Seismic load
TCVN 9386:2012Base shear Fb and storey forces Fi by the equivalent lateral force method of TCVN 9386:2012 §4.3.3.2 — regular buildings, horizontal design spectrum.
About the seismic load tool
Computes base shear Fb with the equivalent lateral force method of TCVN 9386:2012 §4.3.3.2: ag = γI·agR, design spectrum Sd(T) (3.13)–(3.16), Fb = Sd(T1)·m·λ, inverted-triangle Fi.
What you enter
Location or agR (in g), soil A–E, importance class I/II/III, height H, storey count, seismic weight W = ΣGk+ΣψE,i Qk, behaviour factor q, and T1 from Ct·H^{3/4} or a user value.
What the result means
ag, T1, Sd(T1), λ, base shear Fb (kN) and storey forces Fi. Warnings when ag ≤ 0.04g (not required), weak earthquake, or T1 outside (4.4).
When to use it
Low- to mid-rise regular buildings (H≤40 m) in Annex H zones; use Fb/Fi as the horizontal seismic load before a later accidental combination ticket.
Method
This tool computes the seismic base shear Fb and horizontal storey forces Fi for buildings that are regular in elevation, using the equivalent lateral force method of TCVN 9386:2012 §4.3.3.2.
You pick a location (Annex H) or enter agR, soil type A–E (Table 3.2), importance factor γI, height, storey count, seismic weight W and behaviour factor q. The tool evaluates ag = γI·agR, the design spectrum Sd(T1) from (3.13)–(3.16), Fb = Sd(T1)·m·λ and Fi from (4.11) with equal storey masses. Modal RSA, the vertical spectrum, Chapter 5 detailing and the TCVN 2737 accidental combination are out of scope.