## 2 System Configuration of SLDRFPB and SLDTFPB  
As is known, each classic FPB is located separately under the column. Different from classical FPB, the developed super-large displacement friction pendulum bearing has one or several spherical shells of super-large span and super-large curvature radius above the foundation. The integrated sliding isolation layer consists of spherical shell with sliding surface and sliding block under each column or sliding frame. The sliding isolation layer with one spherical shell is called super-large displacement rotation friction pendulum bearing (SLDRFPB), as shown in Figure 1. The superstructure can roll along the spherical shell upwards opening. Sliding blocks under nondeformable frame columns slide on the surface of the super-large spherical shell. Since the superstructure serves as a huge sliding block of classic FPB, super-large horizontal displacement of the isolation layer can be achieved.  
Figure 2 shows the sliding isolation layer with several spherical shells. It is noted as super-large displacement translation friction pendulum bearing (SLDTFPB) because of the translation motion pattern of the superstructure. Several sliding frames, which are used as the basement or mechanical floor, act as sliding blocks of classic FPB. Each group of spherical shells is made up of two of the same spherical shells with large radius and span, which are located at the top and bottom of one sliding frame, respectively. The superstructure connects with the top of SLDTFPB and they slide together on the top surface of these sliding frames. Sliding frames slide on the bottom of SLDTFPB at the same time. Particularly, the superstructure equipped with SLDTFPB translationally moves along its orbit. The reason is that when the top surface of each group couples rigidly and forms integrally, each sliding frame slides together between corresponding spherical shells due to compatibility of vertical deformation.  
Figure 1: Cross-sectional view of super-large displacement rotation friction pendulum bearing (**a**) without deformation and (**b**) with deformation.  
Figure 3 shows the details of the two developed FPBs. Similar materials and manufacturing processes were used to manufacture SLDRFFB and SLDTFFB. The spherical shell is integrally corrected with high-strength concrete, full cross-section reinforcement and a spherical corrosion-resistant plate. Configuration of the sliding block is similar to a flat stainless-steel cylinder with a spherical outside surface and horizontal inside surface. In order to avoid failure of the spherical shell caused by local compression, the outside surface of the sliding block and spherical shell have the same shape and radius. Teflon, silicone lubricant or other low-friction materials and antifriction are adopted on the surface of the spherical shell and sliding block. The coefficient of friction and compressive bearing capacity of Teflon can satisfy design requirements [39]. The Bevel edge of the sliding block is beneficial to smooth sliding. Some end joints welded on different directions are used for connecting additional reinforced girders and columns. Cast-in-site columns and sliding blocks are connected by stud anchors and bolt nails.  
SLDRFPB and SLDTFFB are suitable for different situations derived from the quantity and location of spherical shells. As shown in Figures 1 and 2, the motion of the superstructure equipped with SLDRFFB or SLDTFFB is rotating or translating, respectively. Width of SLDRFFB is designed much larger than that of the first story of the superstructure in order to reserve super-large horizontal sliding displacement. Considering the fact that deformation of SLDTFFB occurs between the top and bottom of the isolation layer, the width of SLDTFFB is not necessarily larger than that of the superstructure, while the height of the whole isolation layer is not small. In practical implementation, the choice of SLDRFFB or SLDTFFB depends on the inclination of the superstructure and space shape of the foundation.