gumjae bridge - extradosed bridge parametric study
DESCRIPTION
MidasUser.comExtradosed Bridge Design and Construction Gyumjae Bridge ProjectTRANSCRIPT
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Extradosed Bridge Design
and Construction
Modeling, Integrated Design & Analysis Software
MIDAS Information Technology Co., Ltd.
Naga Ravi Kiran
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Extra Dosed Bridge – A Introduction1
Contents
Gyumjae Bridge Project2
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Introduction
Cable Stayed Bridge Extradosed Bridge
What is the difference?
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Introduction
Cable Stayed Bridge
Tension
Compression
Extradosed Bridge
Compression
Tension
Prestress
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Structural Behavior
Cable Stayed Bridge Extradosed Bridge
Stay cables vertically support the girder like
elastic bearings to the girder
Extradosed cables transmit longitudinal force
to the girder like post-tensioning tendons with
very large eccentricities.
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Design Criteria for Geometry
Span by depth ratio: L/hc = 30-35
Span by tower height ratio: L/Ht = 15
Side span to main span ratio: L1/L = 0.6-0.8
Cable arrangement: Semi-fan or harp cable arrangement
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Advantages
Suitable for spans of 100-200 m
No need for diaphragms at anchorage locations
Use of normal prestressing anchorages
No need for tendon adjustment
Smaller stress change in cables due to live loads
More compact pylons
Less changes in deck deflection during construction by Balanced Cantilever Method
Simplified construction due to Lower height of pylons.
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Analysis Procedure
Analysis for an Extradosed bridge is done in 2 steps:
1. Preliminary analysis to find cable forces or Final Stage Analysis:
a) Full Modeling without Construction stages
b) Simple linear static analysis
c) Calculation of Unknown Load factors for Initial Cable force.
2. Design Stage Construction Analysis:
a) Full model along with the Construction stages
b) Application of Initial Cable pretension
c) Construction Stage analysis
d) Time dependent Material Analysis
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Analysis Procedure
Final Stage Analysis:
The starting point for design of a cable stayed bridge is an idealised stressed state at a given
time
This is defined as the “Final Stage”
Static and Dynamic analyses
and section design are
---------undertaken using th
e final stage
The construction sequence and cable
installation forces are developed such
that the final stage is achieved at the
given time
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Analysis Procedure
Cable bridges are highly redundant structures
• This gives the designer flexibility to prescribe a set of cable forces that will achieve a preferred
final stressed state for the deck, pylons and cables under a given loading condition (dead + SDL)
Deflection
Deck Moment Distribution
Instantaneous Dead Load Instantaneous Dead Load + Cable Prestress Forces
Deflection
Deck Moment Distribution
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Analysis Procedure
Design Stage Construction Analysis:
•Objectives of design stage construction analysis
• To determine the forces in the cable stays at each construction stage
• Check stresses in the girder, pylon and cables at each construction stage
• Check deformations of the structure at each construction stage
•Assumptions
•Adopt an assumed construction sequence
•Assumed construction loading and ambient conditions
Arrive at the design final stage condition
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Introduction to Extra Dosed Bridge1
Contents
Gyumjae Bridge Project2
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2. Project outline
Name
Goal
Construction scale
Gyumjae Bridge Basic Design of Construction [Developed by: Seoul Department
of Transportation]
Construction of a Bridge and Highway to connecting Dong Dae Moon Gu Hwui
gyung dong and Jung Lang Gu Myun Mok Dong and deal with the expected
development and traffic flow with Mang Woo Ro, Sa Ga Jung Gil, Dong 2 Ro, Ha
Chun Ro, and etc.
Construction scale
- Total span: 1,085M
- Bridge Length : 393M
Across length of Jung-lang stream: Width 24M, Total Length 225M
Connecting bridge: Width 15M, Length 168M
- Expansion of road: Width 30M, Length 692M
Location The Bridge is located between the three way of Hweekyung Middle and High
School of Dongdaemungu Hweekyung dong, and four way of Junglanggu Myunmok
dong Dong 2 Street.
