Analysis of the correlation between deformation and temperature in a concrete dam

Deformational control of structures has its greatest exponent in large dams monitoring, which, depending on their structural typology, can be subjected to movements generally based on both the pressure that they upport and the temperature.The designer usually calculates the theoretical displacements that the dam will suffer onsidering the hydrostatic thrust and the temperature, but it is also true that these displacements are theoretical and they do not often fit to the real movements, due to the uncertainties that arise during the onstruction of any dam and make the final structure have changes which can be more or less significant with respect to the originally projected one. However, it is worth mentioning that they are usually lower than those theoretically calculated. The present research work focuses on a potential correlation and the subsequent determination of an mpirical model that allows calculating the deformation by means of a polynomial fit, working on the basis of temperature observations held over 14 years. This empirical model is contrasted and validated with the observations taken during the following year, and although it is only valid for the dam where the test has been made (“La Cohilla” Dam), the methodology is suitable for any other structure

Determination of an empirical model for calculating the strain of a dam in terms of hydrostatic thrust

The deformational control of structures has its greatest exponent in the control of large dams, which depending on structural typology, can be subjected to movement generally based on the pressure that it suffers. The designer usually calculates the theoretical displacements that the dam must suffer depending on the ydrostatic pressure, function of the thrust bearing, but it is also true that this calculation is theoretical and it is not usually adjusted to the real movements, due to the uncertainties that arise in the construction of any dam and make the original project have more or less significant changes in the final construction. In favour of the builder, it must be said that the actual displacements are usually lower than the theoretical ones. The present research focuses on the determination of an empirical model that allows calculating the deformation based on practical observations of a direct pendulum over 14 years, which determines the isplacement and the pressure experienced by the dam represented by the height of water contained, by means of a polynomial adjustment. This empirical model is tested and then validated with observations over the ollowing year and, although it is only valid for the dam where the trial (La Cohilla Dam) is made, the ethodology is applicable to any other structure

Determination of an empirical model for the deformation of a dam on the basis of the hydrostatic thrust and temperature

The deformational control of structures has its main exponent in the geometric control of large dams. Considering the constructive typology, they can suffer deformation, which is function of the hydrostatic thrust and the temperature that supports the dam under usual circumstances. The project designer usually calculates the deformation that the dam will suffer on the basis of thrust and temperature, but this calculation is theoretical, and it must be contrasted with the real data about deformation that are periodically observed in the dam, in order to certificate the adequate evolution of the structure through time. This research work is focused on the determination of an empirical model that allows the calculation of the deformation on the basis of the simultaneous observations of a direct pendulum that have been recorded with the correspondent temperatures during 14 years. This empirical model is later contrasted and validated with the records taken during the subsequent year. Although it is only valid for the dam where the tests were held (La Cohilla Dam, Cantabria, Spain), the methodology is suitable for any other structure. The main contribution of this research is the methodology itself, which allows obtaining an empirical model that determines the expected deformation, whatever the conditions of hydrostatic thrust and temperature are. It complements the theoretical model that the project designer has established, which is done just for a certain set of conditions of these variables

Influence of vertical movement in bathymetries and its influence on the measurement conditions

Bathymetries constitute a fundamental element of building objects settled on land submerged land: dikes, docks, underwater pipelines; in addition to dredges, volume of reservoir, etc. In civil engineering the bathymetry affect areas of small extent in which measures should be the most accurate as possible, influencing many factors in its precision. Among these factors can be distinguished: speed of sound in water, positioning system, vessel movements (pitch and roll) and vertical movement of the boat. Vertical movement of the vessel is perhaps one of the least studied factors, but their influence on the accuracy of bathymetries could be very important depending on swell conditions and depth that exists at the time of measurement. This paper defines a mathematical model based on measurements of bathymetry observed with GPS that lets you define wave conditions that found the boat according to its trajectory and speed. From this point, the article quantifies the effect of the vertical movement of the boat to correct its effect on the measured depths with an echo-sounder. Finally, from the results it is possible to obtain a set of recommendations about operations to measure a bathymetry depending on the accuracy that you should obtain

