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The Central Italy earthquake sequence nominally began on 24 August 2016 with a M6.1 event on a normal fault that produced devastating effects in the town of Amatrice and several nearby villages and hamlets. A major international response was undertaken to record the effects of this disaster, including surface faulting, ground motions, landslides, and damage patterns to structures. This work targeted the development of high-value case histories useful to future research. Subsequent events in October 2016 exacerbated the damage in previously affected areas and caused damage to new areas in the north, particularly the relatively large town of Norcia. Additional reconnaissance after a M6.5 event on 30 October 2016 documented and mapped several large landslide features and increased damage states for structures in villages and hamlets throughout the region. This paper provides an overview of the reconnaissance activities undertaken to document and map these and other effects, and highlights valuable lessons learned regarding faulting and ground motions, engineering effects, and emergency response to this disaster.

The seismic soil-pile-structure interaction (SPSI) is a complex mechanism that is usually considered formed by the combination of kinematic and inertial interaction. Both mechanisms generate additional forces on the system related to the stiffness contrast between the soil and the foundation for the kinematic interaction and to the soil response around the foundation due to the inertial contribution of the superstructure for the so-called inertial interaction. While the mechanism of each of these contributions is clear, their combination is still under investigation due to number of parameters involved (i.e. dynamic characteristics of both system and input). An effective way to study this combination is the analysis of actual data on real structures. Due to the fact that these data are hard to find, usually the response of physical scaled models on 1-g and n-g devices are investigated. In this connection, this paper presents some results from an extensive 1-g shaking table testing activity. The scaled physical model is formed by a group of five piles embedded in a by-layer deposit of dry sands with an oscillator connected to the piles through different kind of foundation systems. More specifically, the attention is focused on both pile and structural response when the oscillator is connected to a small group of three piles by means of a stiff foundation. The analysis of the experimental data enhances the role of the resonance between the soil-structure system and the input waves in the general behavior of both structure and piles

An effective way to study the complex seismic soil-structure interaction phenomena is to investigate the response of physical scaled models in 1-g or n-g laboratory devices. The outcomes of an extensive experimental campaign carried out on scaled models by means of the shaking table of the Bristol Laboratory for Advanced Dynamics Engineering, University of Bristol, UK, are discussed in the present paper. The experimental model comprises an oscillator connected to a single or a group of piles embedded in a bi-layer deposit. Different pile head conditions, that is free head and fixed head, several dynamic properties of the structure, including different masses at the top of the single degree of freedom system, excited by various input motions, e.g. white noise, sinedwells and natural earthquake strong motions recorded in Italy, have been tested. In the present work, the modal dynamic response of the soil–pile–structure system is assessed in terms of period elongation and system damping ratio. Furthermore, the effects of oscillator mass and pile head conditions on soil–pile response have been highlighted, when the harmonic input motions are considered.

The geotechnical systems are often studied analysing the response of scaled models in 1-g or n-g devices. A crucial aspect in these kind of models is the capability to read the real response of the system using different instrumentations. In this paper are described the main devices used for the interpretation of the dynamic response of a scaled geotechnical model tested at the Bristol Laboratory for Advanced Dynamics Engineering (BLADE) of the University of Bristol, UK, within the framework of the Seismic Engineering Research Infrastructures for European Synergies (SERIES), funded by the 7th FP of the European Commission. The model is formed by a group of five piles embedded in a bi-layer deposit with different pile head conditions, different dynamic properties of the superstructure (connected at the top of the pile group) and input motions. After some details about the whole experimental campaign and the devices used, the paper shows the main procedures adopted to evaluate the response of the whole system in terms of acceleration, displacement and stresses (only for piles).

The present analytical work discusses the outcomes of a series of 1-g shaking table experimental tests that were carried out to validate numerical models formulated for kinematic and inertial interaction effects on pile-supported systems. Towards this aim, pile models in layered sand deposits were built in the laboratory; such models were subjected to several cyclic tests and an ensemble of earthquake loading. The piles were densely instrumented with accelerometers and strain gauges; therefore, earthquake response, including bending strains along their length, could be measured directly. Different configurations were considered for the shake-table tests; the latter configurations include free-head piles and single-degree-offreedom (SDOF) systems with short and long caps at foundation level. The experimental data have been assessed accurately to estimate the period elongation of the SDOF structures, if any. Additionally, comparisons between the soil free-field response derived experimentally and advanced numerical simulations are also included. The results of the analyses show that the period elongations of the SDOF structure caused by pile-soil-interactions may be significant, thus affecting the evaluation of structural response under earthquake loading. Implications on the assessment of existing structures and the design of new ones are discussed

