In its lifetime, a dam can be exposed to significant water level variations and seasonal environmental temperature changes. The structural safety control of a concrete dam is supported by monitoring activities and is based on models.In practice, the interpretation of recorded concrete dam displacements is usually based on HST (hydrostatic, seasonal, time) statistical models. These models are widely used and consider that the thermal effect can be represented by a seasonal function. The main purpose of this paper is to present an HTT (hydrostatic, thermal, time) statistical model to interpret recorded concrete dam displacements. The idea is to replace the seasonal function with the use of recorded temperatures that better represent the thermal effect on dam behavior. Two new methodologies are presented for constructing HTT statistical models, both based on principal component analysis applied to recorded temperatures in the concrete dam body. In the first method, principal component analysis is used to choose the thermometers for the construction of the HTT model. In the second method, the thermal effect is represented by the principal components of temperature of selected thermometers.The advantage of these methods is that the thermal effect is represented by real temperature measured in the concrete dam body. The HTT statistical models proposed are applied to the 110 m high Alto Lindoso arch dam, and the results are compared with the HST displacement model.

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One of the most important phenomena of the delayed behaviour of mass concrete used in dams is creep, i.e., the increase in deformation over time when subjected to constant stress. Although several studies concerning concrete creep were carried out throughout the last decades in a structural and material level, the physical and chemical phenomena are yet to be fully understood. This paper presents a study on the Alqueva dam’s concrete deformability in which a parameter evaluation was performed using the Baz̆ant and Panula’s basic creep function, based on both in situ and laboratory creep test results. In the first part of the paper, the approach and material properties that better fit the experimental data of a dam’s mass concrete are presented. In the second part, the fitted function for each in situ test was validated using a finite element numerical model that takes into account the time‐dependent behaviour, the applied stress and the monitored temperatures.

To improve the effectiveness of concrete dam safety control in real time, a method is presented for the construction of decision rules for the early detection of developing failure scenarios. The decision rules are based on the use of linear discriminant models developed with data obtained through mathematical models of the dam's behaviour. The aim is to combine the physical quantities measured by the automated monitoring system of the dam, appropriately weighted, into a new single index allowing the classification of the observations into one of two classes (normal behaviour and development of a failure scenario).

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