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T5 Loads and Load Distribution

Ballot Items for the 07 AASHTO

Subcommittee on Bridges andStructures (SCOBS) Annual

Meeting Wilmington, DE

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Acknowledgements Mal Kerley--bigger room and longer time slot

Preceding T5 Chairs: Jim; William and Harry

help, guidance and support of me in transitioning

Ballot Items: 4 groups Simplified Load Distribution (withdrawn)

Whites

Yellows

Endorsement

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Simplified Load Distribution

Informative presentations

Prof. Jay Puckett, 12-62

Dr. Toorak Zokai, 12-26

Good Q & A primarily between T5, Jay, Toorak

Concerns on conservativeness of gdfs

Revisions, dated June 29th; distributed July 2-3

Motion/second/passWithdraw 14, 15, 16, 17,

18, 20, and 21

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WhitesNo Changes to

#19clarification ofde for the case of multi-cell

box girders

#22clarification of dual truck/tandem (both

cant be in same span)

#27clarification of LL dgn Ms for decks

#24, #26Pedestrian Bridges

Urge a check for resonance

Add guidance for maintenance vehicle loads

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LRFD Pedestrian Bridge Provisions

NCHRP 20-07 funding received (Thanks Mal!):

Task 244

Panel comprised of T5 member from ea. Region

+ Sues steel assistant, T6, NYC

Stand-alone documentTNX Tom SBE survey

Comments to be solicited on 2nd draft from

vendors

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WhitesMove to ballot.

#19clarification ofde for the case of multi-cell

box girders

#22clarification of dual truck/tandem (both

cant be in same span)

#27clarification of LL dgn Ms for decks

#24, #26Pedestrian Bridges

Urge a check for resonance

Add guidance for maintenance vehicle loads

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Yellow: #23Simplified Wind Dist.Sub-Item #2

Add the following after Table 3.8.1.3-1:

For the usual girder and slab bridges having an individual span

length of not more than 125 ft. and a maximum height of 30.0

ft. above low ground or water level the following wind loading

may be used:

0.10 KLF, transverse

0.04 KLF, longitudinal

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Yellow: #25 Superimposed

Deformations (CR, SH, TU, PS) FAQ #1Where did the 0.5 value come from?

Artifact accounting for dissipation over time

Should not be used in conjunction with IefforIcr

FAQ #2--Why move CR and SHw/DC, etc?

Coupled w/ material properties (TUreverses)

FAQ #3Why so many different values? Segmentalfactors must be same as DC Typ. Bridgescontinue w/ CR, SHin prestress loss

estimate for superstructure; 0.5 for substructure, only

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Yellow: #25Superimposed

Deformations (CR, SH, TU, PS)

Revise the sixth paragraph of Article 3.4.1 as follows:

The larger of the values provided for load factors of TU, CR and SHshall be

used for deformations and the smaller values for all other effects. Forsimplified analysis ofconcrete substructures in the strength limit state, a

value of 0.50 for TU may be used when calculating force effects, but shall be

taken in conjunction with the gross moment of inertia in the columns or piers.

When a refined analysis is completed for concrete substructures in the

strength limit state, a value of 1.0 for TU shall be used in conjunction with a

partially cracked moment of inertia determined by analysis. For concretesubstructures in the strength limit state, the value of 0.50 for PS, CR, and SHmay similarly be used when calculating force effects in non-segmental

structures, but shall be taken in conjunction with the gross moment of inertia

in the columns or piers. For steel substructures, a value of 1.0 for TU,PS, CR, and SH shall be used.

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Yellow: #25Superimposed

Deformations (CR, SH, TU, PS)

Sub-item 4, cont.

Add a new paragraph to the Commentary as follows:

PS, CR, SH, TU and TG are superimposed deformations as defined in Article

3.12. Load factors for TU and TG are as shown in Table 1. Load factors for

PS, CR, and SH, are as shown in Table 3. For prestressed members in typical

bridge types, secondary prestressing, creep and shrinkage are generally

designed for in the service limit state. In concrete segmental structures, CR

and SH are factored by P for DC because analysis for time-dependent

effects in segmental bridges is nonlinear. Abutments, piers, columns, andbent caps are to be considered as substructure components.

The calculation of displacements for TU utilizes a factor greater than 1.0 to

avoid undersizing joints, expansion devices, and bearings.

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Yellow: #25Superimposed

Deformations (CR, SH, TU, PS)Sub-item 5 Add Table 3.4.1-3 Load factors for Permanent Loads due to

Superimposed Deformations, p as follows:

1.01.0Steel Substructures

Concrete substructures supportingnon-segmental Superstructures

SuperstructuresSegmental

Concrete substructures supporting

segmental superstructures.

CR, SHPSBridge Component

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#28Endorse the 20-07 Task 186

Report on: Updating the Calibration

Report for AASHTO LRFD Code By Kulicki, Prucz, Clancy, Mertz, Nowak

Undertaken because original (Report 368) Completed prior to final s and s

Dated 1999, but actually written in 1991

Objective Document how Strength I was calibrated

Perform reliability analysis on typical girder bridges

Describe universal procedure for future efforts

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