Browsing by Author "Casanova, Euro"

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    Flexural performance of full-scale two-span Nail-Laminated Timber Concrete composite slabs
    (2024) Adema, Andres; Chacon, Matias F.; Santa Maria, Hernan; Opazo-Vega, Alexander; Casanova, Euro; Guindos, Pablo
    This study examines the flexural performance of six 9-m full-scale two-span Nail-Laminated Timber Concrete (NLTC) composite slabs. The slabs were made with lumber beams edge-joined with double nailing, end-joined with butt joints, and the reinforced concrete topping connected with a set of notches, inclined screws, or a combination of both. The multi-span configuration of slabs reduces their deflections simply and effectively. Fivepoint monotonic bending tests were considered for all slabs. Before full-scale slabs, compressive and tensile pullout tests of Timber-Concrete Composite (TCC) shear connections were performed, including notches and inclined screws. Tensile pull-out tests of shear connections were also included to emulate the negative bending moments that occur in the middle of the slabs. Failure modes, load-mid-span deflection relation, bending stiffness, and timber-concrete slip were evaluated for all slabs. A detailed 3D micro-Finite Element (FE) model of the shear connections was built in ANSYS software, whereas a macro-FE model of NLTC slabs was made in SAP2000, demonstrating a good fit for the timber-concrete interaction and the load-carrying capacity of the composite slab at the serviceability range. Moreover, an analytical elastic TCC beam with the Girhammar method was assessed and demonstrated as more precise than the traditional gamma-method. Finally, an accurate prediction of the numerical and analytical (Girhammar) models for the bending stiffness at service loads up to 30% of capacity is observed, with errors in a range of 2-23% and 9-74%, respectively.
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    Optimal TMD design for torsional balance of asymmetrical 3D structures considering soil-structure interaction
    (2022) Espinoza, Gilda; Casanova, Euro; Benedetti, Franco; Mena, Richard; Luis Almazan, Jose
    In this paper, the behavior of a tuned mass damper (TMD), to torsionally control a linear structure subjected to seismic excitations, is investigated. The dynamic system is analyzed taking into account lateral-torsional coupling, soil-structure interaction, and the rotational components of the foundation motion. The system model consists of an asymmetrical structure, founded on a soil modeled as a homogeneous semi-space. A stationary stochastic analysis is performed in the time domain, and a double Clough-Penzien filter of broad frequency content is used to define the random process for the X and Y directions. The torsional balance criterion is employed for the optimization of the TMD design parameters. The influence of the plan static eccentricity over optimum TMD parameters' behavior is also addressed, taking into account the fixed base period, flexible period, torsional frequency ratio, and soil type. Compliance with the torsional balance is verified. The results show that the inclusion of the soil rotational component has a notorious influence on the optimum TMD parameters. Moreover, torsionally flexible structures founded on soft and medium soil show significant influence on the torsional balance. Finally, a transitory response analysis is carried out for a 15-story model, subjected to an artificial bidirectional earthquake with a broadband frequency content. The multistory model response validates the results derived from the stochastic analysis.
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    Stochastic modelling of uncertainty in Chilean radiata pine wood beams subject to lateral torsional buckling
    (2024) Casanova, Euro; Graciano, Carlos; Iturra, Hector; Benedetti, Franco; Crocetti, Roberto
    This paper aims to investigate the effect of the variability in the mechanical and cross-section properties of Chilean radiata pine on the lateral buckling strength of slender wooden beams. The study is conducted numerically through finite element modeling and using linear eigenvalue analysis. The numerical model is validated using experimental results available in the literature. Two approaches are employed in the analysis, firstly a deterministic approach using design of experiments (DOE) techniques to establish the relevance of the parameters, and secondly a stochastic one, through Monte-Carlo simulation to investigate the impact of each parameter on the lateral buckling resistance. Various distribution functions are considered to investigate the effect of uncertainties in the material parameters and their impact on the critical buckling moments. Moreover, Sobol indices indicated that from the total variability of the distribution of the critical moment, an average of 50% of the variability is attributed to the shear modulus $G_{LR}$GLR, 37% to the longitudinal elastic modulus $E_L$EL, and a negligible percentage of the grain angle $F$F.