Laboratorio Central de Estructuras y Materiales
Inspection works on the Ruitelan Bridge with automatic inspection platform
In 2003, the Laboratorio Central de Estructuras y Materiales carried out a series of activities in the areas of technical assistance, experimentation, research and preparing standards and regulations, in the field of construction materials, civil engineering and building structures.
In the area of STRUCTURES, the following are worth mentioning as part of the activities arising from collaboration agreements reached with different Departments in the Ministries of Fomento, Environment and Education, Culture and Sport, or with companies:
Technical assistance was given to the Dirección General de Carreteras regarding bridges and other road structures. The auscultation works on concrete cantilever bridges on the national road network for the Sequeiros, La Rúa, Estrecho, Carril, Azufre, Las Lamas and Ruitelán were performed and, as the deck was inaccessible, a self-supporting platform had to be used. Furthermore, the interior of the box and the infrastructure were inspected, the deck was levelled and, finally, dynamic tests were conducted to determine the modal characteristics of the structures. The pathology of the lightweight concrete pavement of Santa Marta Bridge (Orense) formed part of this technical assistance.
Different auscultation and assessment works were likewise conducted on bridges spanning the River Iregua (Logroño) and River Miño (Orense).
Work progressed for the Dirección General de Obras Hidráulicas y Calidad de las Aguas (for the River Ebro Basin Authority) with monitoring and analysis of the data provided by the concrete dam auscultation systems. During 2003 the SIGAP application (Integrated Dam Auscultation Management System) was applied to further dams.
Auscultation works on the Samprón Bridge, on the Galicia Motorway
Auscultación works on the Puente da Foz Bridge, over the River Miño, in Ribadavia (Orense)
The Laboratory carried on collaborating with the Centro de Estudios Históricos de Obras Públicas y Urbanismo (CEHOPU) with historical-structural work on masonry dams, the purpose of which is to conduct a typological development study and to describe the materials that were used to construct historical Spanish dams, from Roman times until the end of the 19th Century, as well as to find out the effects of these aspects upon the structural and functional results. During 2003, samples taken from several dams were tested and the results analysed.
Technical assistance was given to the Ministry of Education, Culture and Sport concerning structural damage and problems affecting buildings that form part of its heritage, generally national monuments, and work continued on the Casón del Buen Retiro in Madrid, with an assessment and analysis of the modified project in which the basic premises were set out for conserving the current stress/strain state and for achieving negligible effects on the existing dome. The procedure for shoring up, demolishing and laying the new foundations was controlled and specific tests on steel foundation piles were conducted. Pathology studies were also conducted on the Palacio del Infantado in Guadalajara, the Museo Etnológico in Madrid and the Archivo de Indias in Sevilla. This year work was completed on the comparative study concerning different coatings for the stone materials on the outer walls of the Virreyes Palace and the Rei Martí Tower (Aragón Crown Archive) in Barcelona and also in the National Sculpture Museum in Valladolid.
Work involving supplementary tests on the crossing device for a high-speed railway rail crossing, were conducted at the test bay in the Laboratory for the Ente Público Gestor de Infraestructuras Ferroviarias (GIF). The tests consisted of checking new elements designed to improve the fatigue behaviour of the movable core of the crossing.
Work continued on testing structural elements in collaboration with the Laboratorio de Geotecnia, Tierra Armada and Hottinger Baldwin (HBM), so that the behaviour of prefabricated walls could be studied. With a view to this, several wall elements of different typologies were constructed, and instruments placed inside them to measure the development of the long-term response to ground thrust. In 2003 the behaviour of the elements used as bridge abutment was studied. Furthermore, an acoustic panel built with plastic fibre concrete was tested for Tierra Armada.
Tests on steel piles in Casón del Buen Retiro (Madrid)
The company Rib Loc also commissioned the Laboratory to continue conducting a series of tests in order to establish the circumferential stiffness of reinforced PVC pipes.
The experimental activity in the field of the dynamic response of structures revolved around fatigue studies, using the Laboratory's own seismic simulator with six degrees of freedom, different items of mobile railway equipment (communication units, electro-hydraulic motors, air-conditioning units, power feeders, etc.) to be used on a variety of railways.
