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AASHTO/AWS D1.5M/D1.5:2002 Bridge Welding Code Hamilton Nastaran, P. Eng. Founder Weld Canada WPS America September 2 - PowerPoint PPT Presentation


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WPSAmerica.com is proud of being the only online welding software provider, supporting more welding codes than any other software company, plus our service provides many benefits for your company to improve your bottom line. Following are some benefits of our online services:-Huge saving by using from 10,000 prequalified welding procedures and avoid doing unnecessary costly tests. These procedures prepared by code experts and updated with the latest edition of structural steel welding codes.Our prequalified welding procedures ease the complexity of development of weld procedures for structural steel applications (steels, stainless steels, sheets, plates, pipes) in accordance with the AWS D1.1, AWS D1.3 and AWS D1.6 welding codes, ready to be used in your shop right away. -The software continuously updated to meet the latest version of each AWS and ASME welding codes, reducing the costs associated with purchasing new code every year. -Practical weld data and hands-on experts’ presentations save days of taking expensive courses.

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AASHTO/AWS D1.5M/D1.5:2002Bridge Welding CodeHamilton Nastaran, P. Eng.FounderWeldCanada.com WPSAmerica.comSeptember 2003

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Why we are here today

  • Liability issues

  • Code of Ethics (77.2.i) from PE Act, “regard the practitioner’s duty to public welfare as paramount”

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Bridge walk 1987 "Pedestrian Day 1987".  It is estimated that nearly 300,000 people surged onto the roadway.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • AASHTO – American Association of State Highway and Transportation Officials, results in the recognition of the need for a single document that could produce greater economies in bridge fabrication, while at the same time addresses the issues of structural integrity and public safety.

  • The first AWS code for Fusion Welding and Gas Cutting in Building Construction was published in 1928.

  • In 1934, a committee was appointed to prepare specifications for the design, construction, alteration and repair of highway and railway bridges.

  • The first bridge specification was published in 1936.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • In 1974, AASHTO published the first edition of the Standard Specifications for Welding of Structural Steel Highway Bridges.

  • In 1982, a subcommittee was formed by AASHTO and AWS, with equal representation from both, to seek accommodation between the separate and distinct requirements of bridge owner and existing provisions of AWS D1.1.

  • The Bridge Welding Code is the result of an agreement between AASHTO and AWS to produce a joint AASHTO/AWS Structural Welding Code for steel highway bridges that addresses essential AASHTO needs and makes AASHTO revisions mandatory.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • While D1.5 has a superficial resemblance to D1.1, there are significant differences, such as the lack of provisions relating to statically loaded structures, tubular construction or the modification of existing structures. Users are encouraged to develop their own requirements for these applications or use existing documents like, D1.1 with the appropriate modifications.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • Selection of materials and in qualification and control of WPS to ensure that all steel bridge members and welds have sufficient toughness to resist brittle fracture. Additional steps are taken in design and construction of bridges to avoid conditions that may lead to hydrogen-induced or fatigue cracking. The methods used to achieve these goals are based upon the control of welding heat inputs and attendant cooling rates, and the minimizing or avoidance of stress concentrations from weld or base metal discontinuities. Control of transformation cooling rates, in addition to control of weld and base metal chemistry, ensures that required mechanical properties are obtained in welds and adjacent HAZs. Heat input control, in addition to control of preheat and interpass temperatures, ensures that the base metal is not degraded as a result of permanent or temporary welds. These same controls provide safeguards against hydrogen-induced cracking.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • Bridges are cyclically loaded structures, are stressed with full design forces more frequently, with enough applications of design loading to induce fatigue in the member or component.

  • Fracture safety is important for all metal structures. In this code, emphasis is placed upon qualification and control of WPSs and avoidance of hydrogen and fatigue cracks.

  • Nonredundant fracture critical steel bridge members require a higher level of quality in materials and workmanship to ensure safety equivalent to that of redundant bridge members.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • Fracture avoidance, particularly avoidance of brittle fracture, is a primary goal of this code.

  • Brittle fracture is the abrupt rupture of a member or component loaded in tension.

  • Bridge member, the loading is generally transferred to adjacent members and general collapse does not occur. By definition, in non-redundant members, brittle fracture may cause collapse of the structure. Brittle fracture of a tension member is analogous to buckling of a compression member: rarely will either stop before failure is complete if the loading is maintained. However, this code does not address buckling of steel bridge members, as buckling is primarily a design or maintenance consideration.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • Brittle fractures may result from what may have initially appeared to be small, prior to fatigue crack initiation and propagation to critical size.

