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5th WTA Colloquium – Maintenance of Concrete Buildings – June 19th, 2018, Brno (CZ)
Latest discoveries in concrete remediation
Scientific committee:
Prof. Ing. Rostislav Drochytka, CSc., MBA Prof. Dr.‐Ing. Rolf P. Gieler Prof. Dr.‐Ing. Dipl. Chem. Andrea Osburg
Opening speech:
Prof. Ing. Rostislav Drochytka, CSc., MBA Chairman of WTA CZ
Lecture 1: Ing. Josef Zak, Ph.D., CTU in Prague, Faculty of civil engineering BIM technologies in construction design and execution
Lecture 2: Prof. Dr. ‐Ing. Ralf W. Arndt, Fachhochschule Erfurt Non‐destructive testing of Reinforced Concrete Structures
Lecture 3: Prof. Dr. ‐Ing. Rolf P. Gieler, Chairman of WTA TC5 Concrete, Ingenieur‐ und Sachverständigenbüro, Fulda
Engineer‐technical proofs of the life span of reinforced concrete structures according to future sets of rules – experiences and examples
Lecture 4: Dr. ‐Ing. Kay‐Andre Bode, Vestas Central Europe, Hamburg Remediation of Wind Turbine Generator Foundations
Lecture 5: Doc. Ing. Ladislav Klusacek, CSc., Brno University of Technology, Faculty of Civil Engineering
Causes of failures of hanging bridges and prestressed bridges
Lecture 6: Doc. Ing. Jiří Kolísko, Ph.D., Klokner Institute CTU in Prague Diagnostic survey of the Liben Bridge in Prague
Lecture 7: Doc. Ing. Jiri Dohnalek, CSc., BETONCONSULT, s.r.o. Effect of frost resistance of concrete and alkaline reaction of
aggregate in concrete on the strategy of remediation of RF‐concrete structures
5th WTA Colloquium – Maintenance of Concrete Buildings Conference Program II
Lecture 8: JUDr. Ing. Zdenek Dufek, Ph.D., Brno University of Technology, Faculty of Civil Engineering
Public investors attitude to financing repairs and maintenance of building constructions
Lecture 9: Dipl.‐Ing. Reinhard Martin, MC‐Bauchemie Müller GmbH & Co. KG Experiences with structures of energy production
Lecture 10: Prof. Ing. Rostislav Drochytka, CSc., MBA, Brno University of Technology, Faculty of Civil Engineering
New possibilities of remediation materials
Lecture 11: Prof. Dr. ‐Ing. Gesa Kapteina, HafenCity Universität Hamburg Application of corrosion monitoring and inclusion of the upraised
data for the calculated life span
Lecture 12: Doc. Ing. Vit Smilauer, Ph.D., CTU in Prague, Faculty of civil engineering
Effect of hydration kinetics on longterm performance of concrete structures
Summary and conclusion:
Prof. Ing. Rostislav Drochytka, CSc., MBA Chairman of WTA CZ hellgrau markierte Beiträge lagen uns bei Drucklegung als Datei noch nicht vor gray marked contributions were not available to us at the time of printing
Abstracts of the individual contributions available here Abstracts der Einzelbeiträge hier abrufbar: http://s.fhg.de/wtaconcrete18
5th WTA Colloquium – Maintenance of Concrete Buildings
BIM technologies in construction design and execution
From paper to data
Josef Zak, CTU in Prague, Faculty of Civil Enginnering & Skanska, VDC department
Keywords: building information modeling, database systems, quality assuarance, constuction digitalization
The construction industry has been based on 2D drawings and further blueprints for decades. Architects and
enginners have mastered the ability to draw visions and address technical details in 2D plans that specify the
desired project to required level accroding to needs of the project phase. The building information modeling is
based on data utilization instead of 2D plans for these purposes. The lecture addersses current needs of con‐
struction industry and how they can be achieved by data utlization. Several examples of working methods from
projects are described. Part of the lecture is dedicated to Information and Comunication Technologies (ICT). ICT
solutions are gaining ist place at the construction projects and momentum through multiple uses of project
related data. Building Information Modeling (BIM) is a method that is driving inovations and efficiency in con‐
struction industry. The lecture focusess on both theory and best practise examples from comercial, residentian
development and infrastructure projects.