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3. Project Location
Total Length: L=1085m
Road expansion: B=30m, L=692m
Main Bridge: B=24m, L=225m
Connection Bridge: B=15m, L=168m
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4. Structure of Steel Arch Bridge
Pla
nS
ection
Estimated cost of Construction
Budget assumed : $19.87 Million
(Nielsen Arch : $4500/㎡)
Underestimated Construction budget
at preliminary design
$13.54 Million (Arch : $3200/㎡)
Transverse Section
Discu
ssion
◎ Bridge Dimension
Interference between the bicycle path and pier
Irregular span ratio of the main and the connected Bridge
(1:3.5:1)
Lack of originality since Ihwa Bridge which is
preliminary designed has the same structure
L = 40.0 + 140.0 + 40.0 = 220.0m,
B = Nielsen Arch : 24.9m
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Pla
nS
ection
Discu
ssion
◎ Bridge Dimensions
The form as an Extrodosed Bridge will be the first trial in Seoul
but has been imported actively recently
Maximizing the wide open view for the users by locating the Main tower and
Cables in the center
Estimated cost of Construction
About $18.16 Million
(Unit Construction cost: $3400/㎡)
Transverse Section
L = 60.0 + 105.0 + 60.0 = 225.0m, B=23.74m
4. Structure of Extradosed Bridge
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Cable arrangements
FAN arrangement
Harp arrangement
Number
of Cables
7 lines on
one side
(0.6”-27)
(0.6”-29)
(0.6”-31)
Main
Tower Height
H=10,12,14m
L=105.0m
(L/8~L/12)
Section
Uniformed section
H=2.5m
L=105.0m
(L/30~L/60)
Cable arrangement:FAN arrangement
Number of Cables: 7 lines (0.6”-29EA)
Height of the Main Tower:H=12.0m (L/8.75)
Section: Uniformed Section 2.5m(L/40)
Optimum Design of Bridge
Pre
limin
ary
Desig
n
EXTRADOSED Bridge with main tower, 3 span
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Bird’s eye view
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Driver’s eye view
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Transverse section – Main Bridge Transverse section – Connected Bridge
Side Perspective
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5. Construction Method
1) Construction method of EXTRADOSED PSC BOX GIRDER Bridge
The current construction methods of Extradosed PSC BOX Girder Bridges can be categorized in FSM (Full
Staging Method) or BCM (Balanced Cantilever Method).
Construction Method F.S.M
B.C.M
Full Staging Method
Balanced Cantilever Method
Name
Characteristics of the Construction Method
Restrictions Duration Economic Constructability
F.S.M
Restrictions by the bottom
conditions are crucial,
depending on the supporting
system. Restricted by Weather
Construction is fast due to
the lumped pouring method.
Economical efficiency is
determined by the height of the
supporting.
Lower pier is more cost-effective
There are plenty of domestic
bridges constructed by this method.
Easy to construct
B.C.M
Less restrictions by the bottom
condition, weather, and
environment
Slow construction due to
forward construction stage
method
Cost-effective if higher pier or if
there is limited space underneath
the bridge. For instance, bridge
over rail road, bridge over the
sea.
Construction management is
complicated due to having
measurements of each stage.
Similar construction of each stage
will increase the skill to construct
another stage.
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1) F.S.M construction (1/2)
The F.S.M. construction applied for P.S.C Box Girder bridge is a method continuously pouring concrete on site.
The method installs supports for the entire area till concrete gains its proper strength.
The supports are intended to uphold temporarily the self weight of the concrete, concrete forms, and workbenches.
Introduction
Low cost of equipment, simple method of construction
Cost effective for level ground and low bridges
Fast construction, stable supports during construction
Mostly used for PSC BOX Girder bridge
Characteristics
Fully supported Girder Supported
Classification
Partially supported
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The order of Construction
Install supports
Install platform
Install concrete form
Install Reinforcement, P.S steel
Pouring concrete and cure
Pre-stressing
Grouting
Remove concrete form
Remove supports
1) F.S.M construction (2/2)
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2) B.C.M Construction (1/2)
B.C.M construction applied for the P.S.C. Box Girder Bridge is a method pouring concrete on site for each segment. The bridge construction is
started with the construction of the cap of the pier and followed by forming segments of the bridge by using a special device named Form Traveler.