  • The workmanship provisions of the code dictate that notches are to be avoided. The quality of welds specified in Section 3 of the code take this into account, and also provide standards for workmanship and weld sound-ness that help ensure fracture safety in bridge fatigue environment.

  • Fatigue crack prevention is dependent upon high fracture toughness, good design and good workmanship that minimizes stress concentrations.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • AASHTO specifies the minimum fracture toughness of steel plates and shapes used to construct bridge members.

  • Good toughness ensures that cracks, created by any condition and possibly extended by fatigue, may grow to discoverable and therefore repairable size without causing a brittle fracture.

  • The code has been written to protect the hardness and toughness of both welds and HAZs.

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FOREWORD that nearly 300,000 people surged onto the roadway.

  • Quenched and tempered have their strength and toughness affected by excessive welding heat input. Slow cooling rates form excessive preheat and interpass temperatures, combined with high welding heat inputs, may also degrade the mechanical properties of welded joints in these heat treated steels. Fast cooling rates produced by welding with low welding heat input, combined with low preheat and interpass temperatures may produce excessive hardness and hydrogen-induced cracking in these same high strength steels. Proper procedures for welding quenched and tempered steels are explained in the Commentary.

  • Users of the code are encouraged to read all of the code and the Commentary.

  • The Commentary is a nonmandatory addition of this Code.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

  • 1.1 Application

    - 1.1.1 The code is not intended to be used for the following:

    1. Steels with a minimum specified yield strength greater than 690 Mpa (100 Ksi)

    2. Pressure vessels or pressure piping

    3. Base metals other than carbon or low alloy steels

    4. Structures composed of structural tubing

    5. Repairing Existing Structures

    6. Statically Loaded Structure

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

  • 1.2 Base Metals

    - M270M (M270) steels of a designated grade are essentially the same as ASTM A 709M (A 709) steels of the same grade. A 709M (A709) may be used as a reference and a guide to other ASTM “referenced documents;” however, when there is a difference, the provisions of M270M (M270), including the documents referenced in M270M (M270) shall govern.

    - 1.2.3 Thickness Limitations

    -The provisions of this code do not apply to welding base metals less than 3 mm (1/8 in.) thick.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

  • 1.3 Welding Processes

    - 1.3.1 SMAW WPSs which conform to the provisions of Sections 2,3 and 4, are operated within the limitation of variables recommended by the manufacturer, and which produce weld metal with a minimum specified yield strength less than 620 MPa (90 ksi), shall be deemed prequalified and exempt from the tests described in Section 5. WPSs for SAW, FCAW, GMAW, ESW, and EGW shall be qualified as described in 5.12 or 5.13, as applicable.

    - 1.3.3 Stud welding may be used, provided the WPSs conform to the applicable provisions of Section 7.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

- 1.3.4 GMAW-S (shot circuit arc) is not recommended for the construction of bridge members and shall not be used without written approval of the Engineer.

- 1.3.5 Other welding processes not described in this code may be used if approved by the Engineer.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

- 1.3.6 Welding of Ancillary Products. Unless otherwise provided in the contract documents, ancillary products, such as drainage components, expansion dams, curb plates, bearings, hand rails, cofferdams, sheet piling, and other products not subject to calculated tensile stress from live load and not welded to main members in tension areas as determined by the Engineer, may be fabricated without performing the WPS qualification tests described in Section 5, subject to Engineer approval.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

  • 1.4 Fabricator Requirements

    Fabricators shall be certified under the AISC Quality Certification Program, Simple Steel Bridges or Major Steel Bridges, as required by the Engineer, or an equivalent program acceptable to the Engineer.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

C 1.1.1 The design of bridges is not described in the code. This information is specified in the AASHTO Standard Specifications for Highway Bridges or the AASHTO LRFD Bridge Design Specifications.

C 1.1.2 The code is a “workmanship” specification, meaning the quality required is based upon what is readily available. “Suitability for service” is the minimum quality required for the member or weld to perform its intended function.

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Scope of the Bridge Welding Code that nearly 300,000 people surged onto the roadway.

Colorado Department of Transportation

Staff Bridge Branch

Bridge Design Manual, November 5, 1991

- In addition to AASHTO Standard Specifications for Highway Bridges, with current interims, the following references are to be used when applicable for the design of steel highway bridges:

- AASHTO Guide Specifications for Fracture Critical Non-redundant Steel Bridge Members (now replaced with section 12 of D1.5).

- AASHOT Guide Specifications for Horizontally Curved Highway Bridges.

