Effect of Over Weight Vehicle on RCCT Girder Bridge

Abstract

A large number of infrastructure projects have been undertaken in Taiwan in recent years because it is a developing country. These large-scale constructions have caused rapid growth in the number of heavy vehicles in service, as well as a dramatic increase in the size and weight of heavy vehicles. A very serious truck overloading problem has resulted, which significantly affects pavement performance and bridge safety. Overload attributable to increased vehicle loads is becoming an increasingly serious issue in highway transportation. Overload results in damages to bridge structures, degradation of their load-carrying capacities, and even collapse of bridges, which may cause loss of lives and properties. Hence, the actual load-carrying capacity of existing bridges with many years of service and obvious damages is becoming an important concern for researchers and engineers. The paper presents a method for comparing the mechanical effects of overweight and design load vehicles on bridges. There is no restriction on the arrangement of the axles and on the size of the axle loads. The bridge may be a simple span bridge, a continuous girder. Even for a very complex bridge structure the only required parameter of the bridge is the span length. The presented method is a robust and reliable tool for the permitting process of overweight vehicles, which is verified by several thousand comparisons. A software program, SAP-2000, assists authorities in this task. It is based on a comparison of internal forces (bending moments and shear forces) under design-code loads and loads induced by special transport. For this purpose the bridge structure is numerically simplified into a sequence of simply supported beams. By virtue of this simplification the application SAP-2000 is both fast and easy to use. Development of the SAP-2000 program was based on object-oriented methodology. The system model resulting from requirement analysis is shown and shortly discussed. The result of the average weight vehicles of GVW (surveyed by CRRI) by SAP analysis was made comparison with com-governing load of (16.2t, 25t, 40.2t) whose bending moment and shear force was found more than governing load. This shows that overloaded vehicles having effects on bridges which causes wear and tear on bridge structures and also damages, vehicle accidents etc. We should take authorized steps to overcome this problem. So many technologies have been developed by European countries. In India this steps should be taken seriously by I.R.C, C.R.R.I and N.C.H.R.P. to overcome these problems.

Keywords: Axle load, Bending moment, Bridge design, clearance, GVW, SAP, Shear force, Span length, Speed limits

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