System selection and mounting

in the course of structural health monitoring system design

In order to select structural health monitoring system components (SHM), it is necessary to perform a number of procedures, which will help to choose the suitable digital sensors, their quantity, and mounting areas:

  1. Define the controlled parameters and then select the particular SHM subsystems enabling control in accordance with the set requirements.
  2. Find out information on the number of floors and foundation’s square of the controlled object using corresponding design documentation.
  3. Define the necessary amount of the digital sensors to be included in the structural health monitoring system using the information from the clause «System components and controlled parameters».
  4. Mark digital sensors location for each of the levels (floors) of the controlled object (building).

When choosing digital sensor’s location it is necessary to take into consideration further cable connection.

If the building has 7 or fewer floors, the sensors are to be installed at the bottom part (at level/floor, which is as close to the foundation as possible) and at the top part (at the level/floor in direct vicinity to the ceiling). In the case of high structures, it is also necessary to select several intermediate floors for the control purposes in accordance with the information specified in the clause «System components and controlled parameters».

Accelerometers ZET 7150, ZET 7152 and ZET 7156 velocimeters should be mounted on concrete foundations as close to the bearing structures/walls of the building as possible.

For the purpose of the best possible positioning of the accelerometers used for fundamental tone frequency control at the stage of design and survey work one can use  «Mobile measuring system: natural oscillation frequency and decrement measurements».

Акселерометры ZET 7150
Инклинометры ZET 7154

ZET 7154 inclinometers (tilt meters) are to be mounted on elements (intermediate slabs, bearing walls, ceiling bearing structures, bearing elements, etc)  that are subject to tilt control monitoring.

ZET 7110-DS strain-gauge sensors are mounted on structural elements (intermediate slabs, bearing walls, ceiling bearing structures, bearing elements, etc) for the deformation control purposes.

Цифровые акселерометры ZET 7110-DS
Вихретоковые датчики ZET 7140-DS

ZET 7140-S eddy current sensors and ZET 7180-I digital modules together with RF603 laser sensors are used for structural elements relative displacement control. These measuring modules should be installed in the areas where the occurrence of such displacement processes is most likely.

Upon completion of digital sensors installation, it is necessary to choose data acquisition nodes locations as well as the necessary amount of interface converters for each of the electrical cabinets.

When choosing the locations for data acquisition nodes cabinets it is necessary to make the measuring lines as short as possible. While calculating the total amount of the converters to be used, one should take into consideration the limitations concerning the cable line length specified in the clause «Measuring lines: design process», as well as the table of data transfer channel load.

As the locations of data acquisition nodes cabinets are known, it is necessary to design connecting cables routes in the object (building) scheme.

Загрузка канала передачи данных

The modules placed inside of data acquisition nodes cabinets (interface converters, power supply sources and so on) are mounted on DIN-rails.

Each interface converter should be connected to industrial PC of the data acquisition node or (in the case if there are no PC-s in the structure of data acquisition nodes) to the SHM system server – for that purpose, Ethernet converters are used (the Ethernet converters have a corresponding amount of ports).

In the case if the Ethernet data transfer cable line length  (from data acquisition nodes panels to the server) is less than 100 meters, it is possible to use Class 5 twisted pair. In the case of implementing longer cable lines, there should be used a fiber-optic cable with optical media-converters at both ends of the cable.