Browsing by Author "Rahman, P.A."

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    Dynamic Behaviour of Bridge Pier Due to Direct Vehicle Collision
    (Springer Science and Business Media Deutschland GmbH, 2022) Rahman, P.A.; Reddy, G.R.; Venkataramana, K.
    Bridge is the structure that is expected several normal and postulated dynamic loads. Vehicle collision with the bridge pier is one of the postulated dynamic loads considered in the design provisions. The Indian code IRC-6 consider the vehicle collision load as equivalent static load, whereas European standards EN 1991-1-7 gives provisions for both static and dynamic analysis. However the both codes don’t give a simplified mathematical model for the dynamic analysis. The Finite element analysis (FEA) is the popular method used for analysis of pier subjected to the collision load. However, the finite element analysis requires a combination of vehicle and concrete structure modeling which is a tedious process. This analytical study includes calculation of dynamic load on the bridge pier as per Eurocode EN 1991-1-7 and its dynamic responses, due to the direct vehicle collision with pier. In this article a simplified model the pier is discussed. Since majority of mass located at the top of the pier and the collision load is acting at bottom part of the pier, pier is modelled as a Two Degrees of Freedom System and the Lumped mass approach is adopted. The dynamic responses of the pier are calculated by Newmark’s Beta Linear Acceleration Method. The dynamic analysis of vehicle collision load also gives the load transferred to the superstructure and its components like bearings. Comparison study of the effect of the impact of the vehicle having 30 tonnes mass and 300 kN/m stiffness with speed 130, 90, 70 and 50 km/h as per EN 1991-1-7: 2006, shows that there is no significant difference in response of the pier for hard impact when vehicle speed varies from 50 to 130 km/h. This may be due to the peak intensities of dynamic actions affect the structure over such a short time in which the structure cannot properly respond to them. However, acceleration response is significantly high when the velocity of impact increases. And vehicle impact load never fails to induce a considerable amount of base shear in the column which is more than the equivalent static loading suggested IRC-6. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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    Dynamic Behaviour of Road Bridge Deck When a Truck Moves Along the Irregularities of the Road Profiles
    (Springer Science and Business Media Deutschland GmbH, 2022) Rahman, P.A.; Reddy, G.R.; Venkataramana, K.
    Bridge is the structure that is seen several dynamic loads unlike other structures. Ministry of Road Transport and Highways (MORTH) said that 10,876 people were killed due to potholes in the year 2015, which denotes the lack of proper maintenance of road pavements. When a vehicle moves along these surface irregularities, it not only causes uncomfortable to the passenger but also causes dynamic loads on the components like deck slab, bearings. Since the road surface irregularities like unevenness, potholes, etc., are unavoidable, we should understand the dynamic effect on the structure due to such undulations. IRC-6, standard to find the loads and load combinations on the road bridges, doesn’t talk about the dynamic load induced by surface irregularities with respect to the different classes of road profile as per ISO: 8608. On the other hand, IRC-6 only gives provisions of static analysis in the case of the vertical dynamic effect produced by moving vehicles. This study aims to generate road profiles having different degrees of unevenness as per ISO: 8608 and to propose a conservative method to find the vertical dynamic load on the bridge deck and its vertical response. A bridge deck is modeled as a Single Degree of Freedom system and the vertical dynamic responses of the bridge deck are found by Newmark’s Beta Linear Acceleration Method. It is found that the dynamic response, almost doubles when road profile quality changes from one class to the very next class. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.