WG3 –RECOMMENDATIONS AND PRODUCTS

An adequate prediction of behaviour of service life of CBM and structures, namely in its less developed fields that pertain to analysis and control of imposed deformations, requires accepted determination of associated physical/chemical quantities, such as thermal expansion coefficient, autogenous shrinkage development with time, moisture diffusion coefficient and its evolution with progressive hydration, etc. Technical exchanges and round robin tests that are made possible by this Action (within the scope of WG1) will help to understand precisely standardized protocols and associated typical scatter and uncertainties. Proposals for comprehensive and upgraded test standards constitute a first stage of deliverables. It should be noted that the proposals of test standards shall encompass improved versions of existing standards, and new test standards.

Associated test results can be considered as possible secondary specified values according to the standard for material specifications. Discussions shall be organized for establishing such possible specifications, either using direct physical results, or classes, after a step of benchmarking. This will involve checking various possible computational methods to address control of CBM structural deformations and cracking (as well as overall service life behaviour) and assessing associated typical precisions in their prediction ability. This task will benefit from the fact that most of the active European specialists in this field are participant to the project, and that available laboratory and field data have been provided from benchmarking in recent national projects and within this COST Action.

The task of the group will thus consist of analyzing the different models and capacities, drawing general lessons and proposing a standard methodology compatible with the Eurocode standard format to address thermo-hydro-mechanical coupled effects in serviceability design, including transient construction phases. It is therefore intended to provide quantitative and definite ways of considering curing, early temperature development, restraint to deformations and visco-elastic effects in the service life behavioural predictions, with improved capacities and more than one level of complexity analysis. Concurrently, it will address associated material specifications in the material standards and execution provisions in the associated standards.

Based on clarification of the scientific issues stated above, the aim of this Action is to develop guidelines and establish protocols for improving existing standards in the context of combination of imposed/restrained deformations and service loads so as to control serviceability and durability of concrete structures effectively. Although these considerations have sometimes been considered as secondary for ordinary buildings, they are important for synthesizing the different parts of Eurocode 2 in a future unified standard. During this process, it will be necessary to include appropriate provisions which are especially significant for rafts, large industrial facilities, structures with tightness requirements, composite structures where concrete parts may be subject to restraint, large structures built in successive lifts, and numerous structural retrofitting projects including restrained cast-in-situ concrete parts. Furthermore, even in the case of ordinary buildings, several in-service problems are observed even when current regulations are strictly followed. Therefore, improved predictions of behaviour can lead to more sustainable and effective solutions at both economical and environmental levels. The connection of this COST Action with EU standardization agencies is assured by the presence of several members of the Action in CEN TC250, the Technical Committee (TC) of the European Committee for Standardization (CEN) for Eurocode 2: Design of concrete structures (and its national mirror committees). This is one of the main regulations that is targeted in this Action, which should be revised by 2020. The timing itself is interestingly related to the end of this Action (around 2018) and the perspectives of Horizon 2020. This connection with CEN is considered to be a cornerstone of WG3, which is tailored to suit the modus operandi of a standardization agency. It is also expected to interact in a similar manner with other CEN TC’s (e.g. TC 104 for Concrete and related products, in which members of this proposal are also involved) and regulations aimed for testing materials and mix proportioning, among others. Special care will be given to synchronizing operations between the COST Action and activities of CEN TC250, with the COST Action providing strong, systematic and dynamic supply of scientific knowledge to CEN. It may also be noted that there is strong collaboration of this COST Action with the efforts of fib (federation internationale du beton), once again through members of the Action who participate in fib activities. Within fib, special interaction is expected with TG4.1 “Serviceability models”, aiming to positively influence the development of future Model Codes, which are known to be the basis for many of the concepts forwarded in the Eurocodes.

The dissemination of better practices, as well as elaboration and appropriation of new standard documents requires specific efforts that will be launched within the frame of this Action. During the 3 successive yearly workshops (mainly in the first one), specific sessions will be dedicated to discussing advances made in relation to possible updating of standards. Efforts will be made in order to make these workshops coincide with meetings of CEN TC250 or others (both in terms of location and schedule) in order to increase synergy of developments and promote co-participations. The workshops will be opened to non-members of the Action, and may even involve specifically targeted participation invitation to people in charge of scientific organizations and standardization committees. When pre-standard texts become available, they will be used as drafts for discussion in these sessions. During the final meeting, envisaged as an open conference, the draft standards, elaborated as indicated before and possibly improved by discussions with the associated people involved in the standardization process, will be presented to attendees and voluntarily sent for advice to a board of representative parties, so that they can be aware of these results and convergence of ideas and practice can follow. This wide discussion will also be an important assistance to the efforts of CEN in producing well-revised standards suited for all stakeholders. As a matter of fact, the involvement of several industry stakeholders (e.g. owners, contractors, designers) in this COST Action will catalyze a better discussion of the suitability and applicability of the recommendations and standards under development throughout the entire process, and not only in the final meeting.

In parallel with the efforts for elaboration of new proposals for standards, the aims of WG3 are also targeted at promoting an adequate interlinking of the innovative testing techniques and different software developed during the course of the Action with companies that actually develop products for the market. As a matter of fact, the availability of the innovations together with pre-standard documents can bring about interesting opportunities for companies to acquire and introduce into the market. Therefore, in parallel with the networking actions for drafting of recommendations, efforts will be made to ensure contact of the members of the Action with companies and specialists in product development, with a focus on technology transfer. This clear intent of involvement of industry partners is shown by the participation of 20 members from the industry in this COST Action proposal. Preliminary interactions will mainly be coincident with the workshops of the Action, with special attention given to the kick-off workshop in the first year, into which several additional companies will be invited to participate. The companies involved so far have a history of previous collaborations with research members of this COST Action, having thus an existing bond of confidence that makes it easier to ensure the adequate interaction and exchange between industry and researchers.

Specific sessions for product development (both equipment and software) will be held, together with sessions involving designers, contractors and owners for presentation and discussion of industry needs. This approach will assist researchers in better focusing their research efforts towards real necessities of the industry, and to do it with strategies that facilitate the development of the final product.

In terms of deliverables, documentation in concern to product development and industry needs will be issued at each yearly workshop. It is expected that a minimum of two new and innovative products (either experimental techniques or software) are ready for the market by the end of this COST Action. The case-studies of the developed products will be made available to the general research community and publicized to the practising community.

As a final remark, and due to the relevance of involvement of industrial partners (companies) in this COST Action, it is important to summarize the ways in which they can be globally involved, which can take one or more of the following forms:

  1. Brainstorming activities and discussion of industrial needs, throughout the several stages involved in CBM and structures (e.g. design, construction, maintenance)
  2. Taking part in the Round Robin Testing program of WG1, with existing equipments for validation, or with products already under development (within or outside the scope of this Action).
  3. Joining the numerical simulation benchmarking activities envisaged in WG2, for either confirming validity of the currently marketed software, or for establishing the potential of recently developed models.
  4. Developing new products together with the research partners of the Action, benefiting from a wide discussion and dissemination forum provided by the Action itself. It is remarked that product development in this context can relate to materials, testing equipment, software, or any other type of new product that may arise from the collaborative processes within the Action.
  5. Participation, discussion and evaluation during the process of preparation of recommendations and draft standards.