Susana López-Querol

Improved 1-D modelling in compound meandering channels with vegetated floodplains

This paper shows that common open channel flow one-dimensional (1-D) numerical models behave poorly in terms of flow distribution across a section in a naturalized meandering channel with vegetated floodplains.We compared numerical models with new experiments carried out in a physical model on a reach of the Besòs river close to Barcelona that has been restored. The case examined has floodplains with thick vegetation, a low-flow meandering channel and high water depths over the main channel and floodplains. 1-D models overestimate velocities in the main channel but underestimate them on the floodplains. The paper gives a detailed description of an improved 1-D computation method based on the consideration of the total shear stress at the main channel-floodplain interface (the sum of turbulent friction plus lateral momentum transfer) on the one hand, and the influence of upstream velocity distribution with the help of two-dimensional numerical models on the other hand.

Improving Civil Engineering Education: Transportation Geotechnics Taught through Project-Based Learning Methodologies

Previous studies have found that nontechnical skills, like, for example, communication, team work, and solving open-ended problems, are abilities that civil engineers must possess to perform their professional duties. However, the traditional teacher-centered methods employed in civil engineering schools do not encourage students to develop these skills. To address this concern, the educational program at the School of Civil Engineering of Ciudad Real in Spain was designed using a project-based learning methodology, which produced satisfactory results. Recently, to meet new requirements coming from the higher education European degrees, this program modified its curriculum. To further improve the program, the Transportation Infrastructure course, which was previously taught using traditional methods, was redesigned within a project-based learning framework and was renamed Transportation Geotechnics and Pavement Engineering. Because the school is still transitioning from the old program to the new program, a survey was conducted to compare and discuss the opinions of two groups of students who completed these subjects during the 2012–2013 academic year. The results of both the survey and the final marks of the respective groups illustrate better performance of project-Based learning methodologies compared with traditional teaching techniques.

Effect of class F fly ash on fine sand compaction through soil stabilization

This paper presents the results of an experimental investigation carried out to evaluate the effect of fly ash (FA) on fine sand compaction and its suitability as a material for embankments. The literature review demonstrates the lack of research on stabilization of sandy material using FA. The study is concerned with the role of FA content in stabilized soil physical characteristics. The main aim of this paper is to determine the optimum quantity of FA content for stabilization of this type of soil. This is achieved through particle size distribution and compaction (standard proctor) tests. The sand was stabilized with three proportions of FA (5%, 10% and 15%) and constant cement content of 3% was used as an activator. For better comparison, the sand was also stabilized by 3% cement only so that the effect of FA could be observed more clearly. The results were in line with the literature for other types of soil, i.e. as the % of FA increases, reduction in maximum dry density and higher optimum moisture content were observed.

Meshfree Methods Applied to Consolidation Problems in Saturated Soils

A meshfree numerical model, based on the principle of Local Maximum Entropy, with a B-Bar based algorithm to avoid instabilities, is applied to solve consolidation problems in saturated soils. This numerical scheme has been previously validated for purely elasticity problems without water (mono phase), as well as for steady seepage in elastic porous media. Hereinafter, the model is validated for well known consolidation theoretical problems, both static and dynamic, with known analytical solutions. For several examples, the solutions obtained with the new code are compared to PLAXIS (commercial software). Finally, after validated, solutions for dynamic radial consolidation and sinks, which have not been found in the literature, are presented as a novelty. This new numerical approach is demonstrated to be feasible for this kind of problems in porous media.

Numerical Methods for SSI Analysis of Offshore Wind Turbine Foundations

The aim of this chapter is to provide a summary of the numerical methods available to carry out long-term prediction analysis of offshore wind turbine foundations. Different available methods of analysis are discussed.

Historical earthquake parameters by geological and seismic site analysis: the 1908 Cerbón earthquake (Spain)

AbstractSeismic catalogues summarize information mainly on recent earthquakes and seismic events, recorded by means of relatively new instruments. Hence, this information, although being of high quality and quantitative value, sometimes is rather incomplete, since historical earthquakes are neglected in many cases. An example is the 1908 Cerbón earthquake (in Spain). This shake caused a good number of effects in the epicentre and surrounding area, triggering a huge landslide among some other effects. A complete geological and seismic site analysis, accompanied by a historical review of testimonies and journals of the time describing this particular earthquake, has been carried out, along with a deep field investigation to identify the mechanism of this landslide and the characteristics of the involved materials. A retrospective pseudo-static numerical simulation has been carried out to calculate the most probable range of peak horizontal accelerations during the earthquake. The results demonstrate the moderate relevance of this shake, also allowing us to quantify its objective importance. The presented methodology can be easily extended to some other similar cases, if seismic catalogues are to be completed for future designs accounting for seismic considerations.

Frequency-Domain Assessment of Integration Schemes for Earthquake Engineering Problems

Although numerical integration is a technique commonly employed in many time-dependent problems, usually its accuracy relied on a time interval small enough. However, taking into account that time integration formulae can be considered to be recursive digital filters, in this research a criterion based on transfer functions has been employed to characterize a wide range of integration algorithms from a frequency approach, both in amplitude and in phase. By adopting Nyquist’s criterion to avoid the aliasing phenomena, a total of seven integration schemes have been reviewed in terms of accuracy and distortion effects on the frequency content of the signal. Some of these schemes are very well-known polynomial approximations with different degrees of interpolation, but others have been especially defined for solving earthquake engineering problems or have been extracted from the digital signal processing methodology. Finally, five examples have been developed to validate this frequency approach and to investigate its influence on practical dynamic problems. This research, focused on earthquake and structural engineering, reveals that numerical integration formulae are clearly frequency-dependent, a conclusion that obviously has a relevant interest in all dynamic engineering problems, even when they are formulated and solved in the time-domain.