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Structural design in steel.
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A STREETCAR SHELTER FOR THE ARBUTUS CORRIDORA STUDIED SIMPLICITY: EXPRESSING THE W-SHAPE
BENJAMIN BYE | ARCHITECTURE 462 | THURSDAY NOON LAB | LAUREN GARVEY
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SIMPLICITY IN STEEL
In the design of a steel streetcar stop for the Arbutus Corridor in Vancouver, B.C. the exploration of structure as ornament was made. Taking precedent from the structures of Mies Van Der Rohe, the streetcar station showcases the steel that makes its structure. To exemplify and showcase the steel, W-shape mem-bers where utilized for their clear identifi ability as structural ele-ments. To strengthen the purity and clarity of the Van Der Rohe infl uenced structure, a simple and clearly defi ned structural hi-erarchy and load distribution was designed. The structure con-tains four levels of member hierarchy. Purlins act as stiffening members, bracing the weak axis of the cantilevered joists. The joists, running cross sectionally, are the primary spanning mem-bers, collecting the initial snow load and material load on the structure. Two longitudinal girders direct loads from the joists into the four columns. The building is braced through the use of moment connections. Bents are created as the columns are connected by spanning joists and girders. To further brace the structure against strong lateral loads the columns are driven into the ground forming a moment connection at the base of the column. Through the process of designing with pure structural intention a truly simple and beautiful structure can be created. With the focus on clarity and purity of structure, a balance of structural effi ciency and articulation was made. Some members were slightly oversized for this cause, giving more importance to the aesthetic possibilities of the structure than could have been achieved with a purely effi ciency based design. The outcome is one of aesthetically reasoned structural design.
< EXPLODED AXONThe axon brakes apart the streetcar stop and exemplifi es the rational simplicity to which the structure was designed. The ar-ticulation of structural members becomes the ornament of the streetcar stop.
PURLINS
JOISTS
GIRDERS
COLUMNS
CLEAR HIERARCHY
IIT Crown Hall. Mies Van Der Rohe. Structure as Ornament
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AXONOMETRIC DRAWING: STRUCTURAL GEOMETRY
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MODEL PHOTOGRAPHS
STRUCTURAL ARTICULATION
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LONGITUDINAL ELEVATION 1/4”=1’
CROSS SECTION 1/4”=1’
20ft
12ft
8ft
8ft
THE STRUCTURAL UNIT DRAWN
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LONGITUDINAL ELEVATION 1/4”=1’
PLAN 1/4”=1”
20ft
12ft
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EARLY DESIGN WORK:THINKING THROUGH DRAWING
left: many different formal and structural ex-plorations where made at the beginning of the design process, and an evolution was made towards the current structural scheme.
above: day dreaming a simple design detail was born that was to be the genesis of the structure.
below: through drawing, geometries and porpor-tions were tweaked until the final scheme was produced.
thinking through drawing.
unsettling proportions early on... considered, balanced, and appropriate proportions...
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.75 snow load: w= .75k/ft
.75 wind load: 1.8k
.75 wind load: 1.8k
.75 snow load: w= .0375k/ft
dead load: w= .12k/ft
dead load: w= .06k/ft
note: the loads are placed on the joist members because ultimately in this design the purlins purposes is to brace the weak axis of the joists. In studying forces flow in the structure, it was most acurate to distribute loads in this man-ner.
MULTIFRAME: AN OVERVIEW OF THE MODEL
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.75 wind load: 1.8k
Moment Diagram: Because of the high level of wind load on the structure, the columns provide the most lateral resistance so they have the highest moments. The moment graph also illustrates the clear necesity for member hierarchy with the col-umns needing to resit the most force, and the purlins the least. The only member with noticeable weak axis bending is the column, which will be illustrated in the column de-sign check.
Mmax for the structure: 4.825k-ft (column)
Axial Stress Diagram: As tributary mem-bers for all loading on the structure, the columns are the main members that need to take compression and tension stresses in mind. The joists between the columns also contain higher compression stresses, acting as bracing members reacting against the high wind load.
