Performance of Pipes During Earthquakes
Session 2A
1:00
Camille George Rubeiz, PE
Plastics Pipe Institute, USA
This paper summarizes the performance of water and gas piping systems during six earthquakes in the US, Japan, Thailand and Columbia. Also, the paper will present data from the UK, Sweden and Denmark about the performance of pipes in non-earthquake environments. The paper will assist design engineers and owners in selecting pipe materials based on the past performance of the materials and based on the recommendations from the American Water Works Association and the American Society of Civil Engineers. In summary:
1. Most, if not all, US states have experienced some earthquake. As of 2009, the state of Maryland (MD) experienced the lowest magnitude earthquake of 2.6 and the state of Alaska (AK) experienced the highest magnitude earthquake of 9.2.
2. The 1906 San Francisco earthquake destroyed the city downtown and fires burned for 3 days due to lack of water to control the fires. As such, the water system must be better designed to remain operational to avoid a repeat of this fire and destruction in other cities.
3. The 1994 Northridge earthquake resulted in damage to 3 water transmission pipes and failures of over 1500 water system pipelines. It was noted that if this earthquake had occurred in other locations in North America, the water system would have been more heavily damaged than was seen in Northridge because the system was upgraded following the 1971 San Fernando Earthquake. Also, the earthquake resulted in 709 gas pipe leaks (lower pressure, smaller diameter pipes within the distribution and service system) and 35 high pressure, large diameter leaks in the transmission system.
4. After the 1989 Loma Prieta earthquake, it was not clear which leaks can be attributed to the earthquake; however, the researcher listed the leaks in gas mains and services.
5. The effects of the 1995 Kobe earthquake on water and gas pipes was discussed; PE water and gas pipe had a failure rate (0.00 damage/km); Ductile Cast Iron pipe (0.052 for gas pipe and 0.488 for water pipe) and Steel pipe (1.210 for gas and 0.437 for water). The remaining water pipe materials had the following damage rate: PVC (1.430), CIP (1.508) and AC (1.782).
6. The 2005 Thailand Tsunami reported about the prevalent use of HDPE for potable water and the piping system performed ‘very well with few failures’.
7. The 1999 Columbia earthquake reported the following failure rates: PE (0 failures/10 km), DI (0), RC (0), PVC (8), AC (9.5) and CI (9.7).
8. The ASCE 2002 document tabulated the vulnerability to earthquakes of various pipe materials: PE has a low vulnerability to earthquakes; Ductile Iron ranged between Low and Low – Moderate; Steel ranged between Low and High; Concrete Cylinder ranged between Low – Moderate, to High; PVC ranged between Low – Moderate, to Moderate; Cast Iron ranged from Moderate – High, to High; Vitrified Clay ranged from Moderate – High, to High; Asbestos Cement is High.
In addition to the data that was presented on the performance of pipes in past earthquakes, the paper presented data from regular (non-seismic) applications in the UK and Sweden: The Swedish data showed the following failure rates: PE (0.3 failures/10 km), DI (0.4), PVC (1), CI (1.9) and Steel (3.3). The UK data showed the following failure rates: PE (0.32 failures/10 km), DI (0.53), PVC (0.73), Steel (1.11), AC (1.6), Iron (2.01) and Unknown (0.32).
Camille George Rubeiz, PE, Director of Engineering
Plastics Pipe Institute