Modified Structural Computing Model of Ancient City Gate Tower with Method of Structural Dynamical Characteristic Test-A Case Study of Nanjing Drum Tower

In order to develop accurate finite element (FE) model of city gate tower in China for further structural analysis, Nanjing Drum Tower was studied as an example.The FE model of this building was modified by the results of the structural dynamical characteristic test.First, the FE model without considering city gate effect and infilled wall effect was established to analyze the dynamical characteristics.Then, the structural dynamical characteristic test was carried out on site.Through comparison of test results and the calculation results of unmodified FE model, three modified models considering city gate effect and infilled wall effect were put forward, and the calculation results of these three modified models were also compared with the results of the structural dynamical characteristic test.The best modified model which is suitable for this type of heritages was found out eventually.The study results show that: Firstly, the natural vibration frequencies of the model considering city gate effect decrease within 1% compared with the unmodified FE model.Thus, the city gate effect can be ignored when nature frequencies are used to make model updating.Secondly, in the two methods considering infilled wall effect, the result of the integral simplified model is numerically closer to the dynamical test result, and the error is less than 2%, while the error of the results of the equivalent diagonal strut model and the dynamical test is about 45%.The results can provide the scientific basis for the structural computing model modification of the similar ancient city gate towers. © 2020, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.