196,109 research outputs found
Analisi di errori nel rilievo del profilo stradale tramite profilometri con ruota di misura.
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Detecting homogeneous pavement section using econometric test for structural changes in linear model
No full textPavement Management Systems require a preliminary evaluation of road condition data in order to detect homogeneous sections. If surveyed data are regarded as "time series”, they may be adequately described by linear dynamic processes with structural changes; where the change of the coefficients in the model shows the break between two homogeneous sections.
The problem of detecting structural changes in linear regression relationships has been an important topic in statistical and econometric research. The most important classes of tests on structural change are those derived from the generalized fluctuation test framework, on one hand, and tests based on F statistics, on the other.
In this paper, methodological issues related to the application of above mentioned econometric criteria to detect homogeneous road sections, are examined.
The effectiveness of the econometric criteria were verified through the analysis of a case study related to skid resistance measurements within which a comparison between the different approaches has been performed.
The implementation of these methods in the sectioning process shows that a reasonable breakdown of the road using new econometric principles is possible
Preliminary Findings for a Prediction Model of Road Surface Macrotexture
No full textAbstractThe aim of this work is to present a prediction model of macro-texture based on bituminous mix properties. Following a review of existing prediction models where an in-depth critical analysis has been performed, several statistical models are presented where the macro-texture expressed in terms of mean texture depth depends on bituminous mixtures volumetric and grading properties. Different mixtures have been examined and experimental data have been derived from several technical papers or from ad hoc field and laboratory investigations. Data have been combined in order to obtain a more general prediction model, which presents a high level of applicability
Capability of Italian existing bridges to resist the impact against safety barriers
No full textABSTRACT: The aim of this paper is to investigate whether bridges designed according to Italian Standards in place since 1962 may resist the impact loads measured during crash tests of real bridge barriers. Their capacity has been assessed comparing the strength of overhang decks with the maximum values of the internal forces calculated by FEM analyses. Results show that bridges according to the current standard are able to sustain almost all the loads due to impact only if the design values of the internal forces are calculated by a simplified method. On the contrary, the capability to resist of bridges designed according to previous standards depends on barrier containment level, design methodology, cross section considered, impact position, strategy adopted for the reinforcement and width of overhang deck. The results obtained can be used both to check existing bridges and to design the new one
A unified approach for the prediction of vibration induced by underground metro
No full textIn this paper a methodological approach employing a mathematical model to evaluate the vibration level transmitted by railway traffic is proposed. The originality of the approach is related to the explicit coupling of a vibration generation model which is based on the dynamic interaction between the railway vehicle and the superstructure with a vibration propagation model that analyses the dynamic interaction between the railway superstructure and the underlying soil/structures. The vibration level provided by the prediction model has been compared with vibration measurements carried out on a test site located along Turin underground lin
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