Pmax for the Structure: 3.017k (column)
Deflection Diagram: Deflection in the structure is most prominant in the columns with a total deflection of 0.052 inches. The deflection is well below the maximum al-lowed deflection factor. This graph also illustrates how there is a slight torsional effect in the girder due to the support of the joist cantilever. The actual deflection is neg-ligable, it is just exagerated in the deflection diagram.
Total Deflection For Structure: 0.052in
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TYPICAL CANTILEVER JOIST: A-36 Steel | W6 x 9 Shape | Spanning Member
Mx-max : 1.021k-ft
The weak axis My-max is negligable at 0.002k-ft
Pmax : 0.00k
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Max Deflection: 0.005in
Deflection Check:
Allowable Deflection = l = 4ft x 12in/ft = 0.26in 180 180
Allowable Deflection: 0.26in > Max Deflection: 0.005in
passes deflection check
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 1 of 2
Designer: GTF:Ben Bye Lauren Garvey
Material Properties: Section Properties:Steel Type: A36 Section: W6X9
Fy: 36 ksi Area: 2.68 in2
Fu: 58 ksiE: 29000 ksi Axis X-X (Strong Axis) Axis Y-Y (Weak Axis)
Ix: 16.4 in4 Iy: 2.2 in4
Sx: 5.56 in3 Sy: 1.11 in3
rx: 2.47 in ry: 0.905 in
Member Data:Member ID: Typ. Cantilever Axial Properties (Column Buckling):
Unbraced Length - X-Axis: 4 ft Unbraced Length - Y-Axis: 2 ftK-Condition: e K-Condition: eK-Value: 2.1 K-Value: 2.1
Member Loads: Axial Tension P: 0 kipsMoment - Strong Axis: Mx MAX: 1.021 kip-ftMoment - Weak Axis: My MAX: 0.002 kip-ft
Axial - Tension Check [AISC Spec D1]:Utilization:
ft: 0.00 ksi < Ft: 22 ksi OK 0.0%
Axial - Compression Check [AISC Spec E2]:
Strong Axis - X: Weak Axis - X:KL/rx: 40.8 KL/rx: 55.7 <-- Governs
Cc: 126.1
Governing Effective Slenderness Ratio:KL/r = 55.7 Cc = 126.1 Therefore, use EQN E2-1 [AISC]
Utilization:fc: N/A ksi Fc: 17.8 ksi N/A
Flexure Check - Strong Axis [AISC Spec. F1]: Fbx = 0.6Fy
Utilization:fbx: 2.20 ksi < Fbx: 22 ksi OK 10.2%
Flexure Check - Weak Axis [AISC Spec. F2]: Fby = 0.75Fy
Utilization:fby: 0.02 ksi < Fby: 27 ksi OK 0.1%
Designer: GTF:Ben Bye Lauren Garvey
Member ID: Typ. Cantilever
Combined Stress Check:Axial Compression and Bending [AISC Spec H1]:
F'ex: 89.7 ksi F'
ey: 48.1 ksiCmx: 1 Cmy: 1
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 2 of 2
AISC EQN H1-1
AISC EQN H1-2
AISC EQN H1-3
Axial Tension and Bending [AISC Spec H2]:
AISC EQN H2-1
0.00 + 0.10 + 0.00 = 0.10 < 1.0 OK
Section is satisfactory
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TYPICAL COLUMN: A-36 Steel | W8 x 31 Shape | Supporting Member
Mx-max: 4.825k-ft (strong axis)
My-max: 0.646k-ft (weak axis)
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My-max: 0.646k-ft (weak axis)
Max Deflection: 0.052in
P-max: 3.017k compression
Deflection Check:
Allowable Deflection = h = 8ft x 12in/ft = 0.192in 500 500 Allowable Deflection: 0.192in > Max Deflection: 0.052in
