AISC LRFD 1.pdf

Sect. N3.] EVALUATION BY STRUCTURAL ANALYSIS 87accordance with ASTM procedures shall be permitted for this purpose. Otherwise,analyses shall be conducted in accordance with ASTM A751 from the samplesused to determine tensile properties, or from samples taken from the samelocations.4. Base Metal Notch ToughnessWhere welded tension splices in heavy shapes and plates as defined in SectionA3.1c are critical to the performance of the structure, the Charpy V-notch toughnessshall be determined in accordance with the provisions of Section A3.1c. If thenotch toughness so determined does not meet the provisions of Section A3.1c, theEngineer of Record shall determine if remedial actions are required.5. Weld MetalWhere structural performance is dependent on existing welded connections, representativesamples of weld metal shall be obtained. Chemical analysis and mechanicaltests shall be made to characterize the weld metal. A determination shall bemade of the magnitude and consequences of imperfections. If the requirements ofAWS D1.1 are not met, the Engineer of Record shall determine if remedial actionsare required.6. Bolts and RivetsRepresentative samples of bolts shall be inspected to determine markings and classifications.Where bolts can not be properly identified visually, representative samplesshall be removed and tested to determine tensile strength in accordance withASTM F606 or ASTM F606M and the bolt classified accordingly. Alternatively,the assumption that the bolts are A307 shall be permitted. Rivets shall be assumedto be A502, Grade 1, unless a higher grade is established through documentation ortesting.N3. EVALUATION BY STRUCTURAL ANALYSIS1. Dimensional DataAll dimensions used in the evaluation, such as spans, column heights, memberspacings, bracing locations, cross section dimensions, thicknesses, and connectiondetails, shall be determined from a field survey. Alternatively, when available, itshall be permitted to determine such dimensions from applicable project design orshop drawings with field verification of critical values.2. Strength EvaluationForces (load effects) in members and connections shall be determined by structuralanalysis applicable to the type of structure evaluated. The load effects shall bedetermined for the loads and factored load combinations stipulated in Section A4.The design strength of members and connections shall be determined from applicableprovisions of Chapters B through K of this Specification.3. Serviceability EvaluationWhere required, the deformations at service loads shall be calculated and reported.LRFD Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION