Search results for "Truss"
showing 10 items of 48 documents
Optimality conditions for shakedown design of trusses
1995
This paper deals with optimal shakedown design of truss structures constituted by elastic perfectly plastic material. The design problem is formulated by means of a statical approach on the grounds of the shakedown lower bound theorem, and by means of a kinematical approach on the grounds of the shakedown upper bound theorem. In both cases two different types of design problem are formulated: one searches for the minimum volume design whose shakedown limit load is assigned; the other searches for the maximum shakedown limit load design whose volume is assigned. The Kuhn-Tucker equations of the four problems here above mentioned are found by utilizing a variational approach; these equations …
Reliability-based design optimization of trusses under dynamic shakedown constraints
2019
A reliability-based design optimization problem under dynamic shakedown constraints for elastic perfectly plastic truss structures subjected to stochastic wind actions is presented. The simultaneous presence of quasi-static (cyclic) thermal loads is also considered. As usual in the shakedown theory, the quasi-statical loads will be defined as variable within a deterministic domain, while the dynamic problem will be treated considering an extended Ceradini-Gavarini approach. Some sources of uncertainties are introduced in the structural system and in the load definition. The reliability-optimization problem is formulated as the minimization of the volume of the structure subjected to determi…
Stochastic dynamics of linear elastic trusses in presence of structural uncertainties (virtual distortion approach)
2004
Structures involving uncertainties in material and/or in geometrical parameters are referred to as uncertain structures. Reliability analysis of such structures strongly depends on variation of parameters and probabilistic approach is often used to characterize structural uncertainties. In this paper dynamic analysis of linearly elastic system in presence of random parameter variations will be performed. In detail parameter fluctuations have been considered as inelastic, stress and parameter dependent superimposed strains. Analysis is then carried out via superposition principle accounting for response to external agencies and parameter dependent strains. Proposed method yields asymptotic s…
Dissipative connections of rc frames with prefabricated steel-trussed-concrete beams
2020
In the last thirty years, Hybrid Steel-Trussed Concrete Beams (HSTCBs) have been widely used in civil and industrial constructions and, therefore, their mechanical performance must be evaluated with the aim of guaranteeing adequate dissipation of the seismic energy particularly in the beam-to-column joints. However, one of the most frequent peculiarities of HSTCBs is that of using their own steel joist to cover large spans with reduced depth and, in the case of traditional beam-to-column connections, this requires large amount of steel reinforcement inside the panel zone, often made with large diameter rebars. These characteristics make both the panel zone and the beam end potentially vulne…
Optimal Design of Trusses According to a Plastic Shakedown Criterion
2004
The optimal design of elastic-perfectly plastic truss structures subjected to quasi-statically loads variable within a given load domain is studied. The actions are given as the combination of fixed load and perfect cyclic load. Suitably chosen load multipliers are given. A minimum volume formulation of the design problem with assigned limit load multiplier is developed and it is provided on the grounds of a statical approach as well as of a kinematical approach. The incremental collapse (ratchetting) of the optimal structure is prevented, as long as the loads are not greater than some prescribed values, by special constraints suitably introduced in the search problem. The Kuhn-Tucker equat…
Ecomorphological variation within and among the two marine species of genus Salaria: Salaria basilisca and Salaria pavo (Perciformes: Blenniidae)
2022
In order to highlight the variation of the form due to the presence of different ecological factors, we investigated in this paper the morphological variation between and within the two marine species Salaria basilisca and S. pavo. This study was based on two approaches, the Truss network and the geometric morphometric and involved specimens of both species divided into marine and lagoon samples. The two approaches yielded complementary results showing clear morphological discrimination of the two species Thus, S. basilisca is distinguished by a higher depth and length as well as a higher head with a compressed snout compared to S. pavo which has a shortened body, a lower head and a slightl…
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…
Indagine sperimentale su nodi di tralicci in acciaio di travi reticolari miste
2009
Results of experimental tests on welded joints of steel truss of encased composite steel-concrete beams are presented. The welding of the inclined web bars to top bars, both of steel type B450C, and to bottom steel plate, the latter made of S355 steel type, are tested. Two analytical expressions for prediction of welding strength are derived: the one based on a resistance criterion and the other based on a limit domain of the welding section. Guidelines for choosing the effective dimensions of the fillet weld, necessary to determine the strength, are provided. A high precision digital scanner is used to validate the suggested guidelines to determine the geometrical characteristics of the fi…
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,…