Search results for "shear"
showing 10 items of 804 documents
Body mass variation in Scopoli’s Shearwaters Calonectris diomedea breeding at Linosa Island.
2012
Geological modeling of Altavilla Milicia (Sicily) using HVSR data
2014
At today the use of inversion of HVSR curves is mainly limited to derive average parameters of the shear wave velocity, although recently they have been used also for a detailed reconstruction of the roof of the seismic bedrock (Di Stefano et al. 2014). Since ambient vibrations may contain waves travelling in all directions, as body waves and Rayleigh and Love waves, a limit of this method lies in the uncertain composition of seismic noise, in the lack of knowledge about the microseismic field and in the subjective choices regarding the data processing. This work aims to verify the potential and limits of the HVSR inversion for the purposes of geological reconstruction of the subsoil in hea…
The Residual Shear Strength of the Shaly and Sandy Facies of the Opalinus Clay
2018
The paper presents a comprehensive laboratory campaign carried out with the aim to asses the residual strength of the Opalinus Clay. Ring shear tests with vertical effective stress up to 1 MPa were performed on remoulded samples of two different facies of the Opalinus Clay. Test results show that the «Shaly» facies is characterized by a low range of variation of residual strength while the strength of the «Sandy» facies is very sensitive to the variation of grain size distribution. Microstructural analyses (SEM) suggest that the difference in the observed mechanical behavior of the two facies can be related to different particles arrangements along the shear surfaces.
A model for SFRC beams without shear reinforcement
2008
In this paper a physical model, for the prediction of ultimate shear strength of Steel Fibers Reinforced Concrete (SFRC) beams is developed from the plastic Crack Sliding Model (CSM) introduced by Zhang (1997), based on the hypothesis that cracks can be transformed into yield lines. In this work the effectiveness factors are recalculated for SFRC beams and some further developments are introduced in the CSM, taking into account the fundamental post cracking tensile strength contribute of SFRC. The proposed model is validate by a large set of tests collected in literature and some numerical analyses were carried out to show the influence of fibers on the failure beams mode.
ANALISI TEORICO-SPERIMENTALE DEL COMPORTAMENTO A TAGLIO DI TRAVI PREFABBRICATE RETICOLARI MISTE
2014
An experimental campaign of three-point bending tests on specimens of Hybrid Steel Trussed Concrete Beams (HSTCBs) is presented. The scope of the experiments is the evaluation of the shear strength in the structural typology object of study. Two series of specimens are tested, subjected to positive and negative bending moment, respectively, with the aim to reproduce, in the first case, the condition in the midspan of a beam belonging to a framed structure and, in the second case, the behavior of the beam next to the column where the sign of the bending moment is reversed. The obtained experimental results are interpreted by means of an analytical model for the prediction of the shear resist…
Assessment of push-out test response of hybrid steel trussed-concrete beams by FE model
2013
Aiming to investigate the truss-concrete stress transfer mechanism in Hybrid Steel Trussed-Concrete Beams (HSTCBs), a three-dimensional nonlinear FE model is developed. The constitutive laws of the steel composing the plates and the bars is modeled by means of a quadri-linear law, while the concrete behavior is defined by means of a Concrete Damaged Plasticity (CDP) model, suitable for modeling concrete and brittle materials. The CDP model uses the concept of isotropic damaged elasticity in combination with isotropic tensile and compressive plasticity and is able to properly account for the concrete confinement effect. Two main failure mechanisms are considered, namely the tensile cracking …
Evaluation of the shear connection strength of precast hybrid steel-trussed-concrete composite beams
2015
In last decades, significant efforts have been carried out by the scientific community to evaluate the main technical issues of Hybrid Steel-Trussed-Concrete beams, investigating both the first opera-tive phase, i.e. before the concrete casting, when only the bare truss works, and, the second phase, i.e. after the concrete curing, when the beam works as a composite element. In the present study, the attention is focused on the evaluation of the shear strength of the connection between the bottom plate of the steel truss and the concrete core proposing a mechanical model able to predict its ulti-mate resistance. The proposed mechanical formulation is mainly based on the extension of existing…
Finite element modeling of the shear behavior of hybrid steel trussed concrete beams
2015
The development and calibration of a three-dimensional (3D) nonlinear Finite Element (FE) model is presented with the aim of investigating the shear behavior of steel-concrete composite beams realized with a steel truss embedded into a concrete core and named Hybrid Steel Trussed-Concrete Beams (HSTCBs). The model is calibrated on the results of a reference experimental campaign of three-point bending tests on HSTCBs realized at the Laboratory of Structures of the University of Palermo. The actual behavior at the steel-concrete interface has been introduced in the model through the implementa-tion of a cohesive constitutive relationship. Furthermore, the damaged plasticity of concrete has b…
Experimental tests on typical masonry of Messina area (Italy) retrofitted with CAM: A full scale arch
2014
The present paper focuses on an in-situ testing campaign recently developed in the Messina area, Italy, aiming at the assessment of the in-plane shear behaviour of traditional masonry structures retrofitted with the innovative CAM system (a system of 3D pre-tensioned stainless steel ties). The typical masonry of Messina area, is characterised by low mechanical properties, both for its texture and for the bad quality of mortar, as well as lack of transverse connections. The high seismic risk characterizing the zone, amplifies the need for in-plane strengthening and transverse connections improving. The CAM system, Masonry Active Ties or Manufact Active Confining, allows to realise a 3D pre-t…
Shear-flexure interaction of RC elements strengthened with FRP sheets
2005
An approximate physical model for evaluation of the M-V interaction resistance domains for concrete elements strengthened with FRP sheets is presented. The reliability of the model in predicting flexureshear capacity is verified by a comparison with the results of several experimental tests.