SFOBB East Span Seismic Safety Project Steve Margaris, Specifications Engineer, Caltrans.

SFOBB East Span Seismic Safety Project

Steve Margaris, Specifications Engineer, Caltrans


Steel Structures Special Provisions

• Welding

• Steel Audits

• Steel Structures (SAS)


• Applies to all Structural Steel

• Contractor is responsible for QC

--Designate QC Inspector - CWI

• CT is responsible for QA

Welding


• Quality Control Manager (QCM)

--Responsible for quality of welding

--Represents Contractor and subcontractors

--May be an employee of the Contractor

--Must be CWI

--Submits, receives and approves all reports and correspondence

Welding Quality Control


• Quality Control Plan (QCP)– Documentation of qualifications of all welding

personnel and weld processes– Welding NDT methods and frequencies– Method of identification and tracking of each weld– Documentation of CT certification of UT personnel



• Documentation Submittals– Welding Report (within 7 days of welding)– Reports of all visual inspection and NDT Reports– Documentation of evaluation of NDT and

reexamination of repaired welds– Daily welding production log



• Applies to all structural steel – General steel meeting – Contractor’s self audit (Audit Form in Information

Handout)– CT audit (requires 50 working days)– Maximum 3 audits allowed– Documentation submittals--facility list, self audit

submittal

Steel Audit


Steel Structures (SAS)

• Typical Structural Steel

– Girders, plates, connections

– Full scale mock-ups


Steel Structures (SAS)

• Non Typical Structural Steel– Hinge Pipe Beams– Castings

• Portions of saddles

– Modular Joint Seal Assemblies – Circular Segmented Bearings– Travelers


Steel Structures (SAS)• Requires fabricators and suppliers AISC

certification Category Cbr, Major Steel Bridges, with Endorsement F, Fracture Critical Members

• Requires erectors AISC certification Category CASE, Certified Advanced Steel Erector, with Endorsement F, Fracture Critical Members


Steel Structures (SAS)• Working Drawing Fabrication submittal

--Design geometry and fabrication geometry lines

--Details of temporary and permanent fabrication

--Distortion control plan per AWS

--Material and weld designations and shop fabrication processes


Working drawings fabrication (cont’ed)

Orthotropic Box and Pipe Beam

--Method of rib or pipe beam fabrication

--Details of fabrication jigs

--Location of tack welds and the sequence of all welding

--Methods of repair of elements that exceed specified tolerances

--Fabrication schedule


Erection Plan Working Drawings

--Details and limits of each section to be erected

--Details of attachments to each section for transportation and lifting

--Methods of transportation and lifting of each section

--Methods of aligning adjacent sections during erection


Erection Plan Working Drawings (cont’ed)

--Details of temporary work platforms and other aids for field welding

--Locations and methods of tack welds and final welds

--Supplemental calculations indicating the stress on the permanent structure due to attachments and erection and estimates of final dimensions of the in-place condition


Fabrication

--Full size mock-ups are required for tower saddle, tower diaphragm, box panel with closed ribs and pile to footing connection

--Examined visually and by UT or RT and MT

--Sectioned to produce two macroetch samples for each weld and evaluated per AWS


Assembly

Tower sections

--Ends of each lift section shall be milled to meet dimensional requirements. Each end shall be in a horizontal plane when standing on end.

--Sections shall be abutted in the shop to ensure proper fit


AssemblyOrthotropic box

--Shall be fabricated in subassemblies as shown on the plans

--Subassemblies and preassembled sections shall be within the dimensions and tolerances shown on the plans, except for camber

--Preassembly is required--three contiguous sections checked for matching, alignment and camber

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Shop WeldingDimensional Tolerances

--Contractor to submit dimensional control procedure and the use of dimensional control templates for approval

--Dimensional tolerances shall conform to AWS, and as modified by the plans and special provisions.

--Box shall be checked against steel templates

--Box members shall be within 4 mm of theoretical location

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Welding of Closed Ribs to Box shell plate

--Minimum 80% penetration of rib thickness

--Weld procedure trials using the SAW automated welding method performed on a rib prototype 10 m long, stop/restart 2 m

--Rib panel checked for straightness and production tolerances

--Welds are 100% UT tested, rib is split in two and macroetched in 21 locations minimum

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Welding of Closed Ribs to Box shell plateWeld Evaluation Criteria

--Minimum 80% weld penetration

--No gross notches or burn-through at the rib inside surface

--Tack welds shall be consumed

--Acceptable macrosections will be considered qualified welds and will be used as standards of acceptance of production welds

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Welding of Closed Ribs to Box shell plateMonitoring Production Welds

--Each welding machine tested every 4 hours

--Test specimens shall consist of run-off extensions of production test panels

--Test specimen shall be macroetched

--If weld quality found unacceptable, welding parameters must be adjusted and two additional successful specimen trials must be done

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Field Welding--Same requirements as shop welding

--Contractor to provide suitable enclosures to permit field welding in inclement weather per AWS and project requirements

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Field WeldingPile to pile footing connection--Full scale wood mock-ups required of the

pile to pile footing connection

--Full scale steel mockups required of the pile to footing sleeve connection to demonstrate hole drilling, slot cutting, connection plate fitting, welding and inspection

--Submittal of installation and welding sequence procedure for each mock-up


Field WeldingPile to pile footing connection (cont’ed)--Procedure must describe equipment and

details of installing the seal, field cutting slots in the piles and sleeves, installing the connection plates and performing all welding

--Engineer to witness fit-up and welding of each mock-up


Field WeldingPile to pile footing connection (cont’ed)--Mock-up assembly to be MT and UT tested

--Macroetch specimens taken from pile to pile sleeve connector plate. Each specimen shall demonstrate the required weld size and weld profile

--Results of the mock-up installation and welding sequence procedure shall be evaluated and final procedure developed

SFOBB East Span Seismic Safety Project Steve Margaris, Specifications Engineer, Caltrans.

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