CFRP strengthening of beams with planted column loads

[AlbertStructural]

Hello Everybody,
I am having a project where I need to strengthen the RCC beams which are taking new loading from planted columns as clearly visible (in yellow) in attached image. As this will be my first strengthening "design" project so my questions are as follows:

1. Should I request for soft copy of design input file of the structure from client, in which it is being designed so that I can use the same software for checking adequacy of capacity with and without columns?
2. For CFRP strengthening design should I use some spreadsheets or is it ok to use some proprietary software given by CFRP manufacturer e.g. Sika and in that case how should I determine my inputs?

Anybody who has done some CFRP strengthening esp for RCC beams should please refer me to some articles / books / resources in order to get started immediately. This exercise is also sort of my test to design CFRP on my own and my growth also kinda depends on it.

All inputs warmly welcomed.

Thanks and best regards.

 

[Ingenuity]

AlbertStructural,

A good place to start is ACI 440.2 "Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures"

There are several worked examples, with step-by-step details on the calculations, for example:

When starting out I always prefer to do hand calcs, or author an original spreadsheet, before venturing into third-party 'black-box' software programs.

 

[AlbertStructural]

Hi Ingenuity,
Thanks for your input. I have the code ACI 440.2R-08 with me. My question is bit more basic that what should be my exact starting point in terms of data input. I mean I have a structure in front of me with loading (new loading) and some beam sizes given. I need the loading of existing structure (without additional column loads) and I need to analyze the overall structure in terms of moments applied and the capacity of beam required.
What in your opinion is the route should i take to embark on this problem?

 

[Brad805]

Call sika. They will take on the design or get you pointed in the right direction. At some point you need to deal with a supplier or installer, the sooner you get that started the better.

 

[PSEPK]

Here are my 2 cents:
1. Yes, if you are familiar with the use of that software, or can import in the structural software you use.

2. Examples given in ACI 440.2, or those in the books referred at following links, may probably help you understand the required inputs for your project.

a. Strengthening Design of Reinforced Concrete with FRP by Hayder A. Rasheed

b. FRP Composites for Reinforced and Prestressed Concrete Structures: A Guide to Fundamentals and Design for Repair and Retrofit by Perumalsamy Balaguru

Alternately, it would be better to contact some FRP specialist firm (like Sika etc), (as Brad805 has already recommended) to get assistance not only in design but also in supply of materials required.



A good structural engineer is often a blessing for others.

 

[AlbertStructural]

Thank you very much PSEPK for your valuable input especially the names of books. I have gone through ACI 440.2R-08 and the example given there is excellent though skips some steps. I am well versed in STAAD and ETABS and can import drawings into these softwares for checking of structural capacity. Need to design each beam individually and detail them for their additional capacity using CFRP strips.
I also have one software from SIKA but that is too generic and isn't flexible about various conditions. Right now developing my own excel sheet so it will be easier to tackle future strengthening problems and also while developing sheet will learn each and every aspect of strengthening.

For me most interesting and exciting thing is that I will myself be the one who will be executing the design on site as well. So I am sort of design cum execution engineer which makes it all the more interesting.
God forbid if my design fails I will be the first one to suffer as well