- ANSI/AASHTO/AWS D1.5 Bridge Welding Code.

- AASHTO Standard Specifications for Seismic Design of Highway Bridges.

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AASHTO M270/ASTM A709 that nearly 300,000 people surged onto the roadway.

  • Bridge Code Requirements for Base Metal

    - C1.2.2 All approved base metals shall conform to the minimum CVN test values specified by AASHTO for the temperature zone in which the bridge will be located. Weld metal CVN test value requirements are described in Table 4.1/ 4.2, based upon AASHTO Temperature Zones I, II, or III.

    - C1.2.3 Minimum thickness of 3 mm and maximum thickness of 100 mm

    - 12.4.2 Mill orders shall specify killed fine-grain practice for steel used in FCMs.

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AASHTO M270/ASTM A709 that nearly 300,000 people surged onto the roadway.

  • History of Material

  • Equivalent materials, Supplementary requirements, Zone temperature, Fracture/ Non- Fracture Critical & Uncoated (unpainted) material

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Historically, the following fabrication related factors have contributed to bridge member failures;

    - Design details resulting in notches or stress concentrations

    - Design details requiring joints difficult to weld and inspect

    - Lack of base metal and weld metal toughness

    - Hydrogen-induced cracks

    - Improper fabrication, welding and weld repair

    - Unqualified personnel in inspection and NDT

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • The Fracture Control Plan, addition of section 12 of D1.5 in 1995, has replaced the “Guide Specifications for Fracture Critical Non-Redundant Steel Bridge Members-1978” developed by AASHTO.

  • 12.2.2 Fracture Critical Member (FCM) or member components are tension members or tension components of bending members (including those subject to reversal of stress), the failure of which would be expected to result in collapse of the bridge. All attachments and weld to FCMs shall be considered an FCM. Tension members whose failure would not cause collapse of the bridge are not fracture critical. Compression members do not come under the provisions of this plan as they do not fail by fatigue crack initiation and extension, but rather by yielding or buckling.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Example of complete fracture critical bridge members are tension ties in arch bridges and tension chords in truss bridges, provided a failure of the tie or chord could cause the bridge to collapse. Some complex trusses and arch bridges without ties do not depend upon any single tension member for structural integrity; therefore the tension member would not be considered a FCM.

  • Design evaluation

    - A critical part of any complete Fracture Control Plan deals with design and detailing.

    - Fatigue requirements are extensively covered by AASHTO Specifications and, where necessary, are made more conservative for fracture critical members.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

- The designer shall examine each detail for compliance with the fatigue requirements and ensure that the detailing will allow effective joining techniques and NDT of all welded joints.

  • Fine-Grain Practice

    - Steels manufactured using killed fine-grain practice have better resistance to crack initiation and crack propagation than steels not manufactured to this practice.

    - Fatigue crack initiation and growth is dependent upon stress range, stress concentrations and the number of cycles.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Optional Through-Thickness and Low Sulfur requirements

    - Lamellar tearing occurs in the Through-Thickness direction because the base metal has limited ductility in that direction. Normally, sulfides are the most detrimental type of inclusions that contribute to lamellar tearing, however, silicates and alumina may also influence susceptibility to lamellar tearing. Base metal with low sulfur (less than 0.010%) and improved through-thickness properties can be specified, typically at an increased cost.

  • Optional Heat Treatment

  • Toughness

    - Adopted after considerable research and deliberation between representatives of AASHTO/ AISI/ AISC

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Mill Orders

    - All approved base metals shall conform to the minimum CVN test values specified by AASHTO M270M for the temperature zone in which the bridge will be constructed. The Mill order shall specify the CVN that values required.

    - Plate frequency testing requires that each plate shall be heat number identified by the mill, with the corresponding number and the CVN test values shown on the mill test report.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Prohibited Process

    - 12.5.2 For FCM, The Engineer’s approval shall be required for all GMAW WPSs, regardless of mode of transfer (note that MCAW is also considered GMAW since 1980 by AWS).

    -12.5.2 ESW/ EGW shall be prohibited for welding FCMs.

  • Diffusible Hydrogen of Weld Metal

    - The resistance to brittle fracture of a welded connection is dependent upon eliminating conditions that might reasonably be anticipated to lead to the initiation of cracks. The FCP limits the addition of unacceptable levels of diffusible hydrogen during the fabrication of FCM members.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

  • Consumable requirements

    - 12.6.3 Weld Metal Strength and Ductility Requirements shall conform to the requirements of Table 4.1 and 4.2

    - 12.6.4 Weld Metal Toughness Requirements

    - Matching Strength Groove Welds. When matching strength filler metals are required, the code requires that the minimum notch toughness of the filler metal be as described in Table 12.1.

