In the Eurocode 4 in the paragraph regarding beams:
6.2.1.2(1) Plastic resistance moment Mpl,Rd of a composite cross-section it is written:
b) the effective area of the structural steel member is stressed to its design yield strength fyd in tension or conlpression;
c) the effective areas of longitudinal reinforcement in tension and in compression are stressed to their design yield strength fyd in tension or compression. Alternatively, reinforcement in compression in a concrete slab may be neglected;
d) the effective area of concrete in compression resists a stress of O,85fcd, constant over the whole depth between the plastic neutral axis and the most compressed fibre of the concrete, where fcd is the design cylinder compressive strength of concrete.
and regarding composite slabs:
9.7.2 Flexure
(1) In case of full shear connection the bending resistance MRd of any cross section should be determined by plastic theory in accordance with 6.2.1.2(1) but with the design yield strength of the steel member (sheeting) taken as that for the sheeting, fyp,d.
These paragraphs are quite stricts about the rigid-plastic models taken in the design.
and yet in paragraph 3, materials it is written:
for concrete:
(1) Unless otherwise given by Eurocode 4, properties should be obtained by reference to 1992-1-1, 3.1 for normal concrete and to EN
for reinforcing steel:
(1) Properties should be obtained by reference to EN 1992-1-1,3.2.
for structural steel:
(1) Properties should be obtained by reference to EN 1993-1-1,3.1 and 3.2.
Does that mean that we can use for excample parabolic distribution of stress in concrete according to Euurocode 2 in the analysis of composite beams AND slabs according to Eurocode 4?
And to use elastic-perfectly plastic relation for steel?
And don't we need to provide the maximum strain of concrete limitations?
What is the history of a rigid-plastic models from the Eurocode 4? Are they used only for the simplicity or maby there are other regards?
Best Regards,
Bartosz Grzeszykowski
https://books.google.com/books?id=HfVMBgAAQBAJ&pg=PA243&lpg=PA243&dq=rigid-plastic+models+from+the+Eurocode+4&source=bl&ots=9wiZEVNbpz&sig=H9D7AW71013AaXTO-i_6tqtd2SM&hl=en&sa=X&ved=0ahUKEwiv_tfE7ODYAhUBblAKHZJpBMoQ6AEIMzAC#v=onepage&q=rigid-plastic%20models%20from%20the%20Eurocode%204&f=false
Dear H. Naderpour,
In this example rigid-plastic material models without any strain limitations were used, as it is always done in examples regarding class 1 composite beams according to EC4. But my question was different.
For example for composite slabs with very strong additional bottom reinforcement, rigid plastic models without any strain limitations for concrete produce ridiculously high, Mpl,Rd that is obviously too high.
My question was:
Whether the Eurocode's 4 paragraphs directly allow that material models from EC2 and EC3 (for example parabolic with strain limitations for concrete and elastic-plastic for steel) can be used to analyse cross sections of composite beams and composite slabs. Not rigid plastic models without any limitations.
Best Regards,
Bartosz Grzeszykowski
Dear Bartosz Grzeszykowski ,
Perhaps this link might be useful:
http://eurocodes.jrc.ec.europa.eu/doc/WS2008/Hicks_2008.pdf
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