passes deflection check
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 1 of 2
Designer: GTF:Ben Bye Lauren Garvey
Material Properties: Section Properties:Steel Type: A36 Section: W8X31
Fy: 36 ksi Area: 9.12 in2
Fu: 58 ksiE: 29000 ksi Axis X-X (Strong Axis) Axis Y-Y (Weak Axis)
Ix: 110 in4 Iy: 37.1 in4
Sx: 27.5 in3 Sy: 9.27 in3
rx: 3.47 in ry: 2.02 in
Member Data:Member ID: Typ. Column Axial Properties (Column Buckling):
Unbraced Length - X-Axis: 8 ft Unbraced Length - Y-Axis: 8 ftK-Condition: c K-Condition: cK-Value: 1.2 K-Value: 1.2
Member Loads: Axial Compression P: 3.017 kipsMoment - Strong Axis: Mx MAX: 4.825 kip-ftMoment - Weak Axis: My MAX: 0.646 kip-ft
Axial - Tension Check [AISC Spec D1]:Utilization:
ft: N/A ksi Ft: 22 ksi N/A
Axial - Compression Check [AISC Spec E2]:
Strong Axis - X: Weak Axis - X:KL/rx: 33.2 KL/rx: 57.0 <-- Governs
Cc: 126.1
Governing Effective Slenderness Ratio:KL/r = 57.0 < Cc = 126.1 Therefore, use EQN E2-1 [AISC]
Utilization:fc: 0.33 ksi < Fc: 17.7 ksi OK 1.9%
Flexure Check - Strong Axis [AISC Spec. F1]: Fbx = 0.6Fy
Utilization:fbx: 2.11 ksi < Fbx: 22 ksi OK 9.7%
Flexure Check - Weak Axis [AISC Spec. F2]: Fby = 0.75Fy
Utilization:fby: 0.84 ksi < Fby: 27 ksi OK 3.1%
Designer: GTF:Ben Bye Lauren Garvey
Member ID: Typ. Column
Combined Stress Check:Axial Compression and Bending [AISC Spec H1]:
F'ex: 135.5 ksi F'
ey: 45.9 ksiCmx: 1 Cmy: 1
AISC EQN H1-1
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 2 of 2
AISC EQN H1-2
fa/Fa: 0.02 < 0.15
AISC EQN H1-3
0.02 + 0.10 + 0.03 = 0.15 < 1.0 OK
Section is satisfactory
Axial Tension and Bending [AISC Spec H2]:
AISC EQN H2-1
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TYPICAL GIRDER CANTILEVER: A-36 Steel | W8 x 10 Shape | Spanning Member
Mx-max : 1.616k-ft
Pmax : 0k
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Max Deflection: .042in
Deflection Check:
Allowable Deflection = l = 6ft x 12in/ft = 0.4in 180 180 Allowable Deflection: 0.4in > Max Deflection: 0.042in
passes deflection check
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 1 of 2
Designer: GTF:Ben Bye Lauren Garvey
Material Properties: Section Properties:Steel Type: A36 Section: W8X10
Fy: 36 ksi Area: 2.96 in2
Fu: 58 ksiE: 29000 ksi Axis X-X (Strong Axis) Axis Y-Y (Weak Axis)
Ix: 30.8 in4 Iy: 2.09 in4
Sx: 7.81 in3 Sy: 1.06 in3
rx: 3.22 in ry: 0.841 in
Member Data:Member ID: Typ. Girder Axial Properties (Column Buckling):
Unbraced Length - X-Axis: 6 ft Unbraced Length - Y-Axis: 4 ftK-Condition: e K-Condition: eK-Value: 2.1 K-Value: 2.1
Member Loads: Axial Compression P: 0 kipsMoment - Strong Axis: Mx MAX: 1.616 kip-ftMoment - Weak Axis: My MAX: 0.01 kip-ft
Axial - Tension Check [AISC Spec D1]:Utilization:
ft: N/A ksi Ft: 22 ksi N/A
Axial - Compression Check [AISC Spec E2]:
Strong Axis - X: Weak Axis - X:KL/rx: 47.0 KL/rx: 119.9 <-- Governs
Cc: 126.1
Governing Effective Slenderness Ratio:KL/r = 119.9 < Cc = 126.1 Therefore, use EQN E2-1 [AISC]