Bathymetries, history of an evolution in precision and performance

Bathymetries are a fundamental element in civil engineering when the work to be made must be based on the study of submerged terrain. In this sense, they are necessary in many situations: marine constructions such as dikes, docks, etc; dredging volume control, river flood study, etc. Traditionally bathymetries have been a difficult and costly job both in time and effort. However, over time and supported by the development of topographic and geodetic technologies, they have undergone an important transformation and progress in both precision and performance. In this sense, this article reviews the evolution of the different topographic techniques used over time, emphasizing the investigation and study of the accuracies and efficiencies typical of them; especially those that are used today. In this way, it can be concluded that, with the appropriate methodology, currently, bathymetries can be made with centimeter accuracy and with an efficiency that can exceed several square kilometers each day depending on the desired accuracy and the conditions of the bottom to be measured

Quantitative contrast between the methodologies for the volumetric evaluation with cross-sections and 3D models in tunnels excavated with explosives

This research aims to establish the differences that are produced when calculating the volume of the excavation of a tunnel by means of equidistant cross sections obtained from a 3D model, and the 3D model itself, which was obtained from laser scanner data. The purpose of this research intends to contrast numerically a methodology that has been traditionally applied (cross-sections), and a more recent one which is supported by the use of powerful calculation algorithms that are appropriate for 3D models. All this research is applied to a tunnel that is used as spillway of a large dam that serves to regulate the water of a hydraulic facility. The results of this work justify in a quantitative way that, compared to the modern approach, the classical methodology produces deviations that can reach the 10% of the total volume of the excavation, which implies very high expenses, given the costs of this kind of work

The importance of atmospheric correction for airborne hyperspectral remote sensing of shallow waters: application to depth estimation

Accurate determination of water depth is indispensable in multiple aspects of civil engineering (dock construction, dikes, submarines outfalls, trench control, etc.). To determine the type of atmospheric correction most appropriate for the depth estimation, different accuracies are required. Accuracy in bathymetric information is highly dependent on the atmospheric correction made to the imagery. The reduction of effects such as glint and cross-track illumination in homogeneous shallow-water areas improves the results of the depth estimations. The aim of this work is to assess the best atmospheric correction method for the estimation of depth in shallow waters, considering that reflectance values cannot be greater than 1.5% because otherwise the background would not be seen. This paper addresses the use of hyperspectral imagery to quantitative bathymetric mapping and explores one of the most common problems when attempting to extract depth information in conditions of variable water types and bottom reflectances. The current work assesses the accuracy of some classical bathymetric algorithms (Polcyn? Lyzenga, Philpot, Benny?Dawson, Hamilton, principal component analysis) when four different atmospheric correction methods are applied and water depth is derived. No atmospheric correction is valid for all type of coastal waters, but in heterogeneous shallow water the model of atmospheric correction 6S offers good results

Optimization of Photogrammetric Flights with UAVs for the Metric Virtualization of Archaeological Sites. Application to Juliobriga (Cantabria, Spain)

ABSTRACT: Three-dimensional models are required to virtualize heritage sites. In recent years, different techniques that ease their generation have been consolidated, such as photogrammetry with Unmanned Aerial Vehicles (UAVs). Nonmetric cameras allow relatively inexpensive data collections. Traditional aerial photogrammetry has established methodologies, but there are not commonly used recommendations for the selection of parameters when working with UAV platforms. This research applies the Taguchi Design of Experiments Method, with four parameters (height of flight, forward and lateral overlaps, and inclination angle of the sensor) and three levels (L9 matrix and nine flights), to determine the set that offers the best metric goodness and, therefore, the most faithful model. The Roman civitas of Juliobriga (Cantabria, North of Spain) was selected for this experiment. The optimal flight results of the average signal-to-noise ratio analysis were height of 15 m, forward and lateral overlaps of 80%, and inclination of 0° (nadiral). This research also highlights the noticeable contribution of the inclination in the accuracy of the model with respect to the others, which is 16.4 times higher than that of the less relevant one (height of flight). This leads to propose avoiding inclination angle as a variable, and the sole development of nadiral flights to obtain accurate models