Liquefaction hazard during earthquakes at Nocera Scalo, ItalyPart I: Assessment of liquefaction potential using simplified procedures

 

The two main shocks (Ms = 5.5 and Ms = 5.9) of the seismic sequence that strucks the Umbria and Marche regions from September 1997 to june 1998, caused widespread damage to two- and three-storey buildings at Nocera Scalo, a hamlet in the Comune of Nocera Umbra.

 

The two main shocks (Ms = 5.5 and Ms = 5.9) of the seismic sequence that strucks the Umbria and Marche regions from September 1997 to june 1998, caused widespread damage to two- and three-storey buildings at Nocera Scalo, a hamlet in the Comune of Nocera Umbra.

Post-seismic studies demonstrated that at Nocera Scalo building damage and failures could be attributed only partially to the vulnerability ofthe buildings. Significant site effects were recorded during the aftershocks and, moreover, subsequent subsoil investigations showed that the damaged buildings lay on recent shallow alluvial deposit consisting of very loose saturated silly sands and fillings, with the bedrock at a maximum depth ol 18-20 mand a water table in the first 5-5 m. The heterogeneous nature of the loose sandy sediments underlying the buildings in combination with the presence ofthe superficial ground-water table might be responsible for ground settlements due to liquelaction, and this phenomenon might help to explain the damage to some buildings of fairly good quality.

In view of microzoning and rebuilding, a detailed geotechnical investigation was promoted by the Umbria Regional Government to evaluate the risk of liqnefaction in the whole area ofthe deposit underlying the hamlet.

This paper presents the results of field and laboratory testing conducted to assess the mechanical properties of the shallow materials and the results of liquefaction analyses performed by using some simplified SPT and CPT- based procedures, recommended by an international committee of experts and described in the paper of Youn et al. [2001], which resumes the conclusions of two workshops convened in 1996 and 1998, and sponsored by the National Center for Earthquake Engineering Research (NCEER).


  The two …


AUTORI: Crespellani T., Madiai C. Vannucchi G.
RIG ANNO:2001 NUMERO:4
Numero di pagine: 26


Allegato: https://associazionegeotecnica.it/wp-content/uploads/2010/03/RIG_2002_4_26.pdf
Allegato:
Articolo completo: https://associazionegeotecnica.it/wp-content/uploads/2010/03/RIG_2002_4_26.pdf