11.07.2015 Views

AISC LRFD 1.pdf

AISC LRFD 1.pdf

AISC LRFD 1.pdf

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

86Chap. NCHAPTER NEVALUATION OF EXISTING STRUCTURESThis chapter applies to the evaluation of the strength and stiffness under static vertical(gravity) loads of existing structures by structural analysis, by load tests, or by a combinationof structural analysis and load tests when specified by the Engineer of Record or inthe contract documents. For such evaluation, the steel grades are not limited to thoselisted in Section A3.1. This chapter does not address load testing for the effects of seismicloads or moving loads (vibrations).N1. GENERAL PROVISIONSThese provisions shall be applicable when the evaluation of an existing steel structureis specified for (a) verification of a specific set of design loadings or (b) determinationof the design strength of a load resisting member or system. The evaluationshall be performed by structural analysis (Section N3), by load tests (SectionN4), or by a combination of structural analysis and load tests, as specified in thecontract documents. Where load tests are used, the Engineer of Record shall firstanalyze the structure, prepare a testing plan, and develop a written procedure to preventexcessive permanent deformation or catastrophic collapse during testing.N2. MATERIAL PROPERTIES1. Determination of Required TestsThe Engineer of Record shall determine the specific tests that are required fromSection N2.2 through N2.6 and specify the locations where they are required.Where available, the use of applicable project records shall be permitted to reduceor eliminate the need for testing.2. Tensile PropertiesTensile properties of members shall be considered in evaluation by structural analysis(Section N3) or load tests (Section N4). Such properties shall include the yieldstress, tensile strength, and percent elongation. Where available, certified mill testreports or certified reports of tests made by the fabricator or a testing laboratory inaccordance with ASTM A6/A6M or A568/A568M, as applicable, shall be permittedfor this purpose. Otherwise, tensile tests shall be conducted in accordance withASTM A370 from samples cut from components of the structure.3. Chemical CompositionWhere welding is anticipated for repair or modification of existing structures, thechemical composition of the steel shall be determined for use in preparing a weldingprocedure specification (WPS). Where available, results from certified mill testreports or certified reports of tests made by the fabricator or a testing laboratory in<strong>LRFD</strong> Specification for Structural Steel Buildings, December 27, 1999AMERICAN INSTITUTE OF STEEL CONSTRUCTION

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!