Effect of Scour on Load Carry Capacity of Piles on Mat Bridge

Abstract

Critical scour effects on bridge performance helps to predict the bridge load carryingcapacity and as a result, may help prevent unnecessary looses. Very few studies have beenconducted on current condition of Albanian bridge especially on integrations between water,pile foundation and bridge structures. Most of highway bridges in western and center Albaniaare over shallow water, including small creeks, wetlands and marshes. A widely used designand construction procedure for these bridges is to have the bridge superstructure supported onpile bents. Albanian rivers have aggressive flow regime. During major flood events, thevolume and velocity of flood waters can cause considerable scouring. As the load carrycapacity of these pile bent vary inversely with the bent height, a scour in certain height willreduce its load carry capacity.This paper analytically summarizes the effect of the scour on pile bent load carrycapacity. Load carry capacity of piles is calculated analytically, only geotechnical data aretaken from site tests. Site inspections on Mat bridge show that 19 from 32 pile bents haveserious scour problems. Analysis results indicate that pile bents due to scouring height haveloosed a load carry capacity varying from 17.64 to 32.11% of that designed.