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Fracture Critical Non-redundant Members that nearly 300,000 people surged onto the roadway.

- Undermatching Strength Welds. When matching strength filler metal is not required, the Engineer is encouraged to use, where appropriate, lower strength high ductility weld metal that will reduce residual stress, distortion, and the risk of cracking or lamellar tearing in adjacent base metal HAZs. The code required a minimum notch toughness of the undermatching strength filler metal of 34 J @ -30 C [25 ft-lb @-20 F]. Undermatching is most often associated with fillet welds on steels with a minimum specified yield strength greater than 345 Mpa [50 Ksi].

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Design: See a Contract document that nearly 300,000 people surged onto the roadway.

Colorado Department of Transportation

Staff Bridge Branch

Bridge Design Manual, November 5, 1991

  • In addition to AASHTO Standard Specifications for Highway Bridges, with current interims, the following references are to be used when applicable for the design of steel highway bridges:

  • AASHTO Guide Spec. for Fracture Critical Non-redundant Steel Bridge Members (was replaced with section 12 of D1.5 in 1995).

  • AASHOT Guide Spec. for Horizontally Curved Highway Bridges.

  • ANSI/AASHTO/AWS D1.5 Bridge Welding Code.

  • AASHTO Standard Spec. for Seismic Design of Highway Bridges.

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Design: See a Contract document that nearly 300,000 people surged onto the roadway.

Colorado Department of Transportation

Staff Bridge Branch

Bridge Design Manual (Con’t)

  • Fatigue: Except for bridges on interstate and primary highways, fatigue design shall be based on the 20 year projected ADTT as derived from the final Form 463 or as reported by Staff Traffic (C9).

    - Commentary (9) Above paragraph assumes use of the AASHTO Standard Specifications for fatigue design.

  • Fatigue design for all bridges on interstate and primary highways shall be based on the Case I stress cycles in the AASHTO Standard Specifications (C10).

    - Commentary (10) Under normal loading conditions, fatigue failure in steel girders is apparently more common than failure due to member load capacity.

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Design: General, Spec., Fatigue that nearly 300,000 people surged onto the roadway.

  • C1.1 This AASHTO/AWS Bridge Welding Code is specifically written for the use of states, provinces and other governmental members associated with AASHTO. Other organizations that have a need to construct welded steel bridges to support dynamic loads should study the relationship between the fatigue loads imposed on their structure and the design truck loads and number of cycles provided for in the AASHTO Standard specification for Highway Bridges.

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Design: General, Spec., Fatigue that nearly 300,000 people surged onto the roadway.

  • C1.1.1 The design of bridges is not described in the code. This information is specified in the AASHTO Standard Specifications for Highway Bridges or the AASHTO LRFD Bridge Design Specifications.

  • C1.1.2 The code is a “workmanship” specification, meaning the quality required is based upon what is readily achievable. “Suitability for service” is the minimum quality required for the member or weld to perform its intended function.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • C2.1 Engineer should make efforts to minimize the size of groove weld where possible, adequate access for welding and visual inspection to avoid distortion and residual stresses, and may cause lamellar tearing in corner and T-joints.

    - Residual stresses may be reduced by minimizing the volume of weld metal and by lowering the yield strength of the weld metal to the minimum strength acceptable for the design. Undermatching of weld metal strength is encouraged for fillet welds that are designed to transmit only shear stress.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

- Some welded joint configurations for corner and T-joints contribute more than others to the risk of lamellar tearing, cracks parallel to the plate surface caused by high localized through-thickness strains induced by thermal shrinkage. The capacity to transmit through-thickness stresses is essential to the proper functioning of some corner and T-joints. Lamination (pre-existing planes of weakness in the base metal) or lamellar tearing may impair this capacity.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

- In connections where lamellar tearing might be a problem, consideration should be given in design to maximum component flexibility and minimize weld shrinkage strain.

- The details of welded joints provided in Figure 2.4/ 2.5 shall be considered standard and therefore based upon a long history of successful performance during welding and in service.

  • 5.7.7 Contractor are encouraged to use Figure 2.4/ 2.5 joints.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • C2.12.2 Corner Joints: Since lamellar tearing is potentially a serious problem in corner and T-joints where shrinkage stresses pull upon the base metal in the short transverse or “Z” direction, efforts should be made to minimize the potential for tearing. Shrinkage stresses have less adverse effects on plates stressed in the longitudinal direction (parallel to the rolling direction).

