Recent Advances in Steel Bridge Fabrication

CIE‐580: Emerging Technologies in Bridge EngineeringUniversity at Buffalo (UB)North Campus, 140 Ketter Hall

Ronald D. Medlock, PEVP – Technical ServicesHigh Steel Structures, Inc.Lancaster PA

High Steel StructuresHigh Steel Structures• Steel bridge 

f b i t dfabricator and erector

• Four facilities• 50,000+ ton 

capacity• ISO 9001 Certified• AISC certified

– Bridges– BuildingBuilding– Erection

NJ Turnpike~ 10 projects 10 projects

CompetenciesCompetencies

Engineer’s InterestEngineer s Interest

• How to get the bestHow to get the best– CostD li– Delivery

– Quality

Ford

High

Project CostProject Cost

• MaterialMaterial– Market price– Usually 30% – 40% of the FOB costU ua y % % o e O o– Can be up to 70% of the FOB cost

• Hours (labor and overhead)Hours (labor and overhead)– Engineering – Fabrication– Shipping

• Margina gi

Material costs and lead times

CRU Plate Price History2007 through 2011 by Month 20112007 through 2011 by Month

$1,400

$1,600

Sept 2008

2011

$1,000

$1,200

t Ton

$600

$800

US$

per S

hort

$200

$400

$0

$ 760$ 760 $ 760$ 795$ 795$ 810 $ 790$ 790 $ 790 $ 790 $ 790 $ 790 $ 860 $ 890 $ 980 $ 980 $ 1,3 $ 1,4 $ 1,4 $ 1,4 $ 1,4 $ 1,3 $ 1,1 $ 850 $ 810 $ 755 $ 665 $ 610 $ 550 $ 540 $ 560 $ 600 $ 640 $ 630 $ 580 $ 580 $ 630 $ 685 $ 730 $ 830 $ 825 $ 815 $ 760 $ 742 $ 765 $ 740 $ 710 $ 760 $ 870 $ 970 $ 990 $ 1,0 $ 1,0 $ 1,0 $ 1,0 $ 994

J'07 F'07M '0

7A '07

M '0

7J'07 J'07 A '07 S'07 O'07 N'07 D'07 J'08 F'08

M '0

8A '08

M '0

8J'08 J'08 A '08 S'08 O'08 N'08 D'08 J'09 F'09

M '0

9A '09

M '0

9J '09 J '09 A '09 S'09 O'09 N'09 D'09 J '10 F'10

M '1

0A '10

M '1

0J '10 J '10 A '10 S'10 O'10 N'10 D'10 J '11 F'11

M '1

1A '11

M '1

1J '11 J '11 A '11

Definition:Price fob mill for ASTM A36 commercial quality plate in thickness between 3/8 of an inch and 2 inches widthPrice, fob mill, for ASTM A36 commercial quality plate, in thickness between 3/8 of an inch and 2 inches, width between 72 and 120 inches and length between approximately 240 and 720 inches. Any further extras for gauge,

width and length are excluded. For medium sized buyers, with standard packaging. Delivery charges and taxes are excluded. Raw materials surcharges (where applicable) are included. Price refers to current price for forward delivery.

Design Economy

Least weight  does not necessarily equal least cost

NDENDE

Material Optimization?

Best Economy:-Uniform thickness, orAdditional splices?-Additional splices?

Material Optimization – contact industry

Best Economy:-Uniform thickness, orAdditional splices?-Additional splices?

- Add a field splice at ~ 80’

Allow splice location- Allow splice location flexibility

Standardization

• OwnerOwner standards and preferencespreferences

• Industry standards andstandards and guidelines

AASHTO/NSBA– AASHTO/NSBA Steel Bridge CollaborationCollaboration

Project CostProject Cost

• MaterialMaterial– Market price– Usually 30% – 40% of the FOB costU ua y % % o e O o– Can be up to 70% of the FOB cost

• Hours (labor and overhead)Hours (labor and overhead)– Engineering – Fabrication– Shipping

• Margina gi

Steel Bridge ManufacturingSteel Bridge Manufacturing

Sales SchedulingSales SchedulingSales SchedulingSales SchedulingSales SchedulingSales SchedulingSales SchedulingSales

Estimating

Sales

Engineering

Scheduling

Estimating

Sales Scheduling

Estimating

Sales

Engineering

Scheduling

Estimating

Sales

Engineering

Scheduling

Estimating

Sales

Engineering

Scheduling

Estimating

Sales

Engineering

Scheduling

Estimating

Sales

Engineering

Scheduling

Estimating

Sales

Estimating Engineering

Field

EstimatingEstimating EngineeringEstimating EngineeringEstimating EngineeringEstimating EngineeringEstimating EngineeringEstimating

FieldShop Shipping FieldOperationsMaterial ShopMaterial ShippingShopMaterialField