Introduction
Little effect of supporting conditions
Possible for constructing long suspension bridge without heavy duty equipment
Less weather effect
Accuracy of the construction can be enhanced by the correction of errors at each construction stage.
Precise construction and management needed due to changes in the structural system by each construction stage.
High construction fee compared with F.S.M
Characteristics
Continuous arrangements of Sheath which places the reinforcement
Accurate calculation of friction loss and CAMBER management for each construction stage
Disperse of the stress applied to reinforcement connections
Secondary stress due to creep and shrinkage of concrete
If the assumptions change during construction, design should also change with reflecting Feed-Back to construction.
Since the creep and shrinkage of concrete and the relaxation of the reinforcement are considered, the follows should be taken into consideration.
Considerations
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Order of Construction
Assembling Construction
vehicle (F/T)
Start of Construction
Construct supports
Completion of successive support
constructionAssemble Construction
FormAssemble
reinforcement
Assemble Sheath pipe
Pouring/curing concrete
Tension of reinforcement
Grouting
Construct pier, temporary supporting
system and the main tower
Construction of SEGMENT
Construction of side-span support
Water proof of bridge surface
Finish
Move and re-construct the form traveler
Completion of the 1st span / move the
form traveler
Construct the connection
rep
eat
2) B.C.M Construction (2/2)
repea
t
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6. Structural analysis of each construction method
1) Analysis of each construction based on Elastic Link (Compression only) of midas Civil
Examine the principle role of Elastic Link (Compression Only) for midas Civil construction stage
analysis by using a simple example of Prestress Concrete structure with temporary support
Explaining statically indeterminate structure with displacement method
Compression Only stiffness of the Elastic Link is the total force of Compression only added by
each construction stage
Principle
Approach
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S
A
M
P
L
E
1) Analysis theory of each construction stage (1/5)
The problem includes successive
construction model for P.S.C structure by
FSM, which contains 10m beam, eccentric
distance 350mm, and constant Prestressed
Force applied.
M
O
D
E
L
Modeling is based on midas Civil applying
the supports as Elastic Link Boundary
Conditions (Compression Only K=∞)
Compression Only is the total moment
when Dead Load and Prestressed Force
Loading is applied as compressive condition
is effective and the tension boundary
condition is excluded.
[ K3=K4=K5=K6=K7=∞ ) E ffective E lastic Link (C om pression O nly)K 3 K 4 K 5 K 6 K 7
D ead Load & P restressed Force Loading
10.000
850
150
E lastic Link (C om pression O nly)
M odeling
K 1 K 2 K 3 K 4 K 5 K 6 K 7 K 8 K 9
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S
A
M
P
L
E
Analysis : Apply displacement method
Calculate the displacement Δ1 of the
statically determinate structure with the total
of Dead & Prestressed Force Loading.
