# Fatigue Assessment of Prestressed Concrete Slab-Between-Girder Bridges
###### Abstract  
In the Netherlands, the assessment of existing prestressed concrete slab-between-girder bridges has revealed that the thin, transversely prestressed slabs may be critical for static and fatigue punching when evaluated using the recently introduced Eurocodes. On the other hand, compressive membrane action increases the capacity of these slabs, and it changes the failure mode from bending to punching shear. To improve the assessment of the existing prestressed slab-between-girder bridges in the Netherlands, two 1:2 scale models of an existing bridge, i.e., the Van Brienenenoord Bridge, were built in the laboratory and tested monotonically, as well as under cycles of loading. The result of these experiments revealed: (1) the static strength of the decks, which showed that compressive membrane action significantly enhanced the punching capacity, and (2) the Wohler curve of the decks, showed that the compressive membrane action remains under fatigue loading. The experimental results could then be used in the assessment of the most critical existing slab-between-girder bridges. The outcome was that the bridge had sufficient punching capacity for static and fatigue loads and, therefore, the existing slab-between-girder bridges in the Netherlands fulfilled the code requirements for static and fatigue punching. assessment; bridge evaluation; compressive membrane action; concrete bridges; fatigue; fatigue assessment; live loads; prestressed concrete; punching shear; scale model Article  
Fatigue Assessment of Prestressed Concrete Slab-Between-Girder Bridges  
[PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON]. taking place in Germany [6], Sweden [7], Switzerland [8], and other European countries, as well as in the United States [9], where bridge construction peaked during the 1930s (the New Deal) and between 1956 and 1992 (i.e., the construction of the Interstate Highway System). As one can see, the methods used for an accurate assessment of existing bridges are becoming increasingly important, as the safety of the traveling public should be protected, and at the same time, unnecessary bridge replacements or strengthening actions should be avoided [10]. The preliminary assessment of existing bridges in the Netherlands according to the new Eurocodes was based on hand calculations (Quick Scans [11; 12]), where the categories of bridge types that required further study were identified. One such category is the prestressed slab-between-girder bridges; this subset contains about 70 bridges [5]. The structural system of these bridges is a combination of prestressed girders with the deck slab cast in between the girders and is transversely prestressed. As a result, the top of the flange of the girders is flush with the top of the deck. Additionally, prestressed diaphragm beams provide stiffness to the overall system. Upon assessment, the thin deck slabs did not fulfil the code requirements for punching shear. One mechanism that is not considered in the codes, but that enhances the capacity of these thin decks, is the compressive membrane action [13; 14; 15; 16; 17; 18; 19; 20]. Additionally, the fatigue capacity of the thin decks is still subject to discussion, as it remains unknown whether progressive cracking and damage accumulation affect the capacity-enhancing effect of the compressive membrane action [21]. This work summarized the experimental results from testing 1:2 scale models of prestressed slab-between-girder bridges, and then it applied these results to the punching and fatigue assessment of an existing bridge. We demonstrated how compressive membrane action improves the assessment for punching shear, and how the Wohler curve from the fatigue tests could be used for the assessment of the bridge deck under fatigue. The summarized experiments are unique in nature, as the tested specimens give us insights into the behavior of slab-between-girder bridges as a structural system.