Deutscher Beton und Bautechnik Verein

München, Germany

Deutscher Beton und Bautechnik Verein

München, Germany

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Meier A.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2014

Structural engineers are often uncertain about how to deal with the concept of restraint stress. A simple case in point is a parking deck exposed to outside air whose pavements tend to expand in summer and shorten in winter. However, this tendency to move may be obstructed by rigid staircases located at both ends of the building that do not allow for these movements. Reinforced-concrete foundation slabs need not always be designed for late restraint stresses. According to common experience, however, the mandatory check if there is any basis at all to design the slab exclusively for early restraint is almost never carried out. The previously applied underground car park design without natural ventilation resulted in relatively uniform temperature conditions, which is why reinforced-concrete foundation slabs were subjected to restraint stresses over time almost exclusively due to shrinkage in horizontal direction, rather than temperature- induced deformation.


Conrad W.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2010

The Code of Practice on Waterproof Concrete Structures was published in May 2004. According to this code of practice authored by academic, construction and administration experts, the principles and guidelines of this document can be applied to structures in general building and industrial construction but also in a similar manner to other component thicknesses, or they can be transferred to other structural frameworks made of concrete, such as during the construction of waterproof roofs and floors. The Code of Practice on Waterproof includes principles such as the design and storage conditions of roof floors and the ground-plan geometry should enable a clear assessment of the deformation behavior at floor level, strongly articulated floor cross sections should be avoided. This means that, when selecting compact ground-plan geometry, Joints should be inserted where required, and the roof edges (attic) must be concreted in the same work step as the roof floor. To prevent subsequent damage, the layers placed on top of the insulation must be non-vapor retarding.


Schwabach E.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2013

The actual compressive strength of the concrete is necessary to evaluate when converting structures to other uses following damage. The assessment on the basis of the new compressive strength classes calls for an evaluation in accordance with DIN EN 13791, which specifies the procedure for estimating the compressive strength of concrete in structures and for evaluating the conformity of members according to product standards. The compressive strength for the strength analysis can also be evaluated in accordance with DIN EN 13791. The testing of structural concrete covers both the effects and the material properties as well as the execution. Requisite to a correct evaluation of the compressive strength of a structure is the proper choice of test ranges and locations. A test range comprises in these cases one or several members in the structure where the concrete is known or assumed to originate from the same population.


Construction products manufactured by the building materials industry in accordance with the so-called harmonized European Standards will be provided with a declaration of performance as of July 1, 2013, according to the Construction Product Regulation. This declaration is in general complemented by the CE marking. In this way, the manufacturer attends the European single market of construction products and verifies that his construction products have demonstrated their marketability being agreed, on a harmonized basis, throughout Europe. A harmonization of rules for load-bearing precast concrete elements, which are to be sold on the European single market without trade barriers, does not only also imply a uniform definition of the manufacturing process and the geometrical characteristics but also harmonized rules concerning the materials used as well as uniform design and execution rules. Apart from CE marking, that confirms marketability, a verification of applicability represented by a Ü mark, will have to be harmonized.


Meier A.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2013

Various points in time during the construction process have an influence on different aspects of construction and the coordination between structural engineer and construction contractor. The so-called early strength develops during the first days after concreting. Knowledge of this parameter is important in structural engineering, primarily for verifying the reinforcement required to limit the calculated crack width for the scenario of early restraint during the dissipation of the heat of hydration. After the early hardening phase, the development of concrete strength is crucial to determine formwork stripping times and the duration of protective concrete treatment after casting. However, the structural engineer must get involved in the case of more demanding specifications. The final strength of concrete is of relevance to the structural engineer, for instance for determining the amount of reinforcement required to limit the calculated crack width to respond to the scenario of late restraint stresses.


Meier A.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2013

Structural engineers, in cases of exact structural design, must specify to constructors the required roughness of construction joints. The contractors will have to assume that construction joints must be executed in keyed form or must request the required roughness. Constructors or consulting engineers, moreover, calculate accordingly taking account of additional work steps such as high-pressure water jet or additional formwork with tested roughness in the joints. Section 8.2 of DIN 1045-3:2012-03 provides detailed information on the work steps required for creating construction joints.


Schwabach E.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2013

The European standard for the execution of concrete structures, DIN EN 13670, comprises the European standard DIN EN 13670 and the corresponding national application rules, DIN 1045-3. For precast concrete components, the curing period of at least half a day specified for execution classes X0 and XCI may be reduced, provided the maturity of the concrete has been certified. Curing compounds may not be used on surfaces subject to visual requirements, unless evidence has been provided that they do not negatively affect the appearance of the concrete surface. Temporary supports, scaffolding and formwork may only be removed after the concrete has attained sufficient strength in order to prevent damage to the surfaces during formwork removal. If retention of the concrete component in the formwork is part of the curing process, the minimum curing times must be taken into consideration in determining the formwork stripping times. The standards do not explicitly specify minimal stripping times.


Pisarsky L.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2010

The method to be used to seal cracks and voids in waterproof concrete structures is described in the relevant Code of Practice [1], which provides principles and guidelines for this method. This code of practice (1] requires the designer to consider unexpected leakages that are detected after completion already in the course of designing the waterproof concrete structure. Section 7, (5) of the code of practice (1) states that the design must provide for sealing measures in accordance with section 12 for separating cracks that occurred unexpectedly, or separating cracks that are wider than specified in the design. According to the Code of Practice on Waterproof Concrete Structures [1], section 12.3, (1), cracks, leaking joints and concrete textures must be filled with sealants in accordance with the DAfStb Code of Practice on the 'Protection and Repair of Concrete Structures (Repair Code of Practice)' (4], Part 2. The Code of Practice on Waterproof Concrete Structures also permits the application of special methods for subsequent sealing.


Meier A.,Deutscher Beton und Bautechnik Verein | Goldammer K.-R.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2010

Waterproof structures design and execution is governed by the applicable DAfStb Code of Practice. The contractor commissioned by the client with the construction of the shell built an underground car park as a waterproof concrete structure. The building design documents were prepared by a structural engineer contracted by the client. Following the completion of the works and the covering of the underground car park with soil, the water drainage system was disconnected, which caused the ground water level to rise. The relatively high ground water level then resulted in water penetration into the structure through separating cracks in the foundation slab and in the walls. The design must provide for waterproofing measures if self-healing does not set in at isolated points in the structure, or if it remains incomplete. The construction process must be aligned with these requirements. Other finishing components, such as floor coverings, should be installed only after completion of the self-healing process.


Kiltz D.,Deutscher Beton und Bautechnik Verein
Betonwerk und Fertigteil-Technik/Concrete Plant and Precast Technology | Year: 2014

The brief for building design or identification of needs is an established tool that is also appropriate for parking facilities to systematically capture the needs of the client/user and to document them in a design brief. This paper considered the aspects of serviceability, durability, comfort and commercial viability, referring to the example of a directly accessed parking facility built in reinforced concrete to explain the implications that maintenance requirements defined by the client/user may have on the design of parking facilities.

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