[BIM model, Modernization of Česká Lípa railways station, CZ]
[BIM model, Kungens Kurva bridge, Stockholm, Sweden]
5th WTA Colloquium – Maintenance of Concrete Buildings
Engineer‐technical proofs of the life span of reinforced
concrete structures according to future sets of rules –
experiences and examples
Rolf P. Gieler, Ingenieur‐ und Sachverständigenbüro Prof. Dr.‐Ing. Rolf P. Gieler, Fulda, Germany
Schlagworte: Maintenance, improvement, reinforced concrete, prestressed concrete, chloride, wear‐out,
DAfStb, expert planning engineer, concrete repair work, principle solution, repair concept, principle, method.
In order to maintain the bearing capacity and usability of reinforced concrete constructions and prestressed
concrete structures during their utilisationBE phase, the durability of the individual components is of great
importance. In order to ensure this, rules and regulations for the design of new buildings require an appropri‐
ate maintenance effort, see e. g. B. DIN EN 1992‐1‐1[1]. Therefore, the requirements for scheduled mainte‐
nance, which according to DIN 31051[2] is divided into the basic measures of preventive maintenance, inspec‐
tion, repair and improvement, are defined in much more detail in the future DAfStb guideline maintenance of
concrete components [3] than in the previous repair guideline [4]. Repair is often required on reinforced con‐
crete construction parts because the reinforcement corrodes due to carbonation of the concrete and/or the
penetration of chlorides into the concrete. In order to assess the actual condition of a building or component,
inspections must be carried out as part of scheduled maintenance. In addition to visual control, investigations
of carbonation depth and chloride content may also be required.
The results of these tests serve to determine the remaining wear stock and thus to forecast the remaining use‐
ful life, i. e. the period of time during which a concrete component fulfils or exceeds the requirements (mini‐
mum target condition) with sufficient probability during scheduled maintenance.
For this purpose, the future maintenance guideline of the DAfStb [3] presents simplified engineering verifica‐
tion procedures for determining the remaining useful life and for measuring the layer thickness of concrete
replacement on the basis of detailed scientific investigations for exposure class XC according to [6] and for
exposure classes XS/XD according to [7]. For chemically stressed concrete components, a performance‐based
concept for durability design was presented in [8].
The procedures of the objects examined according to [3] and examples of the procedure are presented.
[1] DIN EN 1992‐1‐1:2011‐01 Eurocode 2: Bemessung und Konstruktion von Stahlbeton‐ und Spannbetontrag‐
werken – Teil 1‐1: Allgemeine Bemessungsregeln und Regeln für den Hochbau.
[2] DIN 31051:2012‐09 Grundlagen der Instandhaltung.
[3] DAfStb‐Richtlinie Instandhaltung von Betonbauteilen (Instandhaltungs‐Richtlinie), Entwurf (2016‐06‐14).
[4] DAfStb‐Richtlinie Schutz und Instandsetzung von Betonbauteilen (Instandsetzungs‐Richtlinie), 2001‐10.
[5] DIN EN 1504‐9:2008‐11 Produkte und Systeme für den Schutz und die Instandsetzung von Betontragwerken
‐ Definitionen, Anforderungen, Qualitätsüberwachung und Beurteilung der Konformität ‐ Teil 9: Allgemeine
Grundsätze für die Anwendung von Produkten und Systemen.
[6] Greve‐Dierfeld S. von (2015): Bemessungsregeln zur Sicherstellung der Dauerhaftigkeit XC‐exponierter
Stahlbetonbauteile. Heft 622 der Schriftenreihe des Deutschen Ausschusses für Stahlbeton, Beuth
Verlag, Berlin.
[7] Rahimi, A. (2016): Semiprobabilistisches Nachweiskonzept zur Dauerhaftigkeitsbemessung und ‐bewertung
von Stahlbetonbauteilen unter Chlorideinwirkung. Dissertation. Technische Universität München, Lehrstuhl für
Werkstoffe und Werkstoffprüfung im Bauwesen.
[8] Gerlach, A. (2017): Ein performance‐basiertes Konzept zur Dauerhaftigkeitsbemessung chemisch bean‐
spruchter Betonbauteile. Dissertation. Gottfried Wilhelm Leibniz Universität Hannover, Fakultät für Bauingeni‐
eurwesen und Geodäsie.