  • Controlling weld volume, limiting weld metal yield stress, increasing preheats, using PWHT, and the use of controlled sulfur inclusion stress reduces the risk of lamellar tearing. Not all methods are needed for every application.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • The following precautions may reduce the risk of lamellar tearing during fabrication in highly restrained welding conditions;

    - On corner joints, where feasible, the bevel should be on the through-thickness member

    - The size of the weld groove should be kept to a minimum consistent with the design, and unnecessary welding should be avoided

    - Subassemblies involving corner and T-joints should be fabricated completely prior to final assembly. Final assembly should preferably be at butt joints

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

- A predetermined weld sequence should be selected to minimize cumulative shrinkage stresses on the most highly restrained elements

- Undermatching using a lower strength weld metal, consistent with design requirements, should be used to allow higher strain in the weld metal, reducing stress in the more sensitive through-thickness direction of the base metal

- “Buttering” with low strength weld metal, peening, or other special procedures should be considered to minimize through-thickness shrinkage strains in the base metal

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Material with improved through-thickness ductility may be specified for critical connections (where tensile loading is in through-thickness direction and in this case material should be UT inspected).

  • Engineer should selectively specify UT inspection, after fabrication or erection or both.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • C2.1.3 Partial joint penetration (PJP) groove welds are limited to joints designed to transmit compression in butt joints with full-milled bearing surfaces, and to corner and T-joints. PJP groove welds also may be used in nonstructural appurtenances such as ancillary products. In butt joints, they may be used to transmit compressive stress, but should never be used to carry tensile stress in bridge members because of short fatigue life.

  • Longitudinal web-to-flange welds designed for tensile stresses parallel to the weld throat have the same allowable fatigue stress range whether designed as a fillet weld or a CJP groove weld with backing removed. PJP groove welds and CJP groove welds with backing remaining in place have a lower allowable fatigue stress range.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • There will be no increase in bridge safety as a result of specifying CJP groove welds where PJP groove welds or fillet welds, at considerably less cost, will carry the design stress. Smaller weld volumes, consistent with design stress requirements, create less residual stress and less chance that there will be unacceptable distortion or lamellar tearing.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Connection Details

    2.17.6 Connections or splices in beams or girders when made by groove welds shall have CJP groove welds. Other connections or splices with fillet welds shall be designed for the average of the calculated stress and the strength of member, but no less than 75% of the strength of member. When there is repeated application of load, the maximum stress or stress range in such connections or splices shall not exceed the fatigue stress allowed by the AASHTO specifications.

  • 2.17.5 Transition of Thicknesses or widths of butt joints

    - No more than 1 transverse to 2.5 longitudinal

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • C2.12.1 For thicker materials,the most economic CJP groove weld joint preparations are often J and U groove preparations. These joints provide the best access for welding at the root and use the least amount of weld metal. However, J and U groove preparations are rarely used in shops prior to assembly because of assumed high costs since prior to assembly, they can only be produced by machining.

  • C2.13 PJP prohibited in any application where tensile stress may be imposed by live or dead loads normal to the weld throat.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Prohibited Joints /Welds

  • 2.3.1.4 Flare groove welds shall not be used to join structural steel in bridges

  • 2.14 Prohibited Joints /Welds

    - All PJP groove welds in butt joints except those conforming to 2.17.3

    - CJP groove welds made from one side only without any backing, or with backing other than steel, that has not been qualified in conformance with 5.13

    - Intermittent groove/ fillet weld

    - Flat position bevel-groove and J-groove welds in butt joints where V-groove and U-groove welds are practicable

    - Plug and slot welds in members subject to tension and reversal of stress

    -Tubular structure

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Prohibited Welding Process

    - C12.5.2 GMAW-S Short-circuiting transfer is suited for sheet metal applications of less than 1 mm thick and typically less than 6 mm. It may lead to a condition where fusion to the base materials is not achieved (cold lap).

    - 2.13.1.1 All PJP groove welds made by GMAW-S shall be qualified by the WPS qualification tests described in 5.13

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Processes to be Avoided

    - 12.5.2 GMAW process of any modes of transfer shall not be used in the construction of bridge members without the written approval of the Engineer.

    - 1.3.4 Short circuiting GMAW-S is restricted because of its propensity to form fusion discontinuities called cold laps. Properly qualified GMAW WPSs, operated in the spray of globular mode of metal transfer are allowed.

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Design of Welded Connections that nearly 300,000 people surged onto the roadway.

