Gusset Plate Research Update

7/28/2019 Gusset Plate Research Update

1/41

TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTER

Gusset Plate Research UpdateGusset Plate Research Update

Joey Hartmann

FHWA Turner-Fairbank

Highway Research Center

Research that is Essential, Indispensable,

and Connected to our Customers

Research that is Essential, Indispensable,

and Connected to our Customers


2/41


Incompletedesign of U10

gusset plate

prompted NTSB

to issue interim

Recommendation

H-08-1 on 1.15.08


3/41


NTSB Interim Recommendation H-08-1NTSB Interim Recommendation H-08-1

For all non-load-path-redundant steel truss bridges within the

National Bridge Inventory, require that bridge owners conduct

load capacity calculations to verify that the stress levels in allstructural elements, including gusset plates, remain within

applicable requirements whenever planned modifications or

operational changes may significantly increase stresses.


4/41


Technical Advisory 5140.29

January 15, 2008U.S. Departmentof TransportationFederal Highway

Administration

Load ratings required according to the AASHTO Manual for

Condition Evaluation of Bridges. The following supplemental

actions are recommended:

New or replaced truss bridges check gusset plate capacity as part

of the initial load rating.

Existing truss bridges check gusset plate capacity when load rating

after condition or load changes of the structure.

Review previous load rating calculations for truss bridges that have

undergone significant changes is stress levels previously in theirservice life.


5/41


Nashville MeetingNashville Meeting

Ed Wasserman, TN DOT

Rick Crawford, TN DOT

Firas Ibrahim, FHWA Bill Wright, FHWA

Joey Hartmann, FHWA

John Kulicki, M&M

John Fisher, Lehigh

Ted Galambos, U. of MN Joe Yura, UT

Rob Connor, Purdue

Outcomes

Insufficient research to support further refinement of the FHWA Guide.No clear consensus on what might typically govern gusset plate design.


6/41


Gusset Plate RatingGusset Plate Rating

The best available knowledge

FHWA compiles Load Rating Guidanceand Examples For Bolted and Riveted

Gusset Plates in Truss Bridges


7/41


FHWA NCHRP Joint Study (Project 12-84)FHWA NCHRP Joint Study (Project 12-84)

Underway in late 2008

Expected completion in late

2010 Objective is to verify or create

better knowledge...that can be

used to revise (if necessary) or

extend the FHWA Guide and

result in AASHTO specifications


8/41


NCHRP PanelNCHRP Panel

Ed Wasserman, TN DOT

Chair

Wahid Albert, NYS DOT Ralph Anderson, IL DOT

Matt Farrar, ITD

Paul Liles, GA DOT

Anne Rearick, IN DOT

Kevin Western, MN DOT

John Kulicki, Modjeski and

Masters

Dennis Mertz, University ofDelaware

Tom Everett, FHWA Liaison

Stephen Maher, TRB

Liaison

Waseem Dekelbab, NCHRPStaff


9/41


Research TeamResearch Team

Bill Wright, VaTech

Don White, GaTech

Roberto Leon, GaTech

Justin Ocel, Turner-Fairbank

Several GaTech and VaTech Grad Students

Joey Hartmann, Turner-Fairbank


10/41


Gusset Plate Research NCHRP 12-84Gusset Plate Research NCHRP 12-84 Task 1 Literature Review

Task 2 Evaluation of Gusset Plate Configurations

Task 3 Finite Element Methodology Task 4 Finite Element Results

Task 5 Experimental Design

Task 6 LRFD Calibration for Truss Bridges


11/41


Task 2 Gusset Plate Configuration and RatingTask 2 Gusset Plate Configuration and Rating

Reviewed 20 truss plans from eight different states

Spans ranged from 114 to 825 feet

Designed between 1929 and 1990


12/41



Rt 23 Bridge, St Cloud

SR 54-13Over Cattaraugus Creek I-80 Over Clarion River

I-40 Over French Broad River

SR 56 Over Caney Fork River

SR 67 OverWa tauga River Station 0+09 Over Cumberland River

SR 100 Over Harpeth River

SR 24 Over Round Lick Creek SR 375 OverH arrell Bridge

I-35W Over Mississippi

SR 14 Over I.C.R.R. & Nonconnah Creek

Kootenai Highway, Moyie River Bridge I-94 Over Little Calumet River

I-474 Over Illinois River SR 56-TOver Salt Fork Creek

I-64 Over Ohio River

Bridge Over Ohio R iver, Mauckport

Bridge Over Ohio River, Cannelton

I-275 Over Ohio River


13/41



Gusset plate thickness ranged from 3/8 to 2-1/16,~45% of these ranged from 1/2 1

Thick plates (>1-1/4) were shingled Plates used either grade ~30, 36, 50, or 100 material

