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Showing posts from August, 2020

Indian Road Congress (IRC) and Bridge Loading Standards: IRC Class AA, 70R, A and B Loading

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Indian Road Congress Indian Road Congress (IRC) is the governing body which decides the rules and regulation along with technical details regarding roads, highways, and bridges. The first loading standard in India was published by IRC in 1958 and subsequently reprinted in 1962 and 1963.   The metric version was introduced in the second revision published in 1964. IRC Bridge Loading Standards The standard IRC loads specified in IRC: 6-2000 are not changed since 1958 and grouped under four categories as detailed below: 1. IRC Class AA Loading In this category, two types of vehicles are specified and they are grouped as tracked vehicle and wheeled vehicles. The tracked vehicle simulating an army tank of 700 KN and wheeled vehicle of 400 KN (a heavy army truck) are standardized for the designing of all the bridges located on National Highways and State Highways. 2. IRC Class 70R Loading The following vehicles are considered for the design under this category: (a)     The

Bridge Engineering: What is bridge and bridge engineering? Bridge as key element in transportation

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Bridge A bridge is a structure that is built to provide a passageway over an obstacle of rivers, valley, or road, etc. without closing the way underneath. This passageway is used to facilitate the movement of traffic or loads across these physical obstacles. Bridge maybe considered as the lifeline of the modern era. Being a passageway over the physical obstacles, it facilitates the transportation of goods and passage of people from one side to another. In the post bridge era, these physical obstacles have blocked mankind of different regions to connect to each other, share their culture and knowledge, and to facilitate business with each other. But the construction of bridges came as a boon for mankind. With the facilitation of connecting each other came the sharing of knowledge and doing business which resulted in the growth of mankind. What is bridge engineering? Bridge engineering is an engineering discipline that deals with the design, construction, operation, and maintenance o

Slope failures, types and causes of slope failures

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Introduction Slope failure is generally the failure of sloped surfaces due to physical factors that may result in loss of properties and even life. Why do we need to understand slope failures? You must have heard about plain and non-plain areas. So, if we talk about it the plain areas are those where the earth or lands do not show any elevation or slight elevations that can be neglected. Non-plain areas are those where the lands have sufficiently larger elevations that need to be considered for any activity. Now, if any land has elevations then it forms slope. For example, consider mountains they generally have slopes though it may be narrow or steep but if any kind of construction or any other activity, if happens there, then, these slopes need to be taken into account and how are they going to affect the outputs of the work going on. But here we will not talk about the difficulty faced for routes and inaccessibility of the area rather we will talk about the physical difficu

Truss: Simple, Deficient and Redundant Truss & Determinate and Indeterminate Truss

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  Truss A truss is basically a pin-jointed slender member structure that is used to carry loads. You might have noticed the use of trusses in supporting roofs and bridge decks. The roof trusses and bridge trusses generally use trusses of steel, however, wooden trusses are also used in supporting various structures that are not too heavy. Steel trusses are also used in transmission towers. But notice one thing, in most of the roof and bridge trusses, the members of the truss lies in a single plane whereas, in transmission towers, the truss members do not lie in a single plane.  So, the trusses which have all the members in a single plane are known as plane truss otherwise the truss is known as space truss. In trusses, the connection is supposed to be pin-jointed but in reality, no extra effort is made to make it so. However, the experiments have shown that the results are consistent with the results obtained by considering the joint as a pin joint. Pin-jointed connection in other

General principles and laws in solid mechanics: Newton’s law of mechanics, the law of transmissibility, parallelogram law of addition, principle of superposition and moment of forces

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Since we have to study the deformation and motion of solid objects under the action of forces, we should have knowledge about the force as a vector quantity and its moment and along with this we should have perfect knowledge of different principles involved in solid mechanics. Newtonian’s mechanics is used while solving an engineering problem so; one should have knowledge of Newton’s laws of mechanics: It involves Newton’s three laws of motion and law of universal gravitation: Newton’s first law of motion  It states that any object whether is in rest or motion will remain as such until it is forced to change its state of rest or motion by an external agency. Consider a ball rolling on the ground; we all know that after a certain period of time it will come to rest but according to Newton’s first law of motion, it should have continued in motion unless some external agency is forcing it to change its state from motion to rest. And, we all know that it is friction. If somehow one