ICC S1 Structural Steel and Bolting cheat sheet

Special inspection of structural steel is governed by IBC Chapter 17; the structural steel provisions are IBC Section 1705.2, which references AISC 360 Chapter N.

The special inspector reports to the building official and has authority to inspect all structural steel work and to access both fabrication shops and the erection site.

Work must conform to approved construction documents; any shop or field change requires approval of the engineer of record and, where the code requires, the building official before proceeding.

The fabricator's and erector's quality control programs are the first line of inspection; special inspection is independent verification of those programs (AISC 360 Chapter N).

Discrepancies are first reported to the contractor for correction; items not corrected are reported in writing to the building official.

The special inspector's scope is limited to verifying conformance with the approved plans, specifications, and referenced standards; the inspector does not perform design or approve substitutions.

A preconstruction meeting establishes hold points, inspection procedures, reporting lines, and documentation requirements before structural steel work starts.

Verify that member sizes, ASTM grades, and general notes on the structural drawings match the shop and erection drawings before fabrication or erection is accepted.

Weld symbols per AWS A2.4 convey weld type, size, length, spacing, groove preparation, finish contour, all-around and field designations, and tail references.

Bolted connection callouts must state the bolt standard and grade (ASTM F3125 Grade A325 or A490), diameter, hole type (STD, OVS, SSH, LSL), and the tensioning method.

Standard hole diameter equals bolt diameter plus 1/16 in. for bolts 1 in. and smaller, and plus 1/8 in. for bolts larger than 1 in.

Oversized holes equal bolt diameter plus 1/8 in. for bolts 7/8 in. and smaller, and plus 3/16 in. for bolts larger than 7/8 in.

Determine whether each connection is bearing (snug-tight permitted) or slip-critical (pretensioned, with a specified faying-surface class), because this drives the bolting inspection plan.

Confirm nondestructive testing requirements: percentage of welds to be ultrasonically or radiographically tested, acceptance criteria (AWS D1.1 Table 6.1), and required NDT personnel qualification level.

Confirm coating, galvanizing, fireproofing, and shear-stud requirements are shown and are coordinated with the inspection and hold-point plan.

ASTM A992 is the standard grade for rolled W-shapes: minimum yield strength 50 ksi, minimum tensile strength 65 ksi, with yield limited to 65 ksi and tensile to 80 ksi.

ASTM A36 has a minimum yield strength of 36 ksi and tensile strength of 58 to 80 ksi, and is commonly used for plates, angles, and miscellaneous members.

ASTM A500 is the standard for hollow structural sections: Grade B has 46 ksi minimum yield, Grade C has 50 ksi minimum yield.

ASTM A588 and A709 Grade 50W are weathering steels for exposed unpainted applications; A847 is the weathering grade for hollow structural sections.

ASTM F3125 Grade A325 has a minimum tensile strength of 120 ksi for diameters up to 1 in.; Grade A490 has 150 ksi for diameters up to 1-1/2 in.

Certified mill test reports must be traceable by heat number to the delivered members and must show chemistry and mechanical properties conforming to the specified ASTM designation.

Substitution of steel grade, product form, or bolt grade requires approval of the engineer of record before the material is incorporated.

Holes may be punched full size only in material 3/4 in. thick or less; thicker material must be drilled, or subpunched and reamed (AISC 360 M2.6).

Verification includes member length, camber, sweep, cross-section, hole spacing, hole size, and squareness measured against approved shop drawings.

Welding fit-up, edge preparation, and joint geometry are checked against the WPS and AWS D1.1 before production welding begins.

Welder qualifications and WPSs must be reviewed and accepted before production welding; the inspector confirms each welder is qualified for the process and position used.

Shear studs are installed and bend-tested in accordance with AWS D1.1 stud welding requirements and the project specifications.

Galvanizing is performed per ASTM A123; vent and drain holes must be detailed so molten zinc can flow, and coating thickness requirements increase with base metal thickness.

Fabrication defects are repaired only by an approved repair procedure, and repaired areas are re-inspected to the original acceptance criteria.

Snug tight is the condition where plies are in firm contact, achieved by a few impacts of an impact wrench or the full effort of an ironworker on an ordinary spud wrench.

Turn-of-nut from snug tight: 1/3 turn for bolts 1 in. and smaller and 1/2 turn for bolts larger than 1 in., when bolt length is not more than four diameters.

Calibrated wrench tightening requires verifying the wrench at least once per day and after adjustment, using three representative bolts in a tension-calibrating device.