Utilization:fc: 0.00 ksi < Fc: 10.3 ksi OK 0.0%
Flexure Check - Strong Axis [AISC Spec. F1]: Fbx = 0.6Fy
Utilization:fbx: 2.48 ksi < Fbx: 22 ksi OK 11.5%
Flexure Check - Weak Axis [AISC Spec. F2]: Fby = 0.75Fy
Utilization:fby: 0.11 ksi < Fby: 27 ksi OK 0.4%
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 2 of 2
Designer: GTF:Ben Bye Lauren Garvey
Member ID: Typ. Girder
Combined Stress Check:Axial Compression and Bending [AISC Spec H1]:
F'ex: 67.7 ksi F'
ey: 10.4 ksiCmx: 1 Cmy: 1
AISC EQN H1-1
AISC EQN H1-2
fa/Fa: 0.00 < 0.15
AISC EQN H1-3
0.00 + 0.11 + 0.00 = 0.12 < 1.0 OK
Section is satisfactory
Axial Tension and Bending [AISC Spec H2]:
AISC EQN H2-1
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TYPICAL BRACING JOISTA-36 Steel | W6 x 9 Shape | Bracing Member
Mx-max : 2.735 k
Pmax : 0.768 k Compression
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Max Deflection: .02in
Deflection Check:
Allowable Deflection = l = 4ft x 12in/ft = 0.133in 360 360 Allowable Deflection: 0.133in > Max Deflection: 0.02in
passes deflection check
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 1 of 2
Designer: GTF:Ben Bye Lauren Garvey
Material Properties: Section Properties:Steel Type: A36 Section: W6X9
Fy: 36 ksi Area: 2.68 in2
Fu: 58 ksiE: 29000 ksi Axis X-X (Strong Axis) Axis Y-Y (Weak Axis)
Ix: 16.4 in4 Iy: 2.2 in4
Sx: 5.56 in3 Sy: 1.11 in3
rx: 2.47 in ry: 0.905 in
Member Data:Member ID: Typ. Brace JoistAxial Properties (Column Buckling):
Unbraced Length - X-Axis: 4 ft Unbraced Length - Y-Axis: 4 ftK-Condition: a K-Condition: aK-Value: 0.65 K-Value: 0.65
Member Loads: Axial Compression P: 0.768 kipsMoment - Strong Axis: Mx MAX: 2.735 kip-ftMoment - Weak Axis: My MAX: 0.02 kip-ft
Axial - Tension Check [AISC Spec D1]:Utilization:
ft: N/A ksi Ft: 22 ksi N/A
Axial - Compression Check [AISC Spec E2]:
Strong Axis - X: Weak Axis - X:KL/rx: 12.6 KL/rx: 34.5 <-- Governs
Cc: 126.1
Governing Effective Slenderness Ratio:KL/r = 34.5 < Cc = 126.1 Therefore, use EQN E2-1 [AISC]
Utilization:fc: 0.29 ksi < Fc: 19.6 ksi OK 1.5%
Flexure Check - Strong Axis [AISC Spec. F1]: Fbx = 0.6Fy
Utilization:fbx: 5.90 ksi < Fbx: 22 ksi OK 27.3%
Flexure Check - Weak Axis [AISC Spec. F2]: Fby = 0.75Fy
Utilization:fby: 0.22 ksi < Fby: 27 ksi OK 0.8%
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DEPARTMENT OF ARCHITECTURESchool of Architecture and Allied ArtsUniversity of Oregon
Architecture 462/562Mark Donofrio
Winter 2012
W ShapesStructural Design - Steel Design Spreadsheet
Copyright © 2011 by Mark Donofrio 2 of 2
Designer: GTF:Ben Bye Lauren Garvey
Member ID: Typ. Brace Joist
Combined Stress Check:Axial Compression and Bending [AISC Spec H1]:
F'ex: 935.9 ksi F'
ey: 125.6 ksiCmx: 1 Cmy: 1
AISC EQN H1-1
AISC EQN H1-2
fa/Fa: 0.01 < 0.15
AISC EQN H1-3
0.01 + 0.27 + 0.01 = 0.30 < 1.0 OK
Section is satisfactory
Axial Tension and Bending [AISC Spec H2]:
AISC EQN H2-1