  • Welds in combination with Rivets and Bolts

    - 2.16 In new work, rivets or bolts in combination with welds shall not be considered as sharing the stress, and the welds shall be provided to carry the entire stress for which the connection is designed. Bolts or rivets used in assembly may be left in place if their removal is not specified.

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Design:Welded Connections Golden Gate Bridge.

  • Compare Bridge Code with CSA W59

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Golden Gate Bridge Golden Gate Bridge.

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Golden Gate Bridge Golden Gate Bridge.

  • The dream of spanning the Golden Gate Strait had been around for well over a century before the Golden Gate Bridge opened to traffic on May 28, 1937.  On Sunday, May 24, 1987, this dream come true was celebrated as the Golden Gate Bridge turned fifty.  With great fanfare, people from all over the world came to pay homage to the Bridge, become part of an historical celebration and create lifelong memories.  The day began as "Bridge walk 87", a reenactment of "Pedestrian Day 37".  It is estimated that nearly 300,000 people surged onto the roadway. 

  • Just over four years.  Construction commenced on January 5, 1933 and the Bridge was open to vehicular traffic on May 28, 1937.

  • The cost to construct a new Golden Gate Bridge would be approximately $1.2 billion in 2003 dollars. The total price depends on a many factors including the extent of the environmental reviews and the cost of labor and materials.

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Golden Gate Bridge Golden Gate Bridge.

  • Many misconceptions exist about how often the Bridge is painted.  Some say once every seven years, others say from end-to-end each year. Actually, the Bridge was painted when it was originally built.  For the next 27 years, only touch up was required.  By 1965, advancing corrosion sparked a program to remove the original paint and replace it with an inorganic zinc silicate primer and acrylic emulsion topcoat.  The program was completed in 1995.  The Bridge will continue to require routine touch up painting on an on-going basis.

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Golden Gate Bridge Golden Gate Bridge.

  • The fabricated steel used in the construction of the Golden Gate Bridge was manufactured by Bethlehem Steel in plants in Trenton, New Jersey and Sparrows Point, Maryland and in plants in three Pennsylvania towns: Bethlehem, Pottstown, and Steelton. The steel was loaded, in sections, onto rail cars, taken to Philadelphia and shipped through the Panama Canal to San Francisco. The shipment of the steel was timed to coincide with the construction of the bridge.

  • http://www.goldengatebridge.org/research/factsGGBDesign.html

  • http://www.goldengatebridge.org/photos/bridgewalk.html#

  • http://www.goldengatebridge.org/research/facts.html

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Electrode/ Wire Golden Gate Bridge.

  • AWS Definition about Metal Core Wire

    GMAW may be performed with solid electrodes or metal-cored electrodes.

    - When introduced in the mid 1970s, metal-cored electrodes were originally classified as flux cored for FCAW-G welding.

    - In early 1990, the AWS A5 Filler Metal Committee determined that it was more appropriate to classify the welding performed with MCAW as GMAW, because metal-cored electrodes did not leave behind the residual slag blanket consistent with the FCAW process.

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Electrode/ Wire Golden Gate Bridge.

  • Table 4.1 versus Table 4.2

    - C5.7.4 Table 4.1 Processes – all welding processes approved for use by the code have been used successfully for many years and have longer history of successful use than Table 4.2 processes, and are considered to be more tolerant of changes in process variables without adversely affecting weld soundness or required mechanical properties.

    - C5.7.5 Table 4.2 Processes – welding consumables in this table are either those that produce very high strength weld metal or require a higher level of care to produce sound welds.

    - The placement of a welding process in Table 4.2 does not indicate that the process is inherently less suitable than another. GMAW and FCAW-S WPSs may require closer control of welding variables and techniques to provide sound welds with the specified properties, compare to SAW, SMAW, and FCAW-G processes.

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Electrode/ Wire Golden Gate Bridge.

  • WPS Qualification for consumables

  • 12.6.1 All welding consumables shall be heat or lot tested by the manufacturer to meet FCP based on AWS A5.01

    - 12.6.1.1 For manufacturer audited by one or more of the ABS, ASME or Lloyd's Register of Shipping then Clause 12.6.1 requirement can be exempted

  • What is recommended for matching & Exposed Bare Application

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Procedure Qualification Test Golden Gate Bridge.

  • Pre-Qualified Procedures

    - C1.9 Each weld shall be made using an approved WPS. Two exceptions are:

    1) SMAW that has a minimum specified yield strength less than 620 Mpa (90 Ksi), provided the WPS conforms to manufacturer’s recommendations for weld variables, and the welding shall be done in conformance with provisions of Section 4, Part B (please note that only SMAW on Table 4.1 is pre-qualified).

