Coordinative similitude method considering overturning effect for scale model testing of structures with rubber bearings

Summary Generally, when a prototype is scaled down to a scale model, all parameters of the scale model should be designed to satisfy the similitude criteria. For a base‐isolated structure with rubber bearings, however, it is technically difficult to obtain small‐sized rubber bearings with the first shape factor satisfying the similitude criteria. This distortion affects the similitude ratio of the vertical stiffness of the bearings and, thus, influences the similitude ratio of the horizontal response of the structure because of the overturning effect. To solve this problem, a coordinative similitude method is proposed for scale model testing of structures with rubber bearings by adjusting configuration of the isolators to match the similitude ratio of the overturning stiffness of the isolation layer. A full‐scale and two 1/3 scaled bearings were designed and tested, and their similitude relations were evaluated. Test results of the model bearings were extrapolated to the OpenSEES model of a conventional model building and a coordinative building designed based on the conventional similitude method and the coordinative similitude method, respectively. A comparison between seismic responses of two model buildings against the prototype building indicates that the coordinative similitude method has significantly larger accuracy than the traditional similitude method.