In civil Engineering, most of the structures are designed with reinforcement in order to accomplish the desired load for a desired period of time. The common reasons for the failure of reinforced concrete could be overloading – loading the structure more than designed load, insufficient reinforcement, corrosive reinforcement, improper handling of the structure at the early stage and environmental issues. The common failure of reinforced concrete appear in the form of cracks and they should be treated with adequate concern as they root to severe damages like decrease of durability, existence and performance of the structure for which it designed. The impact of load can cause the critical problem in any reinforced structure. As the success of reinforced structural project depends on it, it’s the duty of the engineering team to predict the impact loads and to calculate the effective design for it. In designing a structure, the building codes and regulations specify that the structure should be able to withstand for all the expected loads. For that a clear understanding on the available types of load is desirable.
Types of load
Dead loads
Dead loads or permanent loads or static loads are the loads which continue to remain through-out the life time of the structure, permanently which means dead loads are constant over time.
eg: Self weight of structure & its elements, immovable elements such as wall partitions, roofing, inbuilt cupboards and etc.
Live loads
Live loads or dynamic loads or imposed loads are the loads which can be moveable and temporary. The live loads may be concentrated or scattered to give an effect or vibration or acceleration in a structure.
eg: Weight of people/occupants, furniture, equipment. If it is a roof – equipment, materials and occupants produce live loads when maintain or cleaning the roof.
Environmental loads
Environmental loads are the loads which act on the structure due to the change in weather conditions. Wind, snow, seismic waves, hydraulics, temperature are such environmental loads that should be considered in calculations.
The application of loads on a structure result to produce forces and when those forces crosses its limitation it result a failure on the structure.
Shear Force and Structural Analysis
Shear force is a force in any structure that acts perpendicular to that structure. Structural analysis is analysing dead or live loads and forces acting on a structure using available construction codes or theories to avoid structural failure in the lifetime of that structure. The design of reinforced concrete was introduced in the construction is to achieve the flexural and shear strength on a concrete structure as to increase its life time. Here the issue is that provided reinforcement is not enough or causes some structural failures without any warnings. For that as a remedy the designing engineering teams of every project, analysis the structure to avoid such failures. Achieving the shear strength is the main concentration of every designing engineer. The structural engineer provides the most effective design that could fit with client’s requirement, safe and economy using the available structural codes like Eurocodes, British Standard code and ACI building codes. Also, some structural software available for the structural analysis and design with minimum effort when compare to calculating with the use of standard codes.
BS code
BS code – British Standard codes are produced to set up quality and standard service or products. For the reinforced concrete structure and pre-stressed structure BS 8110 is applicable. The code is designed by considering the limit state design principal. BS 8110 was published in 1985for the first time and then revised in 1997and override by Euro code in 2010.
Eurocode
Eurocodes are adopted from BS and provide technical specification frame for building products as well how the structures should be designed under the standardization. Ten European standards each with number of parts are established from 1990 – 1999. The 1st ideal Eurocode was released in 1980s.
ACI
ACI – American Concrete Institute is an organization which develops standard practise in the field of engineering construction. The 1st building code was established in 1910 and later some other standards were established. The ACI building code was renamed as ACI 318 in 1941. Introduction of chapters on pre-stressed concrete, ultimate strength design, design for seismic, reinforced concrete design were done with the step by step improvement in the code from the year 1963 to 2015.