Marine concrete study
In the field of construction MATERIALS the most outstanding activities undertaken by the Laboratorio Central were as follows:
As far as concrete was concerned, the Laboratory carried on with a research program regarding the different factors that affect the behaviour of demolition products such as aggregates for concrete for the Dirección General de Calidad y Evaluación Ambiental, under the authority of the Ministry of Environment. The first part of the research involved establishing the properties of the recycled aggregate and its range of variation.
The Ente Público Puertos del Estado commissioned the Laboratory to carry out theoretical-experimental research work into the behaviour of the concrete used in floating caissons. The aim of the activities was to obtain greater in-depth knowledge of the way concrete behaves in the marine environment, to detect the pathologies that affect concrete in this environment and to establish criteria and requirements for the constituent materials of the concrete used to manufacture caissons for harbour breakwaters, with a view to improving their useful working life in this environment. Floating caissons in three harbours, Castellón, Barcelona and Valencia were studied as well as the effects of sea salt water on concrete curing.
The Company Soluziona Ingeniería commissioned Laboratory to inspect and analyse the concrete used to construct several dams: Castrejón (Toledo), Belesar (Lugo), Charco del Cura (Ávila) and Portodemouros (La Coruña). Mechanical, chemical and microscopy characterization of concrete cores were completed in order to study the aggregate-cement attack.
Work in collaboration with Burgos Polytechnic University progressed for the Regional Government of Castilla y León. The activities included mineralogical and petrological description tests on the aggregates used in the study (Silos dolomites), as well as perfecting new methods, based upon the use of X-ray diffractometry and scanning electron microscopy, to find out the potential radioactivity of these types of aggregates when exposed to alkaline solutions.
The Laboratory carried on working on the quality of the plastic materials used for waterproofing reservoirs for the Dirección General de Obras Hidráulicas y Calidad de las Aguas, with the monitoring of more than 40 reservoirs on the Mainland, the Balearics and the Canary Isles.
Work on materials for equipping highways continued for the Dirección General de Carreteras, laboratory tests being conducted on a variety of materials (paints, microspheres and retroreflective plates for road signs), together with in situ measurements of the optical characteristics of road markings, using the Ecodyn system, which enables the operator to control these materials from a mobile laboratory vehicle at speeds that are compatible with the road traffic. Other activities involving road equipment included a series of tests performed on galvanised metallic barriers.
Recycled aggregate for concrete
Work also continued for the Dirección General de Carreteras with in situ test to analyse the long-term behaviour of a variety of different types of geotextiles. In 2003 tests were conducted on geotextiles after a period of installation in a road.
In the case of road sign materials and galvanized steel barriers, most of the activity concerned product certification, specifically for the quality mark N (AENOR). The photometry laboratory is the only one in Spain with the equipment necessary to test conventional reflecting materials and the newest developments in the industry, as micro prisms.
Railway elements tested on the dynamic shaking table
Some of the most noteworthy certification tests conducted to obtain the AENOR "N" quality certificate for construction products, were as follows: active and passive reinforcements, corrugated wire for electro-welded grids, public lighting standard lamps and supports, steel piping and sections, copper pipes for thermo-hydrosanitation use, steel plating and sections, aluminium sections, galvanised metallic bars, ceramic sanitation apparatus, heat insulation materials, windows, anonized materials, cements, ceramic materials, polystyrene arches, granites and limestones and cement floor tiles. Furthermore, work was carried out for other seals of quality, tests on aluminium lacquering (international QUALICOAT mark) and double-glazing elements. In 2003 the Laboratory reached the figure of 50,000 test certificates issued since its foundation in 1898.
A new activity associated with the Spanish Concrete Code and the materials concerned (cements, ready-mix concrete and reinforcement) having a recognized quality mark, is to conduct tests on specimens selected on the market (buildings or public works under construction or materials stocked by commercial providers) in order to check that they reach the performance levels and meet the requirements that the quality mark guarantees.
