Assessment of a capacity spectrum seismic design approach against cyclic and seismic experiments on full‐scale precast RC structures

Abstract

Summary Within the last decades, simplified methods alternative to dynamic nonlinear analysis have been developed to estimate the seismic performance of structures toward a performance‐oriented design. Considering drift as the main parameter correlated with structural damage, its estimation is of main importance to assess the structural performance. While traditional force‐based design deals with calibrated force reduction factors based on the expected structural ductility, other methods are based on the definition of a viscous damping factor defined as a function of the expected energy dissipated by the structure. An example is the capacity spectrum method. This method can be applied even without any a priori calibration or designer arbitrariness. This allows considering several peculiarities of the seismic behavior of precast structures, which may be influenced by nontraditional hysteresis of connections and members, interaction with the cladding panels, P‐δ effects, etc. The paper aims at verifying the soundness and accuracy of this method through the comparison of its predictions against the results of cyclic and pseudodynamic tests on precast structures, including single‐ and multistory buildings either stiff or flexible, obtained on full‐scale building prototypes tested within the framework of recent research projects (namely, “Precast Structures EC8,” “Safecast,” and “Safecladding”). Two simple methodologies of determination of the equivalent viscous damping from a force‐displacement cycle, based on the dissipated energy in relation to 2 different estimates of the elastic strain energy, are addressed and compared. Comments on the possible use of this procedure for the estimation of the seismic performance of precast structures are provided.

Tension-only ideal dissipative bracing for the seismic retrofit of precast industrial buildings

“…The method, originally proposed by Freeman (1978), was later implemented in many structural codes worldwide, although modified with several restrictions to its general potential. The application of the general CSM approach for the preliminary evaluation of the seismic performance of precast structures with either standard or innovative connections was assessed against experimental full-scale testing in Dal Lago and Molina (2018).…”

Slope topographic effects on the nonlinear seismic behavior of groups of similar buildings

“…This software is utilized to analyze underground tunnels, earthquake response, slope stability, soil-structure interaction, and other geotechnical/structural applications. 54,55 In this study, the effects of slope topography on three buildings are considered a TSSSI system, which is compared with SSSI and SSI systems in terms of seismic responses of buildings. In TSSSI analysis, the angle and height of the slope are considered as i = 30 B/a = 3-5 are used in modeling to decrease and eliminate the boundary effects (see Figure 3).…”

“…MIDAS GTS NX is a comprehensive finite element software package used to simulate the nonlinear analysis of the seismic response of slopes and buildings placed adjacent to the slope crest. This software is utilized to analyze underground tunnels, earthquake response, slope stability, soil‐structure interaction, and other geotechnical/structural applications 54,55 . In this study, the effects of slope topography on three buildings are considered a TSSSI system, which is compared with SSSI and SSI systems in terms of seismic responses of buildings.…”

Multi-Stripe Seismic Assessment of Precast Industrial Buildings With Cladding Panels

“…Within the spread mass model, the in-plane and out-ofplane forces in the panel connections have been recorded as the concentrated horizontal shear actions on the beam elements simulating the panels in correspondence of the link with the roof master node. Considering the shear key connector successfully used in the experimentation related to both pendulum and rocking systems in the Safecladding test program (Negro and Lamperti Tornaghi, 2017;Toniolo and Dal Lago, 2017;Dal Lago and Molina, 2018), whose structural behavior under simple shear and combined shear-axial forces is described in Figure 13, the D/C ratios and failure rates could be evaluated. The results, collected in Figure 14, show peculiarly low D/C ratios apart from the higher stripes of the L'Aquila site.…”

“…Details about each arrangement and numerical modeling strategies can be found in Dal Lago (2019). Each of these arrangements was previously subjected to seismic testing on full-scale prototype within the SAFECLADDING project (Negro and Lamperti Tornaghi, 2017;Toniolo and Dal Lago, 2017;Dal Lago and Molina, 2018). This paper is aimed at providing indications on the seismic behavior of precast industrial frame structures with Isostatic cladding connection arrangements based on probabilistic seismic vulnerability assessment.…”