In Situ Dynamic Characteristic Test and Seismic Performance Analysis of Hybrid Brick‐Concrete and Timber Structure of Historic and Cultural Architectures

ABSTRACT

In order to study the dynamic characteristics and seismic performance of the hybrid brick‐concrete and timber (HBCT) structure, an in situ dynamic characteristic test was carried out, and peak picking method was used to calculate natural frequencies, damping ratios, and vibration modes. Considering semi‐rigid mechanical characteristics, a finite element model of the hybrid structure was established, and the calculation results agreed well with the test results. Kobe, El Centro and an artificial ground motion were input for displacement and acceleration response analysis. A set of fifteen ground motion records were selected, and incremental dynamic analysis and seismic fragility analysis were conducted. Results show that the first and second natural frequencies of the HBCT structure are 4.327 and 4.375 Hz, and the vibration modes are translation in the east–west direction and in the north–south direction, respectively. Taking the Kobe ground motion as an example, the maximum displacement of the pillar top of the second‐floor timber structure is 6.12 times that of the pillar top of the first‐floor brick‐concrete structure. The peak inter‐structural layer drift of 1/155 is less than the standard limit. Dynamic coefficients of the overall structure are less than 1, which indicates that the HBCT structure exhibits good shock absorption performance. The performance at different seismic intensities is in accordance with the “Three‐level and Two‐stage Seismic Fortification Goals,” which means no damage under minor earthquake, repairable damage under moderate earthquake, and no collapse under large earthquake.