M
O
D
E
L
Calculate springs reaction force by
calculating the displacement of Indeterminate
Force Loading, and the displacement
calculated are indicated as function
F3~F7. Δ2 = f(Fi)
Unknown reaction force is analyzed by
calculating the secondary Indeterminate
Force (Fi) which occurs due to the mean
displacements (Δtot=Δ1-Δ2, Δtot=(K/Fi) ) of
each springs (K3~K7)
Δ tot
Δ 2Δ 1
Δ tot = Δ 1 - Δ 2
Δ tot = f(K /Fi) : Function of Fi & K (stiffness of spring for bents)
= K now n value ( D isplacem ent of D eterm inate B eam )
D ead Load & P restressed Force Loading
Δ 1 = D isplacem ent of D ead & P restrssed Force Loading
Δ 1
F3 F4 F5 F6 F7
Δ 2
Δ 2 = D isplacem ent of Indetderm inte Force Loading
= f(Fi) Function of Fi(indeterm inate Force)
1) Analysis theory of each construction stage (2/5)
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S
A
M
P
L
E
Model that applied Elastic Link (Compression only) to each temporary support
Tendon 1
10.000
850
150
A p= Φ 12.7- 3E A
1.500
850
150
F
S
M
M
O
D
E
L
1) Analysis theory of each construction stage (3/5)
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D
E
A
D
+
P
T
M
O
M
E
N
T
(1)
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
-3.8
14250(Stress) 14250(Stress)
2 .857 2.985
-2.679
-2 .679 -0.453 -0.453
-2.679
-2.679
2.985 2.857
MIDAS/Civil
POST-PROCESSOR
BEAM DIAGRAM
MOMENT-y
2.98548e+000
2.47056e+000
1.95564e+000
1.44073e+000
9.25809e-001
4.10892e-001
0.00000e+000
-6.18942e-001
-1.13386e+000
-1.64878e+000
-2.16369e+000
-2.67861e+000
STAGE:CS1
CS: Dead Load
Last Step
MAX : 9
MIN : 7
FILE: PSC BEAM-B~
UNIT: tonf·m
DATE: 11/09/2005
VIEW-DIRECTION
X: 0.000
Y:-1.000
Z: 0.000
-13.526
-5.000 0.897 0.892 -0.305 -0.305 0.892 0.897
-5.000
-13 .526
MIDAS/Civil
POST-PROCESSOR
BEAM DIAGRAM
MOMENT-y
8.97181e-001
0.00000e+000
-1.72517e+000
-3.03634e+000
-4.34752e+000
-5.65869e+000
-6.96987e+000
-8.28104e+000
-9.59221e+000
-1.09034e+001
-1.22146e+001
-1.35257e+001
STAGE:CS1
CS: Summation
Last Step
MAX : 8
MIN : 1
FILE: PSC BEAM-B~
UNIT: tonf·m
DATE: 11/09/2005
VIEW-DIRECTION
X: 0.000
Y:-1.000
Z: 0.000
Moment Summation Dead Load Moment
1) Analysis theory of each construction stage (4/5)
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M
O
M
E
N
T
(2)Tendon Primary Moment Tendon Secondary Moment
5 .669 11.338
17.006 17.006 13.732 13.732 17 .006 17.006 11.338
5.669
MIDAS/Civil
POST-PROCESSOR
BEAM DIAGRAM
MOMENT-y
1.70065e+001
1.54604e+001
1.39144e+001
1.23683e+001
1.08223e+001
9.27625e+000
7.73021e+000
6.18416e+000
4.63812e+000
3.09208e+000
1.54604e+000
0.00000e+000
STAGE:CS1
CS: Tendon Secon~
Last Step
MAX : 3
MIN : 1
FILE: PSC BEAM-B~
UNIT: tonf·m
DATE: 11/09/2005
VIEW-DIRECTION
X: 0.000
Y:-1.000
Z: 0.000
-13.526 -13.526 -13 .526 -13.526 -13.526 -13.526 -13.526 -13.526 -13.526 -13 .526
MIDAS/Civil
POST-PROCESSOR
BEAM DIAGRAM
MOMENT-y
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
-1.35257e+001
STAGE:CS1
CS: Tendon Prima~
Last Step
MAX : 1
MIN : 1
FILE: PSC BEAM-B~
UNIT: tonf·m
DATE: 11/09/2005
VIEW-DIRECTION
X: 0.000
Y:-1.000
Z: 0.000
Summation DeadTendon
Primary
Tendon
SecondaryRemarks
F3 -1.68 -10.62 0 8.94
+ Tension (tonf)
- Compression (tonf)
F1, F2, F8, F9 are excluded
F4 -4.74 -1.65 0 -3.09
F5 -3.86 -3.5 0 -0.36
F6 -4.74 -1.65 0 -3.09
F7 -1.68 -10.62 0 8.94
Axial Load of Springs (ton)
1) Analysis theory of each construction stage (5/5)
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Steps of Construction
