PSI - Issue 64

Nicoletta Bianchini et al. / Procedia Structural Integrity 64 (2024) 352–359 Bianchini N., Sabra Z, Green K.. Wrigth, R. Structural Integrity Procedia 00 (2024) 000 – 000

356

5

A monitoring station near the bridge (SU 87070 45570) captured detailed water level measurements (Fig. 5). The highest recorded level was 59.154 meters on January 5, 2024, at 10:30 AM, while the lowest point was 56.410 meters on August 29, 2020, at 1:30 PM.

Fig. 5. (a) Water level data by http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. Minimum and maximum levels in the red circles. A key observation emerged from this analysis: the water level has exhibited a significant increase since the installation of a temporary cofferdam at the upstream end of the Waverley Mill bridge, which likely diverted the water flow into the adjacent Mill Waste bridge that is 100m away. The temporary cofferdam was installed by the private landowner who is situated on the southern side of the bridge to undertake refurbishment works for their property. The prediction of this trend was not easy to depict due to the limited information available related to the flow rate. Based on the consideration of Section 1.1, a detailed numerical model was built, and the role of flooding effects investigated by means of a sensitivity limit analysis. 3. Modelling Due to the strict deadlines requested by the Client, a fast and reliable numerical method was selected to undertake these analyses using the LimitState: RING 4.0 software, which verifies the stability of masonry bridges assuming a given distribution of backfill and infill as investigated on site. In total, four models were built as follows in Table 1 and Fig. 6 and different vehicles locations were taken into account according to CS 454 and CS 458, however for sake of succinctness for this study only the results for 11.5 tons (single axle) are presented.