## 6 Conclusions  
In this work, an extensive array of non-destructive tests for sites of cultural significance were presented and performed for the Castle of Lanjaron, Spain. The works explored the application of a Schmidt hammer, Schmidt pendulum hammer, penetrometer, scratch test  
Figure 15: Results from the pushover analysis of the west wall with fully fixed end condition: (**a**) minimum principal stress (view from the outside of the wall); (**b**) maximum principal strain (view from the inside of the wall). device, and a series of direct and indirect sonic tests for wave-based methods to characterize the materials of the structure and their mechanical properties. Dynamic identification was employed to register ambient vibrations and obtain relevant information for the numerical models. Three primary modes were obtained from the dynamic identification process under 15 Hz, being 7.58 Hz, 10.84 Hz, and 14.13 Hz. The fundamental frequencies of vibration were selected manually and further validated using EFDD and SSI-UPC methods. Operational Modal Analysis was used to calibrate and validate a developed homogenized 3D FE model for the west wall of the castle. This was used to assess the seismic behavior of the site using non-linear static analysis in addition to limit analysis. The behavior of the structure was evaluated for safety in accordance with current design codes. The efficacy of wave-based methods and OMA were highlighted in the study; sonic test results were able to effectively predict the range of the elastic modulus (1.5-2.0 GPa) that resulted from an eigenvector analysis of the model, which considered an initial value of 2.0 GPa but was ultimately successful in calibration with a value of 1.5 GPa. The values obtained from indirect sonic testing were within 3% of the calibrated elastic modulus for the wall, while those from direct testing were around 33% higher. The Modal Assurance Criteria were used to validate the movement of the west wall in the FE model and the experimentally gathered data from OMA to above 85% agreement for all modes presented. The calibrated frequencies for the FE model were 7.52 Hz, 11.01 Hz, and 15.4 Hz, which displayed an average absolute error of 3.8% and maximum absolute error of 9.0%. Limit analysis and FEA allowed for the evaluation of the seismic behavior of the wall in the out-of-plane direction, the most vulnerable for masonry structures. Common failure patterns were explored, ultimately concluding that the structure could withstand the local peak gravitational accelerations of 0.18 g as defined by the Spanish seismic design codes due to seismic activity. A safety factor of 1.39 was obtained from the ratio of the minimum peak value achieved from non-linear static analysis, 0.25 g, to the PGA of the area, 0.18 g.  
The novelty of this case study presents findings that should be observed and considered for all future works on the Castle of Lanjaron. The approach presents a framework that can be adopted for the evaluation of regular and irregular historical masonry structures alike. It is especially relevant for sites that are otherwise difficult to perform common NDTs on. While more traditional NDTs (Schmidt hammer, Schmidt pendulum hammer, penetrometer, and scratch testing instrument) were less successful in their application on the irregularly surfaced masonry, the wave-based tests and modal analysis were extremely successful in their application. These methods were able to wholistically approximate the mechanical behavior of the structure in terms of a homogeneous modulus of elasticity and modal parameters including mode shapes and frequencies of vibration. These wholistic values complemented the use of the macro-modeling approach for masonry and the homogenization assumptions that it entails. These methods can strongly be recommended for the preliminary seismic assessment of a site where resource availability and the applicability of analog methods is difficult. Further analyses beyond the scope of the paper for the Castle of Lanjaron are recommended.