FONTES, Fabio; DONATO, Marina; GOUVEIA, Bruno; SANTANA, Glaudeny; SILVA, Marcelino. Analysis of the influence of tropical soil classification methods on railway subgrades according to repeated load triaxial (RLT) and light weight deflectometer (LWD) tests, Case Studies in Construction Materials, Latest issue, Volume 17, 2022.

Resumo: Recently, non-destructive in-situ tests have emerged that can predict the resilient modulus (MR) of materials that make up railway sidewalk layers in an agile and low-cost manner. These are in contrast to laboratory tests that require more infrastructure and are more time-consuming to perform. However, few studies have been directed to the resilient behavior compared to in-situ and laboratory tests for soils classified as tropical. This paper aims to determine the relationship between the estimated modulus of elasticity (ELWD) and the estimated resilient modulus (MR) from the repeated load triaxial test (RLT) for use in tropical soil railway subsoils. The samples of subgrade soils belong to a railway stretch in Brazil, present in the states of São Paulo-SP and Minas Gerais-MG, which has large circulation of minerals and commodities. The soils are classified as lateritic and non-lateritic according to the Brazilian Miniature, Compacted, Tropical (MCT) methodology, in addition to grain size, compaction, LWD and RLT tests. It is noted that the modulus of elasticity (ELWD) tends to decrease according to the increase in strain obtained in LWD. For soils classified as lateritic, as the soil moisture increases the ratio between the moduli obtained by RLT and LWD tend to increase. However, non-lateritic soils have the opposite performance, i.e., the ratio between the modulus of the tests decreases with increasing moisture. In this study, the LWD test is a possible viable alternative with good accuracy and effectiveness for geotechnical investigations in tropical soils.

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BALTAR, Marina; RIBEIRO, Glaydston; SANTOS, Rafael. Exploratory analysis of incidents in an urban area focused on broken-down vehicles: The case of Rio de Janeiro, Transport Policy, Volume 10, Issue 1, 2022.

Resumo: This paper proposes a methodology to perform an exploratory analysis of incidents focused on broken-down vehicles using the city of Rio de Janeiro as a case study. We analysis the incidents that most impact the road traffic and try to understand the causes of these occurrences. The method used is based on historical data of the incident responses and on traffic flows. Our database was provided by the Traffic Engineering Company of Rio de Janeiro which has more than 204,000 incidents occurred between 2015 and 2017. Using statistical tools, the profile of the most frequent incidents is analyzed and policies are discussed to reduce its number and the response time.

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