2) FSM construction stage analysis (1/4)
종 단 면 도 개 요
하부 기초시공
교대 및 교각 시공
A1
P1 P2
A2
1단계 공사
주형 1단계 상부거더 설치용 동바리
주형 1단계 거푸집 설치및 철근
4단계 공사
주탑부 시공
A1
P1 P2
A2
H.W.L 17.05
A1
P1 P2
A2
5단계 공사60.000m105.000m60.000m
60.000m105.000m60.000m
16.000m
동부간선도로
(B=14.0X4.7m)
주형 1단계 콘크리트 타설
A1
P1 P2
A2
2단계 공사
(1단계 타설)
74.500m
75.000m
주형 2단계 상부거더 설치용 동바리
주형 2단계 거푸집 설치및 철근
A1
P1 P2
A2
75.000m
(2단계 타설)
74.500m
15.000
사재케이블 Pylon1 Pylon2 대칭으로
2단계 상부거더 설치용 동바리 철거
H.W.L 17.05
74.500m
74.500m
3단계 공사
16.000m
동부간선도로
(B=14.0X4.7m)
16.000m
동부간선도로
(B=14.0X4.7m)
동부간선도로
(B=13.0X4.7m)
동부간선도로
(B=13.0X5.93m)
16.000m
동부간선도로
(B=14.0X4.7m)
동부간선도로
(B=14.0X5.97m)
동부간선도로
(B=13.0X4.7m)
15.000
(1단계 타설)
면목역
면목역
면목역
면목역
면목역
휘경여중고
휘경여중고
휘경여중고
휘경여중고
휘경여중고
STEP
거치
가공조립
거치
가공조립
주형 2단계 콘크리트 타설
주형 1단계 상부거더 설치용 동바리
철거
1단계
2단계
3단계
4단계
5단계
74.500m
15.000
동부간선도로
(B=13.0X4.7m)
74.500m
15.000
동부간선도로
(B=13.0X4.7m)
상부주형 시공완료
내측부터 순차적으로 거치 및 긴장
Pylon1 Pylon1
시공완료
(1단계 타설)
(1단계 타설)
1
2
3
4
5
Profile
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1st Construction Stage: Model and activate side span temporary supports by Elastic link and Support
2nd Construction Stage: Remove side span temp. supports, and activate temp. supports of main span
3rd Construction Stage : Activate the main tower and place the diagonal tension-cables in order
2) FSM construction stage analysis (2/4)
Structural Analysis of each construction stage using MIDAS CIVIL
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4th Construction Stage: Complete diagonal Tension Cables, and remove temp. supports of main span
5th Construction Stage : Pavement and Finishing => Completion of Construction
Design Condition
① Structure: 3 span continuous EXTRADOSED P.S.C BOX Bridge ② Grade: Excellent
③ Dimensions: L = 60.0 + 105.0 + 60.0 = 225.0 m ③ Bridge Width: B = 23.740 m (4 lanes both way)
⑤ Thickness: H = 2.50 m (equal section) ⑥ Inclination: S = (±) 0.5 %
⑦ Plane surface alignment: R = ∞ ⑧ Construction method: F.S.M (Full Staging Method )
⑨ Prestress construction: Post-Tensioning Method
Structural Analysis of each construction stage using Midas Civil
2) FSM construction stage analysis (3/4)
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Upper Combined Stress (Mpa)
Allowable Tensile Stress:
3.20 Mpa
Maximum Tensile Stress:
0.24 Mpa
Allowable Compression
Stress:
-16.00 Mpa
Maximum Compression
Stress:
-10.10 Mpa
2) FSM construction stage analysis (4/4)
Lower Combined Stress (Mpa)
Allowable Tensile Stress:
3.20 Mpa
Maximum Tensile Stress:
0.88 Mpa
Allowable Compression
Stress:
-16.00 Mpa
Maximum Compression
Stress:
-11.75 Mpa
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1st Construction Stage: Construct Main Pier and Pylon
`
2nd ~9th Construction Stage: Employ F/T Seg. Construct Diagonal cables
10th Construction Stage: FSM construction for Side Span and apply Pylon1girder Time Load as 255 days
Structural Analysis of each construction stage using Midas Civil
3) BCM Construction Stage Analysis (2/4)
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7. Economical Analysis
F. S. M B. C. M
Equipment,
Maintenance &
Operation time
Equipment Time Equipment Time
Construction time of temp. supports for Side-Span
Maintenance time of temp. supports for Side-Span
Maintenance time of temp. supports for Side-Span
& Main Span
Maintenance time of temp. supports for Main Span
20 days
14 days
21 days
21 days
8Seg. × 15 days (Time per each Seg.)
