Lehrstuhl und Inst. für Massivbau [u.a.]
Zur Verbundverankerung bei Vorspannung mit sofortigem Verbund in Hochleistungsbetonen
Abstract
dc:descriptionPrestressed concrete structures with pretensioned strands have been accomplished for several years. Generally, normal strength concrete with a density of 2.4 kg/dm³ and a cylinder compressive strength up to 50 N/mm² is used. In prestressed concrete, the bond anchorage behavior of prestressing strands is an important constructional element in prefabricated concrete structures and is regulated in DIN 1045-1, DIN 4227, Eurocode 2, Model Code 90 and ACI 318-02. However, there are no verified experimental design rules for the bond behavior of prestressing forces in high-performance concrete, especially for lightweight and self-compacting concrete. Also, a consistent design concept for the transfer length of prestressing forces is missing. In this work, the applicability of existing rules and standards from literature for the bond anchorage behavior has been investigated for high-performance concrete. Based on these investigations, an own design concept has been developed. The bond anchorage behavior of 7-wire-strands and 12mm ribbed bars was investigated in over 400 pull-out-tests, 27 tests for the transfer lengths and eleven beam tests with pretensioned strands in high-strength lightweight concrete and self-compacting concrete. Within the tests, three different types of high-strength lightweight concrete (LC 35/38 with rho = 1.4 kg/dm³, LC 55/60 with rho = 1.6 kg / dm³ and LC 75/85 with rho = 1.8 kg/dm³), and three self-compacting-concrete types (powder-type with fly-ash, powder-type with limestone-powder and combination-type with fly-ash) were tested. At this point, the stress dependent part of 7-wire strands and 12mm ribbed bars, as well as the general bond anchorage behavior in prestressed concrete beams were examined. Based on the experimental test results a modified design approach was developed. Now the code rules for ordinary concrete can be applied to prestressed concrete structures in high-strength lightweight concrete and self-compacting concrete. With these own design proposals to DIN 1045-1 and “DAfStb-Richtlinie” for self-compacting concrete, the normative foundations are available. This is the basis to allow a broader application of these concrete types in Germany. The accompanying nonlinear numerical investigations showed that the bond anchorage behavior can be modelled successfully. However, it is not possible to describe the multiaxial failure behavior of concrete under different load stages. Assuming the engineering boundary conditions the load-deformation-behavior could be simulated in a satisfactory manner.
Degree
thesis:*- Grantor dc:publisher
- Lehrstuhl und Inst. für Massivbau [u.a.]
- Year dc:date
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Kommer, Boris
- Contributors dc:contributor
-
- Hegger, Josef
Subjects
dc:subject × 11Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger