AASHTO LOAD AND RESISTANCE FACTOR LRFD BRIDGE DESIGN - - PowerPoint PPT Presentation

▶
aashto load and resistance factor lrfd bridge design
SMART_READER_LITE
LIVE PREVIEW

AASHTO LOAD AND RESISTANCE FACTOR LRFD BRIDGE DESIGN - - PowerPoint PPT Presentation

Oct 31, 2023 361 likes •956 views

AASHTO LOAD AND RESISTANCE FACTOR LRFD BRIDGE DESIGN SPECIFICATIONS LRFD IMPLEMENTATION BY OHIO DEPARTMENT OF TRANSPORTATION 1. All new bridges on which States initiate preliminary engineering after October 1, 2007, shall be

slide-1
SLIDE 1

AASHTO LOAD AND RESISTANCE FACTOR “LRFD” BRIDGE DESIGN SPECIFICATIONS

slide-2
SLIDE 2

LRFD IMPLEMENTATION BY OHIO DEPARTMENT OF TRANSPORTATION

slide-3
SLIDE 3

http://www.fhwa.dot.gov/bridge/lrfd/index.htm

  • 1. All new bridges on which

States initiate preliminary engineering after October 1, 2007, shall be designed by the LRFD Specifications.

slide-4
SLIDE 4

http://www.fhwa.dot.gov/bridge/lrfd/index.htm

  • 2. All new culverts, retaining

walls, and other standard structures on which States initiate preliminary engineering after October 1, 2010, shall be designed by LRFD Specifications, with the assumption that the specifications and software for these structures are "mature" at this time.

slide-5
SLIDE 5

http://www.fhwa.dot.gov/bridge/lrfd/index.htm

  • 3. States unable to meet these

dates will provide justification and a schedule for completing the transition to LRFD.

slide-6
SLIDE 6

http://www.fhwa.dot.gov/bridge/lrfd/index.htm

  • 4. For modifications to

existing structures, States would have the option of using LRFD Specifications

  • r the specifications which

were used for the original design.

slide-7
SLIDE 7

http://www.dot.state.oh.us/se/

slide-8
SLIDE 8
slide-9
SLIDE 9
  • 1. Major Projects as defined by the

PDP – Projects starting Step 6 after July 20, 2007 shall have the structures designed using the LRFD Bridge Specifications.

slide-10
SLIDE 10
  • 2. Minor Projects as defined by the

PDP – Projects starting Step 3 after July 20, 2007 shall have the structures designed using the LRFD Bridge Specifications.

slide-11
SLIDE 11
  • 3. Minimal Projects as defined by

the PDP – Projects starting Step 1 after July 20, 2007 shall have the structures designed using the LRFD Bridge Specifications.

slide-12
SLIDE 12
slide-13
SLIDE 13

Local projects using the Federal Aid and the ODOT PDP process shall have the structures designed using the LRFD Bridge Specifications after October 1, 2007 .

slide-14
SLIDE 14

This commitment does not apply to the rehabilitation of existing structures. Until further notice, the design for rehabilitation

  • f existing structures should be in

accordance with the AASHTO Standard Specifications for Highway Bridges, 17th Edition, and the ODOT Bridge Design Manual.

slide-15
SLIDE 15

This commitment does not apply to the rehabilitation of existing structures. Until further notice, the design for rehabilitation

  • f existing structures should be in

accordance with the AASHTO Standard Specifications for Highway Bridges, 17th Edition, and the ODOT Bridge Design Manual.

slide-16
SLIDE 16

This commitment does not apply to the rehabilitation of existing structures. Until further notice, the design for rehabilitation

  • f existing structures should be in

accordance with the AASHTO Standard Specifications for Highway Bridges, 17th Edition, and the ODOT Bridge Design Manual.

The Department’s Consultants Committee has decided that completion of specific training courses will not be a prequalification requirement. However, beginning immediately all website postings for new consultant contracts that include bridge design will include a requirement to address the training and experience (in LRFD) of the proposed staff. Additionally, firms with current contracts that will require LRFD as a result of the project development schedule will be required to demonstrate an adequate combination of training and experience in the new design methods.

slide-17
SLIDE 17

ODOT LOAD AND RESISTANCE FACTOR DESIGN TRAINING COURSES

slide-18
SLIDE 18
slide-19
SLIDE 19

LRFD Loads & General Overview

slide-20
SLIDE 20

Steel Design Reinforced Concrete Design Prestressed Concrete Design

slide-21
SLIDE 21

Foundation Design

slide-22
SLIDE 22

ONLINE REGISTRATION

slide-23
SLIDE 23
slide-24
SLIDE 24
slide-25
SLIDE 25

LRFD BRIDGE DESIGN SPECIFICATIONS AND THE 2007 ODOT BRIDGE DESIGN MANUAL

slide-26
SLIDE 26
slide-27
SLIDE 27
slide-28
SLIDE 28

LISTS AND ADDRESSES THE EXCEPTIONS TAKEN BY THE OhioDOT TO THE LRFD BRIDGE DESIGN SPECIFICATIONS BDM SECTION 1000:

