Enrique Gil

Flexural Strengthening of Damaged T-Joists with Severe Corrosion Using CFRP Sheets

This paper evaluates the residual safety of isolated T-joists with severe corrosion for the two extreme cases of boundary conditions, simply supported and fixed-ended, in order to help in making decisions about the magnitude of the necessary intervention. When the T-joist is part of a complete slab, the boundary conditions will be in an intermediate situation between these two extreme cases, so that it is possible to assess the safety with respect to its degree of embedding. The research is conducted for the cases of healthy T-joist, T-joist with complete corrosion of the lower reinforcement, and repaired T-joists with a variable number of CFRP sheets. This work is based on the ACI 318 load test to maintain a structure in use and proposes a Load Factor (LF), which estimates the safety reserve. The simply supported T-joists specimens with severe corrosion do not meet the Load Factor or ACI 318 criteria, even with a large number of CFRP sheets. On the other hand, fixed-ended cases can be kept in use despite corrosion by applying light CFRP strengthening, and with four sheets the initial safety is restored.

Diagnosis and Intervention Criteria in Slabs Damaged by Severe Corrosion of Prestressed Joists

This research defines diagnosis criteria in RC one-way slabs with severe corrosion at the lower prestressed reinforcement of the joists and proposes specific actuation criteria and constructive recommendations to increase safety. The corrosion of this reinforcement is the most common damage in building structures, and the use of aluminous cement in the precast joists can aggravate the corrosion. The usual cases of entire residential buildings with different degrees of damage and with a few or all joists affected in a slab have been simulated. American Concrete Institute load test for existing structures is used as an acceptance criterion in the simulations, and a ratio between the ultimate load and the service load is defined as a valuation coefficient. In this way, the residual safety for a damaged structure is known. Results are in accordance with extensive experience in real intervention cases, which often still have high safety reserves.

Analysis of the Residual Safety Level in R/C Slabs with Severe Joist Corrosion

AbstractAn analysis until the failure on a series of one-way slabs with severe corrosion at the lower reinforcement of the RC joists is presented. Different positions in the slab and number of damaged joists have been studied, obtaining the residual safety assessment in cases of slabs damaged by flexural failure mechanisms. Since the boundary conditions have proved decisive for obtaining the behavior, the damaged slab has been evaluated as part of the entire building, as precisely as possible, taking into account the different phases of the construction process and deterioration in time, and the complex behavior of concrete, steel and masonry. The results of the proposed methodology are consistent with the pathology of the observed cases. As a result of this study the authors propose practical recommendations to help in making decisions about the magnitude of the intervention, always necessary in this type of pathology.

Exposure Factors Influence Stone Deterioration by Crystallization of Soluble Salts

The present work tries to determine the factors that influence the crystallization of soluble salts in the stone material used in the construction of buildings in Valencia (Spain). Samples are obtained from a building which has served to accomplish observations and laboratory experiments necessary in order to determine the pathology of deterioration of the material. It was particularized in the exposition conditions of the material as a base for determining the morphologies of deterioration caused by salts in the same lithotype. The main contribution is the petrological study from the architectural point of view considering its orientation, sunlight in facade, and so forth. This study proves that both material petrology (its mineralogy and texture) and the properties related to the movement of water inside rocks play a decisive role in the conservation and development of elements in the alteration.

Methodology for Thermal Behaviour Assessment of Homogeneous Façades in Heritage Buildings

It is fundamental to study the thermal behaviour in all architectural constructions throughout their useful life, in order to detect early deterioration ensuring durability, in addition to achieving and maintaining the interior comfort with the minimum energy consumption possible. This research has developed a methodology to assess the thermal behaviour of facades in heritage buildings. This paper presents methodology validation and verification (V & V) through a laboratory experiment. Guidelines and conclusions are extracted with the employment of three techniques in this experiment (thermal sensors, thermal imaging camera, and 3D thermal simulation in finite element software). A small portion of a homogeneous facade has been reproduced with indoor and outdoor thermal conditions. A closed chamber was constructed with wood panels and thermal insulation, leaving only one face exposed to the outside conditions, with a heat source inside the chamber that induces a temperature gradient in the wall. With this methodology, it is possible to better understand the thermal behaviour of the facade and to detect possible damage with the calibration and comparison of the results obtained by the experimental and theoretical techniques. This methodology can be extrapolated to the analysis of the thermal behaviour of facades in heritage buildings, usually made up of homogeneous material.

