

`


Lighting Design

Design of Lighting of Daycare Facility• Minimum Footcandles of 30fc• Fluorescent Luminaries• 120’ x 56’ Space to Illuminate• 2’ x 4’ Fixtures with 3” Louvers Spaced

on a 16’ x 8’ grid• Specification From Lithonia• Workplane of 2-1/2 ft.


Lighting Design

Designed Using LuxiconRenderings on April 15, 2003

• At 9:00 am with Daylighting• At 1:30 pm with Daylighting• At 5:00 pm with Daylighting• Without Daylighting


Lighting Design

9:00 am


At 1:30 pm

Lighting Design


At 5:00 pm

Lighting Design


• Without Daylighting

Lighting Design


Lighting Design

The Lighting Design Meets Required Parameters of 30fc


Conclusion

In Conclusion, Composite Steel Construction is a Better Alternative to Non-Composite Construction.

Composite Steel is a Viable Alternative to a Two-Way Flat Slab System


Shout Outs’My Family

My Friends

The AE Student Body

The Entire AE Faculity

Smislova, Kehnemui, & Associates, P.A.

Computer Associates

The ‘U’

And All Of Those Out There That Stuck With Me


Questions

?

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