For the assessment of existing slab-between-girder bridges, the shear capacity and failure mode are under discussion. Previous research showed that the static and fatigue punching capacity of the ...slabs is sufcient as a result of compressive membrane action. The girders then become the critical elements. This research studies the shear capacity of prestressed concrete bridge girders. For this purpose, four (half) girders were taken from an existing bridge that was scheduled for demolition and replacement and tested to failure in the laboratory. Two loading positions were studied. The results show that there should be a distinction between the mode of inclined cracking and the actual failure mode. In addition, the results show that for prestressed concrete girders, the influence of the shear span-depth ratio should be considered for shear span-depth ratios larger than 2.5. These insights can be used for the assessment of existing slab-between-girder bridges in the Netherlands. Keywords: bridge assessment; concrete bridges; flexure-shear; large-scale testing; prestressed concrete; shear; shear-compression; shear-tension.
For the assessment of existing slab-between-girder bridges, the shear capacity and failure mode are under discussion. In particular, preliminary assessment calculations showed that the critical ...failure mode of the girders is shear-tension. In this paper, four girders taken from a demolished bridge that were tested in the lab are analyzed according to existing codes. The comparison between the experiments and the analysis shows that the Dutch RBK provisions are conservative and the ACI 318-19 provisions result in good predictions of the shear capacity at inclined cracking and at ultimate. These observations are then combined into recommendations for the assessment of prestressed concrete girders in existing slab-between-girder bridges for shear cracking and the ultimate shear capacity. Keywords: bridge assessment; concrete bridges; flexure-shear; large-scale testing; prestressed concrete; shear; shear-compression; shear-tension.
Previous research showed that the capacity of existing slab-between-girder bridges is larger than expected based on the punching shear capacity prescribed by the governing codes, as a result of ...compressive membrane action. A first series of fatigue tests confirmed that compressive membrane action also acts under cycles of loading. However, a single experiment, in which first a number of cycles with a higher load level and then with a lower load level were applied, seemed to indicate that this loading sequence shortens the fatigue life. This topic was further investigated in a second series of fatigue tests with three static tests and 10 fatigue tests. The parameters that were varied were the sequence of loading and the effect of a single or a double wheel print. The results show that the sequence of load levels does not influence the fatigue life. Keywords: bridge evaluation; compressive membrane action; concrete bridges; fatigue; fatigue testing; laboratory testing; prestressed concrete; punching shear.
In the Netherlands, slab-between-girder bridges with prestressed girders and transversely prestressed decks in between the girders require assessment. Static testing showed that compressive membrane ...action increases the capacity of these structures and that the decks fail in punching shear. The next question is if compressive membrane action also increases the capacity of these decks under repeated loads. Therefore, the same half-scale bridge structure as used for the static tests was subjected to repeated loads at different fractions of the maximum static load, different loading sequences, and for single- and double-concentrated loads. A relationship between the load level and number of cycles at failure (S-N curve) for the assessment of these bridges is proposed, but the influence of the loading sequence was not successfully quantified yet. The conclusion of the experiments is that compressive membrane action enhances the punching capacity of transversely prestressed thin decks subjected to repeated loads. Keywords: bridge evaluation; compressive membrane action; concrete bridges; fatigue; fatigue testing; laboratory testing; prestressed concrete; punching shear.
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