Earthquake Damage To Buried Pipelines Near a Fault: a Case Study in Hveragerði During the 2008 M6.3 Ölfus Earthquake

Abstract eng:
A strong earthquake with moment magnitude 6.3 occurred in South Iceland on 28 May 2008. This earthquake caused a lot of damage to the buried pipelines in the small town of Hveragerði, which lies very close, about 3-4 km, from the epicentre of the causative faults of the earthquake. The damages sustained by the pipelines were very well recorded in video footages obtained from camera-mounted robots that were passed through all the buried pipelines waste water pipelines in Hveragerði. A detailed inspection, analysis, and classification of the damages recorded in the video footages have revealed many interesting phenomena. It was observed that the most common type of damage is due to circular cracks in the pipes. Damages due to crushing of bell-spigot connections between the pipes were also very frequent. Such damages were more frequent in brittle joints which consist of cement-sand mortar, but significantly lower in flexible joints consisting of rubber gaskets. It was also observed that several improvements in concrete pipe manufacturing in Iceland that were introduced around the year 2000 improved the seismic performance of the pipes greatly. Damage rates in the new pipes were half of that in the older pipes. It was observed that the sewage pipes and the drainage pipes, which are similar in construction material and size, suffered very different damage rates, the former only suffering half the damages (per unit length) suffered by the latter. The repair rates estimated from ground motion recorded in the town along with standard fragility curves were found to significantly under-estimate damage rates suffered by the pipes in Hveragerði. The observed rates of major damages are about six times higher than the upper bounds estimated from standard fragility curves. This indicates that seismic risk management of underground lifelines in the South Iceland lowland should not rely on standard fragility curves calibrated elsewhere, but rather on local data and observations. The efforts made in detail recording and analysis of the damages suffered by the pipelines in Hveragerði during the Ölfus Earthquake is an important contribution in this regard. It is also an important lesson for other parts of the world to systematically collect and analyse damage data after major earthquakes.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket