One of the most used arguments for plastic pipe systems is the flexibility and durability. If a question appears about earthquake fitness, the plastic pipe industry normally replies by showing damage-statistics. And indeed, the statistic results are very convincing, especially with damage statistics of rigid pipe systems. In the last editions of our IMPROFIL magazine we published many reports regarding earthquakes (mainly from our friends in Japan)- but a practical orientated dynamic test of a complete plastic pipe system with all aspects of different jointing methods, fittings and constructions has never been done before.
Below please find the summarized technical report with the original title:
“Conduction of dynamic tests of conduits system including pipes, fittings, containers, wells, and pump stations of trade mark “KRAH PIPES” with assessment of the opportunity of their application in the regions of Russian Federation with seismic intensity 7-9 magnitudes”.
The technical report is using the results of experimental researches of polyethylene conduit elements of the trade mark “KRAH PIPES”, designed for outdoor sewerage, disposal of waste water and ventilation. The tests were conducted on the stand which was specially designed by JSC Research Center of Construction, Research Institute of Building Constructions. The stand is a pendulum-type platform vibrator.
The purpose of the laboratory tests is estimation of workability and exploitative reliability of polyethylene pipe conduit elements in seismic regions of Russian Federation with 7÷9 degrees of intensity according to the MSK-64 scale.
The report is issued in accordance with the requirements of existing regulations. The terms and definitions from SNIP II-7-81* were used for describing methods and results of seismic stability experimental researches of polyethylene pipe conduit elements for outdoor sewerage, disposal of waste water and ventilation.
Worldwide the risk of earth quakes is a big issue, the population in the “red” areas is high and so the infrastructure is a critical point.
A Krah Pipe system is assembled by using typical jointing procedures:
The pipe system is installed as a loop, including different pipe diameters between DN/ID 300 and DN/ID 500 mm, different kinds of fittings like bends and reducers and also a manhole-shaft. For the pipes, fittings, bends and manholes typical profiled wall structure is used. The complete setup is filled with water.
Everything is installed on a vibration platform, designed for the simulation of earthquake loads under consideration of typical accelerations and amplitudes.
The vibration tests were conducted in the day time at an air temperature lower than +15˙C. During the tests the vibration platform acceleration, by the data of accelerometers which were installed on the platform, was changed in intervals from 1.04 to 8.36 m/s2. Oscillation frequencies of the system were changed in intervals from 1.0 to 11.4 Hz, the oscillation amplitudes were changed in intervals from 0.7 to 33.2 mm.
On the basis of dynamic tests results analysis of conduit elements of trade mark ‘’KRAH PIPES” it may be noted that:
Examplary Accelerograms (m/s2) and spectrums of the maximum value of amplitudes (mm),
recorded by installed sensors:
Picture 5: Spectrums of the maximum value of amplitudes (mm) for installed sensors.
The test mode #25 (frequency f = 10.4 Hz; amplitude A = 0.9 mm)
KRAH PIPES GmbH & Co. KG
Betzdorfer Str. 8