Principal Investigator: Thanos Papanicolaou
Sponsors & Partners
IIHR-Hydroscience & Engineering
About this Project
Brief Project Description & Background
Conventional monitoring methods of erosion of bank soils and removal of abutment fill material have difficulty capturing the exact time of the event because they provide only net measurements since the previous sampling. Moreover, these methods are laborious and expensive, which often leads to undersampling. This pilot study will develop of a protocol for monitoring erosion near bridge abutments using innovative technology, namely Photo-Electric Erosion Pins (PEEPs) with a test study near the US Highway 965 bridge crossing over the Iowa River in Johnson County, IA. PEEPs provide automated and continuous monitoring of localized erosion, especially, in areas that channel surveying and/or installation of erosion pins is difficult to take place. The primary goal of this pilot study is the development of a protocol for monitoring erosion near bridge abutments using innovative technology (namely PEEPS).
The primary goal of this pilot study is the development of a protocol for monitoring erosion near bridge abutments using innovative technology (namely Photo-Electric Erosion Pins).
This project will provide continuous rates of bank erosion at a highly traveled, but threatened, Iowa bridge crossing. In addition, the results will identify key hydrological and climatic conditions leading to failure near bridge abutments. The primary products for this project include a thorough and well illustrated, operational manual for local engineers describing an innovative monitoring procedure via a new instrument (Photo-Electric Erosion Pins) for continuous, automated evaluations of bank erosion.
Stream bank degradation has resulted in approximately $1.1 billion in damages to US bridge infrastructure mainly due to abutment failure. Not only is the financial cost staggering, but also the threat to public safety and surface transportation is overwhelming. In Iowa, alone, 6,661 bridges are either structurally deficient or functionally obsolete with many due to bank failures. Stream banks near bridge abutments fail because they are subject to climatic and hydrologic forces (e.g. high flows, eddies, seepage, freeze/ thaw) that weaken the bank soil's overall strength and remove the fill material at the abutments. The effects of these processes are difficult to capture with conventional monitoring methods (e.g., erosion pins, channel surveys), which are difficult to be performed at approach flows and behind abutment structures. This means that erosion event timing and failure in the vicinity of the abutments under different conditions is uncertain. A more robust technique that quantifies erosion and determines the precise amount of fill material that is removed from the abutments and adjacent banks, especially during extreme conditions, is needed. This project will address that concern through utilization of a new instrument, a Photo-Electronic Erosion Pin (or PEEP) with wireless dataloggers, which will continuously monitor abutment fill and bank material erosion at a bridge crossing along the Iowa River, IA. The primary goal of this pilot study is the development of a protocol for monitoring erosion near bridge abutments using innovative technology (namely PEEPs). In order to accomplish this goal, a coupled laboratory/ field approach has been developed. Project results will provide the amount of the abutment fill and adjacent bank material that is eroded at the US Highway 965 bridge over the Iowa River. This information will assist engineers in identifying the key hydrological/ climatic conditions leading to abutment failure.
Technology Transfer Activities
This protocol will assist engineers in monitoring bridge structures during extreme conditions, when failure is most likely, thus improving the overall infrastructure safety by offering new opportunities for monitoring high risk sites.