Where Laboratory accreditation was concerned, the ENAC accreditations were renewed for conducting certification tests on metallic crash barriers for vehicles. Audits were also carried out for the tests conducted on the following steel products used in construction: sections, piping and reinforcements for concrete. Accreditation for road sign tests is at the implementation phase.
The Laboratorio Central de Estructuras y Materiales continued to play an active part on numerous Spanish and European committees involved in standardising structures and materials, and carried on collaborating with many inter-departmental commissions dealing with construction material, details of which are contained in another part of this document.
Where preparing technical standards for structures was concerned, work continued for the Secretaría General Técnica of Ministry of Fomento on monitoring and analysing the work developed on a national and European scale regarding the Structural Eurocodes, with a view to the aforementioned Department being able to take more suitable measures for incorporating those Codes into the current national regulations.
Experimental field for geotextiles
Improvements to refurbishment of the installations, facilities and equipment at the Laboratorio Central de Estructuras y Materiales continued. New data acquisition and analysis systems to be used in dynamic tests were provided, as well as new digital control for a prestressed-steel testing-machine. The pendulum used for the Charpy Test on steel specimens was also replaced.
New techniques and equipments for concrete durability analysis, such as a reinforcement corrosion meter, were also implemented.
Monographic article
Tests on construction products and materials
Although most of the activities undertaken at the Laboratorio Central de Estructuras y Materiales revolve around the works included in the Collaboration Agreements entered into with the Ministries of Fomento and Environment and with other Government Departments or private companies, the laboratory also permanently carries out other activities at the same time, and these constitute a basic part of the everyday tasks performed by the Laboratory. One example of such activities is conducting tests to describe the properties and performances of a large number of construction materials and products.
This activity is one of the basic reasons why the Laboratorio Central was established in 1898, i.e., so that it could give its support to the incipient construction industry, the construction companies and the Administration itself as a developer and constructor. Since that time over 50,000 records of such tests have been issued, some of which were highly complex and of major importance. the Laboratorio Central has been a pioneer in designing and preparing many of these tests and including them as part of the national regulations and standards (Standards MELC and AENOR) or international standards and regulations (CEN and RILEM), and it is currently the only laboratory in Spain that can conduct certain tests and trials.
Test on a steel specimen
There are a variety of reasons for carrying out these descriptive tests, including the following: issuing certificates and licenses for products with marks of quality; approving and authorising manufactured products; European Community markings; monitoring the market; pre-regulatory research work; providing descriptions of the construction materials available on the market; receiving products on work sites and controlling the industrial manufacturing process.
At present, most of the tests and trials carried out at the Laboratorio Central are conducted for the purpose of issuing certificates guaranteeing that the products tested comply with the regulations established for the granting of certain quality markings. The certification bodies that the laboratory habitually works with are basically AENOR and, to a lesser extent, QUALICOAT and ARCER. The tests for approving and authorising products are mainly performed on steel products for foreign companies that wish to commercialise their products in Spain. Tests are sometimes conducted for the EC market, with a view to enabling the products concerned to be commercialised without problems throughout Europe. Another major group of tests and trials is carried out for CEDEX itself, as part of more general agreements. Therefore, tests for providing a description of construction materials are often conducted, especially on concrete, steel and aggregates coming from works that are being subjected to auscultation and assessment. Finally, the Laboratory often carries out tests for a variety of clients so that specific quality controls can be conducted on work sites, or on prototypes for new products or materials.
Some of the groups of tests conducted are shown below:
Steel products: tests performed with a view to granting the AENOR quality mark N for active and passive reinforcements, hollow steel pipes and sections and bars to be used for structural purposes. The tests are generally carried out with a view to establishing size characteristics, determining the mechanical properties (strength, elasticity modulus, ductility, resilience, fatigue, stress, strain and chemical properties). A large number of items of equipment are used for testing and measurement purposes.
Specimens for testing the quality of aluminium lacquering for building elements
Copper pipes and accessories: these tests are conducted with a view to granting the AENOR quality mark N for copper pipes that are to be used for thermo-hydrosanitation, and for air conditioning and cooling and sanitation purposes. The main tests are: establishing the size, chemical composition, carbon content, tensile strength, and bending tests.
