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This article presents the validation of a non-linear FE numerical model of a multi-span stone arch railway bridge based on experimental tests and under in-service freight trains. Static loading tests allow evaluating the bridge response in terms of vertical displacements in the arches, opening/closure deformations on specific block joints of the arches, and vertical compressive stress variations in the piers. The bridge FE model is developed by combining the potentialities of a global continuous homogeneous model, based on FEM and Drucker-Prager model, and a local modelling approach based on a dedicated non-linear contact model. The freight vehicle modelling is based on a flexible FE approach, and the validation of the dynamic behaviour of the train-bridge system involved the comparison between numerical and experimental responses. All the numerical responses are in very good agreement with the experimental responses. Finally, a simulation of the dynamic behaviour of the train-bridge system is performed for realistic scenarios of freight traffic considering speeds between 40 and 140 km/h.

This paper reports on a numerical study focused on the characterization of the masonry and infill material behaviour of stone arch railway bridges. The study is based on experimental data from testing campaigns carried out in materials of two granite stone bridges. The campaigns comprise lab tests on stone masonry samples (blocks and joints) collected from the bridge structure, as well as in-situ flat-jack testing and Menard pressuremeter tests on masonry and infill components, respectively. A strategy was developed resorting to Finite Element (FE) methodologies involving local scale numerical simulation of the joint lab tests (shear tests) and both in-situ tests (Flat-jack and Menard pressuremeter tests), aiming at the calibration and validation of the material parameters to be used in global scale numerical simulations of the bridges' structural behaviour. The joint shear behaviour is simulated using a FE discrete formulation based on contact elements whereas the Flat-jack and Menard pressuremeter testing is simulated using FE continuous homogeneous nonlinear materials based on a Drucker-Prager (D-P) model. The calibration of the D-P model input parameters is performed through a sensitivity analysis followed by an optimization strategy based on a genetic algorithm. The methodology showed the potential to calibrate the material constitutive parameters to be adopted in FE numerical models of this type of bridge.

A study on the time development of local scour around a complex pier was developed using a small-scale model embedded in a sediment bed. A total of 15 laboratorial tests were performed at the Hydraulics Laboratory of the Faculty of Engineering of the University of Porto. The duration of each experiment was previously established to progressively characterize the scour cavity. After each experiment, the flume was gradually emptied to facilitate the application of close-range photogrammetry. The scour depth values resulting from the application of photogrammetry at the pile cap front agree well with the values obtained experimentally. The temporal development of the scour cavity is presented and discussed. Empirical formulas for the scour cavity time development and for the relation of scour depths to scour cavity volumes were obtained. The obtained three-dimensional models can also be used for calibration and validation of numerical models.

The transportation planning process is considered to be the initial step to incorporate the safety analyses of a transport system. Recently, tools have been created for this incorporation, although the vast majority has been applied at an area level. Despite the capacity of these tools to provide safety information, they are unable to identify hazardous locales in the network. The primary objective of this article was to develop a tool based on accident prediction models, which enable the forecasting of the highest accident-risk entities (i.e., nodes or links) using the information available as well as meeting the main issues that are decided at the planning level. Analyzing the influence of macrolevel road design variables on accident risk was the second objective, providing knowledge for planners and decision makers. To accomplish these objectives, generalized linear modeling techniques were employed to develop models for nodes and links using data from Porto, Portugal. The result analysis demonstrates that the additional macrolevel variables are statistically significant and improves the model. Thus, the results lead to a general conclusion that the proposed models are the suitable tool because they embody the balance between the needs and constraints inherent to the planning level. © 2013 Copyright Taylor and Francis Group, LLC.

The most efficient strategy to ensure long-term road network safety is to integrate safety analysis into the planning process of a network or a corridor. Safety planning decision-support tool outcomes should be reliable and realistic, taking into account the main characteristics of this particular level, which is characterized by scant and generalized data. However, the tools developed and presented in previous studies are based on models with a quantitative response. To develop a more suitable tool while maintaining a measure assessment character, this work presents a qualitative response model whose outcome is the risk of occurring three degrees of hazards: low, medium, and high. In this study, an ordered probit model was applied to an urban road network using Porto city data. Hazard categories were defined using accident frequency to reflect a measure of the safety of the road network studied. The developed model provides a safety risk analysis considering road data that are easy to gather or estimate at the planning level. In addition, an analysis of hypothetical scenarios for two sample segments is presented to illustrate an application of the categorical model in typifying an accident risk analysis at a planning level. © 2012 Copyright Taylor and Francis Group, LLC.

Performance-based earthquake engineering methodologies often require a probabilistic model of structural demand. Since observations masking the probability distribution of the majority of the data are frequently found, robust estimation methods are proposed to estimate the probabilistic model parameters (i.e., central value and dispersion). The performance of thirty-three robust dispersion estimators is evaluated, for different sample sizes, using the chord rotation, curvature, shear force, and inter-story drift demands obtained after analyzing five reinforced concrete structures under real earthquake records scaled to several intensities. Based on the results, combinations involving dispersion and central value (defined in a companion article) estimators are proposed.

This paper describes the design of an evaluation methodology—the Plan-Process-Results (PPR) approach—and its application to the municipal urban plans currently in force in the two largest Portuguese cities, Lisbon and Oporto. After the identification of the main contributions from a literature review, the fundamental elements of this methodology are characterised. Each case study is appraised according to rationality, performance and conformance, and a number of planning proposals are presented to improve planning practice in each of these cities. Finally, the main similarities and differences between both case studies, as well as the main reasons for these, are identified.