Title of Invention

A REINFORCED TRANSITION APPROACH ROAD FOR A CROSSOVER STRUCTURE AND A METHOD OF MAKING THE SAME .

Abstract

A reinforced transition approach road (1) for a crossover structure (5) such as bridge, cross drainage or flyover and a method of making the same. A stiffner system comprising a metallic, reinforced cement concrete, neoprene or fibreglass grid (2) having granular material (7) compacted in the interstices (6) thereof and a load distributor (8) comprising a high strength geosynthetic material sheet or metallic sheet provided on the grid on lthe prepared subgrade (3) at the site of construction with one end thereof rigidly fixed to the abutment (4) of the crossover structure. Road elements (10A, 10B, 10C, 10D) are built on the stiffner system one above another (Fig 1).

Full Text

FIELD OF THE INVENTION This invention relates to a reinforced transition approach road for a crossover structure and a method of making the same. Crossover structure includes bridge, cross drainage or flyover. PRIOR ART A crossover structure is connected to road by an approach road which may be flexible type or rigid type comprising road elements built on the prepared subgrade one above another at the site of construction. The foundation of the abutment of the crossover structure rests on non-yielding strata whereas the approach road is prone to settlement due to which a level difference at the interface between the abutment and approach road gradually develops and increases with time depending upon the subgrade. When the level difference at the interface between the abutment and approach road is substantial, vehicles moving on the interface experience sudden jerks causing discomfort to passengers. It hinders speed of vehicles and affects smooth flow of traffic. It may also cause accidents/damage to vehicles particularly when they are moving at high speed. Besides periodic maintenance to level up the interface is also required. This is expensive, inconvenient and troublesome. DETAILED DESCRIPTION OF THE INVENTION An object of the invention is to provide a reinforced transition approach road for a crossover structure which does not give rise to any significant level difference at the interface between the abutment and the transition approach road and does not cause sudden jerks to vehicles moving on the interface and discomfort to passengers. Another object of the invention is to provide a reinforced transition approach road for a crossover structure which does not hinder the speed of vehicles and which allows smooth flow of traffic. Another object of the invention is to provide a reinforced transition approach road for a crossover structure which does not cause accidents/damage to vehicles particularly when they are moving at high speed due to level difference at the interface between the abutment and the transition approach road. Another object of the invention is to provide a reinforced transition approach road for a crossover structure which does not require periodic • maintenance to level up the interface between the abutment and the transition road and avoids expenses and inconvenience and efforts for such purpose. Another object of the invention is to provide a method of making such a reinforced transition approach road for a crossover structure which is simple, easy and convenient to carry out. According to the invention there is provided a reinforced transition approach road for a crossover structure such as bridges and the like comprising a stiffner grid system provided on a subgrade prepared at the site of construction, one end of the said stiffner grid system being rigidly fixed to an abutment of the said " crossover structure, said grid being provided with load distributor such as herein described and road elements being built one above the other on the said stiffner system. According to the invention there is also provided a method of making a reinforced transition approach road for a crossover structure comprising supporting a stiffner grid system on the prepared subgrade at the site of construction with one end thereof rigidly fixed to the abutment of the crossover structure providing a load distributing means thereon and building road elements on the stiffner system one above another. The following is a detailed description of the invention with reference to the accompanying schematic drawings in which the sole Fig 1 is a cut section isometric view of a reinforced transition approach road and approach road of a bridge according to an embodiment of the invention. Referring to Fig 1 of the accompanying drawings, the reinforced transition approach road 1 comprises a stiffner system comprising a metallic grid 2 supported on the prepared subgrade 3 at the site of construction. The metallic grid may be made of metal such as aluminium or galvanised iron or steel. One end of the metallic grid is rigidly fixed to the abutment 4 of the bridge 5. The interstices 6 of the metallic grid is having granular material 7 compacted therein. 