Concrete Structure Management Guide To Ownership And Good Practice

Construction projects are undertaken to meet a variety of business, service and aspirational objectives and needs. The success of a building or an element of infrastructure depends on how well it meets the owner's needs and interests or those of the users. Recent changes in owner attitudes to construction are reflected in an increasing interest in through-life costs, i.e. not only the capital costs of construction but also the operational costs associated with a structure's functional performance for a defined life span. The owner can greatly improve the likelihood of achieving the value they seek from the facility by being intimately and effectively involved in the definition of performance requirements at the start of the construction procurement process. The objective of fib Bulletin 44 is to provide guidance to owners of concrete structures on: the management of their concrete structures (buildings and infrastructure) as part of their business goals or the service objectives of their organization; best practice in the management of concrete structures; their responsibilities with respect to the management of their concrete structures; the wider context and issues of service life design; information and direction needed by the supporting professional team of architects, engineers, specifiers, contractors and others. This Guide also provides background information on topics such as deterioration processes and technical procedures used for the management of concrete structures, including reference to international standards for the protection and repair of concrete structures. These activities are illustrated by application examples/case histories and by a section addressing frequently asked questions. A brief review is made of some potential future developments.

This guide to good practice focuses on the techniques for the repair and strengthening of reinforced and prestressed concrete structures - covering the planning, design, implementation and monitoring of repair and strengthening projects.

Connections are among the most essential parts in precast structures. Their performance relates to the structural limit states, as well as to manufacture of the precast elements and erection and maintenance of the structure itself. Proper design of connections is one major key to a successful prefabrication. The principal aim of fib Bulletin 43 is to encourage good practice in the design of structural connections in precast concrete structures. This is achieved through a good understanding of structural connections as parts of the overall structural system and of basic force transferring mechanisms. The bulletin consists of two parts; the first part concerns general considerations and philosophy in the design of structural connections, and the second part deals with basic force transferring mechanisms within structural connections. The main focus is on the design of structural connections with regard to their structural function in ordinary design situations in the serviceability and ultimate limit states, and in accidental/abnormal design situations, like fire, lack of fit and impact/accidental loads. Other aspects considered include production, handling and site erection of elements, building physics, durability and maintenance. Bulletin 43 applies to structural connections for precast concrete buildings, although the information on basic force transfer mechanisms can also be applicable to other types of prefabricated structures.

The vast extent of the investment in concrete structures in modern times has emphasized the need to maintain these structures in a systematic manner, so that they retain their structural integrity and full usefulness. Such maintenance must be preceded by regular and thorough inspection. This Guide to Good Practice describes the many types of damage - slight or more serious - which may be discovered and the equipment used to carry out inspections. Suggested inspection intervals, related to the severity of loadings and environmental conditions, are given.

The idea of preparing a technical document for the repairs and interventions upon concrete structures goes back to the former fib COM 5: Structural Service Life Aspects, being the goal of the then TG 5.9. After a long period of reduced activity, and taking into account the reorganization of fib commissions that meanwhile took place, on June 2017 a different approach was proposed to push forward the task of TG 8.1 (formerly TG 5.9). The (new) goal of TG 8.1 was to deliver a ‘how-to-do’ guide, gathering together protection, repair, and strengthening techniques for concrete structures. Chapters are intended to provide both guidelines and case-studies, serving as support to the application of fib MC 2020 pre-normative specifications. Each chapter was written by an editorial team comprising desirably at least a researcher, a designer and a contractor. Templates have been prepared in order to harmonize the contents and the presentation of the different methods. Following the writing process, chapters were reviewed by experts and, after amendments by the authors, they underwent a second review process by COM 8 and TG 3.4 members, as well as by different practitioners. For each protection, repair and strengthening method addressed in this guide, readers have a description of when to adopt it, which materials and systems are required, which techniques are available, and what kind of equipment is needed. It then presents a summary of stakeholders’ roles and qualifications, design guidelines referring to most relevant codes and references, the intervention procedure, quality control measures and monitoring and maintenance activities. Due to the extent of the guide, it was decided to publish it as bulletin 102, addressing protection and repair methods, and bulletin 103, addressing strengthening methods. We would like to thank the authors, reviewers and members of COM 8 and TG 3.4 for their work in developing this fib Bulletin, which we hope will be useful for professionals working in the field of existing concrete structures, especially those concerned with life-cycle management and conservation activities. As noted above, this Bulletin is also intended to act as a background and supporting document to the next edition of the fib Model Code for Concrete Structures, which is currently under development under the auspices of TG10.1 with the working title of ‘fib Model Code 2020’.