    2) 1.3.6 Ancillary product welding

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Procedure Qualification Test Golden Gate Bridge.

  • 1.3.6 Welding of Ancillary Products exempt from WPS:

    - SMAW, SAW, FCAW and GMAW WPSs, provided that welding is performed in conformance with all other provisions of the code

    - All welding shall be conducted within limitations of welding variables recommended by the filler metal manufacturer

    - Weld attaching ancillary products to main members shall meet all requirements of the Code, including WPS qualification testing

    - The Engineer is the final judge

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Procedure Qualification Test Golden Gate Bridge.

  • Limited Prequalification for SMAW as explained before

    - For FCMs only E7016, E7018, E7018-1 and E8018-X (including those with the “C” alloy and “M” military classifications and the optional supplemental designator “R” designating moisture resistance, shall be prequalified.

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Procedure Qualification Test Golden Gate Bridge.

  • Test Plate Thickness

    - 5.6.1 WPSs for SMAW, FCAW, GMAW, and SAW shall be based on PQR test plates with thicknesses greater than or equal to 25 mm, and shall qualify the WPS for use on all steel thicknesses covered by this code.

    - 5.6.2 EGW and ESW WPSs. Test plates shall conform to Table 5.4 (17).

    - 5.6.3 Fillet weld soundness test plate thickness shall conform to Figure 5.8.

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Procedure Qualification Test Golden Gate Bridge.

- C5.6 Previous editions of the code have required WPS qualification on two thicknesses of steel.

- Study/ research: The thicker plates were expecting to generate higher cooling rates, resulting in higher strength levels and lower ductility and thin plates also expected to result in lower toughness values. From previous data on several tests, the average yield strength of thin plate specimens was 94% and the average tensile strength was 99% of that associated with the thicker plate. CVN test values were affected to a greater extent than the tensile strength and elongation values, but no uniform trend was seen. This was deemed to be due to other variables than the cooling rate. Frank and Abel evaluated several hundred PQRs and found that plate thickness, as well as a variety of other essential variables described in the code, did not serve as a good predictor of the probable mechanical properties. After analyzing this data, committee decided to standardize all WPS testing on one plate thickness.

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Procedure Qualification Test Golden Gate Bridge.

  • Position of test welds

    - 5.8.1 Each WPS shall be tested in the position in which welding will be performed in the work, except that test welds made in the flat positions qualify for flat and horizontal welding.

  • Base Metal for WPS

  • Backing for WPS

    - 5.4.5 Steel backing used in weld tests shall be of the same specification and grade as the weld test plates, but CVN tests shall not be required.

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Procedure Qualification Test Golden Gate Bridge.

  • NDT

    - C5.17 All WPS are required to be radiographed with the provisions of Section 6 to demonstrate soundness before mechanical testing, regardless of the welding process used.

    - 6.10 Backing need not be removed for RT

    - 6.26.5.2 NDT for M270M [M270] Grades 690/690W [100/100w] steel shall performed not less than 48 hours after completion of welds.

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Procedure Qualification Test Golden Gate Bridge.

  • WPS Qualification Test, Pretest,Verification of Pretest PQRs

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Procedure Qualification Test Golden Gate Bridge.

Type of tests and purpose as listed in Table 5.5

- 5.15 Mechanical testing shall verify that the WPS produces the strength, ductility, and toughness required by Tables 4.1, 4.2, or as approved by the Engineer for the filler metal tested. Please note that CVN test values of FCMs shall be as specified in 12.6.4 (not Table 4.1/ 4.2). The tests are as follows:

- 5.15.1 Groove Welds

1) All weld-metal tension tests to measure tensile strength, yield strength, and ductility.

2) CVN test, to measure relative fracture toughness.

3) Macroetch tests, to evaluate soundness, and to measure effective throat of weld size:also, used to gage the size and distribution of weld layers and passes.

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Procedure Qualification Test Golden Gate Bridge.

4) RT test to evaluate weld soundness.

- In addition, the following tests shall be required for matching weld strength groove welds (so not required for undermatching).

5) Reduced section tensile test, to measure tensile strength.

6) Side-bend test, to evaluate soundness and ductility.

- 5.15.2 Fillet Welds

- 5.15.2.1 Mechanical properties shall be measured by testing groove weld unless otherwise specified in the contract documents.

- 5.15.2.2 Macroetch to evaluate soundness and to gage the size, shape, and distribution of individual weld passes as per Figure 5.8.

