Relationship between piezometric level and ground deformations measured by means of DInSAR in the Vega Media of the Segura River (Spain)

Differential SAR Interferometry (DInSAR) is a remote sensing method with the well demonstrated ability to monitor geological hazards like earthquakes, landslides and subsidence. Among all these hazards, subsidence involves the settlement of the ground surface affecting wide areas. Frequently, subsidence is induced by overexploitation of aquifers and constitutes a common problem that affects developed societies. The excessive pumping of underground water decreases the piezometric level in the subsoil and, as a consequence, increases the effective stresses with depth causing a consolidation of the soil column. This consolidation originates a settlement of ground surface that must be withstood by civil structures built on these areas. In this paper we make use of an advanced DInSAR approach - the Coherent Pixels Technique (CPT) [1] - to monitor subsidence induced by aquifer overexploitation in the Vega Media of the Segura River (SE Spain) from 1993 to the present. 28 ERS-1/2 scenes covering a time interval of about 10 years were used to study this phenomenon. The deformation map retrieved with CPT technique shows settlements of up to 80 mm at some points of the studied zone. These values agree with data obtained by means of borehole extensometers, but not with the distribution of damaged buildings, well points and basements, because the occurrence of damages also depends on the structural quality of the buildings and their foundations. The most interesting relationship observed is the one existing between piezometric changes, settlement evolution and local geology. Three main patterns of ground surface and piezometric level behaviour have been distinguished for the study zone during this period: 1) areas where deformation occurs while ground conditions remain altered (recent deformable sediments), 2) areas with no deformation (old and non-deformable materials), and 3) areas where ground deformation mimics piezometric level changes (expansive soils). The temporal relationship between deformation patterns and soil characteristics has been analysed in this work, showing a delay between them. Moreover, this technique has allowed the measurement of ground subsidence for a period (1993-1995) where no instrument information was available.

Forensic analysis of buildings affected by mining subsidence based on Differential Interferometry (Part III)

This work presents a forensic analysis of buildings affected by mining subsidence, which is based on deformation data obtained by Differential Interferometry (DInSAR). The proposed test site is La Union village (Murcia, SE Spain) where subsidence was triggered in an industrial area due to the collapse of abandoned underground mining labours occurred in 1998. In the first part of this work the study area was introduced, describing the spatial and temporal evolution of ground subsidence, through the elaboration of a cracks map on the buildings located within the affected area. In the second part, the evolution of the most significant cracks found in the most damaged buildings was monitored using biaxial extensometric units and inclinometers. This article describes the work performed in the third part, where DInSAR processing of satellite radar data, available between 1998 and 2008, has permitted to determine the spatial and temporal evolution of the deformation of all the buildings of the study area in a period when no continuous in situ instrumental data is available. Additionally, the comparison of these results with the forensic data gathered in the 2005–2008 period, reveal that there is a coincidence between damaged buildings, buildings where extensometers register significant movements of cracks, and buildings deformation estimated from radar data. As a result, it has been demonstrated that the integration of DInSAR data into forensic analysis methodologies contributes to improve significantly the assessment of the damages of buildings affected by mining subsidence.

The episcopal complex of Eio-El Tolmo de Minateda (Hellín, Albacete, Spain). Architecture and spatial organization. 7th to 8th centuries AD

The episcopal complex of Eio, located in El Tolmo de Minateda, was built between the end of the 6th century and the beginning of the 7th century, possibly as a political decision taken by the ecclesiastical authority in the capital of the Visigothic kingdom (Toletum). With the comprehensive study of the whole complex presented below (construction cycles, furniture, decoration and location of spaces), we can interpret the function of each space in the basilica and the domus episcopi, the liturgical and general movement routes, the existence of some hierarchical environments, and specify the chronological development of the buildings. After the Arab-Berber conquest of Hispania in the early 8th century, the whole complex will experience a series of transformations that will convert the religious and monumental public area into a private, residential and industrial Islamic quarter.

A methodology for evacuation route planning inside buildings using geospatial technology

Evacuation route planning is a fundamental task for building engineering projects. Safety regulations are established so that all occupants are driven on time out of a building to a secure place when faced with an emergency situation. As an example, Spanish building code requires the planning of evacuation routes on large and, usually, public buildings. Engineers often plan these routes on single building projects, repeatedly assigning clusters of rooms to each emergency exit in a trial-and-error process. But problems may arise for a building complex where distribution and use changes make visual analysis cumbersome and sometimes unfeasible. This problem could be solved by using well-known spatial analysis techniques, implemented as a specialized software able to partially emulate engineer reasoning. In this paper we propose and test an easily reproducible methodology that makes use of free and open source software components for solving a case study. We ran a complete test on a building floor at the University of Alicante (Spain). This institution offers a web service (WFS) that allows retrieval of 2D geometries from any building within its campus. We demonstrate how geospatial technologies and computational geometry algorithms can be used for automating the creation and optimization of evacuation routes. In our case study, the engineers’ task is to verify that the load capacity of each emergency exit does not exceed the standards specified by Spain’s current regulations. Using Dijkstra’s algorithm, we obtain the shortest paths from every room to the most appropriate emergency exit. Once these paths are calculated, engineers can run simulations and validate, based on path statistics, different cluster configurations. Techniques and tools applied in this research would be helpful in the design and risk management phases of any complex building project.