OperationsShippingShopMaterial

Purchasing ProjectManagement

ProjectManagement

ProjectManagement

ProjectManagementPurchasing ProjectManagement

ContinuousImprovement

QualityControl

ContinuousImprovement

QualityControl

ContinuousImprovement

QualityControl

ContinuousImprovement

UnloadingUnloading

UnloadingUnloading

AssemblyAssembly

Assemblyy

Assemblyy

Engineer’s InterestEngineer s Interest

• How to get the bestHow to get the best– CostD li– Delivery

– Quality

Fabrication Cycle TimeFabrication Cycle Time

Critical for StartCritical for Start• Shop Drawingsp g

– Designs• Complete?• Web and Flange Information• Web and Flange Information

– RFI answers– Field information– Utility information– ApprovalM t i l• Materials– Web and flange information– DrawingsDrawings

Steel Bridge Technology

MaterialsMaterials• HPS

– 70W– 100W

• A1010

ModelingModeling

• Past Workflow

ShopDesign Shopdrawings

Hand layout of geometry by tapeand soap stone

Hand punch hole layout and drillAssemble and ream

• Current workflow

Design Shopdrawings Models CAM

• Parametric 3D models created for

CalculationsParametric 3D models created for

cross frames

• One associative part model utilized by all disciplines

Eliminates manual calculationsCAM Model of • Eliminates manual calculationsComponent

CAD Drawings

BOMPart Model

• Parametric 3D models created for

CAD/CAM/CNC InterfaceParametric 3D models created for

girder parts

• One associative part model shared by all disciplines

Reduces redundant efforts• Reduces redundant efforts

CNC Code

CAD Drawings

Part Model

BOM

CAM ToolpathPart Model

PunchingPunching

• Models created for complex welded

Visualization

pieces or complex geometry

•Accomplishes clearance checks

• Validates fabrication sequence

blDetail of Connection

Assembly

Visualization

ModelingModeling

• Current workflowCurrent workflow

Design Shopd i Models CAM

F t kfl

g drawings

• Future workflow

M d li Improved quality and efficiencyModeling- Design- Models- CAM

₋ Improved quality and efficiency₋ Faster project delivery

Cold Bending• New AASHTO clarification for cambering beamscambering beams

From Bendco

Welding ‐ GMAWWelding  GMAW

Welding ‐ ESWWelding  ESW

ESW Advantages• Productivity

– No bevel ‐ square edge preparationN t ki– No tacking

– No preheat or interpass– Single pass full penetration– Little slag removal and waste– No distortionNo distortion

• Safety / Environmental– no arc– nearly smokefreenearly smokefree– virtually noiseless

• Quality– No multi‐pass associated defectsNo multi pass associated defects– No arc spatter, arc strikes

ESW Limitations• Thicker joints only• Thicker joints only• Vertical up welding• Practical limits to weld length• Not for Q&T or TCMP materials (HPS)Q ( )

Heating

CoatingsCoatings• 3 coat most popular– Inorganic zinc– Epoxy primerEpoxy primer– Urethane top coat

• 2 cost systems• 2 cost systems– Organic zinc– Urethane top coat

• Galvanizing• Metalizing• Metalizing

Weathering SteelWeathering Steel

Shipping/Fabrication Piece Limits

• Most competitive:p‐ Length < 125 feet‐ Weight < 35 tons‐ Height < 9 feet tallg

• General truck limit:‐ Length ~ 175 feet 

(rules vary)(rules vary)‐ Weight ~ 80 tons 

(rules vary)‐ Height < 13.5 feet g

(on side) or 9.5 feet (upright)

Shipping/Fabrication Piece Limits

11” deck~ 12 ½ foot depth allowancep

Maximum weight 85 tons (at 70 feet)(at 70 feet)

.

NCHRP 12‐79NCHRP 12 79

Recommendations for detailing andRecommendations for detailing and associated analysis

• Straight Straight Skewed Bridges• Straight, Straight‐Skewed Bridges– Total deal load (TDL) fit / detailingC d B d• Curved Bridges– Steel dead load (SDL) fit / detailing

• Complex Bridges, Tub Girders Bridges– No‐load fit (NL) fit / detailing( ) g

SummarySummary• Effective projects

– Use standard details, materials, and practices; consider shipping b lcapability

– Speak with industry to get answers– Provide timely answers

• Materials– Use of grade 50 and 50W (weathering steel) is the norm– Increased used of HPS 70W– Advent of HPS 100W and A1010

• Modeling– More automation less handwork– More automation, less handwork– Improved accuracy– Less assembly

Improved workflow– Improved workflow– Synergy on design / build projects?

SummarySummary• Welding

– Increased use of GMAWIncreased use of GMAW– Increased use of ESW (ESW‐NG)

• Erection– Understand system behavior on skewed bridges– Future guidance from NCHRP 12‐79 (no‐load, steel‐load full dead‐load)load, full dead load)

• Durability– Weathering steel provides excellent performanceg p p– Zinc‐primer systems are excellent– Metalizing is good but expensiveG l i i i t ti f bi b– Galvanizing is not an option for big members