Side Span Key Seg. Connection
Main Span Key Seg. Connection
120 days
30 days
30 days
Maintenance time of temp. support placed in water2.5
monthsF/T Operation time 6 months
Cost
Quantity Cost Quantity Cost
Temp. support 11.2M
(USD)
F/T(4 vehicle of 2 group)
Set up, pull down (twice)
Operation Cost
1
1
35 Seg.
1.8M
0.3M
0.05M
Camber 35 times 0.15M
Net Construction
Cost13M (USD) 14.1M (USD)
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8. Conclusion
Cost effective
For applying F.S.M. there has been 10% reduction of the construction Cost.
Construction B.C.M has a long term of construction since it requires accuracy of managing Camber and
several Seg. Construction stage.
Applying F.S.M workability increases and construction time can reduce
Comparison and analysis of applicative and efficiency B.C.M. with F.S.M.
⇒ F.S.M. is cost effective, easier to construct, structurally conservative than B.C.M.
For considering restrictions of lower part of F.S.M., midas Civil uses Elastic Link-Compression only function to
analyze each construction stage and optimizes the temporary support usage plan
Analyzed for the considerations of constructing Gyumjae bridge which is construction above Junglang river,
construction over east-west highway, flood control. ⇒ Comparison and summary of analysis of F.S.M. and B.C.M.
using equal section height of 2.5m Extradosed Bridge.
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Dead Load
B.C.M: Maximum negative moment on supports are relatively greater than Maximum
positive moment in the middle point. The moments are concentrated to the supports.
F.S.M: The moment of the supports and the middle point are relatively balanced.
Moment after 10,000 days
Method F. S. M B. C. M
Dead
Load`
Mid-point 255,900 kN-m 22,540 kN-m
Support -384,800 kN-m -531,500 kN-m
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Cable Force
Reaction force of the moment force due to Dead load
Since on B.C.M positive moment does not occur for diagonal cable forces and the resistance force of
cantilever beam dead load is required, the stress distribution to diagonal cables can be higher than F.S.M.
Moment after 10,000 days
Method F. S. M B. C. M
Cable
Force`
Mid-Point -212,000 kN-m 0 kN-m
Support 297,900 kN-m 449,900 kN-m
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Dead + Cable Positive moment of B.C.M is twice smaller than Positive moment of F.S.M
Negative moment also occurs very small and B.C.M shows profitable stress distribution.
Moment after 10,000 days
Method F. S. M B. C. M
DEAD +
CABLE`
Mid-Point 48,840 kN-m 27,560 kN-m [56.4%]
Support -86,890 kN-m -81,540 kN-m [93.8%]
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Tendon Primary
For B.C.M construction Cantilever Tendon is added on the upper part to resist excessive negative moment.(Efficient to place internal tendon especially bottom tendon)
For F.S.M. construction it is difficult to place certain tendon at the negative and positive moment. Comparing the sum of moment BC.M. shows more efficient aspect on Positive and Negative moment.