5th WTA Colloquium – Maintenance of Concrete Buildings
Libeň Bridge in Prague
Diagnostic, static analysis, reconstruction options
Jiri Kolísko, Czech Technical University in Prague, Klokner Institute
Keywords: diagnostic methods, concrete, durability, deterioration, sulphur attack, rebar corrosion, load capacity
The Klokner Institute in cooperation with Pontex and Inset comp. carried out a wide diagnostics of Libeň
Bridge. The survey was conducted throughout the year 2017, and the goal was to obtain comprehensive
information about the state of the bridge. The customer required to deal with the possibility of reconstructing
the bridge in order to meet the current standard of its load capacity and durability, but also the possibility of
building a new bridge.
The diagnosed Libeň Bridge over the Vltava river in Prague consists of five vault parts 28.0 + 38.5 + 42.8 + 42.8
+ 32.5 m built up from plain concrete, designed as three‐hinge vault and two reinforced concrete frame
structures as bridge heads. The total length of the bridge is 210 m with the width of 21 m. Each vault is divided
in the longitudinal direction into four separate strips. The bridge was built between 1924 and 1928. Since its
erection, the bridge has not undergone any major maintenance or reconstruction works.
As part of the diagnostic survey, a detailed visual inspection of the bridge, endoscopic inspection of the vault
hinges and acoustic tracing of the surfaces of the structures were carried out. Static and dynamic load tests
were carried out, too. For an extensive program of material laboratory tests and analyses, more than 500
samples of concrete were collected. Laboratory analyses aimed at determining the durability, mechanical and
physical properties of the concrete. Samples of concrete were subjected to microscopic, chemical analyses and
further tests for the assessment of corrosion and degradation effects, particularly with regard to chlorides,
sulphates, carbonation, the identification of the alkaline‐silica reaction of the aggregate, and the thickness of
the covering layer as well as the corrosion state of the reinforcement. Relatively very low strength in some
parts of bridge and very poor durability of concrete were determined. Sulphur corrosion of concrete at
foundation and pillars was found. Analyses were also carried out on samples of backfill material, waterproofing
and other materials. To determine the type and load‐bearing capacity of the subsoil, 4 deep bore holes were
made. The detected relatively poor state of the bridge and material properties were used as input parameters
of static linear and nonlinear analyses to determine the load capacity of the bridge. Insufficient load capacity of
the bridge was calculated.
Frame structures of the head of the bridge are no longer repairable, including stairs, and are in run‐down state.
For this reason, in January 2018, the bridge was temporarily closed. A temporary support of non‐compliant
parts of frame structures was designed and built up. The conceptual design of the reconstruction
(strengthening) of the vault bridge part was worked out. To ensure the load capacity according to the currently
valid standards, strengthening by replacing two centre strips of vaults in all five vaults was proposed.
Strengthening of the degrading foundation of the pillars and the supports was proposed, too. In view of the
current valid standards, achieve the required load capacity of the bridge this very radical, complex and highly
demanding reconstruction can only. However, the lifetime of the reconstructed bridge will be lower than that
of a new one and will therefore require more careful and demanding maintenance and monitoring, as the
original material of the structure would be preserved. An intensive discussion is underway to decide whether to
demolish or repair it.
Fig. 1 Left‐ General view of vault part of Libeň Bridge. Middle‐ Massive corrosion of rebar of frame part. Right‐
Sulphur attack of concrete of pillar.
5th WTA Colloquium – Maintenance of Concrete Buildings
Public investors attitude to financing repairs and
maintenace of building construction
Zdenek Dufek, Faculty of Civil Engineering, Brno University of Technology
Schlagworte/Keywords: public procurement, life cycle cost, evaluation criteria, public budgets
One of the outstanding characteristics of the construction industry is the fact that approximately half of the
contracting authority are public sector entities. For these entities, a specific form of contractation is prescribed
by law. The process is defined by the Public Procurement Act. For the state of the construction sector as a
whole, three factors are very important in this context:
(a) the total amount of funds available in public budgets,
(b) the way in which contracting authorities approach the choice of expenditure priorities, and
(c) the method of assessment (selection) of contractors of the works.
The overall situation in the construction sector in the Czech Republic over the last decade has been very marked by the economic crisis after 2008 and the dramatic fall in public tax revenues, which was reflected, among other things, in the reduction of investment expenditures. Another important factor was and is the possibility of drawing of European Cohesion Funds in the programming periods 2007 ‐ 2013 and 2014‐2020. The priority of the contracting authorities is to implement projects for which they can draw subsidy support. The award of public works contracts is largely allocated on the basis of the lowest bidding criterion and the life cycle cost factor is not taken into account. In 2015, for example, the criterion of the lowest bid price was used in more than 80% of cases. The lowest bid criterion is used primarily for reasons of simplicity and because of the fear that control authorities will impose a penalty for faulty implementation of a public contract. The greatest percentage of sanctions awarded in connection with mistakes in the implementation of European projects in the years 2013 to 2016 stems from breaches of public procurement rules (between 87% and 74% in individual years).
