Adolfo Cavallari
Resonant Column Testing Challenges

The standard procedure to determine dynamic parameter of soils in the laboratory is the Resonant-Column test (ASTM D-4015). The objective of the present work is to overview alternative testing and interpretation methods based on small-strain measurements using continuous sinusoidal, pulse signals or random noise. The use of unconventional excitation signals and frequency domain methods extends the possibilities of testing. A technique, already applied to the analysis of nonlinear systems, combines sinusoidal signals and random noise showing a good potential for a quick evaluation of the dynamic properties of soils. Starting from this technique, we propose a procedure devoted to soil testing combining chirp with strain amplitude control and random noise. The aim is to improve the quality and to reduce the testing time for the evaluation of the dynamic properties of soils vs. frequency. The use of a dynamic simulator allows a quick testing of new analysis software devoted to RC testing systems giving greater confidence in the quality of work done to face this challenging test.

Silvano Marchetti, Diego Marchetti, Paola Monaco
Flat dilatometer (DMT). Applications and recent developments

Since the original basic paper on the flat dilatometer (Marchetti 1980) a large number of papers, including manuals and standards, have been published. Aims of this paper are: (a) to briefly describe this in situ test; (b) to summarize the essential related content available in the literature; (c) to give an overview of its main applications; (d) to give information on the most recent developments, thereby permitting the unfamiliar reader to gain in a short time a basic knowledge of the DMT.

Sotiria Karapetrou, Dimitris Pitilakis
Seismic vulnerability of a high-rise hospital building using field monitoring data

In this study, the seismic vulnerability of a high-rise hospital building is evaluated, combining numerical analysis and field monitoring data. The target building is an eight-storey reinforced concrete (RC) structure composed by two units separated through a structural joint. The assessment of the dynamic characteristics is performed using ambient noise measurements recorded by a temporary seismic network deployed inside the hospital. The modal identification results are used to update and better constrain the initial finite element model of the building, which is based on the available design and construction documentation plans. Three-dimensional incremental dynamic analysis is performed to derive the fragility curves for the initial as built model and for the real structures as they are nowadays. Results indicate that the consideration of the actual state of structures may significantly alter their expected seismic performance leading to higher vulnerability values.

S. Cafiso, C. D’Agostino, B. Capace, E. Motta, P. Capilleri
Comparison of in situ devices for the assessment of pavement subgrade stiffness

The subgrade is the top surface of a roadbed upon which the pavement structure is constructed. The purpose is to provide a platform for construction of the pavement and to support the pavement without unwanted deflection that would reduce its performance. For those reasons subgrade bearing capacity have to be investigate during the construction process as a quality control, based on the design results. The dynamic in situ Falling Weight Deflectometer (FWD) tests are nowadays widely used and considered the most reliable and suitable approach to determine bearing capacity of road pavements and elastic moduli. In addition, the use of the Light Weight Deflectometer (LWD) takes the advantage of the dynamic application of load, and the flexibility of the handling of the equipment on construction area and unbound layer. In the present paper, a wide literature review is presented on the topic of correlation between different subgrade bearing capacity in situ tests. In order to assess the transferability of LWD measures, these results were compared with FWD test and Dynamic Cone Penetrometer (DCP) test. Soil samples, taken from the site, have also been investigate in laboratory to relate geotechnical and in situ test results.

S.Imposa, E. Motta, P. Capilleri, G. Imposa
HVSR and MASW seismic survey for characterizing the local seismic response: a case study in Catania area (Italy)

Many recent researches show that the site seismic response is strongly influenced by stratigraphic and topographic features. Site response can reduce or amplify the earthquake induced ground motion. An integrated approach based on passive (HVSR) and active (MASW) seismic surveys, was carried out at the Garibaldi Hospital, located in Catania downtown, in order to evaluate the seismic site response. Fourteen environmental noise records, located near some previously mechanical drillings, were carried out and processed by using the Horizontal to Vertical Spectral Ratio (HVSR) technique. Successively, two MASW prospections were performed at the northern and the southern sides of the Hospital building, following the information deduced from the stratigraphic characteristics of soil drillings. The data obtained from this coupled analysis, method and the information derived by mechanical drillings previously performed, allowed us to obtain the site transfer function which can be related to the H/V average spectrum. Such integrated approach, based on passive and active seismic prospections, showed to be a reliable and quick method to obtain information for a site seismic characterization. According to Italian code a Vs30 profile was achieved and the soil type category was determined.