International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
A STUDY ON APPLICATION OF PASSIVE CONTROL TECHNIQUES TO RC BRIDGES THROUGH NON LINEAR DYNAMIC ANALYSIS Mr Praveen J. V1, Adarsh N Hegde 2, Mr Raveesh R M 3 1,2 Sri
Siddhartha institute of technology agalkote, tumakuru – 572105,Karnataka, India Engineer, Sculpture consultancy Tumakuru – 572105,Karnataka, India ---------------------------------------------------------------------***------------------------------------------------------------------3 Design
Abstract - Present study focuses on the study of effect of TMD with optimum parameters (frequency ratio and mass ratio). In this study TMD is used to reduce the vibrations in RC bridges. A RC bridge with different span with and without TMDs has been considered for the analysis. 3D models and analysis has been done by using a FE package SAP2000 by using direct integration method. TMDs with different mass ratios 2%, 3% and 4% are considered. The models were used to represent bridges located in zone 5 of India. The systemic parameters studied are natural period, base shear, roof displacement, lateral displacement, storey drift and shear force, bending moment of column. Time history analysis has been considered out .the structures has been subjected to a set-off ground motion Buhl for the bridges with, without TMDs and the results are interpreted Key Words: TMD; RC bridge; Natural period; Base shear; Roof displacement; lateral displacement; Storey drift and shear force; bending moment of column 1. INTRODUCTION In the transportation systems highway and railway bridges play a vital role. In the design of these bridges the vibrations caused by the passageway of vehicles have become an important contemplation. Particularly the interaction problem between the moving vehicles and the bridge structures has attracted much attention during the last few decades. This is due to the speedy increase in the proportion of high-speed vehicles and heavy vehicles in the highway and railway passage and the tendency to use high-performance materials and more slight sections for the bridges.
1950, Ayre and Jocobsen 1950) and moving mass (Jeffcott, 1929). The model of moving force is the simplest model whereby researchers can capture the necessary active characteristics of a bridge under the action of a moving medium, even though the interaction Between the vehicle and bridge is mistreated. Where the inertia of the vehicle camion is regarded as little, a moving mass mode is often adopted as an alternative. Though the moving mass model suffers from its inability to consider the bouncy effect of the moving mass, which is important in the presence of road surface irregularities or for vehicles running at high speeds. The high-speed digital computer invention few decades ago made it possible to analyses the interaction problem with more complicated bridge and vehicle models. Vibration of different types of bridges such as girder bridges, slab bridges, cable-stayed bridges and suspension bridges due to affecting vehicles and trains could be considered by using moving vehicle representation, in which a vehicle was modelled as a mass-spring-damper, single-axle or multi-axle dynamic system. Even though wide-ranging studies have been done in this field, high-performance analysis methods are still required for accurate forecast of dynamic response of these bridges under moving trains and vehicles.
Communication between the vehicle-bridge is a complex vibrant occurrence, which is a non-linear problem dependent on many parameters? These parameters include the natural frequencies of vibration and type of bridge, vehicle kind, vehicle speed and traversing pathway, number of vehicles and their relative positions on the bridge, highway surface irregularities, the damping description of bridge and vehicle etc. The first recorded research into bridge vibration appears to be a report published in the 19th century (Willis, 1849), which discussed the reasons for fall down of the Chester
Alternatively, Allow for the dynamic effects resulting from the passage of vehicles, plenty of design codes such as American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Highway Bridges (1996) require that the inactive live loads be increased by an impact problem, which is defined as the ratio of the maximum dynamic retort to the maximum static retort of the bridge minus one. AASHTO Specifications (Standard 1996), the impact factor is specified as a function of span distance end to end only. It is certainly a simplification. It’s been reported that the force factors calculated according to these codes may not be traditional in many cases. There exists an urgent need to develop reasonable design formulae based on accurate calculation of the true behaviour of the entire bridge-vehicle structure.
Railway Bridge. In the first half of the 20th century, investigation into bridge vibration were mainly concerned with developing analytical solutions for simple cases of moving force (Timoshenko 1922, Lowan 1935, Ayre et al
The cost-effective analysis methods development as well as the clear classification of the important parameters that govern dynamic response will positively be of great help to better understanding of the true performance of the entire
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