CE-405 STRUCTURAL ENGINEERING - WEC...
Transcript of CE-405 STRUCTURAL ENGINEERING - WEC...
1 1
CE-405
STRUCTURAL ENGINEERING
Credit Hours (3+0)
Instructor:
Muhammad Haroon
Assistant Professor,
Wah Engineering Colleg, Univ of Wah
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 3Dr. Syed Mohammad Ali
What is Bridge?
• A1.2
• Bridge is a structure that has the heaviest responsibility in carrying a free flow of traffic
• Width of the bridge (number of lanes) dictates the traffic volume of a road segment
• The Load Carrying Capacity of a bridge
would dictate the weight of truck allowed
to cross the bridge (load limits can be
posted )
•
– The volume and
– Weight of the traffic of the transportation system.
Golden Gate Bridge California
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 5Dr. Syed Mohammad Ali
Roles and Responsibilities of a Bridge Engineer
• Safe and Economical Design
• The bridge engineer is often involved with several or
all aspects of bridge planning, design, & management
• This situation is not typical in the building
Architect usually heads a team (architects, civil,
structural, mechanical, & electrical engineers)
• In the bridge engineering, the bridge engineer works
closely with other civil engineers (roadway alignment
and design)
• After the alignment is determined, the engineer
often controls the bridge type, aesthetics, and
technical details
• The bridge engineer has significant control over – The design,
– construction, and
– maintenance processes
Sher Shah Bridge Collapse 2007Karachi
Hen-Shen Expwy Japan , Kobe EQ6.9 Mw, 1996
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 6Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Broad Classification of Bridges
Bridge Classification
Material
Steel Concrete Wood Hybrid Stone/Brick
Usage
Pedestrian Highway, Railroad, Aircraft
Structural Form
Slab Girder Truss Arch Suspension
Cable-Stayed
Type Traffic
Highway, Pedestrian, trains, transit, others
Span
Short , Medium & Long
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 7Dr. Syed Mohammad Ali
Classification According to Traffic
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 8Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Classification as per Structural Form
– Girder Bridge
– Arch Bridge
– Truss Bridge
– Suspension Bridge
– Cable-Stayed Bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 9Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Girder Bridge– Most commonly constructed
– Usually used for Short and Medium spans (up to 50 m)
– Structural Action is to carry load in Shear and Flexural
– Economical and long lasting solution for vast majority of bridges
– Decks and girder usually act together to support the entire load in highway bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 10Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Girder Bridge
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 11Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Typical Deck Super-structures Table A4.6.2.2.1-1
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 12Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Typical Deck Super-structures Table A4.6.2.2.1-1
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 13Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Typical Deck Super-structures Table A4.6.2.2.1-1
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 14Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Typical Deck Super-structures Table A4.6.2.2.1-1
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 15Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Typical Deck Super-structures Table A4.6.2.2.1-1
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 16Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Span lengths for various types of Super-structures
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 17Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Arch Bridges
• Arch action reduces flexural stresses (that is Tensile Stresses )
• Arch is predominantly a compression member. Buckling needs attention.
• Can be economical as compared to equivalent straight simply supported girder or truss bridge
• Suitable site would be Valley which has strong foundations on a rocks
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 18Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Arch Bridges
• Generally conventional curved arch rib has high fabrication & erection costs
• Erection easiest for Cantilever Arch and most difficult for Tied Arch
Bridge in Neelum Valley, AJKIs it an Arch?
Tied Arch
Wooden Arch Bridge, Rocky Mountains, Colorado, USA
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 19Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Arch Bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 20Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Truss Bridges
• The primary member forces are axial tension or compression
• The open web system allows deep girders than for an equivalent solid web girder
• This may lead to economy in material and reduced dead weight
• The cost of fabrication and maintenance is high
• The truss is attractive choice in suspension bridges due to its superior aerodynamic behavior
• Truss results in light structure that can be assembled member by member using small lifting capacity equipment
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 21Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Truss Bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 22Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Suspension Bridges
– Major element is a flexible cable, that transfers the loads to the towers and anchorage
– This cable is from High Strength wires
– The deck is hung from the cable by Hangers also of high strength ropes (in tension)
– Suitable for very long spans
– Expensive to build and maintain
Totakan (near Swat)Thakot Bridge over River Indus Golden Gate Bridge California
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 23Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Cable-Stayed Bridges
– In comparison to suspension bridge, the cables are straight rather than curved. Therefore the stiffness is greater
– The cables are anchored to the deck
– All individual cables are shorter than full length of the superstructure.
