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CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)
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CM - Jauregui - Sapienza University of Rome (60 min, part ii, connections modified)

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Slide del seminario Load Rating of Riveted Steel …

Slide del seminario Load Rating of Riveted Steel
Arch Bridge Connections svolto dal Prof. Jauregui nel corso di Costruzioni Metalliche.

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  • 1. Load Rating of Riveted Steel Arch Bridge Connections David V. Jauregui, PhD, PE November 28th, 2013 Sapienza University of Rome
  • 2. Overview • Introduction • Load Rating Method • Load Rating of: StringersSplices Stringer Splices Spandrel Splices Column Splices Arch RibsSplices Rib Splices • Conclusions & Recommendations
  • 3. Introduction Bridge Background • Name: The Los Alamos Canyon Bridge (a.k.a. the Omega Bridge) • Steel arch riveted bridge • Designed & built in 1951 following 1944 AASHTO specifications • Carries traffic from town of Los Alamos and the LANL (Los Alamos National Laboratory) • Bridge reduced the travel distance from 1.9 miles on a steep grade to 820 ft: critical for emergency vehicles • Owned and maintained by the LANL
  • 4. Introduction Research Objectives Connections commonly assumed to have equal or greater capacity than the members they adjoin Failure of connections could be critical • Provide the LANL with up-to-date rating factors for the Omega Bridge splice connections LRFD is the required method of design by FHWA since October 2007: Need for rating methodology consistent with the design method. No guidance in rating connections • Provide guidance in load rating connections using LRFR method to bridge engineers
  • 5. Introduction Research Aids • 2003 AASHTO Manual for Condition Evaluation and Load and Resistance Factor Rating of Highway Bridges • Research by Tuyen (2005) • RISA for structural analysis • MathCAD to calculate rating factors • Others: Original plans of the bridge, AISC steel manual, etc.
  • 6. Load Rating Method: LRFR
  • 7. Load Rating Method LRFR • Load rating provides the basis for determining the safe load capacity of a bridge in terms of a rating factor. • Rating factor is the ratio of the available to required live load capacity: Available live load capacity RF = ≥ 1.0 Required live load capacity
  • 8. Start Load Rating Method LRFR Design Load Check RF > 1 (HL-93) -No Restrictive Posting Requireda -May be evaluated for permit vehicle Inventory Level Reliability • Three Stages of load rating in LRFR: Design Load Rating RF <1 Check at operating level reliability RF <1 Legal load Rating AASHTO or State legal loads Legal Load Rating RF > 1 a b RF > 1 Evaluation level reliability RF <1 Higher Level Evaluation (Optional) -Refined analysis RF <1 RF > 1 -Load testing -Site-specific load factors -Direct safety assessment -Initiate load posting and/or repair/rehab -No permit vehicles -No restrictive posting requiredb -May be evaluated for permit vehicles Permit Load Rating For AASHTO legal loads and state legal loads within the LRFD exclusion limits For AASHTO legal loads and state legal loads having only minor variations from the AASHTO legal loads
