1,720,983 research outputs found
“Case Study: Mechanical Reliability Of Sub-Grade Layer Built With Demolition Waste Materials
No full text“Chemical and Mechanical Reliability of Sub-Grade Layer Built with Demolition Waste Materials
No full textCoal Mining Waste As An Alternative Material To Natural Aggregates For Road Construction
No full textGli sfridi di estrazione del carbone come materiale alternativo agli aggregati di cava. Sfruttamento delle risorse locali e valorizzazione dell’ambiente
No full text
FE simulation and experimental analysis on bearing capacity of the runway strips
No full textThe aim of this study was to establish reasonable values for both maximum deflection and minimum bearing capacity of runway strips, conforming to regulations specified by the Italian Civil Aviation Authority (ENAC), to implement in the design and reabilitation of the runway strips of the Cagliari Airport in Italy. The ENAC regulations state that the bearing capacity of runway strips must be designed based on the characteristics of both the critical aircraft and emergency vehicles which may transit on the runway. However, it does not specify a minimum bearing capacity value. Therefore, based on the instructions given by ENAC regulations, required values for both maximum deflection and minimum bearing capacity were determined using a Finite Element Method (FEM) simulation to design runway strips. In particular, a non‐linear analysis was conducted with FEM to simulate the mechanical behavior of granular soil under high instantaneous pressures. The paper explains how the theoretical analysis was conducted, which materials were tested, and how runway strips were designed. Before the construction, extensive on‐site testing was performed to validate the results obtained with the theoretical analysis. In particular, 122 series of single and double cycle bearing capacity plate and Light Weight Dropping (LWD) tests were performed. Results from these tests were used to define critical areas and to estimate any degree of correlation between the bearing capacity plate and LWD tests. The theoretical and experimental analyses carried out on this case study have enabled a design criterion and facilitated the rebuilding of the emergency strips of the Cagliari Airport in Italy, conforming to regulations specified by the ENAC. The results obtained with the theoretical analyses were validated by performing extensive on‐site testing
EXPERIMENTAL INVESTIGATION ON THE USE OF C&DW MATERIALS AS AGGREGATES FOR ROAD SUB-BASE
No full textMore than 95% of road infrastructures materials consist of aggregates. Highway and
construction industries consume annually a huge amount of aggregates, causing
considerable energy and environmental losses (Hüseyin et al, 2007). Many country
are substituting quarry aggregates with construction and demolition waste (C&DW)
materials. However in Italy there is the need to overcome the distrust for the use of
C&D materials. Thus, the aim of this research is to evaluate the suitability of
construction and demolition waste (C&DW) materials, produced in Sardinia (Italy),
from the physical and mechanical point of view. Laboratory tests were conducted to
evaluate physical characteristics and also an experimental road has been built to
evaluate mechanical performances in situ. The research has been divided in two main
phases: in the first phase laboratory tests were carried out such as Sieve analysis,
Limits of Atterberg, CBR test, L.A. abrasion test. In the second phase in situ tests
were carried out consisting of: dry density of soil by sand replacement method and
both static and dynamic plate tests. Other tests were carried out to study the behaviour
of the material during its use (short term behaviour and in the long term), in order to
evaluate environmental compatibility of the material in place under working
conditions, as well as the mechanical performance in situ or in a real scale test. The
first results are encouraging, the material is non-plastic, the Los Angeles abrasion test
shows the tendency to fragmentation of the aggregates, but within the limits, therefore
allowing their use in road sub-grade layer also the material shows good bearing
capacity. The introduction in the market for the construction of roads of solid waste
materials helps to limit the exploitation of renewable natural resources
The structural performance of road pavements made with modified bituminous conglomerate
No full textThe characteristics of traffic loads are changing . In particular, they are increasing in quantity and magnitude. Therefore
the mechanical characteristics of materials used for building road superstructures, as bituminous conglomerate and
bonding agent, need to be improved. The more recent researches are aimed to improve the stress-strain behaviour by
increasing the modulus of elasticity of bituminous conglomerate. In fact, the behaviour of the pavement improves
significantly using “modified bituminous”. For modified bituminous the higher the modulus of elasticity the higher the
flexural rigidity and the dynamic resistance are. Also, the higher the modulus of elasticity the less the thermal
susceptibility and plastic deformation are. Overall, the main benefit is a longer service life of the pavement.
Two different models of pavement were analysed using the finite element method. The two models were designed with
same geometry (equal number of layers and same thickness) and bearing capacity of the agger, whereas either
pavements were made with modified bituminous. The behaviour of the materials was simulated assuming an elastoplastic
model. The load was applied in both static and dynamic conditions.
The magnitude of both stress and strain was measured in correspondence of the interface between the base and the
subbase of the pavements. The magnitude was resulted lower for the pavement made with modified bituminous. That
becomes more evident long the wheeler-paths for superstructures made with low stiffness and bearing heavy loads. It
was observed also that the structural characteristics of the pavement improves using modified conglomerate.
The research will be carry on about the effect of dynamic loads on the durability of the pavement
Analisi sperimentale e simulazione FEM del comportamento vibrazionale della nuova metropolitana leggera di Cagliari
No full textNella memoria viene analizzato il comportamento vibrazionale della Nuova Metropolitana Leggera di Cagliari
e condotta una valutazione di alcuni differenti interventi di mitigazione.
Un particolare sito sperimentale è stato monitorato prima della costruzione della nuova linea metropolitana,
realizzata attraverso l’adeguamento di una preesistente ferrovia a scartamento ridotto.
Lo studio, dapprima condotto sperimentalmente, ha compreso una serie di misurazioni lungo allineamenti
perpendicolari alla linea ferrata, per circa 45 m., in corrispondenza del passaggio dei convogli ferroviari.
Ciò ha permesso di costruire il profilo di attenuazione delle vibrazioni e validare il modello agli elementi finiti,
utilizzato nella seconda fase della ricerca per simulare il fenomeno.
Il modello così validato è stato successivamente testato, modificando l’input della forzante generata dai
nuovi convogli e trasmessa al terreno dal nuovo armamento.
I risultati hanno confermato il migliore comportamento della nuova metropolitana e, in modo meno banale,
hanno permesso di quantificare l’attitudine di 4 tecniche differenti per lo smorzamento delle vibrazioni.
Il fenomeno è stato poi studiato parametricamente modificando gli input del modello quali materiali, potenza
degli strati e configurazione al contorno. Infine, vengono illustrati i risultati del monitoraggio condotto in fase
di costruzione e collaudo dell’opera
- …
