Claudio Ceccoli

Non-linear seismic analysis of base-isolated RC frame structures

In this paper, seismic analysis of plane RC frame structures with High Damping Rubber Bearings (HDRBs) base-isolation systems is performed in the non linear range. For RC members, a modified version of hysteretic Park model is used. For HDRB isolators, a new hysteretic model is presented, which is able to accurately predict the mechanical response in the large strain range. The dynamic equilibrium equations are solved making use, at each time step, of a block iterative Newton–Raphson scheme: the frame is divided into superelements (beams and columns) with master nodes at the extremities and internal local nodes for the computation of relations between end moments and relative rotations at superelement extremities. The effectiveness of HDRB base-isolation systems to reduce inelastic deformations in the RC superstructures is investigated through some numerical examples. Copyright

Correlations Between the Experimental Results of Pseudo-Static Tests with Cyclic Horizontal Load on Concrete/Polystyrene Sandwich Bearing Panels and their analytical counterparts

In recent years, the seismic behavior of reinforced concrete bearing squat walls structures has been the object of several research works. This paper presents a summary of the results obtained in a wide experimental/analytical/numerical correlation campaign carried out as a joint effort between the University of Bologna and the EUCENTRE labs in Pavia. This effort was devoted at the assessment of the seismic performances of structures composed of (lightly reinforced) concrete/polystyrene sandwich bearing squat walls. In this paper: (1) the results of a number of pseudo-static tests with cyclic horizontal load have been briefly recalled; (2) extensive analytical developments have been carried out to evaluate the mechanical characteristics and the seismic behavior of lightly reinforced concrete panels; (3) a comparison between the analytical and the experimental results has been performed. The comparison shows a good agreement between the experimental results and their analytical counterparts.

Seismic Analysis for the Structural Retrofit of “Palazzo della Civiltà Italiana” in Rome EUR, Italy

The “Palazzo della Civiltà Italiana” is a monumental building characterized by a reinforced concrete structure composed of parallel (cast in situ) portal frames and composite (reinforced concrete + hollow bricks floors which spans between adjacent portals: a common construction technique in Italy. The floors being characterised by a large span of about 10.0 meters. The construction took place between 1939 and 1943, most likely according to the Italian building code published in 1939. The authors have coordinated a comprehensive experimental campaign aimed at (a) the identification of the characteristics of the structural materials and members, and (b) the identification of eventual damages. Based upon the experimental results a number of analytical and numerical investigations have been developed in order to assess the structural reliability of the “Palazzo” which up to date still is remains in its “original” configuration, as no substantial intervention of structural retrofit or rehabilitation have been implemented so far. These analysis allowed to identify two major reliability issues: (i) the load bearing capacities of the floors do not allow the intended use, and (ii) the seismic vulnerability of the building does not satisfy the reliability standards required by current codes. On the basis of all data acquired and investigations performed, a simple (non invasive) structural retrofit solution capable of bringing the “Palazzo” to the level of structural safety required by current codes is identified.