The idea of preparing a technical document for the repairs and interventions upon concrete structures goes back to the former fib COM5: Structural Service Life Aspects, being the goal of the then TG5.9. After a long period of reduced activity, and taking into account the reorganization of fib commissions that meanwhile took place, on June 2017 a different approach was proposed to push forward the task of TG8.1 (formerly TG5.9). The (new) goal of TG 8.1 was to deliver a ‘how-to-do’ guide, gathering together protection, repair, and strengthening techniques for concrete structures. Chapters are intended to provide both guidelines and case-studies, serving as support to the application of fib MC2020 pre-normative specifications. Each chapter was written by an editorial team comprising desirably at least a researcher, a designer and a contractor. Templates have been prepared in order to harmonize the contents and the presentation of the different methods. Following the writing process, chapters were reviewed by experts and, after amendments by the authors, they underwent a second review process by COM8 and TG3.4 members, as well as by different practitioners. For each protection, repair and strengthening method addressed in this guide, readers have a description of when to adopt it, which materials and systems are required, which techniques are available, and what kind of equipment is needed. It then presents a summary of stakeholders’ roles and qualifications, design guidelines referring to most relevant codes and references, the intervention procedure, quality control measures and monitoring and maintenance activities. Due to the extent of the guide, it was decided to publish it as bulletin 102, addressing protection and repair methods, and bulletin 103, addressing strengthening methods. We would like to thank the authors, reviewers and members of COM8 and TG3.4 for their work in developing this fib Bulletin, which we hope will be useful for professionals working in the field of existing concrete structures, especially those concerned with life-cycle management and conservation activities. As noted above, this Bulletin is also intended to act as a background and supporting document to the next edition of the fib Model Code for Concrete Structures, which is currently under development under the auspices of TG10.1 with the working title of "fib Model Code 2020".

While it is generally accepted by owners and users that vehicles such as airplanes or cars must be subjected to a pre-defined maintenance plan during their lifetime, this is less obvious in public opinion for engineering structures and buildings. This may be related to the general feeling that “moving objects” should be more sensitive to aging and deterioration than “structures anchored in ground”! This may also relate to the fact that detailed maintenance manuals, which are considered obligatory by insurance companies, are generally for aircraft, boats and cars, but not systematically for civil engineering structures, except for iconic or major projects. The performance-based approach to the durability design and assessment of concrete structures is also becoming increasingly popular in the construction sector. In recent years, numerous studies have been carried out worldwide in order to better assess the expected properties related to the durability of concrete. This has led to the standardization of test protocols, but also to a better understanding of the main parameters impacting the overall durability of concrete. Documentation related to durability indicators will then become increasingly necessary for the accurate implementation of a performance-based approach that enables the promotion of sustainable materials. Durability models have a strong need for relevant in-field data feedback in order to define accurate inputs for modelling both during the design process (gathered from previous projects) and during the follow-up process to allow for re-calibration of inputs and re-assessment of durability expectations by the models if judged necessary. A framework for data collection was therefore considered extremely importance by the fib Commission 8: Durability, and is the objective of this fib Technical report “Birth-certificate and Through-Life Management Documentation”. It is indeed very important to collect relevant data within a comprehensive and standardized format, as now proposed by this fib Bulletin. Thanks to its pre-defined format, compatible with the general fib framework, “Birth-certificate and Through-Life Management Documentation” will definitively be useful to owners for the maintenance plan and intervention strategies of their assets. This operational technical report will also be very useful for designers, as it should encourage the collection of relevant information in databases to be used for future projects where a realistic assessment of expected properties is considered through largely similar concrete mix designs under given exposure conditions. The Commission, which deals with durability aspects, hopes that this Bulletin will provide users a valuable tool and perspective on service life management issues.