Effect of vehicle speed and road surface roughness on the impact factor of simply supported bridges due to IRC Class A a
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Effect of vehicle speed and road surface roughness on the impact factor of simply supported bridges due to IRC Class A and B loading Bindesh Nunia1 · T. Rahman1 · S. Choudhury1 · Prashanth Janardhan1 Received: 18 July 2019 / Accepted: 8 April 2020 © Springer Nature Switzerland AG 2020
Abstract Indian Road Congress (IRC)-06 specifies consideration of impact factor for dynamic analysis of bridge loaded with Class A and Class B vehicles. As per IRC-06 specifications, the impact factor is estimated based only on the span length of the bridge. In the present study, the effect of vehicle speed, road surface roughness condition and span length of the bridge on the impact factor is investigated. The dynamic response of a simply supported bridge loaded with IRC Class A and Class B vehicle loads are considered for the study. For simplifications, the vehicles are idealized as a series of moving mass spring damper system. The interaction between the bridge and vehicle is accomplished by coupling the equation of motion using the interaction force at the contact point of the wheel and bridge. The coupled equation of motion is solved using Newmark’s beta method. The model is validated using past available literature. The vehicle is considered to move at a consistent speed between 20 and 100 km/h. The excitation caused due to the presence of road surface roughness at various vehicle speeds on the bridge response with span lengths varying between 20 and 100 m is investigated. Parametric studies are also conducted using frequency ratio. From the studies, it is observed that the response of the bridge subjected to IRC Class A vehicle is 40% higher than the response of the bridge subjected to IRC Class B vehicle. It is also observed from the parametric study that, the bridge response becomes critical when the vehicle moves at resonance speed and the amplitude increases with deterioration of road surface condition. The results of the impact factor study show that IRC-06 specifications underestimate the response of the bridge for high speed moving vehicles under different road surface conditions. The findings of this study can be utilized to update the IRC specifications at the time of analysis and design of both short and as well as long-span highway bridges. Keywords IRC loading · Vehicle speed · Road surface condition · Impact factor · Vehicle bridge interaction · Frequency parameter
1 Introduction With expanding open interest, the business activity of fast vehicles become increasingly famous. As a result of the gigantic measure of dynamic vitality conveyed by the fast vehicles, it might collaborate essentially with the extension structure and even reverberate with it in specific situations. This roused the analysts to attempt different new methods for researching the response of the vehicle
bridge interaction system. The majority of the research in this area is limited to wind and earthquake loading but ignoring the effect of high-speed vehicle bridge interaction [1]. The bridge response to a moving vehicle is governed by many p
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