  • 9. Load Rating Method LRFR General Equation for LRFR: φcφsφRn − γ DC DC − γ DW DW RF = γ LL LL(1 + IM ) where RF = Rating Factor φc, φs = Condition and system factor, respectively φRn = Splice capacity γDC, γDW, γLL = factors for dead load due to components and attachments, wearing surface, and live load, respectively DC, DW, LL = effects due to dead load due to components and attachments, wearing surface, and live load, respectively IM = Dynamic load allowance (or impact factor)
  • 10. Load Rating Method LRFR φcφsφRn − γ DC DC − γ DW DW RF = γ LL LL(1 + IM ) Super Structure Condition Ratings: 5.0 and higher: Condition Factor, φc = 0.95 (LRFR Table C6-1 and 6-2) System Factor, φs: (LRFR Table 6-3) 1.0 for stringers Redundant stringer systems between floor beams 0.9 for spandrel beam, columns, and arch ribs Riveted members in twogirder/truss/arch bridges
  • 11. Load Rating Method LRFR φcφsφRn − γ DC DC − γ DW DW RF = γ LL LL(1 + IM ) Load Factors: γDC = 1.25 γDW = 1.5 γLL = 1.75 for inventory 1.35 for operating
  • 12. Load Rating Method LRFR (a) TRUCK LOADS: HS-20 and Design Tandem 8k φcφsφRn − γ DC DC − γ DW DW RF = 32k 32k 25k γ LL LL(1 + IM ) 25k For each member, distribution factor for different force effects must be applied: i.e., to 30moment or DFshear 4 ft 14ft 14 DF ft Live Load Effect = γ LL DF [Lane + Design Tandem IM)] Truck (1 + (Longitudinal) HS-20 (Longitudinal) (b) LANE LOAD Controlled by larger effect between HS-20 or Design Tandem Lane Load = 0.64 klf
  • 13. Load Rating Method LRFR • Three Stages of load rating in LRFR: Design Load Rating Legal Load Rating Permit Load Rating
  • 14. Load Rating of Stringer Splice
  • 15. Rating Stringer Splice Basic Information CL Bearing Abutment #1 Arch CL South 407’-3” • 2 Exterior Stringers: ASTM A36 Steel (Fy = 36 ksi) – W21x83 14’-9” • 4 Interior Stringers: 31’ASTM A7 Steel 29.5’ y = 33 29.5’ ) – W21x62 (F 29.5’ ksi 29.5’ 29.5’ 29.5’ 31’ 31’ 31’ 31’ 31’ 29.5’ SP#1 SP#2 • Total of 27 spans: 6’-9” SP#3 SP#4 SP#5 SP#6 SP#7 SP#8 SP#9 SP#10 SP#11 SP#12 Six approach spans of 31 ft on each end SP#13 7’-4 1/2” 15 interior spans of 29.5 ft over arch 3@ 6’-9” 7’-4 1/2” • 6’-9” Total of 26 splices: 6 ft from the floor beam supports 6’-0” (Typical) Exterior Stringers Stringer Splice Interior Stringers Spandrel Beams Floor Beam
  • 16. Rating Stringer Splice Splice Configuration • Same splice configuration for both interior and exterior stringers 5 SPA @ 3” = 1’- 3” 1 1/2” Min. 7/8”φ H.S. Bolts (Typical) PL 5/16” x 12 1/2” x 1’- 6” (Both Sides of Web) 1’- 6” 4 SPA @ 3” = 1’- 0” 1 1/2” Min. 1 11/16” 2’- 6 1/2” 1 1/2” Min. (Typ.) 1/2” Max. 3” (Typ.) 1 1/2” Min. 1 1/2” Min. 12 1/2” PL 7/8” x 8 1/4” x 2’- 6 1/2” (Typ. Both Flanges)
  • 17. Rating Stringer Splice Loads • Dead load applied to the stringers: •Interior Stringer – WDead = 556 lb/ft •Exterior Stringer – WDead = 609 lb/ft • Live load applied using moving load tool in RISA:
  • 18. Rating Stringer Splice Loads • Used Influence Line for lane load placement 0.64 klf 0.64 klf 0.64 klf
  • 19. Rating Stringer Splice Force Distribution on the Cross-Section CflangePL CwebPL Flange PL NA Stress at outside edge of Web PL Web PL dwebPL TwebPL Stress at inside edge of Flange PL dflangePL TflangePL Stress at outermost surface Stress, σ Force = σ x Ai Splice 1 controls for both moment and shear! c