Structural Flexural Bending Assessment of Prestressed Concrete Joist with Corrosion

The number of situations where it is necessary to intervene in existing structures is increasing. In Spain, rehabilitation and maintenance of buildings accounts for 30% of the activity of the construction sector and it is growing. This paper evaluates the residual safety of T prestressed joists with severe corrosion at the lower reinforcement. The reliability is assessed with the application of the ACI-318 load test. It is demonstrated that there is sufficient safety in cases of corroded prestressed joists. At any rate, it’s recommended to make a light repair under the damaged joists.

Basis of Stone Panel Pathology and Application of Infrared Thermography in the Pathology Study of Back-Ventilated Façades with Stone Panels

The technique of back-ventilated facades with stone panels has been used very much over the last decades. They have replaced the buildings designed with blocks or masonry. The holding technique of these panels has been usually solved by specific anchorage points, with pin, cylindrical rod, or flat bar. One of the most common injuries on these building facade is a shear failure with frustoconical shape. The aim of this research is to study the causes that led this pathology in a particular building of Valencia (Spain). This is the tourist office, built with stone panels of sandstone. We analyze the material composition, as well as cyclic and wetting–drying tests. Non-destructive techniques have many advantages, and in this research, we have used thermal imaging technology. To identify and diagnose these stone defects, we have used specifically the passive thermography, which uses the Sun’s energy to heat and cool the building materials. An early identification of pathology in the building facades can be very interesting to be able to repair or replace the panels before they are detached from the anchors.

Graphic Survey and Analysis of the Outer Walls and Floor Plan of the Royal Corpus Christi College-Seminary in Valencia

The construction of the Royal Corpus Christi College-Seminary in Valencia was begun in the late sixteenth century. The building was designed in accordance with the principles laid down by the Council of Trent and explained in detail in a treatise by Saint Charles Borromeo. In the present study a laser scanner was used to achieve a high degree of accuracy in tracing the buildings outer walls and internal floor plan. The two most important of the outer walls, the south and west, were given special attention as regards regulating lines and different proportional relationships.

Analysis Method for Studying Groundwater under a Church

The Church of Asunción of Llíria (Valencia, Spain) is one of the best examples of the Valencian Baroque of the seventeenth century. This research is based on the study of the building from an urban, historical, and especially, a constructive view. The location of this particular church is unique because it is embedded in a mountain. First, some excavations were made into the mountain before the construction of the church started. Thus, there is a slope between the main entrance of the church and the rear. This research work provides the analysis of the ground humidity throughout the Ground Penetrating Radar (GPR) technique. We have analysed the subsoil of the whole church by various cuts or paths. Longitudinal and transversal measurements allowed us to produce a three-dimensional model of the land on which the church stands. We have also analysed the homogeneity or heterogeneity of the subsoil in each area and the presence of certain ground water routes. The rising moisture has been analysed on the walls and pillars of the church. To this end, a moisture analyser has been employed to monitor the moisture content over a period of six months. With this information, it was possible to identify points that are systematically more humid.

Assessment of Energy Efficiency in Different Façade Solutions

One of the main objectives when designing a building must be perform an enclosure that properly insulate from the outside temperature. This façade must protect in the best possible way the inside of the building. In this work, different façade solutions are analyzed using different materials and constructive arrangements. However, most energy loss occurs in the singular points, e.g. the façade-slab connections or open holes in the enclosures. Therefore, the thermal performance of enclosures with different solutions is evaluated. This research provides an overview of the design of façades and singular points that helps to make responsible decisions in the building envelope design in various geographic locations.