Construction of 17-19th century domes in the province of Alicante (Spain): the case of San Juan Bautista in Cox

From the late seventeenth to early nineteenth centuries, many religious temples have been built in the province of Alicante (south east of Spain) with brick domes as their main characteristic feature. Often, the limited data available about these remarkable constructions make rehabilitation interventions become into real research projects, with a high value for their historic conservation over time. The aim of this paper is to show a detailed refurbishment analysis of a religious temple built in 1778, showing the need of preservation of historic buildings as a part of the architectural heritage by establishing a common pattern of materials, geometry and constructive systems, specifically in their domes. In most cases, there was not an architectural project for the construction, that is why the analysis of any documentary and archival sources available is essential to find different ways to proceed on the use and maintenance of these religious buildings.

How to measure healthiness in buildings: Experiences in teaching with BIM tools

Introducing teaching about healthy solutions in buildings and BIM has been a challenge for the University of Alicante. Teaching attached to very tighten study plans conditioned the types of methods that could be used in the past. The worldwide situation of crisis that especially reached Spain and the bursting of the housing bubble generated a lack of employment that reached universities where careers related to construction, Architecture and Architectural Technologist, suffered a huge reduction in the number of students enrolled. In the case of the University of Alicante, students’ enrolment for Architectural Technology reached an 80% reduction. The necessity of a reaction against this situation made the teachers be innovative and use the new Bologna adapted study plans to develop new teaching experiences introducing new concepts: people wellbeing in buildings and BIM. Working with healthy solutions in buildings provided new approaches for building design and construction as an alternative to sustainability. For many years sustainability was the concept that applied to housing gave buildings an added value and the possibility of having viability in a very complex scenario. But after lots of experiences, the approved methodologies for obtaining sustainable housing were ambiguous and at the end, investors, designers, constructors and purchasers cannot find real and validated criteria for obtaining an effective sustainable house. It was the moment to work with new ideas and concepts and start facing buildings from the users’ point of view. At the same time the development of new tools, BIM, has opened a wide range of opportunities, innovative and suggestive, that allows simulation and evaluation of many building factors. This paper describes the research in teaching developed by the University of Alicante to adapt the current study plans, introducing work with healthy solutions in buildings and the use of BIM, with the aim of attracting students by improving their future employability. Pilot experiences have been carried out in different subjects based on the work with projects and case studies under an international frame with the cooperation of different European partner universities. The use of BIM tools, introduced in 2014, solved the problems that appeared in some subjects, mainly building construction, and helped with the evaluation of some healthy concepts that presented difficulties until this moment as knowledge acquired by the students was hard to be evaluated. The introduction of BIM tools: Vasari, FormIt, Revit and Light Control among others, allowed the study of precise healthy concepts and provided the students a real understand of how these different parameters can condition a healthy architectural space. The analysis of the results showed a clear acceptance by the students and gave teachers the possibility of opening new research lines. At the same time, working with BIM tools to obtain healthy solutions in building has been a good option to improve students’ employability as building market in Spain is increasing the number of specialists in BIM with a wider knowledge.

The influence of rock fabric in the durability of two sandstones used in the Andalusian Architectural Heritage (Montoro and Ronda, Spain)

Natural stone has been a popular and reliable building material throughout history appearing in many historic monuments and in more recent buildings. Research into the intrinsic properties of specific stones is important because it gives us a greater understanding of the factors that limit and act on them. This can help prevent serious problems from occurring in our buildings bringing both esthetic benefits and financial savings. To this end, the main objective of this research has been to study the influence of the fabric and the mineral composition of two types of sandstone on their durability. The first is a red continental sandstone from the Buntsandstein Age called “Molinaza Roja”, which is quarried in Montoro (Cordoba). The second is quarried in Ronda (Malaga) and is sold under the trade name of “Arenisca Ronda”. It is a light pink-whitish calcarenite deposited during the Late Tortonian to Late Messinian. We characterized their petrological and petrophysical properties by studying their rock fabrics, porous systems and mechanical properties. In order to obtain a complete vision of the behavior of their rock fabrics, we also carried out two decay tests, the salt crystallization and the freeze–thaw tests. We then measured the effects on the textures of the altered samples during and after the decay tests and we evaluated the changes in the porous system. By comparing the results between intact and altered samples, we found that Arenisca Ronda is less durable because it has a high quantity of expandable clays (smectites) and a high percentage of pores in the 0.1–1 μm range, in which the pressure produced by salt crystallization is strongest. In Molinaza Roja the decay agents caused significant sanding due to loss of cohesion between the clasts, especially during the salt crystallization test. In both stones, the anisotropies (oriented textures) have an important role in their hydric and dynamic behavior and also affect their mechanical properties (especially in the compression resistance). No changes in color were detected.