【国外标准】 Standard Test Method for Evaluating Bond Strength for 0.600-in. [15.24-mm] Diameter Seven-Wire Steel Strand, Grade 270 [1860], Used in Prestressed Ground Anchors

4.1 Seven-wire steel strand is used in pre-tensioned and post-tensioned concrete construction.4.2 0.600 in. [15.24 mm] diameter, Grade 270 seven-wire steel strand is used to make prestressed ground anchors which are often bonded to cement grout.4.3 Manufacturing processes, subsequent handling, and storage conditions may influence the strand bond.4.4 The primary use of this test method is to establish the relative bond strength of 0.600 in. [15.24 mm] seven-wire steel strand.4.5 The relative bond strength is determined by recording the pullout force at a certain displacement of the strand.AbstractThis test method deals with the standard procedures for establishing the relative bond strength of Grade 270 prestressing steel strands of specified diameter in cement grout as used in prestressed ground anchors for evaluating the effects of manufacturing practices on bond strength. The bond strength values obtained shall not be used to design the bond strength of ground anchors that depend on field conditions. This test method is not intended to be used as a bond test for pretensioned concrete applications. The test specimen shall be cut from standard production coils and shall not be wiped or cleaned. Pull test shall be made in accordance with the method.1.1 This test method describes procedures to establish the relative bond strength of 0.600 in. [15.24 mm] diameter, Grade 270 [1860] seven-wire steel strand in cement grout as used in prestressed ground anchors for the purpose of evaluating the effects of manufacturing practices on bond strength.1.2 The bond strength values obtained are not intended to be used to design the bond length of ground anchors that depend on field conditions.1.3 This test method is not intended to be used as a bond test for prestressed concrete applications.1.4 The values stated in either inch-pound or SI units are to be regarded as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.