  • 20. Rating Stringer Splice Limit States • Limit States for the Flange PL Group: Yielding on the gross section Fracture on the net section Block Shear Shear strength of the rivets Bearing strength of the plates • Limit States for the Web PL Group: Yielding on the gross section Fracture on the net section Shear strength of the rivets (for a single rivet) Bearing strength of the plates (for a single rivet)
  • 21. Rating Stringer Splice Limit States Tensile Limit States (kip) Stringer Yielding on Gross Area Fracture on Net Area Block Shear Shear Strength of Rivets Bearing Strength of Plate Interior 214.4 270.7 610.7 126.3 831.6 Exterior 233.9 237.9 550.5 126.3 730.8 Shear Limit States (kip) Stringer Yielding on Gross Area Fracture on Net Area Shear Strength of Rivetsa Bearing Strength of Platea Interior 200.5 222.8 25.26 24.50 Exterior 218.7 195.8 25.26 16.82 a Values for a single rivet
  • 22. Rating Stringer Splice Combined Loading at Web V/12 V c.g. of Web PL R1 V/12 R2 V V c.g. of Rivet Group M V/12 MT = M + Ve R4 R3 Ry4 Rx4 e Total Moment on web splice PL MT = M +V ⋅e Resultant shear due to moment and direct shear: VR = Rx 2 V   +  Ry +  12   2
  • 23. Rating Stringer Splice Distribution Factors Interior Stringer: LRFD Table 4.6.2.2.2b-1 Shear DF Moment DF One Lane Loaded Two or More Lanes Loaded 0.1 g m.i.1 0.4 0.3  S   S   Kg   = 0.06 +       12.0 Lt 3   14   L   s  g m.i.2  S   S   Kg   = 0.075 +       12.0 Lt 3   9 .5   L   s  0.6 All Range of Applicability are met 0.2 g v.i.1 = 0.36 + 0.1 g v.i.2 S 25.0 S S  = 0 .2 + −   12  35  2.0
  • 24. Rating Stringer Splice Distribution Factors Exterior Stringer: LRFD Article 4.6.2.2.2d Moment DF One Lane Loaded Lever Rule Shear DF Lever Rule Two or More Lanes Loaded g m.e.2 = e ⋅ g m.i.2 g v.e.2 = e ⋅ g v.i.2 One Lane Loaded - RBM Rigid Body Motion Rigid Body Motion Two or More Lanes Loaded -RBM Rigid Body Motion Rigid Body Motion
  • 25. Rating Stringer Splice Distribution Factors DF Type Interior Stringer Moment Shear Exterior Stringer Moment Shear One Lane Loaded 0.494 0.630 0.667 0.667 Two or More Lanes Loaded 0.627 0.725 0.621 0.580 0.451 0.451 0.632 0.632 0.667 0.667 Rigid Body Motion One Lane Loaded N/A Two or more Lanes Loaded Controlling DF 0.627 0.725
  • 26. Rating Stringer Splice Rating Factors Stringer Moment (Flange Splice Plates) Shear Web splice plates Single Rivet Inventory Operating Inventory Operating Inventory Operating Interior 1.10 1.43 2.30 2.98 1.19 1.54 Exterior 1.02 1.32 2.43 3.15 1.33 1.72
  • 27. Load Rating of Spandrel Splice
  • 28. Rating Spandrel Splice Basic Information CL Bearing • 2 Abutment #1 Beams: Spandrel South ASTM A7 Steel (Fy = 33 ksi) • Total of 21 spans: Three approach spans of 62 ft on each 14’-9” end 62’ 6’-9” 62’ SP#1 SP#2 SP#3 Arch CL 407’-3” 62’ 29.5’ 15 interior spans29.5’ 29.5ft29.5’ 29.5’ 29.5’ of 29.5’ SP#9 SP#10 SP#11 over arch SP#4 SP#5 SP#6 SP#7 SP#8 29.5’ SP#12 SP#13 7’-4 1/2” • Total of 26 splices: First five splices: 15.5 ft from pier and 3@ 6’-9” skewback column supports 7’-4 1/2” 6’-9” 15.5’ Typ. Remaining splices: 7.25 ft from arch column 7.25’ Typ. supports Exterior Stringers Spandrel Beams Floor Beam Interior Stringers
  • 29. Rating Spandrel Splice Splice Configuration 3” 2.5” 4” 4” 1.5” 3” 1.75” 2.5” 3” 12 ½” x 5/16” x 2’-1” 4” 12 ½” x 5/16” x 1’-5” 3 ½” x 3 ½” x ½ x 2’-0 ½” 12 ½” x 5/16” x 5’-0” 12 ½” x 5/16” x 4’-8” 16 @ 3” 5 ¼” x 1/2” x 3’-6 ½” 3” 5” 6” x 1/2” x 3’-6 ½” 3” 3” 6” x 5/8” x 3’-6 ½” 7” x 1/2” x 3’-6 ½” 3”
