BIRD-WATCHING BOARDWALK ON DUDDINGSTON LOCH
VIRIDIANA AMARAL GURGELANTON ANIKEEVLACHLAN ANDERSON FRANKALEXANDRA ZERVUDACHI
view toward main bird landing
view to Arthurs Seat
view of village
natural camouflage among the reeds
platform faces away from the sun path to avoid being blinded when looking up at the sky
SITING STRATEGYWe decided to site our bird watching boardwalk on the southeast side of Duddingstone Loch, away from the more busy north west side close to the village. Access is from the nearby running track. We felt that this more secluded site gives birdwatchers the opportunity for both long range birdwatching across the lake, as well as close observation of birds within the wetlands, which are currently innacessible. The design leads birdwatchers from the shore onto an island, which they can explore freely.
DESIGN STRATEGYOur design strategy focused on creating a structure for birdwatchers, going beyond a simple viewing plat-form. We applied variations to a simple modular geogetry to create a more elaborate and exciting shape. The zig-zaging shape of the broadwalk provides wider angles of views across the loch as well as offering space for wheel chair manoevering. Structurally it also provides bracing for the broadwalk.
AESTHETIC STRATEGYThe aesthetic strategy of our broadwalk was to integrate it within its surroundings by immitating the slender verstical shape of the reeds that grow out of the water. The variations in height of the balustrade allow for bird watchers to look out across the landscape at the lower points and conceal themselves behind the heigher points in order to observe birds without scaring them off.
STRUCTURE _ PLANS
Columns
Primary beams
Secondary beams
Decking
Variation in pattern
1:50
1:100
STRUCTURE _ SECTION
1:50 section
STRUCTURE _ CONNECTION DETAILS
1:5 section A
1:20 section A
PRO
DU
CED
BY
AN
AU
TOD
ESK
ED
UC
ATI
ON
AL
PRO
DU
CT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY A
N A
UTO
DESK
EDU
CA
TION
AL PR
OD
UC
T
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
1:20 section B
A
B
PRO
DU
CED
BY
AN
AU
TOD
ESK
ED
UC
ATI
ON
AL
PRO
DU
CT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY A
N A
UTO
DESK
EDU
CA
TION
AL PR
OD
UC
T
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY
AN
AU
TOD
ESK
ED
UC
ATI
ON
AL
PRO
DU
CT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY A
N A
UTO
DESK
EDU
CA
TION
AL PR
OD
UC
T
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
STRUCTURE _ CONNECTION DETAILS
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY
AN
AU
TOD
ESK
ED
UC
ATI
ON
AL
PRO
DU
CT
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
PRO
DU
CED
BY A
N A
UTO
DESK
EDU
CA
TION
AL PR
OD
UC
T
PRODUCED BY AN AUTODESK EDUCATIONAL PRODUCT
C
1:5 section C
1:5 plan
STRUCTURE _ BALUSTRADE DETAIL
1:5 section
Sculpture made of larch wood Nicholas Pope,1980 Venice Bienale
1:10 elevation
Discrete steel cable fulfils need for structural bracing while not breaking the vertical aesthetic of the broadwalk
TIMBER PROPERTIESChoice of wood - British Larch
European Larch is known for its natural strength, durability and wateprood property, ideal for the
outside without the use of treatement. Aesthetically, its warm reddish brown or terracota colour with
golden streaks, which fade to silver after prolonged exposure to sunlight perfectly matches the subtle
colour scheme of the loch and its surroungings.