The present analytical work discusses the outcomes of a series of 1-g shaking table experimental tests that were carried out to validate numerical models formulated for kinematic and inertial interaction effects on pile-supported systems. Towards this aim, pile models in layered sand deposits were built in the laboratory; such models were subjected to several cyclic tests and an ensemble of earthquake loading. The piles were densely instrumented with accelerometers and strain gauges; therefore, earthquake response, including bending strains along their length, could be measured directly. Different configurations were considered for the shake-table tests; the latter configurations include free-head piles and single-degree-of-freedom (SDOF) systems with short and long caps at foundation level. The experimental data have been assessed accurately to estimate the period elongation of the SDOF structures, if any. Additionally, comparisons between the soil free-field response derived experimentally and advanced numerical simulations are also included. The results of the analyses show that the period elongations of the SDOF structure caused by pile-soil-interactions may be significant, thus affecting the evaluation of structural response under earthquake loading. Implications on the assessment of existing structures and the design of new ones are discussed

The cyclic and seismic response of soil-pile-structure systems is assessed through comprehensive experimental tests performed on the 3mx3m shaking table of the Bristol Laboratory for Advanced Dynamics Engineering (BLADE), University of Bristol (UK). Such tests were carried out in the framework of the Seismic Engineering Research Infrastructures for European Synergies (SERIES). The present work discusses preliminary results of the cyclic response of a pile group in a bi-layered soil profile. The outcomes of the test results discussed hereafter emphasize that kinematic effects are of paramount importance for the seismic analysis and design of structural systems with piled foundations. Appropriate combination rules to account for both inertial and kinematic effects are deemed necessary. The experimental results derived with the shaking table tests will be employed to calibrate numerical models, which, in turn, will be utilized to perform comprehensive parametric analysis aimed at providing sound design rules to be implemented in next generation performance-based seismic codes of practice.

The region of the central Apennines affected by the 2016 earthquake sequence has numerous towns, villages, and isolated dwellings connected by local secondary roads and a few state highways. The roadway network includes several bridges that are important to the economy of the region and play an important role in the post-earthquake resilience of local communities. Within this network, 12 bridges and a rockfall protection tunnel were inspected in coordination with local officials, with relatively cursory reconnaissance of most of the remainder of the network. All inspected reinforced concrete and steel–concrete composite bridges performed adequately. Two historic masonry bridges near Amatrice and Tufo suffered significant damage after the 24 August 2016 main shock, and collapsed after the 30 October 2016 event. Recovery strategies related to the bridge collapse near Amatrice, where two temporary bridges were built within 10 days from the first main shock in August, are discussed. An inspected rockfall protection tunnel experienced earthquake pounding effects.

The Central Italy earthquake sequence initiated on 24 August 2016 with a moment magnitude M6.1 event, followed by two earthquakes (M5.9 and M6.5) on 26 and 30 October, caused significant damage and loss of life in the town of Amatrice and other nearby villages and hamlets. The significance of this sequence led to a major international reconnaissance effort to thoroughly examine the effects of this disaster. Specifically, this paper presents evidences of strong local site effects (i.e., amplification of seismic waves because of stratigraphic and topographic effects that leads to damage concentration in certain areas). It also examines the damage patterns observed along the entire sequence of events in association with the spatial distribution of ground motion intensity with emphasis on the clearly distinct performance of reinforced concrete and masonry structures under multiple excitations. The paper concludes with a critical assessment of past retrofit measures efficiency and a series of lessons learned as per the behavior of structures to a sequence of strong earthquake events.

Soil Structure Interaction (SSI) is a complex phenomenon that may radically change the earthquake response of structural systems, as consequence of the variation of the natural frequency and the damping ratio. One of the most effective means for evaluating SSI is the use of physical models. In this study the physical model considered is formed by an oscillator founded on a group of piles embedded in a horizontally layered deposit of dry sand. The benchmark experimental campaign was carried out at the Bristol Laboratory for Advanced Dynamics Engineering (BLADE) at the University of Bristol (UK), financed by the Seismic Engineering Research Infrastructures for European Synergies (SERIES). An accurate parametric numerical study is performed and the results are discussed. The study investigates the effects of the dynamic properties of the oscillator on the period elongation and piles re-sponse. By means of advanced numerical analyses the outcomes of the present work provide insights into the quantitative evaluation of period elongation and the strength of inertial con-tribute to the bending moment at the pile head, when the system approaches resonance condi-tions.