The theory is that the cost of project documentation and construction is approximately 20% of the life cycle
cost. At the same time, the planning stage has the greatest potential to influence future operating costs. From
this point of view, the choice of the cheapest designer or the cheapest constructor is not appropriate.
In 2017, the author of the paper made a series of lectures for public investment representatives on effective
public investments, in which he could conduct a managed dialogue with representatives of a representative
sample of more than 70 public contractors. The survey results can be summarized as follows:
(a) Maximum priority is given to projects for which EU grant funding can be obtained.
(b) Own budget resources are used to co‐finance European projects.
(c) Regarding the previous two points, normal repairs and maintenance of existing buildings are limited.
(d) Contracting authorities do not take into account the issue of quality and life‐cycle costs when determining
the terms and conditions for competition.
(e) Quality and life cycle costs are not defined because contracting authorities are concerned about the imposi‐
tion of sanctions for breaches of public procurement rules and beause they do not know how to incorporate
the requirements for quality and life cycle costing into the competition rules.
It is clear from the survey that there is a need to provide methodological guidance on how to assess the quality
and lifecycle costs of public procurement. In addition, public space should be emphasized that it is not sustain‐
able in the long run to neglect routine maintenance and repairs.
5th WTA Colloquium – Maintenance of Concrete Buildings
Experiences with structures of energy production
Repair and surface protection
Reinhard Martin, MC‐Bauchemie, Bottrop
Schlagworte/Keywords: Hydropower, pumpstorage, thermal power plant, cooling tower, chimney, injection
technology, soil stabilization, sealing, concrete repair, surface protection.
Energy production is one of the most important tasks of the modern society. The sources used, are depending
on the location of the power plants, the topographic prerequesites, the availability of fuels and, more and
more, from the environmental point of view.
Decades ago the main task was, to erect these structures with the best possible durability and cost effectively.
Today the repair and protection is of more importance, to ensure the stability and the operation of the plants
with the lowest possible maintenance for the future.
MC‐Bauchemie is focused on structures of the energy production since 50 years. This presentation will show
some chosen projects with the technique and the materials used for their refurbishment and protection.
5th WTA Colloquium – Maintenance of Concrete Buildings
Application of corrosion monitoring and inclusion of the
upraised data for calculated life span
Kapteina, HafenCity Universität Hamburg.
Keywords: monitoring, chloride induced corrosion, durability, service life design, chloride ingress
In Germany severe damage on reinforced structures exposed to de‐icing salt causes yearly costs in a range of
several million Euros. There is a considerable saving potential just by detecting the deterioration with its di‐
mension in time and subsequently carrying out appropriate intervention measures before damage is visible or
even occurs. The monitoring of structures provides data linked to condition assement and therewith enables a
straightforeward approach for optimizing maintenance and repair action. For concrete structures, which are
subjected to severe environmental loads, this has gained increasing importance over the last few decades. This
is especially true in the field of infrastructure buildings, as budget resources for the maintenance of public
structures are generally scarce. One should bear in mind that extensive repair action on buildings of supra‐
regional significance is usually also associated with extensive restriction measures leading to tremendous sub‐
sequent costs. For example, traffic jams have a great impact on the envirnoment and the economic perfor‐
mance of the respective region. Also, these subsequent costs can be limited by a pro‐ative desion making pro‐
cees, which considers the condition of the structure. Further fields of interest are the installation of sensors in
important structure elements, which are not accessible after completion or can not be inspected easiliy. In
addition, monitoring data can be used for an economic quality control. Hereby proving the proper operation of
coatings and hydrophobic treatments. Due to theses benefits, also private owners of concrete structures
should have an interest in monitoring their structures.
In this context typical application examples will be given for sensors monitoring the initiation period linked to
chloride induced corrosion. These sensors may monitor the water content in the concrete or the depth of the
depassivation front. This information can be used to execute intervention measures on time, before the rein‐
forcment becomes depassivated. Furthermore, the obtained information from monitoring action can be inte‐
grated within a full probabilistic service life calculation via Bayesian Update. This enables the prediction of the
service life span by taking the actual structure condition into accout. Consequently, information of sensors
contributes to the enhancement of durability performance over service life.