Felipe Pedro Álvarez Rabanal

Collapse of a Masonry Wall in an Industrial Building: Diagnosis by Numerical Modeling

AbstractThis paper presents the analysis of a failure involving the partial collapse of a masonry wall made of precast concrete blocks in an industrial building as a result of the action of the wind. A field survey was carried out to investigate the origin of the failure, which pointed to defective building practices as the possible cause. At the same time, complementary numerical modeling was performed to simulate the coupled fluidstructure behavior, as well as a parametric study and optimization based on Design of Experiments (DOE) to determine the influence of the principal variables in the wall behavior in the presence of wind loads. The lessons learned in the course of the study are explained in the final section.

Optimization of an acoustic test chamber involving the fluid-structure interaction by FEM and experimental validation

The aim of this work is to determine the optimal design of two acoustic test chambers using systems of optimization by means of finite elements. In this way, we have modelled a set of tests composed of a source chamber and a receiving chamber according to the basic requirements of the standard rule. The constructive element whose acoustical behaviour is being evaluated is placed between both chambers. Applying the finite element method (FEM), a two-dimensional coupled finite element model with fluid-structure interaction has been made, using finite elements of the fluid-type both for the air and fluid-structure interface, and finite elements of solid-type with its elastic properties for a multilayered wall. The geometry of the chambers has been parameterized as design variables (DVs) and an objective function has been defined from the absolute value of the difference between the transmission loss (TL) values of the laboratory test and the TL of the numerical simulation in order to minimize it. To find an optimal design of the geometry of the acoustic chamber, a new cascade optimization procedure has been successfully developed. Finally, the numerical simulation results are compared with the acoustic laboratory results, and conclusions are exposed.

Optimization Based on Design of Experiments (DOE) Using Finite Element Model (FEM) Analysis Applied to Retrofitting the Church of Baldornon, Spain

This study addresses the failures in the Church of Baldornon, in Gijón, Province of Asturias, Spain, and proposes a retrofitting procedure based on the design of experiments (DOE), finite element model (FEM) analysis, and experimental tests. The failures are due to lack of soil stiffness, giving rise to an important structural damage. To tackle this problem, a practical solution based on the nonlinear coupled analysis of the soil and a reinforced concrete structure by FEM is proposed. The solution is to strengthen the previous existing rock-filling wall by means of gunite concrete and counterforts with anchorages embedded in the soil. Finally, conclusions and lessons learned from this study are detailed.This study addresses the failures in the Church of Baldornon, in Gijon, Province of Asturias, Spain, and proposes a retrofitting procedure based on the design of experiments (DOE), finite element model (FEM) analysis, and experimental tests. The failures are due to lack of soil stiffness, giving rise to an important structural damage. To tackle this problem, a practical solution based on the nonlinear coupled analysis of the soil and a reinforced concrete structure by FEM is proposed. The solution is to strengthen the previous existing rock-filling wall by means of gunite concrete and counterforts with anchorages embedded in the soil. Finally, conclusions and lessons learned from this study are detailed.

On the significance of the climate-dataset time resolution in characterising wind-driven rain and simultaneous wind pressure. Part II: directional analysis

Both semi-empirical methods and CFD simulations use real climate datasets as a basis for determining the building facade exposure to wind-driven rain and simultaneous wind pressure. The time resolution of these datasets and the number of variables considered (commonly rainfall intensity, wind speed and wind direction) determine the required calculation effort and the accuracy of the result. Omitting the wind direction, a former article (Part I of this research) has analysed the effect of this time resolution on two scalar exposure indices obtained by semi-empirical methods: driving rain index (aDRI) and driving-rain wind pressure (DRWP). However, the wind direction during precipitation events also causes significant exposure variations between possible facade orientations. Thus, it is also necessary to clarify the influence of the time resolution of the dataset, on the accuracy of the directional semi-empirical calculation of aDRI and DRWP. To meet this challenge, the article examines 10-min climate records collected between 2001 and 2016 at 6 Spanish locations, uses them to obtain hourly, daily, monthly and annual datasets, and analyses the accuracy of the directional exposure indices associated with each time resolution. The results show that a daily dataset would allow identifying the most exposed orientation with an error less than 45°. However, even the hourly datasets cause errors close to 10% in the exposure values identified on each facade orientation. Finally, adjustment relationships that allow estimating the maximum value of directional exposure from simple scalar indices are obtained.