All fasteners were either 7/8 or 1 diameter rivets orA325 bolts

Free edge slenderness under the compressiondiagonal ranged from 8.3 to 74.7


14/41



Selected four typical connections to be used for

detailed finite element study


15/41


Task 2 Gusset Plate Configuration and RatingTask 2 Gusset Plate Configuration and Rating Bridge 40 selected for shingle plate detail


16/41


Task 2 Gusset Plate Configuration and RatingTask 2 Gusset Plate Configuration and Rating Bridge 23 selected for shallow entry angle of diagonals


17/41


Task 2 Gusset Plate Configuration and RatingTask 2 Gusset Plate Configuration and Rating Bridge 94 selected for steep entry angle and stand-offdistance of diagonals


18/41


Task 2 Gusset Plate Configuration and RatingTask 2 Gusset Plate Configuration and Rating Bridge 80 this connection was modified for use asexample in FHWA Guide


19/41


Task 3 Finite Element MethodologyTask 3 Finite Element Methodology

Analyze joints in a two panel truss configuration

Use shell elements represent the joint locally, beam

elements everywhere else


20/41



2-Step Analysis

1) Apply 1.25(DL)

2) Apply 1.75(LL + IM)

and amplify untilfailure

** Applied loading caused axial forces

in compression diagonal and chord

nearest to it to match construction

plans, others were close. **

)(75.1)(25.1 IMLLAFDLPFEA


21/41



Shell elements used nonlinear material properties

0

10

20

30

40

50

60

70

80

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16

Stress(ksi)

Strain(in/in)

Truestress&strain(Fy=50ksi)

Truestress&strain(Fy=36ksi)


22/41


Task 3 Finite Element MethodologyTask 3 Finite Element Methodology Fasteners modeled with Abaqus Connector elements to avoid modeling holes

Fasteners given nonlinear shear force/shear displacement relationship

Fasteners have a radius of influence to spread out load from connector (i.e. head and nut

diameter)

0.00

49.48

65.98

82.47

87.20

0.00

37.88

50.51

63.14

66.76

0.00

16.96

22.62

28.2729.89

0.00

12.99

17.32

21.65 22.89

0

10

20

30

40

50

60

70

80

90

100

0 0.2 0.4 0.6 0.8 1 1.2

Shear Displacement (inch)

Fastener

Force

in

Single

Shear

(kips)

1" dia. bolts

7/8" dia. bolts

1" dia. Rivets

7/8" dia. Rivets


23/41


Task 4 Finite Element ResultsTask 4 Finite Element Results In all four connections, the members failed (fully

plastified) prior to the gusset plate. Therefore

members were specified with elastic properties to

force failure in gusset plate. In a one cases, the fasteners had to be assigned

elastic properties to force gusset plate failure modes


24/41


Task 4 Finite Element Results (Bridge 40, AF=2.98)Task 4 Finite Element Results (Bridge 40, AF=2.98)

- 0 ksi

- 16 ksi

- 72 ksi

- 8 ksi

- 64 ksi

- 24 ksi

- 56 ksi

- 32 ksi

- 48 ksi

- 80 ksi

- 40 ksi

< ---- yield

Von Mises Stress

- 0

Plastic Strain

- 10

- 10010 - 5009

- 15010 - 20000 - 25000 - 30000 - 35000 - 40000

Shingle Plate Hidden Shingle Plate Shown

Lesson

Shingle plate may not

attract as much load as

assumed in design


25/41


Task 4 Finite Element ResultsTask 4 Finite Element Results Bridge 40

Vertical Deflection at L9 (in)

0 1 2 3 4

LiveLoadAmplificationFactor(AF)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

STRENGTH I(AF = 0.97)

Ultimate Capacity (AF = 2.98)

"Failure"(AF = 1.92)

U8

L7

Tension

Ten

sion

Compression

Compression

L9


26/41


Task 4 Finite Element Results (Bridge 40, AF=2.98)Task 4 Finite Element Results (Bridge 40, AF=2.98)

Plastic Strain

- 10

- 10010 - 5009

- 15010 - 20000 - 25000 - 30000 - 35000 - 40000

- 0

Lesson(?)