Mechanical Properties
- strength class C24
- Bending fm,k = 24
- Parallel compression fc,0,k = 21
- Perpendicular compression fc,90,k = 2,5
- Shear fv,k = 2,5
- Mean elasticity modulus E = 11.103
Modification factors
Assuming that:
- Service class 3 (external use, fully exposed)
- Load duration long term
- Material solid timber
Therefore,
strength modification factor Kmod = 0,55
height factor (assuming d > 150mm) Kh = 1,0
Instability factor (full torsial constraint) Kcrit = 1,0
Load sharing factor (span < 6m) Kls = 1,1
Moisture factor (solid timber, class 3) Kdef = 2,0
Material factor (soid untreated timber YM = 1,3
CALCULATIONS _ COLUMNSAssume column dimension 100 x 100 mm (100 x 97 in Table 12) x 3000mm
E0.005 = 7.4 kN/mm Rx-x= 28 mm Kc,y = 0.2793
Total area of floor carried by column (worst case) A= 2 x 1.8 = 3.6 m2
(column carries half of the adjacent spans)
Total load carried by each column P = 3.6 m x 4.5 kN/m2 = 16.2 kN
For stress class C24,
Compressive strength parallel to the grain fc,0,k = 21 N/mm2
E 0.05
fc,0,k
=7400
21= 352.58
Slenderness ratio l y =Le
rxx=
300028
=107.14
Maximum permissible stress in the column
€
fc,0,d =kmod ⋅ kc,90 ⋅ kls⋅ fc,0,k
gM
=0.60⋅ 1.0⋅ 1.1⋅ 21
1.3=10.66 N /mm2
kc,90 = 1 as there is no increase in the bearing strength because the applied length ℓ of the
uniformly distributed load q is 3 m > 100 mm
Actual compressive stress
€
s c =PA
=16.2⋅ 103
100⋅ 100=1.62 N /mm2
1800
2000
Check for buckling strength:
Compressive stress (
€
s c ) < Maximum allowable stress (
€
kc,y ⋅ fc,0,d )
1,62 N/m2 0,28.10,66 = 2,97 N/m2
Therefore the Column is safe against buckling
Beam supporting largest area
CALCULATIONS _ PRIMARY BEAMSAssume rectangular section 50mmx220mm
- Area A = 50.220 = 11.103 mm2
- 2nd moment of inertia Ixx = 44,4.106 mm4
- Section modulus Zxx = 403.103 mm3
Bending strength
Maximum bending moment For uniformly distributed load (UDL), w = surface load.span = (imposed load + dead load).span = (5,0 + 0,5). 2,0 = 5,5. 2,0 = 11,1 kN/m
For a point load, P = point load / 2 = 4,5 / 2 = 2,25 kN
→ Total Mmax = Mmax for UDL + Mmax for point load = 4,46 + 1,01 = 5,47 kNm
Maximum bending stress
Bending stress Bending strength13,58 N/mm2 > 11,17 N/mm2
Therefore section is NOT satisfactory in bending, sizing must be reconsidered
Bending strength must be greater than or equal to the maximum bending strength
→ →
Therefore an appropriate section modulus Zxx must be greater than 490
Considering Zxx = 500,2
New section size is 50mm x 245mm
Bending stress Bending strength10,94 N/mm2 < 11,17 N/mm2
Therefore section is satisfactory in bending
Now assume new rectangular section 50mmx245mm
Shear strength
€
fv,d =kmod ⋅ kls⋅ fv,k
gm
=0,55⋅ 1,1⋅ 2,5
1.3=1,16 N /mm2
Maximum shear force for UDL, V = surface load.span.length 2
€
=5,5⋅ 1,8
2= 4,95kN
Maximum shear force for point load, V = P/2 = 2,25 / 2 = 1,13 kN
→ Total maximum shear force V for UDL + V for point load = 9,9 + 1,13 = 11,03 kNm
Maximum shear stress in rectangular section
€
t d =3V2bd
=3⋅ 6,08⋅ 103
2⋅ 50⋅ 245= 0,74N /mm2
Shear stress < Shear strength1,35 N/mm2 1,51 N/mm2
Therefore section is satisfactory in shearing
Deflection of beam
- 2nd moment of inertia Ixx = 61,3.106 mm4
- Section modulus Zxx = 500,2.103 mm3
Max deflection for UDL,
€
wmax =5
384⋅
w⋅ L4
E ⋅ Ixx
=5
384⋅
11,1⋅ 1,8⋅ 103( )4
11⋅ 61,3⋅ 109 =5,83⋅ 1014
2,59⋅ 1014 = 2,25mm
Max deflection for point load,
€
wins =P⋅ L3
48⋅ E ⋅ Ixx
