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Friday, December 27, 2013

Can We Predict Concrete Structure Life?


Most of the structure engineers are focusing on design a safe structure by following the parameters and factors in the code and standard that requested in the project specifications. After finishing the design stage the structure engineers who work on site receive the drawings and the specifications from the designer and start their role by performing the project construction. Then their colleagues who are on the operations and maintenance phase will start monitoring and maintain the structure performance along its life time. So around this project life cycle all the structure engineers are focusing on the same target that the structure is working safely along its service life according to the design code. The main objective of this book  to cover the methods that enable us to have a reliable structure along its life time during all the project phases and also presenting the up to date methods to  predict the  structure remaining life time from practical point of view.

The structure engineers have a famous  statement  called a “factor of safety” and some engineers thinking that they can satisfy and sleep well as their structure design has a factor of safety  by following a partial factors as in British Standard  or reduction factor as in American code for strength and another factors for load, so the reliability book for concrete structure (www.amazon.com/author/elreedyma )  will assist us to understand from where these factors  come from to provide us the sense about the problems that we may face in case of deviating  from these factors and to be sure that, this factor of safety will not guarantee to let us sleep peacefully until following some precaution to avoid the potential mistakes and errors.
Many researches are discussing the reliability analysis which provides the same meaning as calculation of the structure probability of failure and this calculation depends mainly on the statistics and theory of probability.

The book dedicated a whole chapter is discussing all the statistics methods,  tools and probability theory which are  used in structural and civil engineering field from practical point of view and away from complicated approach that bother us and don’t benefit us in a real practical life. It is worth to mention that, there is an increase in researches about structure reliability as we have a lot of data worldwide from which we can calculate the concrete structure reliability.

Due to the fast development of communication, any engineer can work on any project worldwide so one will  find that some  countries follow ACI code and the another countries follow British standard, in addition to Eurocode and another local code for different countries. Hence, it is usually raise a question in mind what is the best code or standard to follow, I try to answer this question on the reliability book..    

You can find that the code and standard should be specific for each country but in some specific projects which financing through international assistance. As the country which provides the financial usually requests to work by their code, so you can work by this code but should considering the different conditions surrounding the structure. The best code which comes from the country itself depends on the country economics, society behavior, laws that govern the country. Therefore, the design factors should be extracted from the country statistics of loads and resistance and the way of obtaining these factors will be discussed in detail in this book to be a practical guide to differentiate between different code and standard and assist the structure engineers to understand the philosophy of every code and standard that can help them to work in any international codes and standard around the world.

For the mature structure, there is a change in concrete structure resistance capacity with time depending on the surrounding environmental condition and also the loads that affecting the structure along its life time so all these factors should be considered  to assess the old structure and calculate its probability of failure.

The effect of the steel bars corrosion on the structure’s probability of failure will be discussed for different concrete members you can see the book in http://www.amaazon.com/author/elreedyma. By going through the methods of reliability assessment will present also the precaution to be considered to have a design for durable concrete structure.

The column is considered the most critical member in the building as it affects the structure probability of failure, so will concentrated about it and considering the effect of corrosion on the column probability of failure and the precautions and guide for column design to follow to obtain a durable concrete structure.

The book provides a guidelines and tools to evaluate the existing concrete structure by professional way and also assess the new structures.  So  all the available methods and test that enable us to evaluate the structure and focusing on the visual inspection technique, nondestructive testing for concrete strength and also corrosion test to know the status of the corrosion in the steel reinforcement.

So It is helpful for junior and senior engineers who are working in any phase of concrete structure projects from the design until the maintenance phase by increasing the sense of the structure behavior and the feeling about the codes and standards factors, and the allowable limits in the construction phase and its effect on the concrete structure probability of failure and provide the practical way to evaluate and predict the remaining service life of the existing buildings. We have a webinars about it for register. http://www.elreedyman.com