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Title: 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


1
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.
2
AASHTO/AWS D1.5M/D1.52002Bridge Welding
CodeHamilton Nastaran, P. Eng.FounderWeldCanada
.com WPSAmerica.comSeptember 2003
3
Why we are here today
  • Liability issues
  • Code of Ethics (77.2.i) from PE Act, regard the
    practitioners duty to public welfare as
    paramount

4
Bridge walk 1987 "Pedestrian Day 1987".  It is
estimated that nearly 300,000 people surged onto
the roadway.
5
FOREWORD
  • 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.

6
FOREWORD
  • 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.

7
FOREWORD
  • 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.

8
FOREWORD
  • 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.

9
FOREWORD
  • 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.

10
FOREWORD
  • 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.

11
FOREWORD
  • 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.

12
FOREWORD
  • 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.

13
FOREWORD
  • 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.

14
Scope of the Bridge Welding Code
  • 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

15
Scope of the Bridge Welding Code
  • 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.

16
Scope of the Bridge Welding Code
  • 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.
  •  

17
Scope of the Bridge Welding Code
  • - 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.
  •  

18
Scope of the Bridge Welding Code
  • - 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.

19
Scope of the Bridge Welding Code
  • 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.

20
Scope of the Bridge Welding Code
  • 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.

21
Scope of the Bridge Welding Code
  • 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.

22
AASHTO M270/ASTM A709
  • 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.

23
AASHTO M270/ASTM A709
  • History of Material
  • Equivalent materials, Supplementary requirements,
    Zone temperature, Fracture/ Non- Fracture
    Critical Uncoated (unpainted) material

24
Fracture Critical Non-redundant Members
  • 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

25
Fracture Critical Non-redundant Members
  • 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.

26
Fracture Critical Non-redundant Members
  • 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.

27
Fracture Critical Non-redundant Members
  • - 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.

28
Fracture Critical Non-redundant Members
  • 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

29
Fracture Critical Non-redundant Members
  • 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.

30
Fracture Critical Non-redundant Members
  • Prohibited Process
  • - 12.5.2 For FCM, The Engineers 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.

31
Fracture Critical Non-redundant Members
  • 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.

32
Fracture Critical Non-redundant Members
  • - 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 _at_ -30 C 25 ft-lb _at_-20 F.
    Undermatching is most often associated with
    fillet welds on steels with a minimum specified
    yield strength greater than 345 Mpa 50 Ksi.

33
Design See a Contract document
  • 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.

34
Design See a Contract document
  • Colorado Department of Transportation
  • Staff Bridge Branch
  • Bridge Design Manual (Cont)
  • 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.

35
Design General, Spec., Fatigue
  • 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.

36
Design General, Spec., Fatigue
  • 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.

37
Design of Welded Connections
  • 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.

38
Design of Welded Connections
  • - 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.

39
Design of Welded Connections
  • - 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.

40
Design of Welded Connections
  • 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.

41
Design of Welded Connections
  • 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

42
Design of Welded Connections
  • - 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

43
Design of Welded Connections
  • 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.

44
Design of Welded Connections
  • 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.

45
Design of Welded Connections
  • 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.

46
Design of Welded Connections
  • 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

47
Design of Welded Connections
  • 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.

48
Design of Welded Connections
  • 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

49
Design of Welded Connections
  • 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

50
Design of Welded Connections
  • 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.

51
Design of Welded Connections
  • 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.

52
There are approximately 600,000 rivets in each
tower of Golden Gate Bridge.
53
DesignWelded Connections
  • Compare Bridge Code with CSA W59

54
Golden Gate Bridge
55
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.

56
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.

57
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/factsGGBD
    esign.html
  • http//www.goldengatebridge.org/photos/bridgewalk.
    html
  • http//www.goldengatebridge.org/research/facts.htm
    l

58
Electrode/ Wire
  • 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.

59
Electrode/ Wire
  • 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.

60
Electrode/ Wire
  • 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

61
Procedure Qualification Test
  • 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 manufacturers 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

62
Procedure Qualification Test
  • 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

63
Procedure Qualification Test
  • 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.

64
Procedure Qualification Test
  • 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.

65
Procedure Qualification Test
  • - 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.

66
Procedure Qualification Test
  • 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.

67
Procedure Qualification Test
  • 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.

68
Procedure Qualification Test
  • WPS Qualification Test, Pretest,Verification of
    Pretest PQRs

69
Procedure Qualification Test
  • 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 sizealso,
    used to gage the size and distribution of weld
    layers and passes.

70
Procedure Qualification Test
  • 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.

71
Procedure Qualification Test
  • Options for WPS Qualification or Prequalification
  • Essential variable

72
Procedure Qualification Test
  • What else about WPS

73
Control of test documentation
  • 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

74
Types of bridges
75
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.
76
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.
77
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).
78
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.
 
79
Types of Cable Attachment
Parallel attachment pattern
Radial attachment pattern
80
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

81
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