Experimental Study On Seismic Behavior Of Sliding Isolation Mortar Joints For Stone Structures

Stone structures are widely used in the south part of Fujian Province, which is located at the junction of the Pacific plate and the Eurasian plate. And the region has high seismic risk. The seismic behavior of some existing stone structures is poor because of lacking rational seismic designs and details. In order to reduce the seismic force and prevent collapse of existing stone structures, a new sliding isolation mortar joint was proposed. Experimental studies were conducted for the traditional and isolation mortar joints, and the main contents and findings are as follows:Twenty four specimens were tested under low cyclic loading, including nine specimens with red-soil mortar, nine specimens with sliding isolation mortar joints and six specimens with sliding isolation mortar joints and extra restraints. Different levels of compressive stresses were applied for each kind of specimens to investigate the influence of the compressive stresses on the seismic behavior of traditional and isolation mortar joints. To reduce the discreteness of test results, three specimens were tested for the same parameters.The energy dissipation capacities, the sliding forces, the decreased thicknesses and the friction coefficients of both traditional and isolation mortar joints were investigated. It is indicated that: The energy dissipation capacities of the traditional mortar joints and the seismic isolation mortar joints without restraints were more stable than those of isolation mortar joints with restraints. The sliding forces of the three kinds of specimens were almost the same under the compressive stress of 0.2MPa. The average maximum sliding forces of specimens with isolation mortar joints decreased by 20% under the compressive stress of 0.4MPa and by 45% under the compressive stress of 0.6MPa, compared with the corresponding specimens with traditional mortar joints. The average friction coefficients of isolation mortar joints were lower than those of traditional mortar joints. The average thicknesses of the traditional mortar joints decreased quickly at the beginning of test, while the average thicknesses of seismic isolation mortar joints started decreasing at a larger displacement.