|
|
Mar 25, 2019 In addition to the main codes used to describe the structure and operation of catch basins, “Survey codes” and so-called “Additional codes” are also defined in accordance with EN 13508-2 [ [EN13508-2:2011]]. These two code groups do not serve a damage description purpose, but are simply used for a further description of the inspected catch basins. Subsequently, they will not be described in detail, but illustrated in the form of a table. (Table: Summary … |
|
|
Mar 25, 2019 |
|
|
Mar 25, 2019 As shown in the preceding sections, drain and sewer systems are prone to a variety of types of damage due to different causes. The subsequently described damage analyses are done separately for drains and sewers as well as manholes, inspection chambers and catch basins. |
|
|
Mar 25, 2019 Ever since leaking sewer systems came into public focus in the Federal Republic of Germany, finding answers to questions about the actual damage potential and the most favourable point in time for damage repair (rehabilitation) has been of great relevance from an economic, ecological and legal point of view. For that purpose, the DWA has started nationwide surveys among network operators in 1984/85 [ [Kedin87]]. The latest survey from 2009 brought … |
|
|
Mar 25, 2019 With the introduction of EN 13805 in 2003 and the defect coding system defined there with the objective of a uniform approach towards the determination of the condition of manholes and inspection chambers in the context of the visual inspection, these structures received special attention on the part of the network operators. Already, a DWA survey on the “condition of the sewer systems in Germany” [ [DWA2001]] had taken manholes and inspection chambers … |
|
|
Mar 25, 2019 The condition of the catch basins in the public road area was captured as a part of a nationwide survey carried out by Ruhr University in Bochum [ [Stein2008]] for the first time in 2006. The survey - which is presently the only one of its kind in that form - was based on regular surveys that are carried out by Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V. (DWA) in order to assess the condition of public sewers, manholes and … |
|
|
Mar 25, 2019 |
|
|
Mar 25, 2019 Sewer systems are either permanently or temporarily subject to different physical, chemical, biochemical and biological forms of stress. The second volume of the 2nd edition of "Rehabilitation and Maintenenance of Drains and Sewers" deals with the various types of defects and damages threatening drains, sewers, manholes and catch basin systems. |
|
Nov 20, 2023 Course Investigation is the first of four fundamental measures within the scope of integral sewerage and drainage management. It should cover all performance aspects of the drainage system to an appropriate extent in order to establish the foundation for assessing the performance of the drainage system. The obtained results serve as evidence of compliance with due diligence and, in particular, as a basis for planning all activities related to operation, maintenance, and rehabilitation. The focus is on the structural investigation of drainage systems and addresses various options for condition assessment.
The course consists of 7 modules:
1. Investigation to Determine the Structural and Operational Condition of Drain and Sewer Systems
2. Geotechnical Investigations
3. Geophysical Site Investigation
4. Inspection from the Inside for Qualitative Condition Assessment
5. Inspection from the Inside for Quantitative Condition Assessment
6. Application of Coding Systems Using the Example of EN 13508-2
7. Coding of damages (findings), their causes, and consequences
The course is successfully completed after 30 hours of intensive learning units within 4 weeks. Before each topic area, you will find an introductory page that provides an overview of the learning objectives, lesson duration, and content covered. We warmly welcome you to this module and wish you success in your studies!