Traffic signalling materials tested for optical properties
Aluminium lacquering: certificates for aluminium lacquering products for an international licensing body -QUALICOAT-, with respect to three types of material: specimen test tubes already lacquered at commercial lacquering plants (the suitability of the plant is accredited), paints for lacquering (the specimen test tubes are painted in the laboratory itself, and the paint is certified) and products for preparing the base material for lacquering (the specimen test tubes are treated in the laboratory and the suitability of the prepared product is accredited). The main tests are as follows: gloss, thickness, adherence, Buchholz hardness, drawing, bending, impact, Kesternich test, resistance to acetic salt fog, Macu test, accelerated aging with xenon lighting, polymerisation test, resistance to mortar, resistance to boiling water and resistance to damp in a constant atmosphere. There are many test resources, and the pilot lacquering plant, the accelerated aging chamber (Weather-o-Meter ATLAS Ci 65) and the saline fog chamber are just a few of those worth mentioning.
Products for insulation: tests conducted on materials to be used for heat insulation are conducted on a variety of products, split into three activities: for granting and monitoring the EC Marking, in its capacity as the Notified Body authorised to do so by the Ministry of Science and Technology, for granting and monitoring the AENOR N Mark and granting and monitoring the INCE Seal, for double glazing. The following materials are basically covered: expanded and extruded polystyrene, polyurethane, mineral wools and elastomeric foams, and the main tests to be conducted on those products are heat conductivity, mechanical resistance and behaviour when exposed to water.
Materials and products for road signs and signals: the Laboratorio Central de Estructuras y Materiales is the Spanish laboratory that is responsible for conducting the tests for granting quality marks and for monitoring these (basically AENOR mark N) for two types of products: on the one hand, signs, signals and retroreflective direction panels and, on the other hand, retroreflective plates with glass microspheres plates. In general, the characteristics studied for these are physical and chemical (resistance to the cold, heat, damp, saline fog, the falling of an object, accelerated aging and to the outdoor elements or natural resistance) and optical characteristics, which include the colorimetric characteristics (colour coordinates and the luminance factor) and photometric characteristics (coefficient of retroreflection and luminous intensity). The photometry equipment available, which is the only equipment in Spain, can reproduce the geometric and angular conditions set out in both in the national and European regulations.
Control board for automatic testing of sanitary elements
Sanitation apparatus: tests are conducted for granting, extending and monitoring the AENOR mark N, as well as for giving approval to sanitation apparatus for the Ministry of Science and Technology, and it is the only laboratory in Spain that conducts tests for baths. These tests generally involve establishing the physical and chemical characteristics, the construction characteristics and the functional and mechanical properties of a wide range of apparatus, such as baths, washbasins, bidets, lavatories and shower unit floors; the baths are made of both acrylic and metallic material (enamelled cast iron and enamelled steel).
Metallic crash barriers: tests are conducted for granting and monitoring the AENOR brand N, and generally involve establishing the size, the characteristics of the galvanising and a chemical analysis of the base steel. Methods are also perfected for determining how these crash barriers are to be correctly fitted and an assessment of their durability, by conducting saline fog tests.
Steel barrier for road vehicle safety
All in all, the engineers, workers and apparatus for the tests used to describe materials and products have to be constantly trained and updated, the deadlines for conducting the tests must be complied with and adapted in an ongoing way to the changes in the Spanish and European regulations. Furthermore, to guarantee the traceability of the results and findings from the tests and to offer the user sufficient guarantee where work quality is concerned, it has been necessary to implement a Quality System that is in accordance with Spanish Standard UNE-EN-ISO/IEC 17025:2000, which amounts to a further economic and organisational effort.
In most cases, the Laboratorio Central is accredited by ENAC (aluminium lacquering, heat insulators, vehicle crash barriers or sanitation apparatus), or is in the process of being accredited (steel for reinforcements and sections, road signs and signals). The tests for certifying products, together with the standard tests for characterising the construction materials or products, currently account for almost 1,500 test reports issued every year.