# Changes for page Concrete Design

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edited by IwonaBudny
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 ... ... @@ -8,8 +8,42 @@ 8 8 9 9 = {{id name="Design forces"/}}Design forces = 10 10 11 +(% style="text-align: justify;" %) 11 11 13 + 14 +The design forces are the forces that the reinforcements should be designed for in the reinforcement directions. The term design forces have meaning only in surface structures like plate, wall or 3D plate. In beam structures the design forces are equivalent to the internal forces. The necessary reinforcement calculations are based on the design forces. 15 + 16 +(% style="text-align: justify;" %) 17 +The way of calculating the design forces is common in all modules and in all standards. 18 + 19 +(% style="text-align: justify;" %) 20 +In FEM-Design the design forces calculation is based on the mechanism of optimal reinforcement calculation for skew reinforcements made by M.P. Niel- sen, Wood-Armer and Dr. Ferenc Németh, see [2]. The following description will show the way of calculation for moments but the way of the calculation is the same for normal forces too. Just substitute the m signs with n and you will have the calculation for normal forces. 21 + 12 12 ((( 23 +(% style="text-align: justify;" %) 24 +For the calculation of the design forces we have given: 25 + 26 +* ξ, η reinforcement directions, 27 +* α, β angle of global x direction and the ξ, η reinforcement directions, 28 +* mx, my, mxy internal forces. 29 +))) 30 + 31 +The results will be the design moments: 32 + 33 +* [[image:1543503447758-943.png||height="25" width="79"]] 34 + 35 +(% style="text-align: justify;" %) 36 +In the first step we are taking a ξ-ϑ coordinate system and transform the internal forces into this system: 37 + 38 +[[image:1543503517958-895.png||height="311" width="399"]] 39 + 40 + 41 + 42 + 43 + 44 + 45 + 46 +((( 13 13 ---- 14 14 ))) 15 15