TECHNICAL COMMISSION 7 - STRUCTURAL BEHAVIOR AND DAMAGE DIAGNOSTICS
Technical commission 7 – "Statics" focuses on static and dynamic issues that arise during repair projects.
The technical commission has identified the following additional disciplines that require attention and is considering the establishment of respective working groups:
- Timber statics
- Concrete/reinforced concrete/prestressed concrete
- Masonry construction
- Jack arch floors
- Standards old/new
- Design loads
We expressly call for an intensive discussion of these proposals.
As a result of the technical commission restructuring process, working group 4.3 “Conservation of Masonry – Construction and Load Bearing Capacity“ and the new working group "Determination of the Compressive Strength of Existing Masonry Made of Small Artificial Stones" were attached to technical commission 7. This working group assesses the load bearing capacity of damaged and deformed timber structures.
Working group 7.2 „Historical wooden constructions“
Head of the working group: Dr.-Ing. Thomas Baron
The working group deals with the assessment of the bearing capacity of damaged and deformed wooden structures.
Objective of the working group
In supplement to the content of the existing WTA recommendations, the planned code of practice aims to provide action guidelines for the evaluation of historic timber structures along with information about the design approach. The working group primarily plans to include the following topics:
- The fundamental technique and process of a needs-adequate approach to structural design assessment processes
- Brief description of suitable destructive, minimally destructive and non-destructive testing processes to supplement the existing codes of practice
(insertion of cross-references)
- Depiction of the diagnoses and damage categories taken into account in the code of practice
- Concrete damages contingent load bearing capacity assessment, including a selection of cases combining multiple damage categories
- Diagnoses-based state assessment
- Approach to and process of the load compilation and the generation of the calculation model
- Cross-references to repairs and refurbishment
The guideline was published in July 2019.
Working group 7.3 „Preservation of masonry - construction and load-bearing capacity“
Head of the working group: Prof. Dr.-Ing. Heinrich Wigger, Dr.-Ing. Heiko Twelmeier
The working group is tasked with the revision of the existing WTA code of practice 4-3-98/D “Repair of Masonry – Stability/Load Bearing Capacity” and its reconciliation with parallel standards, such as DIN 18 195 and including the compilation of quality assurance completion check lists.
Objective of the working group
Given that national technical standards that address the conservation of masonry do not exist, owners, special planners, contractors and experts frequently find themselves confronted with uncertainties when it comes to the planning and execution of such work. Consequently, the objective of the code of practice is to give building conservation decision makers assistance with the determination of the actual condition of existing masonry, such as:
- The evaluation of the actual condition of existing masonry with the assistance of load bearing models
- The development of conservation concepts
- The execution planning using modern calculation methods
The assessment of the actual condition is the basis for conclusions about the sustainability, load bearing capacity and usability of the evaluated masonry.
The guideline "Conservation and Repair of Masonry – Construction and Load Bearing Capacity" was published in December 2018.
Working group 7.4 „Determination of the compressive strength of existing walls made of artificial small-format bricks“
Head of the working group: Dipl.-Ing. Jonny Henkel
Due to the modernization of many objects as well as the densification of public space, the quality of existing masonry made of small size tiles plays an increasingly important role for structural reasons. In this context, the characteristic stability of masonry or the permitted masonry stress, which is determined by the compressive strength of the masonry, is a key parameter of static evaluations. The compressive strength of existing masonry or its components can be determined in a number of ways. A large percentage of these testing methods is not standardized or is merely based on the existing standards for new construction. Due to the fact that to date, Germany does not have a fundamental standard or other recommendations for the compressive strength testing process used on existing masonry, the aim is to develop a WTA code of practice that describes the familiar processes, some of which differ regionally and that points out the advantages and disadvantages along with the ancillary conditions. Moreover, it will make recommendations for the sampling, scope of sampling, performance of the test and the analysis of the results.
The guideline was published in November 2021.
Working group 7.5 „Damage Monitoring“
Head of the working group: Dr.ir.-arch. Els Verstrynge
(Language of the working group: English)
The working group intends to meet twice a year and initially prepare a status report.
Working group 7.6 „Masonry properties - determination and evaluation“
Head of the working group: Dipl.-Ing. Claudia Neuwald-Burg
Dipl.-Ing. Jonny Henkel
The aim of the working group is to develop recommendations in a compact form for the most uniform possible procedure for masonry inspections within the framework of the basic determination of load-bearing capacity, for repair planning and for the inspection of repairs. Both structural properties such as masonry structure and state of preservation, as well as mechanical and physical properties, chemical and mineralogical issues and moisture and salt problems are considered. Many of these investigations are already covered in standards or guidelines. Investigations that are not yet clearly regulated elsewhere are to be described in the guideline, whereby emphasis is placed on the fact that the procedures are tried and tested and can be implemented well in practice. Evaluation aids should be provided for the assessment of the examination results. If there are several examination options, recommendations will be formulated for the respective areas of application. The guideline to be developed will partially replace the old guideline 4.5 "Assessment of masonry - masonry diagnostics".
The following recommendations have been published by the Technical Commission "Structural Behavior and Damage Diagnostics":
|7-1 Edition: 12.2018/D|| |
Conservation and maintenance of masonry – Construction and structural behaviour
|7-2 Edition: 07.2019/D|| |
Historical timber structures – State determination and assessment of the load bearing capacity
|7-4 Edition: 11.2021/D|| |
Assessment of the compressive strength of existing masonry made of small-sized bricks or blocks