IN-SITU DYNAMIC CHARACTERISTIC TEST AND SEISMIC RESPONSE ANALYSIS OF HYBRID BRICK-CONCRETE AND TIMBER STRUCTURE OF HISTORIC AND CULTURAL BUILDINGS

In order to study the dynamic characteristics and seismic response of the hybrid brick-concrete and timber structure of a historic and cultural building, in-situ dynamic characteristic test was carried out and the peak picking method was used to calculate the structural natural frequencies and vibration modes. Taking into account the dynamic characteristics and interactions between the second-floor timber structure and the first-floor brick-concrete structure, a finite element model of the hybrid structure was established and the calculated natural frequencies and vibration modes were in a good agreement with the test results. Kobe, El Centro and an artificial wave of various amplitudes were input for displacement and acceleration response analyses. Experimental results show that the first, second and third order natural frequencies of the hybrid brick-timber structure are 4.327 Hz, 4.375 Hz and 5.875 Hz, and that the vibration modes are translation (east-west), translation (north-south) and torsion, respectively. The peak structure displacement is small for the 8-degree frequent earthquake, while the displacement response increases significantly for the design and the rare earthquakes. The maximum displacement of the column top of the second-floor timber structure is 6.12 times the maximum displacement of the column top of the first-floor brick-concrete structure. The maximum interlayer displacement angle of 1/155 is less than the code limit. The maximum acceleration response is larger for the tops of the second-floor columns and the roof, and less for the tops of the first-floor columns. Dynamic coefficients of the overall structural is less than 1 and the structure has a good seismic mitigation performance.