|
|
|
|
Mostly, the travelling speed of the carts is infinitely variable and can be up to 50 cm/s, for example. Due to the fact that the visual inspection has to be done thoroughly and with a work progress that is adjusted to the object’s condition, the average inspection performance per working day is determined by the:
|
|
|
Summary: This module teaches the basics of geophysical soil investigation and is to be understood as a supplement to the module "Geotechnical Investigation". Geophysical measurement methods belong to the indirect exploration methods and allow statements regarding local inhomogeneities in the pipeline zone (e.g. bedding defects, cavities, disruptions, concrete encasements) or, in the case of investigations of existing sewers and pipelines, statements … |
|
|
During damage assessment, but also in the decision for a suitable rehabilitation method, sound knowledge of the bedding conditions of the existing sewer is very important, because, in many cases, these conditions represent the causes of damage. Large-scale insights on the condition and load bearing capacity of the bedding and information on local inhomogeneities such as
can be gained by means of geophysical … |
|
|
The following simplified description of the methods is limited to a selection of geophysical methods of measurement that (with respect to the problem of subsurface investigation as a part of sewer rehabilitation and maintenance methods) can be applied either from the ground surface or from vertical boreholes. Depending on the individually chosen method, information can be provided about:
|
|
|
Seismic technology is by far the most important and prevailing method of exploratory geophysics used to explore deposits such as oil, gas and coal. From an (environmental) engineering point of view, it also provides essential structural information. In seismic methods, elastic waves and wave fields are used as information carriers which can be processed into images of the subsurface. This makes it possible to gain a direct insight into its complex … |
|
|
The underground has an impact on the propagation of seismic (elastic) waves by mechanisms such as: reflection, refraction, diffraction, absorption and scattering. The seismic waves (1) for these analyses are produced artificially (2), e.g. through explosions, blows of a hammer, speakers, vibrators and implosions, and then usually recorded via electro-dynamic receivers (3) (geophones) after they have traversed the underground. The waves that propagate … |
|
|
Seismic methods can be of help in solving the following tasks:
[DWAM149-4:2008] Seismic measurement methods Seismic measurement methods … |
|
|
In reflection seismics (figure), waves are excited at the surface and then reflected at interfaces (boundary layers), and registered within only short distances (relative to the target depth) from the source. The usually very extensive data material that is recorded by multi-channel, telemetric apparatuses can be processed and illustrated using special computer-aided methods to show an image of the underground structure that can be interpreted immediately. … |
|
|
In refraction seismics (figure) the waves are registered at a larger horizontal distance (in relation to the target depth) from the source. This means that in addition to the reflections from the underground, there will also be waves that took other faster travel paths between the source and receivers, resulting in the first arrivals of the seismic signals. After data processing, the results look quite similar to sections from reflection signals but … |
|
|
The following is a comparative comparison of refraction seismics and reflection seismics. (Table: Comparison refraction seismic - reflexion seismic [FI-Steina]) |
|
|
Seismic tomography provides an area picture of the distribution of the compression wave velocity and the amplitude damping and therefore an indirect depiction of the distribution of certain material properties. It relies on the observation of mechanical vibrations that occur artificially or naturally during earthquakes. A condition of their application is the creation of boreholes in the region which is to be examined. Information on the region is … |
|
|
In acoustic seismology, also known as surface wave seismology, the soil particles are vibrated by means of acoustic signals which change in their frequency with time (sweep), in contrast to using impacts, explosives, etc. where a single impulse creates the seismic waves. The advantage of the acoustic source when compared to the other seismic sources is in its handiness, freedom from destruction and its better reproducibility and regularity of the … |
|
|
|
|
|
The earth’s magnetic field is very strongly influenced on the surface by the upper layers of the underground. In the region in which engineering geophysics occurs, these are not the layers themselves but the structures contained in them such as iron components, bunkers, tanks, beams, pipelines, waste, fibres and reinforced concrete foundations. Often, these iron components are not the subject of the investigation but can for instance, “reveal” the … |
|
|
The physical principle of measurement is shown in the figure. The anomaly field can be found in the top half of the image, whereas the lower half represents the formation of the total field by vector addition of the natural Earth’s field with the field of an interference body (anomaly field). At the level of the observation (here as side view) the magnetic anomaly can be observed [Lenz97]. (Image: Physical principle of measurement of magnetism [Lenz1997] - … |
|
|
In the process of Electromagnetic Induction (EMI), the subsurface is subjected to an alternating field by means of a coil and this induces a secondary field. This, again, superimposes itself on the exciting field. The resulting field is measured by a receiver coil. The images show the manual measurement. The frequency used in the EMI method ranges from about 10 Hz to 2 MHz, the spacing between the coils varies from just a few metres up to about 100 … |
1158 search results:
