Jason D. Eady

Jason D. Eady

AE – Structural OptionSpring 2004

The Investment Building

12-story office building380,000 square feet totalLocated in Washington, D.C.

Jason D. Eady The Investment Building

ContentsBuilding Background

o Design Teamo Existing Structure Systemo Architectureo Construction and Cost Implications

Depth: Structural Steelo Proposed Structural Systemo Design Loadso Gravity Designo Lateral Systemo Final Designo Cost

Breadth A: Mechanicalo Increase in Plenum Spaceo Steel Joistso Castellated Beams

Breadth B: Architectureo Integration of Beaux-Arts Façade o Low Floor-to-Ceiling Heightso Decrease in Diameter of Atria o Integration of Concrete Parking Garage

Conclusion

Acknowledgements

Questions


Design TeamGeneral Contractor: The Clark Construction Group, Inc.

Design Architect: Cesar Pelli & Associates, Inc.

Architect of Record: Shalom Barnes Associates, PC

MEP Engineers: B & A Consulting Engineers

Structural Engineers: Tadjer-Cohen-Edelson, Assoc

Civil Engineers: A. Morton Thomas & Associates

Fire & Life Safety Engineers: Schirmer Engineering Corporation

Owner/Developer: The Kaempfer Company


Existing Structural SystemLateral System – monolithically poured slab and columns that transfer moments from the two-way reinforced slab to the columns

Gravity System – Two-way reinforced concrete flat slab with drop panels

Typical Bay Strip – 30’ x 30’ exterior bays and 30’ x 26’ interior bays

Foundations – Level P3 slab-on-grade, 18’ x 18’ typical spread footings

Concrete – Normal weight 3 ksi compressive strength concrete on 8” slabs on levels 2-5 and 7-10. Normal weight 4ksi compressive strength for 9” and 10” slabs and walls and columns


Existing Structural System


Partial Foundation Plan

Existing Structural System

Partial Floor Plan


Architecture1501 K Street Washington, DC 20005

Restored 1920s Beaux-Arts façade

50 foot diameter Atria

Penthouse Roof

Increased floor-to-floor heights


Architecture


Floor Footprint

Construction and Cost

Delivery Method - Design-Bid-BuildContract – GMP of $38,146,000Construction Duration – 3 ½ yearsCost of project- $38.1 M total- $3.0 M in soft costs


Construction and Cost

$38.1MTotal Project Cost

$15,500,000$3,200,000$2,000,000$2,800,000$1,500,000$3,800,000$5,200,000$4,100,000

Structural SystemHVACElectricalPlumbingElevatorsPre-CastSite ManagementPost-tensioned Concrete

(Parking Garage)

Approximate Major Building System Cost




Depth: Structural Steel o Proposed Structural Systemo Design Loadso Gravity Designo Lateral Systemo Final Designo Cost



Conclusion

Acknowledgements

Questions


Alternative Structural System

Composite Steel Deck with Concrete Slab and Wide-Flange Beams


Alternative Structural System

Advantages of Composite Steel System- Light- Economical- Longer spans- Easy and Quick to Erect- Less Site Labor- Earlier Delivery Time


Design LoadsDesign Wind Loads

Lateral Load on structural frame 13.02 PSFRoof uplift 20 PSF

Code minimum design loads based on the following:

Basic Wind Speed, V = 70MPHWind load importance factor, I = 1.0Wind exposure (typical) = BWind design pressure, P, varies with building

height, used maximum value of 13.02 PSF for entire height

Seismic DesignCode minimum design loads based on the

following:Peak velocity-related acceleration, Av = 0.05Peak acceleration, Aa = 0.05Seismic hazard exposure group = Group ASeismic performance category = A

Design Gravity LoadsTypical Floor:

Superimposed Dead Loads-MEP, electrical, ceiling, etc. 62.07 PSF Partitions 20 PSF

Live Loads-Office area 60 PSF** Corridor, stairs and lobby 100 PSF

**(BOCA requires 50 PSF for offices)

Roof : Superimposed Dead Loads-

MEP, electrical, ceiling, etc. 12 PSFRoofing, insulation, etc. 18 PSF

Live Load – Snow (minimum) 17.5 PSF (+ drift)Code minimum snow load based on the

following:Ground snow load, Pg = 25 PSFFlat roof snow load = Pf = 17.5 PSFSnow exposure Factor, Ce = 0.7

Load Summary for Composite Steel System


Gravity Design

30’ x 30’ column spacing in both the N-S and E-W directionsBays adjacent to South façade are 30’ x 22’Bays adjacent to the East façade are 24’ x 30’4” Slab- USD 2” Lok-floor Composite Deck with 18 gage thickness- 2” concrete topping for 1 ½ hour fire proofing


Gravity Design

Live Load Distribution- Areas of high circulation: 100 PSF - Other Areas: 60 PSF


Gravity Design

Jason D. Eady The Investment BuildingTypical Floor Plan

Lateral System

Rigid Braced Frames- Type PR Connection: Beam-to-girder

> 5/8” thick end plate> Six 1/2” diameter A-325 bolts

- Type FR Connection: Girder-to-column> 7/8” thick end plate> Six 7/8” diameter A-325 bolts