Minimum pretension (AISC Table J3.1, kips): 1/2 in. A325 = 12, 3/4 in. = 28, 7/8 in. = 39, 1 in. = 51; A490 values are higher (15, 35, 49, 64).

A direct tension indicator is acceptable when the gap under the indicator is 0.005 in. or less after tensioning, confirmed by refusal of a feeler gauge.

With twist-off (tension-control) bolts, pretension is indicated by shearing of the splined end; inspection confirms splined ends have been removed from all installed bolts.

Slip-critical faying surfaces: Class A has a mean slip coefficient of 0.33 and Class B has 0.50; coatings must be qualified and must not be a prohibited class.

All holes in a connection must have bolts installed, and holes may not be enlarged to accommodate misalignment except by reaming where approved by the engineer of record.

A WPS states the welding variables (process, position, joint detail, filler metal, preheat, current, voltage, travel speed, passes) and must be supported by a PQR documenting mechanical test results.

Prequalified joints per AWS D1.1 Clause 3 may be used without PQR testing only when all prequalification conditions on process, position, thickness, and filler metal are satisfied.

Welder performance qualification follows AWS D1.1 Clause 4; qualification lapses after six months without welding with that process.

Minimum preheat per AWS D1.1 Table 3.2 depends on material thickness and carbon equivalent; thicker or higher-carbon-equivalent steel requires higher preheat.

Visual inspection covers 100 percent of welds and checks size, length, undercut, porosity, cracks, crater treatment, and profile before, during, and after welding.

Fillet weld acceptance criteria include minimum leg size, undercut limits, and freedom from cracks, per AWS D1.1 Table 6.1 and the contract documents.

Nondestructive testing personnel must be qualified to ASNT SNT-TC-1A or an ACCP program, with Level II as the minimum for interpreting ultrasonic or radiographic results.

Low-hydrogen electrodes such as E7018 must be stored in heated holding ovens and kept in portable rod ovens in the field to prevent moisture pickup.

AISC 303 Code of Standard Practice sets erection tolerances, including column plumbness within 1:500 of height measured between working points.

The erector is responsible for temporary guying, bracing, and shoring needed to keep the partially erected structure stable until permanent connections are complete.

Anchor rods are set from approved setting drawings; base plates are aligned and accepted before grouting.

Erection drawings must be approved by the engineer of record before erection begins, and field modifications require the engineer's approval.

Drift pins may be used to align members and bring holes into coincidence but may not be used to enlarge or distort holes.

Final bolt tensioning and completion of all welds are verified before the framing and alignment hold point is released.

Field welding requires an approved WPS and welders qualified for the process and position, and the same inspection criteria apply as in the shop.

Quality control is the fabricator's or erector's own inspection of its work; quality assurance is the independent verification that required quality control is being performed and is effective.

Inspection points include material verification, fit-up, bolt installation and tensioning, weld visual and NDT, structural alignment, and coating application.

For slip-critical joints, the faying surface preparation and condition are verified before assembly, and pretensioning method and calibration records are checked.

Coating dry film thickness is measured with a magnetic gauge per SSPC-PA 2, averaging readings over defined areas against the specified thickness.

Ambient conditions (temperature, humidity, dew point, steel surface temperature) are recorded during coating application and compared to the product data limits.

Nondestructive testing reports, calibration records, and coating reports are reviewed against the acceptance criteria and retained as inspection records.

Hold points are released only after the specified inspection has been performed and found satisfactory.

IBC Section 1705.2 requires special inspection of structural steel, covering welding and bolt installation and verification that member sizes and connections match the approved drawings.

Continuous special inspection requires the inspector to be present at all times the work is being performed; periodic inspection requires presence only at defined intervals or hold points.

Special inspection includes verifying materials, fabrication, welding, bolting, and the completed structural framing and connections.

The special inspector witnesses or observes operations designated as hold points, such as pretensioning of slip-critical joints and performance of NDT.

The special inspector may not approve design changes or substitutions; deviations are documented and reported to the contractor and building official.

Special inspection supplements but does not replace the contractor's quality control program.

Required records include approved shop and erection drawings, mill test reports, WPS and PQR documents, welder certifications, bolt calibration and pretension records, NDT reports, and coating reports.

Daily reports record date, weather, work location, work performed, inspections performed, personnel present, and findings including any deficiencies.

A discrepancy or nonconformance report states the location, description of the deviation, the reference document violated, the disposition, the corrective action, and closure sign-off.

The special inspector's final report to the building official summarizes the scope inspected, inspections and tests performed, discrepancies found, and how each was resolved.

Inspection records must be available to the building official on request and retained for the period required by the code.

Photographs and sketches supplement written records to document deficient or corrected work.