Internal splice plates

attract a lot of load


27/41


Task 5 Experimental DesignTask 5 Experimental Design

Anticipating 12 connections will be tested

Connections will have either 4 or 5 members framing into node

point

Only double gusset plate connections

Members will be reused for all tests

Vertical can be loaded in tension or compression

One chord member can be loaded in tension or compression


28/41


Task 5 Experimental Design Load FrameTask 5 Experimental Design Load Frame


29/41



Alternate jack

positioning to load

chord in tension


30/41



June 18, 2009


31/41



July 1, 2009


32/41


Task 5 Experimental Design Test MatrixTask 5 Experimental Design Test Matrix

A490

A307

L = LongL = ShortL = LongL = ShortThickness

C = 4.5C = 1.0

14.5

~60

L

L

C

148

14


33/41


Task 5 Experimental Design Test MatrixTask 5 Experimental Design Test Matrix

Each specimen will be tested under a variety of

equilibrium load combinations, elastically, to

understand stress flow Elastic load combinations will be studied first

without internal splice plates. Then with the internal

splice plates. Specimen will be brought to failure

with the internal splice plates in place


34/41


Task 5 Experimental Design InstrumentationTask 5 Experimental Design InstrumentationPhotostress camera will be used to monitor one of the gussetplates. This system provides complete strain field unlike discrete

measurements typical with strain gauges


35/41


Task 5 Fastener CharacterizationTask 5 Fastener Characterization

Had a need to understand the single shear behaviorof various fasteners types. Data in literature wasprimarily in double shear.

The data would be used to calibrate non-linear

behavior of Abaqus connector elements. Testing focused on 3/8 and 1/2 thick plates with

either 1.5 or 3.0 edge distances.

Will be testing A307 and A490 bolts, in addition tomodern and in-situ rivets (if available).


36/41




37/41




38/41


Task 5 Fastener CharacterizationTask 5 Fastener CharacterizationFasteners Initially in Bearing

Displacement (inch)

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Load

(kips

)

0

10

20

30

40

50

60

B307_1.5_3_0H776

B307_1.3_3_50815

B307_1.5_4_0H776

B307_1.5_4_50815

B307_3.0_3_0H776

B307_3.0_3_50815

B307_3.0_4_0H776

B307_3.0_4_50815

B490_3.0_3_ND031

B307_1.5_3_200Qty

B307_1.5_4_200Qty

B307_1.5_3_300Qty

B307_1.5_4_300Qty

B307_1.5_3_0H776_3bolt

B307_1.5_4_0H776_3bolt

B307_3.0_3_0H776_3bolt

B307_3.0_4_0H776_3bolt


39/41


TimelineTimeline

Interim report went to panel in April 2009

Comments responded to June 2009

Truss members are fabricated (delivery soon) Panel has indicated that it is satisfied with

responsesspecimen fabrication to begin thismonth

Testing targeted to begin in September

Experimental results by AASHTO 2010


40/41

TURNER-FAIRBANK HIGHWAY RESEARCH CENTERTURNER-FAIRBANK HIGHWAY RESEARCH CENTERPROJECT SCHEDULE

2008 2009 2010TASK

J J A S O N D J F M A M J J A S O N D J F M A M J J A

1) Literature Review

2) Gusset Plate Configurations

3) Define FEA Methodologies

4) Preliminary Gusset Plate RatingProcedures

5) Expanded Work Plan & TestFixture Fabrication

6) Calibration of LRFD for Trusses

7) Interim Report

8) Execute Work Plan

9) Draft 1 Design & RatingRecommendations

10) Discussion of Retrofit Strategies

11) Draft 2 Design & RatingRecommendations

12) Recommendations for OptimalDesign Configurations

13) Final report


41/41


Thank you for the time and attention.Thank you for the time and attention.

Documents

Gusset Plate Research Update