– Economical over 100-350m, some bridges are as long as 800m
Naluchi, Muzaffarabad, AJk
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 24Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Classification with respect to Span
– Small Span Bridges up to 50 feet (15m)
– Medium Span Bridges up to 250 feet (75m)
– Large Span Bridges 150-500 feet (50-150m)
– Extra Large ( Long ) Span Bridges over 500 feet (150m)
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 25Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Small Span Bridges up to 50 feet (15m)
– Culverts
– Slab Bridges – 40 ft (12m)
– T-Beam Bridge – 30-60 ft (10-20m)
– Wood Beam Bridge
_________________
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 26Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Medium Span Bridges up to 250 feet (75m)
– Pre-cast Concrete Box Beam Bridge – 30-150 ft (10-50m)
– Rolled Steel Beam Bridge up to 100 ft (30 m)
– Pre-cast Concrete I-Beam Bridge – 30-150 ft (10-50m)
– Cast-in-place RC Box Girder Bridge (20-40 m)
– Composite Steel Box Girder
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 27Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Large Span Bridges 150-500 feet (50-150m)
– Composite Steel Plate Girder Bridge
– Cast-in-place Post-Tensioned concrete Box Girder
– Post-Tensioned Concrete Segmental Construction
– Concrete Arch and Steel Arch
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 28Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Extra Large ( Long ) Span Bridges over 500 feet (150m)
– Cable Stayed Bridge
– Suspension Bridge
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 29Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Structural Arrangement
• Bridge types can also be classified according to the location of the main structure elements relative to the surface on which the user travels:
– Main Structure Below the Deck Line
– Main Structure Above the Deck Line
– Main Structure coincides with the Deck Line
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 30Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Structure Below the Deck Line
– Arch Bridges
– Truss-Arch Bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 31Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Structure Above the Deck Line
– Suspension Bridges
– Cable Stayed Bridges
– Through-Truss Bridges
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 32Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Structure coincides with the Deck Line
– Slab (solid and voided)
– T-Beam (cast-in-place)
– I-beam (pre-cast or pre-stressed)
– Wide-flange beam (composite & non- composite)
– Concrete Box (cast-in-place, segmental & pre-stressed)
– Steel Plate Girder (straight & haunched)
– Steel box (Orthotropic deck)*
• *An orthotropic bridge or orthotropic deck is one whose deck typically comprises a structural steel deck plate stiffened either longitudinally or transversely, or in both directions. This allows the deck both to directly bear vehicular loads and to contribute to the bridge structure's overall load-bearing behavior. The orthotropic deck may be integral with or supported on a grid of deck framing members such as floor beams and girders.
• The same is also true of the concrete slab in a composite girder bridge, but the steel orthotropic deck is considerably lighter, and therefore allows longer span bridges to be more efficiently designed.
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 33Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Components
Girders
Guard Rails
Pier / column
Transom / Pier Cap
Diaphragms
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 34Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Components
Guard Rails
Pier / column
Abutment
Abutment
Piles
Pile Cap
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 35Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Components
Pile Cap
Piles
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 37Dr. Syed Mohammad Ali
Types of Bridges & Bridge Components
• Main Components
Multi-column Pier
Isolator / Base Isolator
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 38Dr. Syed Mohammad Ali
Bridge Failures
• Bridges do Fail!
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 39Dr. Syed Mohammad Ali
Bridge Failures
• Bridges do Fail!
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 40Dr. Syed Mohammad Ali
Bridge Failures
• Bridges do Fail!
CE-5154 Intro. to Bridge Engg.Lecture # 02 Email: [email protected] 41Dr. Syed Mohammad Ali
Thanks!