R and D Coefficients For Seismic Force-Resisting Systems

Owned by Hakan Şahin
Last updated: Sept 28, 2022 by Zeynep Aladağ
3 min read

  • Building load-bearing system selection, Carrier System Behavior Coefficient R and Strength Excess Coefficient D are under user control.

  • R and D coefficients selected by the user in the analysis settings wizard and report results are checked automatically. R and D coefficients that do not comply with TBDY are not allowed.

Notation

D = Resistance Surplus Coefficient
I = Building Priority Coefficient
M DEV = Tipping moment arising from earthquake loads at the base of the reinforced concrete wall or braced frame
M o = Total tipping moment at the base from earthquake loads for the whole building
R = Structural System Behavior Coefficient

4.3.2. R and D Coefficients According to Carrier System Type

4.3.2.1 - Cast in-situ and precast concrete, steel, mild steel, masonry, wood building structural systems and 4.3.3 't defined for various ductility Annex 4 , as defined in the Structural Behavior Factor R and Resistance Redundancy Factor D Table 4.1 ' is also given.

4.3.2.2 - In composite column systems, R and D coefficients given for steel structural systems shall be used.

According to the definition given in 4.3.2.3 - 3.3.1 , in buildings with externally rigid walls surrounded by basements, (R / I) = 2.5 and D = 1.5 in the lower part of the basement floors.

4.3.2.4 - If one of the two conditions defined in (a) and (b) below cannot be met in any direction, in buildings with reinforced concrete curtain walls and / or steel braced frames with DTS = 1, 1a, 2, 2a, the Structural System Behavior Coefficient in that direction Instead of R , (4/5) R will be considered. No change will be made in the Strength Excess Coefficient D. The tie-beam curtain system satisfying the conditions given in 4.5.4.5 will be considered as a single curtain.

(a) In the structural system, the base overturning moment M DEV taken by a single wall or steel braced frame shall not be more than 1/3 of the total base overturning moment M o resulting from the earthquake loads for the whole building in that direction .

(b) Construction each side axles located screen / screen or steel braced frame / receives base overturning moment of the frames M DEV or M DEV 'the sum of all, that the direction in total floor tilting moment occurring in seismic loads for the entire building M o ' s 1 It will not be less than / 6.