Lateral System

Type PR connection (shear connection)

between beams and girders

Type FR connection (rigid connection)

between girders and columns


Lateral System

Advantages of FR and PR Connections- Plate is shop welded to beam before it is

delivered to the construction site- Fewer bolts are required - Fast erection


Final Design

Jason D. Eady The Investment BuildingTypical Floor Plan

Final Design

Jason D. Eady The Investment BuildingElevation Plan

Cost


Costs

$34,448,000Total Project Cost

$11,848,300$3,200,000$2,000,000$2,800,000$1,500,000$3,800,000$5,200,000$4,100,000

$68,300$150,000$150,000$125,000$38,000$440,000$25,000$180,000

$680,000$550,000$250,000$375,000$467,000$960,000

$3,675,000$650,000

$11,100,000$2,500,000$1,600,000$2,300,000$995,000

$2,400,000$1,500,000$3,300,000

Structural Steel SystemHVACElectricalPlumbingElevatorsPre-castSite ManagementPost-tension Concrete

(Parking Garage)

TotalEquipmentLaborMaterialBuilding System







Conclusion

Acknowledgements

Questions


Mechanical

Mechanical System- Power Induction VAV System using

fresh air from outside

- Variable air handling units, fans, heating coils and plate and frame heat exchangers

- 10” insulated ducts


Mechanical

Issue – The composite steel system and the mechanical system increases the floor thickness (plenum space).


Increase in Plenum Space

Plenum space for existing concrete system



Plenum space for composite steel system



Disadvantages of Composite Steel System- 6” increase in plenum space- Maximum floor-to-ceiling heights – 8’-1”

(8’-7” for the concrete system)- Interference of plenum space with some

window openings in the façade



Possible Solutions:- Steel joists- Castellated beams


Steel Joists

- Composite interaction is required.

- 26” deep joists are required to adequately support gravity loads.


Steel Joists

Disadvantages- Plenum space increases to 2’-6” including

the 4” thick slab- Floor-to-ceiling heights decrease to 7’-10”


Steel Joists

Therefore, it is not feasible to use steel joists, since- Plenum space is greater than the plenum

space of the composite steel system containing wide-flanged section

- Floor-to-ceiling heights decrease further


Castellated Beams


Castellated Beams

Advantages:- Light - Strong- Cheap- Easy to assemble at the construction site- Aesthetically pleasing - Passage of mechanical ducts


Castellated Beams

To adequately carry gravity loads,- HE- 500-B is required as a

substitute for W10 x 22 beamsNominal depth – 1’ – 8”

- HE- 450 B is required as a substitute for W10 x 19 beamsNominal depth – 1’ – 6”


Castellated Beams

Results considering the HE- 500-B: - Plenum space including 4” slab is

2’-0”- Floor-to-ceiling height is 8’-4”

(Floor-to-ceiling heights are 8’-1” using wide-flange sections)


Castellated Beams

Recommendation:Since the plenum spacing required for castellated beams is less than the plenum space required for wide-flange sections, castellated beams are an excellent solution for integrating the mechanical and structural elements in the plenum space.







Conclusion

Acknowledgements

Questions


Architecture

Issues:- Integration of Beaux-Arts Façade - Low Floor-to-Ceiling Heights- Decrease in Diameter of Atria - Integration of Concrete Parking Garage


Integration of Beaux-Arts Façade

Issue:Coinciding of Column/façade window opening


Integration of Beaux-Arts Façade

Solution:- Most columns were place in same

locations as they are in existing structural system (typical 30’ spacing)

- Other columns were place in location where they do not interfere with window openings


Low Floor-to-Ceiling Heights

Issue:- Constant floor-to-floor heights- Increase in plenum space

- Low finished ceilings (8’-1”)- Coinciding of plenum space and façade

window openings


Low Floor-to-Ceiling Heights

Solution:- Use castellated beams to decrease

plenum space- Floor-to-ceiling heights increase to

8’-4” with castellated beams


Decrease in Diameter of Atria

Issue:Because structural elements supporting the atria are to carry equal amount of gravity loads, the geometry of the elements supporting the atria needs to be symmetric.


Decrease in Diameter of Atria

Solution:Diameter of atria decreases by 7’-7” to symmetrically support gravity loads imposed on the atria.

Diameter of atria in existing system: 50’-0”Diameter of atria in composite steel System: 42’-7”


Integration of Concrete Parking Garage

Issues:- Coinciding of concrete/steel columns- Loss of parking spaces



Solution:- offset center of west most column of

superstructure west 4’-6” off center of the west-most column in parking garage

- offset north-most columns of superstructure 3’-0” off center of the north-most columns of the parking garage



Jason D. Eady The Investment BuildingSuperstructure superimposed on concrete parking garage



Depth: Structural Steelo Loadso Gravity Designo Lateral Systemo Final Designo Cost



Conclusion

Acknowledgements

Questions


ConclusionIt is recommended to utilize the Composite Steel System as a alternative superstructure

Reasons:- $3.6 M cheaper than existing system- Quick erection resulting in faster delivery

> Early opening> Owner begins earning revenue immediately

- Mechanical System integrates well- No major impacts on the building’s architecture


Thank you

FacultyDr. Louis GeschwindnerDr. Kevin ParfittDr. Thomas BoothbyJohnathan DoughertyDr. Moses Ling

ProfessionalsBrian FlegelSteve Kalthoff

PeersPaula MartinezShauna Koenig

Family and friendsGODMomAunt PhyllisUncle LeonJulie Vastyan


Questions?


Jason D. Eady

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