Figure A.7: Test set-up for internal support tests

(2) The supports at A and E should be hinged and roller supports respectively. At these supports, rotation about the longitudinal axis of the beam may be prevented, for example by means of cleats.

(3) The method of applying the load at C should correspond with the method to be used in service. NOTE: In many cases this will mean that lateral displacement of both flanges is prevented at C.

(4) In order to eliminate the displacements of the supports, the vertical deflections should be measured at the point of load application C and at two points B and D located at a distance e from each support.

(5) The test span s should be chosen to produce combinations of bending moment and shear force that represent those expected to occur in practical application under the design load for the relevant limit state.

(6) For double span beams of span L subject to uniformly distributed loads, the test span s should normally be taken as equal to 0,4L. However, if plastic redistribution of the support moment is expected, the test span s should be reduced to represent the appropriate ratio of support moment to shear force.

A.5.2.2 Execution of tests

(1) In addition to the general rules for testing, the following specific aspects should be taken into account.

(2) Testing should continue beyond the peak load and the recording of the deflections should be continued either until the applied load has reduced to between 10% and 15% of its peak value or until the deflection has reached a value 6 times the maximum elastic displacement.

A.5.2.3 Interpretation of test results

(1) The actual measured test results R0bs i should be adjusted as specified in A.6.2 to obtain adjusted values /?adj^ related to the nominal basic yield strength/y5 and design thickness t of the steel, see 3.1.3.

(2) For each value of the test span s the support reaction R should be taken as the mean of the adjusted values of the peak load Fmax for that value of s. The corresponding value of the support moment M should then be determined from:

Was this article helpful?

0 0

Post a comment