Analysis and modelling of the seismic behaviour of high ... - Ingegneria

1. INTRODUCTION
research: (i) mechanical and metallurgic characterization of the connection material
in order to estimate fracture toughness parameters like the inelastic crack tip
opening displacement (CTOD); (ii) development of adequate numerical models
taking into account the initiation and subsequent crack growth as well as the
cyclically stable stress-strain curve; (iii) parametric study on some design
parameters which influence the fracture resistance of steel bolted extended plate
connections. More specifically, the effects of the weld-to-base metal yield strength
ratio, the residual stress influence, and the end plate yield-to-ultimate strength ratio
have been determined through detailed two- and three-dimensional non-linear
finite element analyses of isolated Tee stub connections and complete joints.
1.2.2 Seismic response of partial-strength composite joints
This research activity is part of a ECOLEADER Project (3D Full-Scale Seismic
Testing of a Steel-Concrete Composite Building at Elsa, 2004), in which the
University of Trento plays the role of technical coordination. The project was
partially conducted jointly with an ECCS Project (Applicability of Composite
Structures to Sway Frames - 7210-PR-250 Project). In order to evaluate the
feasibility and effectiveness of the composite constructions with partial-strength
beam-to-column joints and partially encased columns in earthquake-prone regions,
the study aims at calibrating design rules affecting the aforementioned components
and the participation of the concrete slab in the relevant transfer mechanisms. The
results of this project led to improved design procedures for composite
constructions (Section 7, Part 1 of Eurocode 8, 2002). On the basis of
constructional considerations and of the favourable seismic behaviour of both the
column web panel and the end plate connection of the previous activity, the
composite solution adopted in the tested structure relies on plain steel columns.
Cyclic and Pseudo-Dynamic (PsD) tests have been conducted on a virtually full-
scale steel-concrete composite 3D structure with two-storey two-bay layout.
Pseudo-dynamic tests were performed in order to evaluate the performance of the
structure in terms of complex hysteretic behaviour under earthquake-like loading.
Moreover, new performance-based seismic design guidelines require that steel-
concrete composite buildings be analysed by using non-linear static pushover
analyses or non-linear dynamic analyses in order to control local and global
performances. For this reason, experimental data of beam-to-column joints
performed with the ECCS Project were then used to validate 3D model assembled
with the ABAQUS code and 1D composite frame set up with the IDARC-2D code.
The 3D model is used to analyse the local behaviour of composite members and
4