# Performance Assessment of a Renovated Precast Concrete Bridge Using Static and Dynamic Tests
## 8 Conclusions  
The development of a SHM strategy is presented in this paper using static and dynamic load tests, as well as numerical simulations. Therefore, the results of the tests and simulations of the static and dynamic response of the bridge subjected to traffic loads using a combination of devices, including interferometric radar and a complex measuring system, have been presented in the article. A static load test was performed to verify and validate the FEM model using measured strains and displacements. The combination of devices used is not common, and due to that, acceptable results were obtained from the presented comparisons. To obtain various types of data and to compare the dynamic characteristics, the combination of acceleration and displacement measurements can be used. Accelerometers are more suitable for detecting mode shapes, whereas interferometric radar can help validate numerical models comparing displacements, which are preferred in practice.  
A satisfactory numerical model has been prepared. Natural frequencies and MAC values match each other, with the error not exceeding 10%. Structure-vehicle dynamic interactions incorporating uneven surface effects and loss of contact have been derived and used. Numerically predicted dynamic displacements and test results match sufficiently in cases of higher velocity of passing trucks (60 km/h), while the difference of amplitudes is doubled in case of smaller velocities (about 20 km/h). However, the results regarding periods match to each other well. Tire stiffness has to be studied and considered more accurately to improve future results. Deterministically defined loads correspond with real conditions and can be useful not only for the comparison of vibration amplitudes, e.g., accelerations and spectral values, but even for the analysis of dynamic strains and displacements caused by traffic. As shown in this paper, precisely modelled traffic can be used as a comparison tool for future applications of structural health monitoring techniques.  
The goal to determine the actual forces in cables has been fulfilled. The presented SHM technique is relatively sensitive, e.g., the weight of only two vehicles could be identified. Moreover, this method provides the specification of the total value of axial force in the cable. Additionally, the natural frequencies of cables measured by accelerometers can be considered a performance indicator. The static and dynamic response of the bridge is similar to the response obtained by the numerical calculations of the FEM model prepared according to the project documentation of the real execution.  
Conceptualization, M.S.; methodology, M.M.; software, M.S., M.V., K.L. and M.M.; validation, M.V., K.L. and M.M.; formal analysis, M.S.; investigation, M.M., M.V. and K.L.; resources, M.M.; data curation, M.V. and K.L.; writing--original draft preparation, M.M., M.S., K.L. and M.V.; writing--review and editing, M.V.; visualization, M.M., K.L. and M.V.; supervision, M.S.; project administration, M.S. and M.V.; funding acquisition, M.S. All authors have read and agreed to the published version of the manuscript.  
This paper was supported by the Grant Agency of the Ministry of Education, Science, Research and Sports of the Slovak Republic VEGA No. 1/0749/19.  
The authors declare no conflict of interest.