Guide for the Structural Rehabilitation of Heritage ... - Test Input

a) Photogrammetric survey (16) b) Laser sweeping survey (21)Figure18: Survey of the geometry of the building3.6 Monitoring of the buildingThe monitoring of the building during a certain period of time can be an adequate measure to helpthe elaboration of the diagnosis, particularly when there may be non-stabilized phenomena,allowing for showing its evolution.The monitoring of the building consists in the measurement of parameters, such as,deformations, movements of cracks, levels, temperature variations, etc., in strategic points ofthe building, at certain moments, during a certain period of time.The monitoring techniques can range from the simple placing of gypsum ‘tell-tales’ (Fig. 19a)or crackmeters on cracks, to a modern monitoring systems using sensors: electricextensometers, displacement transducers, thermometers, accelerometers, etc. (Fig. 19b),connected to a data acquisition device, which can acquire data at pre-defined intervals of time.The photogrammetric technique can also be used as a method of monitoring.The monitoring of the building can also be done during the rehabilitation phase, in which thedata that is being obtained is used as a basis for subsequent decisions, allowing, sometimes,for the reduction of the size of the intervention. Continuing monitoring of the building can also beuseful after the rehabilitation works, or when doubts still remain about the need for more measuresof intervention (long-term monitoring).By comparing of the results obtained from the monitoring of the building with the resultsobtained from its modelling, it will be also possible to refine the modelling (see section 4).Monitoring systems permit the storage of the acquired data and its transmission via landlines or through the internet. They can also function as an alarm, which can be very useful insome situations.23/48