Predicting Internal Compressive Force on Equal Angle Steel Section Upon Various Support Types Using Vibration Method

In a truss structure, which comprises many elements of equal angle steel section, an eccentricity may take place due to the different position between the center of area of equal angle steel section and the center of bolt connection, which might violate the existing vibration theory. This paper present the result of a research project that investigation of slender element of equal angle steel section of L.30.30.3 and of 120 cm in length with 3 variations of support type; that are pinned-pinned, clamped- clamped and pinned-clamped, were tested under axial compressive load and transversal vibration impact simultaneously. The results showed that increasing the axial compressive load leads to a reduction of the natural frequency of the structure. The theory of end rotational stiffness for pinned end support (σ=0) and clamped support (σ=∞) are difficult to occur on the implementation. The analytical predictions of the axial compressive force by regression of the frequency for combinations of pinned-pinned, clamped-clamped and pinned-clamped supports provide better accuracy than that the original data of the frequency of the test results.