slide-29
SLIDE 29

LOADS, LOAD COMBINATIONS AND LIMIT STATES

slide-30
SLIDE 30
  • DD - Downdrag
  • DC - Structural Components

and Attachments

  • DW - Wearing Surfaces and

Utilities

  • EH - Horizontal Earth

Pressure

  • EL -

Locked-In Force Effects Including Pretension

  • ES - Earth Surcharge Load
  • EV - Vertical Pressure of

Earth Fill

Permanent Loads

Load Definitions

slide-31
SLIDE 31
  • BR - Veh. Braking Force
  • CE - Veh. Centrifugal Force
  • CR - Creep
  • CT - Veh. Collision Force
  • CV - Vessel Collision Force
  • EQ - Earthquake
  • FR - Friction
  • IC -

Ice Load

  • LL -
  • Veh. Live Load
  • IM -

Dynamic Load Allowance

  • LS -

Live Load Surcharge

  • PL -

Pedestrian Live Load

  • SE -

Settlement

  • SH -

Shrinkage

  • TG -

Temperature Gradient

  • TU -

Uniform Temperature

  • WA - Water Load
  • WL -

Wind on Live Load

  • WS - Wind Load on Structure

Transient Loads

Load Definitions

slide-32
SLIDE 32

STANDARD SPECIFICATIONS LIVE LOAD MODEL

slide-33
SLIDE 33

LRFD LIVE LOAD MODEL

slide-34
SLIDE 34

EQ IC CT CV Strength I

γp 1.75 1.00

  • 1.00

0.50/1.20 γtg γse

  • Strength II

γp 1.35 1.00

  • 1.00

0.50/1.20 γtg γse

  • Strength III

γp

  • 1.00

1.40

  • 1.00

0.50/1.20 γtg γse

  • Strength IV
  • 1.00
  • 1.00

0.50/1.20

  • Strength V

γp 1.35 1.00 0.40 1.00 1.00 0.50/1.20 γtg γse

  • Ext Event I

γp γeq 1.00

  • 1.00
  • 1.00
  • Ext Event II

γp 0.50 1.00

  • 1.00
  • 1.00

1.00 1.00

Service I

1.00 1.00 1.00 0.30 1.00 1.00 1.00/1.20 γtg γse

  • Service II

1.00 1.30 1.00

  • 1.00

1.00/1.20

  • Service III

1.00 0.80 1.00

  • 1.00

1.00/1.20 γtg γse

  • Service IV

1.00

  • 1.00

0.70

  • 1.00

1.00/1.20

  • 1.00
  • Fatigue
  • 0.75
  • LL

IM CE BR PL LS DC DD DW EH EV ES EL Load Combination FR WL WS WA

Use One of These at a Time

SE TG TU CR SH

Load Combinations and Load Factors

γp

slide-35
SLIDE 35
  • Strength I:

Basic load combination relating to the normal vehicular use of the bridge without wind.

  • Strength II:

Load combination relating to the use of the bridge by Owner-specified special design vehicles, evaluation permit vehicles, or both, without wind.

  • Strength III:

Load combination relating to the bridge exposed to wind in excess of 55 mph.

  • Strength IV:

Load combination relating to very high dead load to live load force effect ratios.

  • Strength V:

Load combination relating to normal vehicular use with a wind of 55 mph.

Load Combination Descriptions

slide-36
SLIDE 36
slide-37
SLIDE 37
slide-38
SLIDE 38
slide-39
SLIDE 39
  • Extreme Event I:

Load combination including earthquakes.

  • Extreme Event II:

Load combination relating to ice load, collision by vessels and vehicles, and certain hydraulic events with a reduced live load.

Load Combination Descriptions

slide-40
SLIDE 40
slide-41
SLIDE 41
slide-42
SLIDE 42
slide-43
SLIDE 43
slide-44
SLIDE 44
slide-45
SLIDE 45
slide-46
SLIDE 46
slide-47
SLIDE 47
slide-48
SLIDE 48
slide-49
SLIDE 49
slide-50
SLIDE 50
slide-51
SLIDE 51
  • Service I:

Load combination relating to normal operational use of the bridge with a 55 mph wind and all loads at nominal values.

  • Service II:

Load combination intended to control yielding of steel structures and slip of slip-critical connections due to vehicular load.

  • Service III:

Load combination relating only to tension in prestressed concrete superstructures with the

  • bjective of crack control.
  • Service IV:

Load combination relating only to tension in prestressed concrete columns with the

  • bjective of crack control.

Load Combination Descriptions

slide-52
SLIDE 52
slide-53
SLIDE 53
slide-54
SLIDE 54
slide-55
SLIDE 55
  • Fatigue:

Fatigue and fracture load combination relating to repetitive gravitational vehicular live load and dynamic responses under a single design truck.

Load Combination Descriptions

slide-56
SLIDE 56
slide-57
SLIDE 57
slide-58
SLIDE 58