2. Preliminary Design
8
1 2.1 Preliminary Design z Definition z Design Considerations » Safety » Economy » Durability » Aesthetics 2.2 All Existing U.S. Bridges 2003 NBI Data 58.0% 40 0% 50.0% 60.0% 31.2% 8.4% 1.5% 0.5% 0.4% 0.0% 10.0% 20.0% 30.0% 40.0% <50 50-99 100-149 150-199 200-249 >=250 Maximum Span (ft) Total Built = 475,000 Bridges 2.3 Bridges Built, 2003 NBI Data 50% 60% P/S 20% 30% 40% Percent Built Steel RC 0% 10% 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year Built 2.4 Bridge Selection Guide WSDOT 0 90 180 270 360 450 540 630 Pipe Concrete Culvert Plate Arch Span Range (ft) Plate Arch RC Slab RC Tee Beam RC Box Girder PT Conc Box Girder Segmental PT Box Girder PS Conc Slab PS Conc Deck Bulb Tee PS Conc Girder Steel Rolled Girder Steel Plate Girder Steel Box Girder Steel Truss Timber Glulam Timber Cable Stay Bridge Suspension Bridge Floating Bridge Arch Bridge Moveable Span Bridge Tunnel
description
3
Transcript of 2. Preliminary Design
1
2.1
Preliminary Design
Definition
Design Considerations» Safety» Economy» Durability» Aesthetics
2.2All Existing U.S. Bridges 2003 NBI Data
58.0%
40 0%
50.0%
60.0%
31.2%
8.4%
1.5% 0.5% 0.4%0.0%
10.0%
20.0%
30.0%
40.0%
0 0%<50 50-99 100-149 150-199 200-249 >=250
Maximum Span (ft)
Total Built = 475,000 Bridges
2.3Bridges Built, 2003 NBI Data
50%
60%
P/S
20%
30%
40%
Perc
ent B
uilt
Steel
RC
0%
10%
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year Built
2.4Bridge Selection GuideWSDOT
0 90 180 270 360 450 540 630
PipeConcrete Culvert
Plate Arch
Span Range (ft)
Plate ArchRC Slab
RC Tee BeamRC Box Girder
PT Conc Box GirderSegmental PT Box Girder
PS Conc SlabPS Conc Deck Bulb Tee
PS Conc GirderSteel Rolled Girder
Steel Plate GirderSteel Box Girder
Steel TrussTimber
Glulam TimberCable Stay Bridge
Suspension BridgeFloating Bridge
Arch BridgeMoveable Span Bridge
Tunnel
2
2.5Bridge Type Selection CriteriaSite» Type of Crossing – Highway / Waterway» Location – Urban / Rural» Site access / Staging area
Schedule – speed of construction, availability of materialsService Life and Life Cycle Cost» PCA Publication, SR342, "Material Usage and Condition
of Existing Bridges in the U.S.", http://www.cement.org/bookstore/ search for SR342
» Life 365 (SFA, Grace, Master Builders)http://www silicafume org/specifiers lifecycle htmlhttp://www.silicafume.org/specifiers-lifecycle.html
» NIST BridgeLCChttp://www.bfrl.nist.gov/bridgelcc/welcome.html
» NCHRP Report 483 - "Bridge Life-Cycle Cost Analysis", http://gulliver.trb.org/publications/nchrp/nchrp_rpt_483a.pdf
2.6
Concrete Bridge Types
Slab BridgesI-Girder BridgesI Girder BridgesBox-Girder BridgesSegmental BridgesSpliced-Girder BridgesArch BridgesCable-Stayed Bridges
2.7Slab Bridges
Simple, easy to constructWell-suited for spans up to about 50 ftCast-in-place or precast. Reinforced or prestressedCan be made continuous with abutments and piers to mobilize the frame action
2.8I-Girder Bridges
Most popular bridge type For spans up to about 160 ft. Common sizes: AASHTO/PCI Type I-VI (28” to 72”) and Bulb-Ts (54”, 63”, and 72”)
Walnut Lane Bridge, Philadelphia, PA
3
2.9Box Girder Bridges
FHWA Showcase Bridge, Cambridge, OH 115’-6” Span
Second-most popular after the I-girder bridgesCommon sizes: AASHTO/PCI Type BI-BIV (27” to 42”)Span Range: 60 ft – 105 ft. Use of side-by-side boxes without a wearing course offers speedy construction
2.10Segmental Bridges
Economical durable aesthetically pleasingSagadahoc Bridge, Bath-Woolwich, ME, Span 420’
Economical, durable, aesthetically pleasingSpan-by-span or balanced cantilever constructionPost-tensioned or/and Cable-stayedTypical segment type: Concrete boxCast-in-place or precastPerfectly suited for gradual and sharply curved alignments
2.11Spliced Girder Bridges
Innovative technique for very long spansLong-segment precast prestressed girders splicedSpans of more than 300 ft have been achieved
Shelby Creek Bridge, KY, Span 250 ft.
2.12Arch BridgesMost efficient shape for supporting gravity loadingCast-in-place or precastThe longest existing
t h b idconcrete arch bridge: Wanxian Bridge, China. Span = 1378 ft. The first segmental precast concrete arch bridge in the U.S.: The Natchez Trace P k F kliParkway, Franklin, Tennessee. Dual Spans of 582 ft. and 462 ft
4
2.13Cable-Stayed Bridges
Structurally efficient use of materials.yConcrete in compression and steel stays in tension.Economical and aesthetically pleasing. Most popular type for signature bridges. The longest concrete cable-stayed bridge in the U.S.: Dames Point, Jacksonville, Fl. Main Span = 1300 ft
2.14
2.15AASHTO Bridge Design Specifications
Standard SpecificationsLRFD S ifi tiLRFD SpecificationsState Practices
2.16
Preliminary Design
CIP Short Span Bridges» Slab Bridges» Slab Bridges» T-Beam Bridges
Precast, Prestressed» Standard AASHTO/PCI Girders
I Girders– I-Girders– Box Girders
5
2.17Properties, Dimensions and Maximum Spans for AASHTO-PCI I-Girders
2.18Properties, Dimensions and Maximum Spans for AASHTO-PCI I-Girders
2.19Properties, Dimensions and Maximum Spans for
PCI Bulb Tee Girders
2.20Properties, Dimensions and Maximum Spans for
PCI Bulb Tee Girders
6
2.21Properties, Dimensions and Maximum Spans for New England Bulb Tee Girders
2.22Properties, Dimensions and Maximum Spans for New England Bulb Tee Girders
2.23Properties, Dimensions and Maximum Spans for AASHTO-PCI Box Girders
2.24Properties, Dimensions and Maximum Spans for AASHTO-PCI Box Girders
7
2.25
Design Chartsfor
I-GirdersSimple Spans
Illinois DOT
2.26
Design Chartsfor
I-GirdersContinuous Spans
Illinois DOT
2.27
5’-6”
Conto.c.
o.c.S/S
5’-6”
Cont
S/S
9’-0”
o.c.
2.28
Design Charts for I-GirdersIllinois DOT
8
2.29
Design Examples developed by FHWA-AASHTO based on LRFD Specs, Second Edition, 1998 and Interims through 2002:
http://lrfd.aashtoware.org/?siteid=34&pageid=339