Moment after 10,000 days
Method F. S. M B. C. M
Tendon
Primary
Mid-Point -70,400 kN-m Total : -21,560 kN-m -57,830 kN-m Total : -30,270 kN-m
Support 62,950 kN-m Total : -23,940 kN-m 80,620 kN-m Total : -920 kN-m
Structural analysis comparison(4/9)
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Tendon Secondary
Tendon Secondary Moment is decided by placement and the amount of tendon. F.S.M.
shows efficiency in both positive and negative moment.
However, in the total sum B.C.M. shows efficiency in analysis.
Moment after 10,000 days
Method F. S. M B. C. M
Tendon
Secondary
Mid-Point 33,390 kN-m Total : 11,830 kN-m 38,940 kN-m Total : 8,670 kN-m
Support 23,200 kN-m Total : -40 kN-m 5,500 kN-m Total : 4,580 kN-m
Structural analysis comparison(5/9)
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Creep Secondary
Creep Secondary Moment behaves similar to the case of Dead Load.
In the total sum of positive moment B.C.M. shows efficiency but, in the negative moment
since the Creep Secondary acts F.S.M. show efficiency.
Moment after 10,000 days
Method F. S. M B. C. M
Creep
Secondary
Mid-Point 4,639 kN-m Total : 16,469 kN-m 0 kN-m Total : 8,670 kN-m
Support -16,950 kN-m Total : -17,690 kN-m -35,730 kN-m Total : -31,150 kN-m
Structural analysis comparison(6/9)
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Shrinkage
Secondary
Shrinkage Secondary Moment shows similarity in both method.
Similar to Creep Secondary moment the total sum of positive moment B.C.M. shows
efficiency but, in the negative moment since the Shrinkage Secondary acts F.S.M. show
efficiency.
Moment after 10,000 days
Method F. S. M B. C. M
Shrinkage
Secondary
Mid-point 9,980 kN-m Total : 26,449 kN-m 9,177 Kn-m Total : 17,847 kN-m
Support -13,230 kN-m Total : -30,920 kN-m -15,060 Kn-m Total : -46,210 kN-m
Structural analysis comparison(7/9)
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Conclusion of
Stress analysis
Structural analysis shows that on the final combination both Method of construction has
similar results.
For stress aspect F.S.M. shows greater and conservative. However since the placement
of Continuity Tendon is functioned to greater section force, it is inefficient for placing
tendon.
Special Loads (D + CF + LI + PS1 + PS2 + CRSH2 + SD)
Method F. S. M B. C. M
Upper limit
stress
(MPa)
Bottom limit
stress
(MPa)
Structural analysis comparison(8/9)
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Diagonal stress
of each
Construction stage
The results of equally sectioned (H=2.5m) and 7 (0.6”-29EA) diagonal cables placed shows
that B.C.M. contains construction stages that exceed the allowable stress and becomes
conservative at the final stage.
Therefore for equal section, diagonal force is greater in B.C.M. and becomes conservative
after constructing continuous⇒ For applying B.C.M varing section is more efficient.
Method F. S. M B. C. M
PY-1
Mid-span
Diagonal
Stress
Construction Allowable Max: 4,221kN Min: 3,554kN Allowable Max: 4,746kN Min: 3,687kN
Finish 4,585 kN Max: 4,109kN Min: 3,833kN 4,585 kN Max: 4,126kN Min: 3,874kN
3200.0
3400.0
3600.0
3800.0
4000.0
4200.0
4400.0
4600.0
4800.0
1단계
2단계
3단계
3-1단계
3-2단계
3-3단계
3-4단계
3-5단계
3-6단계
4단계
5단계
완공단계
시공단계
사재
장력
(kN
)
허용응력
C8
C9
C10
C11
C12
C13
C14
3200.0
3400.0
3600.0
3800.0
4000.0
4200.0
4400.0
4600.0
4800.0
1단계
2단계
3단계
4단계
5단계
6단계
7단계
8단계
9단계
10단계
11단계
12단계
완공단계
시공단계
사재
장력
(kN
)
허용응력
C8
C9
C10
C11
C12
C13
C14
Structural analysis comparison(9/9)
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Q & A