  • 30. Rating Spandrel Splice Limit States Moment Limit States (kip) Plate Group Yielding on Fracture on Shear Strength Bearing Strength of Block Shear Gross Area Net Area of Rivets Plate Top Flange 464.1 556.9 544.5 353.6 722.8 Bottom Flange 382.4 426.9 643.5 353.6 1726 Shear Limit States (kip) Plate Group Yielding on Fracture on Gross Area Net Area Web a For a single rivet 623.7 881.7 Shear Strenght of Rivetsa Bearing Strength of Platea 25.3 23.0
  • 31. Rating Spandrel Splice Distribution Factors • One spandrel beam on each edge of the bridge width Considered as an exterior beam for moment DF • Use the lever rule to determine moment distribution factors: 1.764 2.094 1.929 1.328 4 lanes loaded 3 lanes loaded 2 lanes loaded 1 lane loaded Controls! Includes the multiple presence factor • LRFD Table 4.6.2.2.3.b-1 states the distribution factor for shear of an exterior beam is also determined using the lever rule: DFmoment = DFshear
  • 32. Rating Spandrel Splice Rating Factors Moment Rating Factor Critical Splice Moment Rating RFi Shear Rating Factor Critical Splice RFi RFo Web Splice Plates 4.00 5.19 Single Rivet 0.90 1.16 RFo Top FL Plate Group S1 1.27 1.65 S6 1.33 1.72 Bottom FL Plate Group S1 0.92 1.20 S6 0.92 1.20 Splice S1 had larger moment due to truck load in magnitude Shear Rating
  • 33. Load Rating of Column Splice
  • 34. Rating Column Splice Basic Information • Total of 20 columns: 4 Pier columns 2 Skewback columns 14 Arch columns • Splices in six tallest columns: 55 ft below the deck grade Arch Column Splices S3 S1 Roller S4 S5 S6 S2 Pinned Skewback Column Splice Fixed Skewback Column Splice
  • 35. Rating Column Splice Splice Configuration Arch Column Splice 1.5” 5 @ 3” 4 Angles 4” x 4” x 1/2” 4 Angles 5” x 5” x 3/4” x 3’- 1/2” 3” 3.5” 24” 4 Plates 24” x 1/2” 1.25” 3.5” 3” 8 Plates 12” x 1/3” x 1’- 3” 1.25” 4 @ 3” 5 @ 3” 1.5” 24.5” 1.5” 1.5”
  • 36. Rating Column Splice Splice Configuration Skewback Column Splice 48.5” back to back 4” x 4” x ½” 24” x ½” 48” x ½” 16” 48” 12” 4 @ 3” 4 Angles: 5” x 5” x ¾” x 3’-6 ½” 8 Plates: 12” x 3/8” x 1’-4” 2 Plates: 12” x 3/8” x 3’-4” 2” 42.5”
  • 37. Rating Column Splice Modeling: Member • The riveted connection stiffness is uncertain • Two models: COLUMN and BEAM-COLUMN • Actual connection stiffness somewhere in between COLUMN and BEAM-COLUMN models • Previous work found that BEAM-COLUMN model yielded significantly smaller rating factors: thus, chosen as critical model.
  • 38. Rating Column Splice Limit States Flange Plates: Gross yielding PL based Limit States Net fracture Block shear Rivet based Shear strength of rivets Limit States Bearing strength of PL Total Capacity = smaller of [φRnFlangePL + φRnAngles]PL-Based [φRnFlangePL + φRnAngles]Rivet-Based Angles: Gross yielding Net fracture Block shear Shear strength of rivets Bearing strength of PL
  • 39. Rating Column Splice Limit States Splice Component Plate-Based Limit States (kips) Rivet -Based Limit States (kips) Gross Yield Net Fracture Block Shear Rivet Shear Plate Bearing Plates Arch Column 297.0 330.0 240.9 252.6 501.2 Angle 412.1 538.3 1073 151.5 1743 Control = 653.0 = 404.1 Plates Skewback Column 356.4 429.0 419.5 252.6 501.2 Angle 412.1 538.3 1344 176.8 2055 Control 768.5 429.3 Controls tension capacity for Arch Column Splice!
