TURRIS: an open source database and Python tools to compute the fundamental frequency of historic masonry towers

TURRIS (Towers featURes & fRequencIes databaSe) is a database collecting information of 244 historical masonry towers and information about the associated dynamic identification. Each tower is described by 23 parameters (identification, initial database, reference of the study, building name, country, town, latitude, longitude, height, effective height, shape of the section, regularity of the elevation, width, length, the minimum and maximum wall thickness, its relation with adjacent building, age, bells mass, Young modulus, mass density, Poisson ratio, and any information about the structural state of the tower). Each Operational Modal Analysis survey is described by 8 parameters (fundamental frequency, minimum, maximum, and standard deviation of the fundamental frequencies for long-term analysis, the type of sollicitation, duration of the records, sampling rate, and identification technique). The 244 historical masonry towers are located worldwide (mainly in Europe). The TURRIS database allows studying the relationship between geometrical, material parameters, and fundamental frequency.

The database is regularly updated. Data can be transmitted by completing the following form: https://framaforms.org/turris-database-sharing-information-about-features-of-historical-masonry-towers-1692963128. The details of each metadata field of the TURRIS database are given in the following.

• Id : the identifier for each study
• database : the collection from where the study was taken into account
• references : the reference of the scientific study. The reference id maybe used with the associated bibtex file.,
• building_name : the name of the historical building
• country, town, latitude, longitude : the four parameters describe the location of the building
• input : type of sollicitation
• f0 [Hz] : the measured fundamental frequency
• H [m] : the height of the tower
• Heff [m]: the effective height of the tower computed as the difference between the absolute height of the building and the height of the any adjacent building
• shape : the shape of the tower section (SQ : square, REC : rectangular, CIR : circular)
• elevation_regularity : the regularity of section from bottom to the top
• width [m]: the shorter dimension of the section
• length [m]: the larger dimension of the section
• min_wall_thickness [m]: the minimum thickness of the wall of the tower
• max_wall_thickness [m]: the maximum thickness of the wall of the tower
• relation : the type of connection between the tower and adjacent building (Isolated or bounded)
• period : the age of construction
• bells [kg]: the mass of the bell system
• E [GPa]: the Young modulus
• density [kg.m-3]: the mass density
• Poisson_ratio : the Poisson ratio
• duration [minute]: the duration of the records
• sampling_rate [Hz] : the sampling rate of the records
• info : any information about potential damage or retrofitting actions
• OMA_technique : the technique used to identify modal parameters
• min_f0 [Hz]: the minimum measured fundamental frequency measured over time
• max_f0 [Hz]: the maximum measured fundamental frequency measured over time
• std_f0 [[Hz]: the standard deviation of fundamental frequency measured over time

Python scripts have been developped (@MArnaud, @CGcidou) to compute the fundamental frequency using empirical, physics-based formulations and a Ritz-Rayleigh approach. The TURRIS database is used as an input.

The TURRIS database is a product of the ACROSS project (ANR-20-CE03–0003) founded by the French National Research Agency.