Kraľovanec Jakub, Moravčík Martin, Bujňáková Petra, Jošt Jozef
Department of Structures and Bridges, Faculty of Civil Engineering, University of Žilina, Univerzitná 8215/1, 01026 Žilina, Slovakia.
Laboratory of Civil Engineering, University of Žilina, Univerzitná 8215/1, 01026 Žilina, Slovakia.
Materials (Basel). 2021 Mar 10;14(6):1338. doi: 10.3390/ma14061338.
A diagnostic survey on the precast prestressed bridge Nižná confirmed significant deterioration due to environmental distress. Evidently, decisive failures of the structure have a similar character as in the previous precast prestressed bridge in Podbiel in the northern part of Slovakia. These failures result from the unsuitable concept of the first generation of precast prestressed concrete beams, which was used in the former Czechoslovakia in the second half of the 20th century. Subsequently, experimental verification using the proof-load test was also executed. This bridge was built in 1956, so at the time of testing, it was 60 years old. The paper presents the indirect determination of prestressing level in one precast post-tensioned concrete beam using the saw-cut method. Experimental measurement was executed during the bridge demolition. Subsequently, a 2D numerical model in ATENA 2D Software, with the assumption of nonlinear material behavior for verification of experimental results, was performed. Finally, the residual prestressing force was evaluated and compared with the expected state of prestressing according to Eurocodes after 60 years of service.
对尼兹纳预制预应力桥梁的诊断调查证实，由于环境破坏，桥梁出现了严重恶化。显然，该结构的决定性破坏与斯洛伐克北部波德比尔先前的预制预应力桥梁具有相似特征。这些破坏是由第一代预制预应力混凝土梁的不合适设计理念导致的，这种梁在20世纪下半叶的前捷克斯洛伐克被使用。随后，还进行了使用验证荷载试验的实验验证。这座桥建于1956年，因此在测试时，它已有60年历史。本文介绍了使用锯切法间接测定一根预制后张法混凝土梁中预应力水平的方法。实验测量是在桥梁拆除期间进行的。随后，在ATENA 2D软件中建立了二维数值模型，假设材料行为为非线性，以验证实验结果。最后，评估了残余预应力，并与根据欧洲规范服役60年后的预期预应力状态进行了比较。
