Abstract
In this paper, the following problems are investigated experimentally for 22 specimens of Series 1〜3, under statical lateral loading, (1) moment-rotation characteristics, (2) strength and fracture properties of column-base connections in steel structures. In this way it is intended to obtain basic data which are indispensable for the stress analysis of the steel frame in consultation with the deformation condition of column-base connections. The main results derived from these analysis of our experiments are as following : (1) With regard to the characteristic nature on the M/_<min>M-φ curve it was confirmed that in the case when the first yielding takes place to the anchor bolts, the observed values fit to the calculated values to M/_<min>M_y=1.0, while, in the case when the first yielding takes place to the base then the observed values fit to the calculated values to M/_<min>M_y=1.5. (2) It is made clear by our experiment that the effect of the tightening of anchor bolts is released gradually by repeated loading. In order to estimate the rotation coefficient β in column base, Eq.15 proposed in our paper can be applyed when no axial force is effected. (3) As to the damage or failure of column-base connections, following points are noteworthy, (i) it takes place quite often that fissures and cracks break out in the finish mortar and/or base concrete in the circumference of the anchor bolts after they are yielded. (ii) brittle fractures are apt to take place in the screw of the anchor bolt when it is tigthened too much. (iii) the most important factor that affects to the ultimate strength is the strength of anchor bolts.