8 is a load distributor comprising a high strength geosynthetic material sheet provided on the metallic grid. The geosynthetic material sheet may comprise geotextile or geogrid of 50-60 KN/m. 9 A, 9B, 9C and 9D are road elements built on the stiffner system one above another. The bridge and transition approach road are connected to road (not shown) by approach road 10 comprising road elements 10A, 10B, 10C and 10D built on the prepared subgrade 3 in continuity with the transition approach road in known manner. According to the invention the road elements of the transition approach road are reinforced by the stiffner system whose rate of change of settlement/deformation gradually reduces from the distal end to the proximal end depending upon the moment of inertia thereof. Therefore, effective settlement of the transition approach road at the interface between the transition approach road and the abutment is minimal and insignificant. This continues to be so throughout the life time of the transition approach road. Due to the transition approach road being reinforced by the stiffner system, settlement/deformation of the transition approach road at the interface between the transition approach road and the approach road is also gradual and smooth and is almost in level with the settlement/deformation, if any, of the approach road. Therefore, there will not be appreciable or significant level differences between the transition approach road and the abutment and transition approach road and approach road at the interfaces thereof. As a result sudden jerks to vehicles moving on the interfaces and discomfort to passengers is avoided. There is no hindrance to the movement of the vehicles and there is fast and smooth flow of traffic at the interfaces. Accidents/damage to vehicles particularly when they are at high speed due to level differences at the interfaces is eliminated. The invention obviates the necessity for periodic maintenance to level up the interfaces and avoids expenses and efforts required for such purpose. The high strength geosynthetic material sheet ensures proper load distribution over the entire surface area of the metallic grid. The rate of settlement/deformation of the stiffiier system depends on factors such as the load acting on it, modulus of elasticity of the material of the stiffner system, moment of inertia of the stiffner system, the stiffness characteristics of the subgrade or subgrade reaction. The dimensions and material of construction of the stiffner system are decided and selected having regard to the above factors. Instead of metallic grid, the stiffner system may comprise reinforced cement concrete, neoprene or fibreglass. The load distributor may comprise a metallic sheet such as aluminium or galvanised iron or steel instead of high strength geosynthetic material sheet. Such variations in construction are to be construed and understood to be within the scope of the invention. We Claim: 1) A reinforced transition approach road for a crossover structure such as bridges and the like comprising a stiffner grid system (2) provided on a subgrade (3) prepared at the site of construction, one end of the said stiffner grid system being rigidly fixed to an abutment (4) of the said crossover structure, said grid being provided with load distributor (8) such as herein described and road elements being built one above the other on the said stiffner system. 2) A reinforced transition approach road for a crossover structure as claimed in claim 1, wherein the stiffher grid system comprises a metallic, reinforced cement concrete, neoprene or fibreglass grid having granular material compacted in the interstices thereof and a load distributor is a high strength geosynthetic material sheet or metallic sheet provided on the grid. 3) A reinforced transition approach road for a crossover structure as claimed in claim 2, wherein the metallic grid is made of metal such as aluminium or galvanised iron or steel. 4) A reinforced transition approach road for a crossover structure as claimed in claim 2 or 3, wherein the geosynthetic material sheet comprises geotextile of geogrid having strength characteristic of 50-60 kN/m. 5) A reinforced transition approach road for a crossover structure as claimed in claim 2, wherein the metallic sheet is made of metal such as aluminium or galvanised iron or steel. 6) A reinforced transition approach road for a crossover structure substantially as herein described particularly with reference to figure 1 of the accompanying drawings. 7) A method of making a reinforced transition approach road for a crossover structure comprising supporting a stiffher grid system on the prepared subgrade at the site of construction with one end thereof rigidly fixed to the abutment of the crossover structure providing a load distributing means thereon and building road elements on the stiffher system one above another. 8) A method of making a reinforced transition approach road for a crossover structure substantially as herein described. A reinforced transition approach road (1) for a crossover structure (5) such as bridge, cross drainage or flyover and a method of making the same. A stiffner system comprising a metallic, reinforced cement concrete, neoprene or fibreglass grid (2) having granular material (7) compacted in the interstices (6) thereof and a load distributor (8) comprising a high strength geosynthetic material sheet or metallic sheet provided on the grid on the prepared subgrade (3) at the site of construction with one end thereof rigidly fixed to the abutment (4) of the crossover structure. Road elements (10A, 10B, 10C, 10D) are built on the stiffner system one above another (Fig 1).

Documents:

818-cal-1999-granted-abstract.pdf

818-cal-1999-granted-claims.pdf

818-cal-1999-granted-correspondence.pdf

818-cal-1999-granted-description (complete).pdf

818-cal-1999-granted-drawings.pdf

818-cal-1999-granted-form 1.pdf

818-cal-1999-granted-form 18.pdf

818-cal-1999-granted-form 2.pdf

818-cal-1999-granted-form 26.pdf

818-cal-1999-granted-form 3.pdf

818-cal-1999-granted-gpa.pdf

818-cal-1999-granted-letter patent.pdf

818-cal-1999-granted-reply to examination report.pdf

818-cal-1999-granted-specification.pdf