=2,25⋅ 1,8⋅ 103( )3
48⋅ 11⋅ 61,3⋅ 109 =1,31⋅ 1010
3,24⋅ 1013 = 4,04⋅ 10−4 mm (negligable)
→ Total max deflection = Wmax + Wins
= 3,1 + 4,04.10-4 = 3,1 kNm
Final deflection Wfin = W (1+kdef) = 3,1(1+2,0) = 3,1.3 = 9,3 mm Recommended limit of final deflection for a member of span between two supports is150Maximum allowable deflection = L / 150 = 1800 / 150 = 12 mm
Final deflection < Maximum allowable deflection9,3 mm 12 mm
CALCULATIONS _ SECONDARY BEAMSAssume rectangular section 75mmx147mm
- Area A = 75.147 = 11.103 mm2
- 2nd moment of inertia Ixx = 19,7.106 mm4
- Section modulus Zxx = 270.1.103 mm3
Bending strength
Maximum bending moment For uniformly distributed load (UDL), w = surface load.span = (imposed load + dead load).span = (5,0 + 0,5). 0,67 = 5,5. 0,67 = 3,69 kN/m
€
Mmax =w⋅ L2
8=
3,69⋅ 1,92
8=
3,69⋅ 3,618
=13,32
8=1,67kNm
For a point load, P = point load / 2 = 1,67 / 2 = 0,84 kN/m
€
Mmax =P⋅ L
4=
0,84⋅ 1,84
=1,595
4= 0,4kNm
→ Total Mmax = Mmax for UDL + Mmax for point load = 1,67 + 0,4 = 2,07 kNm
Maximum bending stress
Mmax/ Zxx = 2,07 x 106/ 11,17 = 185,3 mm3
270,1 > 185,3
Shear strength
€
fv,d =kmod ⋅ kls⋅ fv,k
gm
=0,55⋅ 1,1⋅ 2,5
1.3=1,16 N /mm2
Maximum shear force for UDL, V = surface load.span.length
€
=5,5⋅ 0,67⋅ 1,9
2= 3,5kN
2
Maximum shear force for point load, V = P/2 = 0,84 / 2 = 0,42kN
→ Total max shear force = V for UDL + V for point load = 3.5 + 0,42 = 3,92 kNm
Maximum shear stress in rectangular section
For beam 75 x 147 mm
€
t d =3V2bd
=3⋅ 3,92⋅ 103
2⋅ 75⋅ 147= 0,53N /mm2
For beam 150 x 147 mm
€
t d =3V2bd
=3⋅ 3,92⋅ 103
2⋅ 150⋅ 147= 0,27N /mm2
therefore , T1 (0, 53)> 1,93 T2(0,27) > 1,93
Therefore section is satisfactory in shearing
Deflection of beam
Max deflection for UDL,
€
wmax =5
384⋅
w⋅ L4
E ⋅ Ixx
=5
384⋅
3,69⋅ 1,9⋅ 103( )4
11⋅ 39,7⋅ 109 =1,43mm
Max deflection for point load,
€
wins =P⋅ L3
48⋅ E ⋅ Ixx
=0,42⋅ 1,9⋅ 103( )3
48⋅ 11⋅ 39,7⋅ 109 =1,37⋅ 10−4 mm
→ Total max deflection = Wmax + Wins = 1,43 + 1,37.10-4 = 1,43 kNm Final deflection Wfin = W (1+kdef) = 1,43(1+2,0) = 1,43.3 = 4,29 mm
Maximum allowable deflection = L / 150 = 1900 / 150 = 12,6 mm
Final deflection < Maximum allowable deflection4,3 mm 12,6 mm
SECOND FLOORAssume column dimension 150 x 150 mm (150 x 147 in Table 12) x 3000mm
E0.005 = 7.4 kN/mm Rx-x= 42.4 mm Kc,y = 0.5536
Total area of floor carried by column (worst case) A= 2 x 1.8 = 3.6 m2
(column carries half of the adjacent spans)
Total load carried by each column:P = 3.6 m x (5.5x2) kN/m2 = 36.4 kN
For stress class C24, the compressive strength parallel to the grain:fc,0,k = 21 N/mm2
€
E0.05
fc,0,k
=7400
21= 352.58
Slenderness ratio
€
l y =Le
rxx
=300042.4
= 70.75
Permissible stress in the column
€
fc,0,d =kmod ⋅ kc,90 ⋅ kls⋅ fc,0,k
gM
=0.60⋅ 1.0⋅ 1.1⋅ 21
1.3=10.66 N /mm2
Actual compressive stress
€
s c =PA
=36⋅ 103
150⋅ 150=1.6N /mm2
Check for buckling strength:
Compressive stress (
€
s c ) < Maximum allowable stress (
€
kc,y ⋅ fc,0,d )
1,62 N/m2 < 0,55.10,66 = 5,90 N/m2
Therefore the column is safe against buckling
WORK DIVISIONCALCULATIONS
-Columns Lachlan-Primars beams Alexandra-Secondary beams Anton-2nd floor Lachlan
DRAWINGS
-Plans & Sections Alexandra-Connection details Anton-Axonometrics Viridiana-Balustrade detail Alexandra-2nd floor Anton, Viridiana
CONCEPTION / RESEARCH
-Design/structural strategy Group decision-Aesthetic form Lachlan, Anton-Siting decision Alexandra-Choice of Timber Viridiana
Top Related