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A platform for research: civil engineering, architecture and urbanism
Pretensioning in self-consolidating concrete (SCC)
The dimension of the anchorage length can favor the cost-effective design of prestressed concrete girders. A minimum concrete cover must be ensured to avoid splitting cracks. Splitting cracks in the transmission zone of the prestressing force lead to an uncontrolled increase in transmission length and may cause an early failure due to anchorage fracture. Several pull-out tests, tests on transfer of prestressing force, as well as tests on prestressed beams made of self-consolidating concrete (SCC) were carried out. These tests investigated the bond properties of 7-wire strands (dp=0.5''=12.5 mm) and ribbed wires with d=12 mm. The lateral strain dependent bond properties for different concrete types and the behavior in the transmission and anchorage zone were determined. The target was to develop missing bases for code specifications, regulations and standards for the use of bond anchorages of prestressed tendons. Tests on two powder type concretes have been performed: one with fly ash and the other with limestone powder. One combination type concrete with fly ash was investigated. The results of the tests are explained and compared to the common standards DIN 1045-1 (German Code), Eurocode 2 and ACI 318. The bond behavior of prestressed tendons in the transmission zone is influenced by lateral expansion depending on the stress level at the time the prestressing force is released. The specific bond strength of fresh SCC is comparable to vibrated normal strength concrete (NSC). The minimum concrete cover and clear spacing to prevent splitting are the same for SCC and vibrated NSC. Except the ACI, the code regulations (DIN 10454 Eurocode 2) concerning the transmission length adequately reflect the beneficial influence of the compression strength.
Pretensioning in self-consolidating concrete (SCC)
The dimension of the anchorage length can favor the cost-effective design of prestressed concrete girders. A minimum concrete cover must be ensured to avoid splitting cracks. Splitting cracks in the transmission zone of the prestressing force lead to an uncontrolled increase in transmission length and may cause an early failure due to anchorage fracture. Several pull-out tests, tests on transfer of prestressing force, as well as tests on prestressed beams made of self-consolidating concrete (SCC) were carried out. These tests investigated the bond properties of 7-wire strands (dp=0.5''=12.5 mm) and ribbed wires with d=12 mm. The lateral strain dependent bond properties for different concrete types and the behavior in the transmission and anchorage zone were determined. The target was to develop missing bases for code specifications, regulations and standards for the use of bond anchorages of prestressed tendons. Tests on two powder type concretes have been performed: one with fly ash and the other with limestone powder. One combination type concrete with fly ash was investigated. The results of the tests are explained and compared to the common standards DIN 1045-1 (German Code), Eurocode 2 and ACI 318. The bond behavior of prestressed tendons in the transmission zone is influenced by lateral expansion depending on the stress level at the time the prestressing force is released. The specific bond strength of fresh SCC is comparable to vibrated normal strength concrete (NSC). The minimum concrete cover and clear spacing to prevent splitting are the same for SCC and vibrated NSC. Except the ACI, the code regulations (DIN 10454 Eurocode 2) concerning the transmission length adequately reflect the beneficial influence of the compression strength.
Pretensioning in self-consolidating concrete (SCC)
Hegger, Josef (author) / Kommer, Boris (author)
2005
6 Seiten, 10 Bilder, 11 Quellen
Conference paper
English
Pretensioning in Self-Consolidating Concrete (SCC)
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