There are two main testing protocols that have to be applied to seismic base isolation devices. The first one is prototype tests and the sesond one is factory production control tests. According to EN 15129, prototype tests are applied to two real-size samples for each different type of isolation devices. If the difference between axial load capacity, displacement capacity and radius of curvature values are not larger than ±20% for two different devices, then prototype tests can be evaluated for only one of those devices. Prototype tests force isolators to their performance limits with different axial load and velocities; therefore, devices that undergo these tests are not advised to be used again at the end of complete procedure. As a result of prototype tests, base isolation devices are checked according to the acceptance criteria defined in specifications and devices are either accepted or rejected at the end of this evaluation.
Other test protocol that need to be applied to seismic base isolation devices is factory production control (FPC) tests. These tests are conducted on the devices that is being manufactured at the production facility of the manufacturer by means of mass production. Functionality of the isolators and reliability of mass production are being verified by these tests. According to EN 15129, FPC tests shall be performed on 5% of the total manufactured quantity for each different type of curved surface sliders. However, for some projects, FPC tests may be demanded up to 100% of the curved surface sliders. Depending on the client and the project, the sampling frequency may be subjected to change.
Requested factory production control tests, with application methods and acceptance criteria, are listed below for a curved surface slider with axial load capacity of Nsd and displacement capacity of ddaccording to EN 15129.
For each type of curved surface sliders, properties of all devices manufactured during mass production are expected to be the same. This can be checked and possible problems can be detected by randomly selecting curved surface sliders among the manufactured ones and applying the tests listed above. The maximum deviation of shear force shall not exceed ±5% among the tested curved surface sliders. As a result, by evaluating factory production control tests, not only verification of basic properties of curved surface sliders can be achieved, but also reliability of mass production system can be checked.
FPC tests are not as demanding as prototype tests. According to acceptance criteria, there shall not be any visible damage or detoriation on any component of curved surface slider. Therefore, devices can be re-used after FPC tests, so tested curved surface sliders are packaged and prepared for shipment after their test results are approved.
It is essential for the projects to be completed in an effective and efficient way. To achieve this, FPC tests should be applied to manufactured curved surface sliders quickly and correctly. Our company, having its own test rig, is capable to conduct FPC tests for a wide range of device types at its test laboratory, that has EN ISO 17025 basis. This allows us to reduce our delivery time significantly by eliminating outsourcing for FPC tests.