  • 40. Rating Column Splice Second-Order Effect • No bracing between columns: Sway Frame • For a beam-column in sway frame, the maximum first order moments are amplified using the second order effect given in LRFD Article 4.5.3.2.2b • Non-sway and sway moments must be amplified by non-sway (δb) and sway (δs) magnification factors • Previous work determined δb = δs = 1.0
  • 41. Rating Column Splice Second-Order Effect δb < 1.0 Amplified Moment First-Order Moment δb >1.0 Amplified Moment Max. Moment First-Order Moment Max. Moment Splice Location Moment End Moment Higher Limit Lower Limit Range Splice Location Moment End Moment
  • 42. Rating Column Splice Distribution Factors • Columns in eastern arch rib controlled • Live load distribution factors determined using the same method as the spandrel beam DFmoment = DFshear = 2.094
  • 43. Rating Column Splice Rating Factors Moment Rating Factors δb = 1.0 @ splice δb > 1.0 @ splice Splice Average RFi RFo RFi RFo RFi RFo Arch S5 1.41 1.83 0.65 0.84 1.03 1.34 Skewback S2 3.79 4.91 1.84 2.38 2.81 3.65 Shear Rating Factors Splice Web Splice Plates Single Rivet RFi RFo RFi RFo Arch S5 8.39 10.9 1.93 2.50 Skewback S2 36.8 47.8 6.95 9.01
  • 44. Load Rating of Arch Rib Splice
  • 45. Rating Arch Rib Splice Basic Information • Total of 15 arch rib segments per arch plane • Center 13 arch rib segments are spliced (Labeled as S7 through S19 below) South North 9 10 13 14 11 12 15 16 17 18 8 19 7 Pinned Pinned Arch Rib Splice #
  • 46. Rating Arch Rib Splice Splice Configuration 46” x 3/4” 8” x 8” x 3/4” 18 1/2” x 3/4” x 3’ 9” 7 1/4” x 7 1/4” x 7/8” x 3’ 6 ½” 18 1/2” x 3/4” x 9” 71 1/2” x 1/2” 12 1/2” x 5/8” x 2’ 0”
  • 47. Rating Arch Rib Splice Modeling: Member • Two models considered: RIGID and PINNED • Used Influence Line to determine which model produces lower rating factors RIGID Model PINNED Model 1.0 1.45 1.0 rad Skewback Column Quarter Point Arch Splice Skewback Column 1.0 rad Quarter Point Arch Splice
  • 48. Rating Arch Rib Splice Second Order Effect • LRFD Article 4.5.3.2.2c specifies live load moments in arch ribs including impact “shall be increased by the moment magnification factor, δb” Cm δb = ≥ 1.0 Pu 1− φPe Pe = lu = half of the arch length π 2 EI K = f (type of arch, rise-to-span ratio of arch) (Klu )2 Cm = 1.0 Axial Forces (kips) Dead Load HS-20 Lane Moment Amplification Factor, δb S9 1015 43.8 70.4 1.31 S17 1015 42.5 52.8 1.30 Splice
  • 49. Rating Arch Rib Splice Distribution Factors • Arch ribs in eastern arch rib controlled • Live load distribution factors determined using the same method as the spandrel beam DFmoment = DFshear = 2.094
  • 50. Rating Arch Rib Splice Rating Factors Moment Splices (Flange Splice Plates) Inventory Operating S9 1.06 S17 Splices 0.82 0.84 1.09 Shear Web Splice Plates Single Rivet Inventory Operating Inventory Operating S7 13.5 17.5 2.58 3.35 S8 13.8 17.9 2.68 3.47 S11 9.4 12.2 2.37 3.07 S14 8.1 10.4 2.66 3.45 S17 15.8 20.5 2.70 3.50
  • 51. Conclusions & Recommendations
