Purpose: Due to an increase in a number of bridges being constructed, scour depth
around bridge piers is gradually being recognized as one of the possible reasons for bridge
failure. According to [1] about 53% of bridge failures in the US were caused due to floods
and corresponding scour in the rivers. Lots of work has been carried out around the single
pier but in the case of group piers, the work is very less. Hence, it becomes necessary to
calculate the actual scour depth around the bridge piers considering the close location of
bridges as well.
Design/methodology/approach: Recognizing the need for research in this direction,
an experimental study was planned and conducted in the Hydraulics Laboratory of Civil
Engineering Department of National Institute of Technology Kurukshetra, India. Experiments
were conducted in a standard recirculating tilting bed water flume 15 m long, 0.4 m wide,
and 0.60 m deep. The orientation of more than one pier, namely Tandem pattern was
employed for the work. Two pier models, 62 mm and 42 mm diameter were used for the
experimental study. The mobile bed used in the experiments had an average mean size,
d50 = 0.23 mm, 0.30 mm and 0.50 mm.
Findings: The outcomes of the ANN function and M5 model analysis have been used to
compare with experimental results. From the earlier studies, it was concluded that, when
the clear spacing between the pier models was greater than 0D the scour depth around the
piers increase with a rapid rate. However, in the case of modelling techniques, M5 models
show higher predictive accuracy than ANN models.
Research limitations/implications: It is a significant area of research. However,
the present study has been a time and facility- constrained study. Therefore, there is a
large scope to conduct further studies on the subject, Different pattern i.e. Side by Side;
Staggered and Group of piers can be adopted for further investigations.
Originality/value: Sufficient work has been done by number of researchers around the
single bridge pier. But due to rapid urbanization a number of bridges constructed in close
proximity to each other which affects the scour depth of each other. Modelling techniques
used in hydraulic engineering are not always effective in practice. The present study
discusses the effect of spacing on scouring around piers in a tandem arrangement using
experimental as well as modelling techniques. To predict the scour depth of the Tandem
arrangement 89 laboratory data sets have been used.
Local scour around complex pier groups and combined piles at semi-integral bridge
