Upon assessment of existing reinforced concrete short-span solid slab bridges according to the recently implemented Eurocodes that include more conservative shear capacity provisions and heavier axle loads, a number of these structures were found to be shear-critical. The results from recent experimental research on the shear capacity of slabs indicate that slabs benefit from transverse load distribution. Recommendations for the assessment of solid slab bridges in shear are developed on the basis of these experiments. A load spreading method for the concentrated loads is proposed and the applicability of superposition of loading is studied. The resulting most unfavourable position for the design trucks is provided and implemented in the so-called Dutch "Quick Scan" method (QS-EC2). Cases of existing bridges are studied with the previously used QS-VBC as well as with the QS-EC2 that includes the recommendations. As a result of the assumed transverse load distribution, the shear stress to be considered at the support based on the recommendations becomes smaller.Keywords: effective width; live loads; load distribution; reinforced concrete; slab bridges; shear.The shear capacity as prescribed by NEN 6720 3 and NEN-EN 1992-1-1 2 is determined from a statistical analysis of experiments on relatively small, heavily reinforced concrete beams loaded in four-point bending.6 When these expressions are applied to determine the shear capacity of a slab under a concentrated load, the contribution of the surrounding material, which is activated through transverse load distribution, is not taken into account. Moreover, the effective width in shear for slabs under a concentrated load needs to be determined. In practice, the effective width is based on a load spreading method:1. from the centre of the load towards the face of the support as used in Dutch practice (Fig. 1a), resulting in b eff1 ; or 2. from the far side of the load towards the face of the support as used in French practice 7 (Fig. 1b), resulting in b eff2 .To quantify the enhancement due to transverse load distribution in slabs under a concentrated load in shear, a comprehensive series of experiments was carried out. [8][9][10] In a first series of experiments, 18 slabs and 12 slab strips were tested under a concentrated load near the support. In a second series, eight additional slabs were tested under a combination of a concentrated load near the support and a line load. These experiments form the basis for new recommendations for the shear assessment of slab bridges. In sections Experiments and Recommendations, the link between these experiments and the recommendations is discussed.The large number of solid slab bridges that are identified as shear-critical require a systematic approach. In a preliminary general assessment, the database of slab bridges was screened in order to identify the particular bridges that require a more detailed analysis. For this purpose, a fast, simple and conservative tool is required: the "Quick Scan" method (QS-EC2). The fi...

Load testing of bridges is a practice that is as old as their construction. In the past, load testing gave the traveling public a feeling that a newly opened bridge is safe. Nowadays, the bridge stock in many countries is aging, and load testing is used for the assessment of existing bridges. This paper aims at giving an overview of the current state-of-the-art with regard to load testing of concrete bridges. The work is based on an extensive literature review, dealing with diagnostic and proof load testing, and looking at the current areas of research. Additional available information about load testing of steel, timber, and masonry bridges, buildings, and collapse testing is briefly cited. For the implementation of load testing to the aging bridge stock on a large scale, efficiency in procedures is required. The areas requiring future research are identified, based on the available body of knowledge.

Shear in reinforced members has been a topic of study for many decades. Recently, the shear capacity of slabs subjected to concentrated loads -the case between one-way shear (also called beam shear) and two-way shear (or punching shear) -has been given more attention because this case is encountered in bridge engineering. This paper aims to give an overview of the existing code methods for shear and to bring together experiments from the literature on wide beams and slabs failing in shear. The database of collected experiments is then compared with the Eurocode provisions.A large scatter was found in the ratio of experimental to predicted values. This observation indicates that the experiments under consideration should be studied in subsets according to the failure mode and that better methods for determining the shear capacity of wide concrete members are necessary. The database also shows the need for experiments aimed at studying shear in one-way slabs and the effect of different parameters on the shear capacity.Notation a centre-to-centre distance between the load or the centre of gravity of multiple loads and the support a v clear shear span: the face-to-face distance between the concentrated load and the support b specimen width b eff1 effective width based on the load spreading method from Figure 1(a) b eff2 effective width based on the load spreading method from Figure 1width of the load, taken in the span direction b r distance between the free edge and the centre of the load along the width b sup width of the support, taken in the span direction b w web width of the section or, for slabs, the effective width C Rd,c calibration factor in the shear formula d average reinforcement ratio, 0 . 5(d l + d t ) d l effective depth to longitudinal reinforcement d t effective depth to transverse flexural reinforcement e pu eccentricity ratio F test maximum load as applied during the experiment f ck characteristic concrete cylinder compressive strength k size effect factor k 1 0 . 15 k pu geometry factor for eccentric loading for punching l load length of the load; this distance is taken perpendicularly to the span direction n number of loads P exp maximum concentrated load in experiments u punching perimeter V Ed shear force resulting from loading V exp,EC shear force at the support, for which loads close to the support are reduced by â V R,c,beff1 resulting shear capacity using b eff1 V R,c,beff2 resulting shear capacity using b eff2 V Rd,c design shear capacity V test resulting maximum sectional shear force v E shear stress due to loading v min lower bound of the shear stress v pu punching capacity W geometric parameter related to the distribution of shear on the control perimeter z internal lever arm â reduction factor for loads close to the support ª c material parameter for concrete r average reinforcement ratio, r ¼ (r l r t ) 1=2 r l flexural reinforcement ratio r t ratio of transverse flexural reinforcement ó cp axial stress on the cross-section

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