Open AccessOptimal Octagonal Hooked Collar Countermeasure to Reduce Scour Around a Single Bridge Pier
Author(s) -
Rashid Farooq,
Abdul Razzaq Ghumman,
Muhammad Atiq Ur Rehman Tariq,
Ashfaq Ahmed,
Khan Zaib Jadoon
Publication year - 2020
Publication title -
periodica polytechnica. civil engineering/periodica polytechnica. civil engineering (online)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.406
H-Index - 19
eISSN - 1587-3773
pISSN - 0553-6626
DOI - 10.3311/ppci.15966
Subject(s) - pier , collar , bridge scour , geotechnical engineering , structural engineering , countermeasure , bridge (graph theory) , engineering , geology , medicine , aerospace engineering
Pier modification countermeasures are essential as they play a vital role in protecting pier against local scour action. Current study investigates experimentally the scour around vertical pier of octagonal cross section with pier modification such as newly proposed octagonal hooked collar is explored, in steady uniform state, under clear water condition. The results of pier scour without any modification were used as a reference to compute the efficiency of hooked collar provision around octagonal pier. The results show that by increasing the hooked collar width up to 2.5 Wp reduced maximum scour depth significantly. However, the experimental investigation revealed that the best combination to be with a hooked collar width of 2.5 Wp, having sidewall height 0.45 Wp. The best combination minimized around 73.3 % of scour hole depth, compared to octagonal pier without any modification. Using experimental results, a new equation is proposed to predict the scour depth around a bridge pier fitted with hooked collar. Moreover, a relation was developed for maximum scour depth and scour hole volume. Results indicate that the scour hole volume around a bridge pier increases quadratically with maximum scour depth.