Search results for "Steel"

The Effect of Nonlinear Response of the Primary System in Nonconventional TMDs

2023

Tuned Mass Dampers (TMD) have been widely used in the passive vibration control of engineering structures, both under wind and seismic loads. Under wind loads, a proper frequency tuning ensures a significant response reduction of the primary structure. While under wind loads the structure is likely to remain in the elastic range of behaviour, when large earthquakes occur it can experience inelastic deformations and damage, with a consequent de-tuning effect. In this paper, nonconventional TMDs with large mass ratios, realized through Interstory Isolation Systems (IIS), are considered and the influence of the inelastic behaviour of the primary system on the overall structure response is anal…

Mechanical and environmental performance comparisons of improved asphalt pavement wearing courses with high quality aggregates, steel slags, and poly…

2023

The use of waste materials in the construction of hot mix asphalt (HMA) pavements is an important opportunity for environmental sustainability. When properly designed, the alternative mixtures may also guarantee excellent mechanical performance. In this study, the results of an experimental analysis carried out on dense-graded HMAs are presented. In particular, the performance of a "traditional" surface mixture with limestone aggregate (designed with neat bitumen or a polymer-modified bitumen within the typical acceptance requirements for intended use in wearing courses) was compared with two alternative mixtures. The research investigated a surface mixture including coarse basaltic aggrega…

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.

Compressive response of concrete columns under service conditions strengthened by confining devices: from the local to the global behavior.

Il rinforzo di colonne in calcestruzzo armato tramite materiali polimerici fibrorinforzati (FRP) o tramite incamiciature in acciaio conferisce agli elementi strutturali degli edifici esistenti un elevato incremento di capacità portante e deformativa grazie alle proprietà dei materiali che svolgono la funzione di confinamento. Conoscere adeguatamente le proprietà meccaniche degli elementi in calcestruzzo confinato risulta di fondamentale importanza nell’ambito di un progetto di sistemi di rinforzo strutturale. Tuttavia, le normative attualmente vigenti non forniscono prescrizioni su come tenere in considerazione la presenza dei carichi di esercizio sugli elementi strutturali al momento dell’…

Experimental characterization of friction properties of materials for innovative beam-to-column dissipative connection for low-damage RC structures

2023

Low-damage design of structures in seismic-prone areas is becoming an efficient strategy to obtain "earthquake-proof" buildings, i.e. buildings that, even in the case of severe seismic actions, experience a low or negligible amount of damage. Besides the safeguard of human lives, this design strategy aims also to limit the downtime of buildings, which represents a significant source of economic loss, and to ensure an immediate occupancy in the aftermath of an earthquake. In this context, focusing on moment-resisting frames (MRFs), several solutions have been developed for the beam-to-column connections (BCCs) of steel and precast/prestressed concrete structures, but very few for cast-in-sit…

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 …

Innovative connections for steel-concrete-trussed beams: a patented solution

2023

The most recent design strategies welcome the adoption of innovative techniques for seismic energy input mitigation, aiming to achieve high dissipation capacity, prevent the structure from collapse and ensure the serviceability of the construction. Friction damper devices have been widely adopted in framed steel structures for decades, while their introduction in different structural types is still under investigation. This paper presents the outcomes of innovative research supported by the industry and conducted on beam-to-column connections of RC structures in which the beams are Hybrid Steel-Trussed Concrete Beams (HSTCBs) and the columns are classical RC pillars. An innovative solution,…

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…