bryan darrin senior thesis presentation millennium hall drexel campus philadelphia, pa

BRYAN DARRIN

SENIOR THESIS PRESENTATION

MILLENNIUM HALL

DREXEL CAMPUSPHILADELPHIA, PA

+ Introduction- General Building Information- Existing Structural System

- Thesis Objective- Structural Depth- Architectural Breadth- CM Breadth- Final Summary/Conclusions

Millennium Hall

34th Street and Race Street, Philadelphia, PA 19104

Drexel University

Educational Residence Hall

153,000 Gross S.F.

17 Stories Total

General Building Information

Façade of glass and aluminum screen curtain wall

Offset of each floor as a rotation about the central core creates spiral affect.

[Note: For this entire thesis project, the spiral affect has been removed. This includes all data referred to as existing design.]

+ Introduction- General Building Information- Existing Structural System

- Thesis Objective- Structural Depth- Architectural Breadth- CM Breadth- Final Summary/Conclusions

Cast-in-place concrete

Flat plate

Concrete moment frame with concrete shear walls

110 feet wide

70feet deep

15 foot cantilever

- Introduction+ Thesis Objective

- Problem Statement/Solution- Thesis Goals

- Structural Depth- Architectural Breadth- CM Breadth- Final Summary/Conclusions

Thesis Redesign Goals

Depth - Structural

1. Reduce the weight of the overall building by replacing the gravity system

2. Minimize drift with a lateral force resisting system in coordination with the gravity system

3. Verify the impact on the foundation system

Existing Building Problems

Heavy weight due to concreteThick floor slabs due to large cantilever

Redesign Solution

Design as steel moment frameUse composite deck to reduce thicknessMove column line to exteriorAdd braced frames for lateral resistance

- Introduction+ Thesis Objective

- Problem Statement/Solution- Thesis Goals

- Structural Depth- Architectural Breadth- CM Breadth- Final Summary/Conclusions


Breadth #1 - Architectural

4. Determine the impact on the architectural design including floor plan layout


Breadth #2 – Construction Management

5. Determine the impact that the redesign has on the construction schedule and cost of the building

- Introduction- Thesis Objective+ Structural Depth

- Gravity Redesign- Lateral Redesign- Foundation Check

- Architectural Breadth- CM Breadth- Final Summary/Conclusions

SDL = 20 psf + 15 psf = 35 psfLL = 100 psf

1.2 SDL + 1.6 LL




L = 35 + 100 = 135 psf > 147 psf ok

Wu = [1.2(44+5+35) + 1.6(100)](12)/1000 = 3.13 klf

Mu = 452 ft-kips

Use W16x45 with 32 studs spaced at 12 inches




Ram Model

Used to verify hand calculations and determine column sizes

Full composite construction was assumed

Same loading was used

Results #1RAM member sizes were found to be close to the hand calculated but generally smaller.

Results #2Preliminary column sizes were foundW10x33 Typ.As large as W10x100 at interior line




(Allowable Story Drift)

Δseismic = 0.015Hsx = 0.015*10*12 = 1.8 inches

Design Limits (IBC,2006)

(Allowable Building Drift)

Δwind = H/400 = 180*12/400 = 5.4 inches

Design Loads

Wind controls in the North/South direction:

398 kips

Seismic controls in the East/West direction:

327 kips



- Architectural Breadth- CM Breadth- Final Summary/Conclusions Total Drift > 30 inches

Larger member sizes were not making much improvement

First EvaluationETABS Design Process

Model was built in ETABS

Member sizes from Gravity system were used

Columns were aligned with local beam axis

All connections were assigned as moment connection

Diaphragm was assigned to each floor

Loading patterns for seismic and wind were placed as individual story forces



- Architectural Breadth- CM Breadth- Final Summary/Conclusions Maximum drift = 5.33 inches < 5.4 inches

Second Evaluation North/South Wind

Braced frames added to resist North/South drift




Maximum story drift = 1.22 inches < 1.8 inches

East/West Seismic Foundation Check

20 caissons

Assume equal distribution

920 kips / caisson

32 caissons

Assume interior 10 caissons take half

680 kips / caisson

- Introduction- Thesis Objective- Structural Depth+ Architectural Breadth- CM Breadth- Final Summary/Conclusions

Connected directly to column

Connection points every 12 feet

Continuously up building

- Introduction- Thesis Objective- Structural Depth- Architectural Breadth+ CM Breadth- Final Summary/Conclusions

Cost/Schedule Comparison

Cost has been increased by $600,000 or by 35%

Schedule has been reduced by 200 days or by40%

Existing Cost/Schedule

Includes structural concrete, reinforcement, and framing

Estimated structural cost of $1.7 millionEstimated timeline of 330 days

New Cost/Schedule

Includes steel framing, steel decking, metal studs to develop composite strength, concrete, reinforcement, and fire proofing

Estimated structural cost of $2.3 millionEstimated timeline of 130 days

- Introduction- Thesis Objective- Structural Depth- Architectural Breadth- CM Breadth+ Final Summary/Conclusions

Goals Re-evaluated

Summary

1. Reduce the weight of the overall building by replacing the gravity system

2. Minimize drift with a lateral force resisting system in coordination with the gravity system

3. Verify the impact on the foundation system

4. Determine the impact on the architectural design including floor plan layout

5. Determine the impact that the redesign has on the construction schedule and cost of the building

Steel frame and composite deck provide lightweight system

Steel braced frames partnered with steel moment frame reduce drifts to allowable values

Existing caissons have adequate strength for all columns, most could be reduced in size

Minimal façade connection changes and layout adjustments have little impact on floor plan

Structural cost has gone up but entire building schedule time has been reduced

- Introduction- Thesis Objective- Structural Depth- Architectural Breadth- CM Breadth+ Final Summary/Conclusions

Acknowledgements Summary

I would like to thank:

The Harman Group for a unique building idea

Drexel University for allowing me to analyze the Millennium Hall building

The entire AE faculty, especially my Thesis Advisor Dr. Hanagan

Met project goals

Structural design is feasible option

QUESTIONS?

bryan darrin senior thesis presentation millennium hall drexel campus philadelphia, pa

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