Please note that for single pass fillet weld or single pass PJP groove weld only macro etches suggested, see C 5.10.1/ C 5.10.2.

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Procedure Qualification Test Golden Gate Bridge.

  • Options for WPS Qualification or Prequalification

  • Essential variable

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Procedure Qualification Test Golden Gate Bridge.

  • What else about WPS

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Control of test & documentation Golden Gate Bridge.

  • Test Results Required, Retests

  • What should be included in WPDS

  • What types of information should be noticed to our clients in our outgoing letter

  • Sample letters, communication with engineer before and after

  • Suggestion: New form (questionnaire) and addition notes to quality manual

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Arch bridge Golden Gate Bridge.

Beam bridge

Suspension bridge

Cable-stayed bridge

Types of bridges

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Arch Bridge Golden Gate Bridge.Bixby Creek Bridge, Monterey, CA

Arch Bridge

Arch bridges are one of the oldest types of bridges and have great natural strength. Instead of pushing straight down, the weight of an arch bridge is carried outward along the curve of the arch to the supports at each end. These supports, called the abutments, carry the load and keep the ends of the bridge from spreading out.

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Suspension bridge Golden Gate Bridge.Golden Gate Bridge, San Francisco, CA

Suspension bridge anchorage

Suspension Bridge

Aesthetic, light, and strong, suspension bridges can span distances from 2,000 to 7,000 feet -- far longer than any other kind of bridge. They also tend to be the most expensive to build. True to its name, a suspension bridge suspends the roadway from huge main cables, which extend from one end of the bridge to the other. These cables rest on top of high towers and are secured at each end by anchorages.

The towers enable the main cables to be draped over long distances. Most of the weight of the bridge is carried by the cables to the anchorages, which are imbedded in either solid rock or massive concrete blocks. Inside the anchorages, the cables are spread over a large area to evenly distribute the load and to prevent the cables from breaking free.

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Beam bridge Golden Gate Bridge.

Beam Bridge

A beam or "girder" bridge is the simplest and most inexpensive kind of bridge. According to Craig Finley of Finley/McNary Engineering, "they're basically the vanillas of the bridge world." In its most basic form, a beam bridge consists of a horizontal beam that is supported at each end by piers. The weight of the beam pushes straight down on the piers. The beam itself must be strong so that it doesn't bend under its own weight and the added weight of crossing traffic. When a load pushes down on the beam, the beam's top edge is pushed together (compression) while the bottom edge is stretched (tension).

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Cable-stayed bridge Golden Gate Bridge.Clark Bridge, Alton, IL

Cable-Stayed Bridge

Cable-stayed bridges may look similar to suspensions bridges -- both have roadways that hang from cables and both have towers. But the two bridges support the load of the roadway in very different ways. The difference lies in how the cables are connected to the towers. In suspension bridges, the cables ride freely across the towers, transmitting the load to the anchorages at either end. In cable-stayeded bridges, the cables are attached to the towers, which alone bear the load.The cables can be attached to the roadway in a variety of ways. In a radial pattern, cables extend from several points on the road to a single point at the top of the tower. In a parallel pattern, cables are attached at different heights along the tower, running parallel to one other.

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Types of Cable Attachment Golden Gate Bridge.

Parallel attachment pattern

Radial attachment pattern

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Following are some link for different Suspension Bridges. The length of main span portion of suspended structure (distance between towers) are shown only that not include side spans:

  • Akashi-Kaikyo Bridge, Japan,6,532 feet main span, 1998

  • Great Belt East Bridge,Denmark, 5,328 feet main span, 1997

  • Humber Bridge, England, 4,626 feet main span, 1981

  • Jiangyin Yangtze River Bridge, China, 4,544 feet main span, 1999

  • Tsing Ma Bridge,China, 4,518 feet main span, 1997

  • Verrazano Narrows Bridge,New York, 4,260 feet main span, 1964

  • Golden Gate Bridge, San Francisco, 4,200 feet main span, 1937

  • High Coast Bridge, Sweden, 3,970 feet main span, 1997

  • Mackinac Straits Bridge, Michigan, 3,800 feet main span, 1957

  • Minami Bisan-Seto Bridge, Japan, 3,609 feet main span, 1988

  • Second Bosphorous, Turkey, 3,576 feet main span, 1992

  • First Bosphorous, Turkey, 3,523 feet main span, 1973

  • George Washington Bridge,New York, 3,500 feet main span, 1931

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Build a bridge together now! The length of main span portion of suspended structure (distance between towers) are shown only that not include side spans:

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