  • 52. Conclusions Floor System Splice Moment Shear Web Splice Plates Single Rivet RFi RFo RFi RFo RFi RFo Interior Stringer 1.10 1.43 2.30 2.98 1.19 1.54 Exterior Stringer 1.02 1.32 2.43 3.15 1.33 1.72 Spandrel Beam 0.92 1.20 4.00 5.19 0.90 1.16 All splices rated greater than 1.0 at operating: South CL Bearing Abutment #1 31’ Arch CL Critical Interior and Exterior Stringer Splice (S1) for Shear and Moment 31’ 31’ 31’ 31’ 31’ 29.5’ 29.5’ No posting required Safe for AASHTO and State legal loads without major Critical Spandrel Splice variation from (S1) for Moment AASHTO legal loads Critical Spandrel Splice (S4) for Shear 29.5’ 29.5’ 14’-9” 29.5’ 29.5’ 29.5’
  • 53. Conclusions Columns & Arch Ribs Splice Moment Shear Web Splice Plates Single Rivet RFi RFo RFi RFo RFi RFo Arch Column 1.03 1.34 8.39 10.88 1.93 2.50 Skewback Column 2.81 3.65 36.85 47.77 6.95 9.01 Arch Rib 0.82 1.06 8.05 10.4 2.37 3.07 All splices rated greater than 1.0 at operating: Critical Arch Column Splice (S5) for Shear and Moment South North No posting required Safe for AASHTO and State legal loads without major variation from AASHTO legal loads Critical Arch Rib Splice (S9) for Moment Critical Arch Rib Splice (S11) for Shear – Single Rivet Critical Skewback Column Splice (S2) for Shear and Moment Critical Arch Rib Splice (S14) for Shear - Web Splice Plates
  • 54. Recommendations • Load test recommended to better estimate the rotational stiffness of the riveted connections for the spandrel beams, columns, and arch ribs • Uncertainty in second-order effect of column splice moments: Lower end amplified moment rated as low as 0.84 at operating. A thorough examination of column splice strongly recommended A more detailed analysis of the second-order effect recommended in future analysis
  • 55. Recommendations • Several rivets reported missing during last inspection Recommended to identify missing rivets and replace them • Lateral load analysis due to wind and earthquake load recommended • 3-D finite element model recommended to better evaluate the member and splice forces and refine the analysis
  • 56. References American Association of State Highway and Transportation Officials (AASHTO). (2003). Manual for Condition Evaluation and Load and Resistance Factor Rating (LRFR) of Highway Bridges, Washington, DC. American Association of State Highway and Transportation Officials (AASHTO). (2004). LRFD Bridge Design Specifications, 3rd Edition, Washington, DC. American Institute of Steel Construction (AISC). (2001). Manual of Steel Construction: Load and Resistance Factor Design, 3rd Edition, Chicago, IL. FDOT (Florida Department of Transportation). 2007. 24 August 2007 <http:www.dot.state.fl.us/structures/LoadRatingSummit/AskTheProfessor.htm> Garrett, Gregory P. “Analytical Load Rating of an Open-Spandrel Arch Bridge: Case Study.” Journal of Bridge Engineering (January/February 2007): 13-20. Gaylord, Edwin H., Charles Gaylord, and James Stallmeyer. Design of Steel Structures, 3rd Edition. New York: McGraw-Hill, 1992 McCormac, Jack C., and James K. Nelson Jr. Structural Steel Design: LRFD Method, 3rd Edition.Upper Saddle River, NJ: Prentice Hall, 2002 Salmon, Charles G. and John E. Johnson. Steel Structures: Design and Behavior, 4th Edition. New York: Harper Collins, 1996 Tuyen, Nguyenngoc. Load Rating of a Riveted Steel Arch Bridge. Las Cruces, NM: New Mexico State University, 2005 Vinnakota, Sriramulu. Steel Structures: Behavior and LRFD. New York: McGraw-Hill, 2006
  • 57. Questions?

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