EN 1998-1 Horizontal Design Spectrum (Malaysia NA)
EN 1998-1 code spectra (Malaysia)
For Rock soil sites
| Limits | Equation | Segment |
|---|---|---|
| 0 ≤ T ≤ TC | ((2 x π)2 x γl x SDR(1.25) / (TC x TD)) / q | Constant |
| TC ≤ T ≤ TD | ((2 x π)2 x γl x SDR(1.25) / (T x TD)) / q | Constant/T |
| TD ≤ T ≤ 4s | ((2 x π)2 / T2 x [λl x SDR(1.25) + γl x mr x (T - TD))] / q | Constant/T2 |
For Stiff soil sites
| Limits | Equation | Segment |
|---|---|---|
| 0 ≤ T ≤ TC | ((2 x π)2 x γl x SDR(1.25) x 1.5 / (TC x TD)) / q | Constant |
| TC ≤ T ≤ TD | ((2 x π)2 x γl x SDR(1.25) x 1.5 / (T x TD)) / q | Constant/T |
| TD ≤ T ≤ 4s | ((2 x π)2 / T2 x [λl x SDR(1.25) x 1.5 + γl x mr x (T - TD))] / q | Constant/T2 |
For Flexible soil sites
| Limits | Equation | Segment |
|---|---|---|
| 0 ≤ T ≤ TC | ((2 x π)2 x γl x SDR (1.5TS) x 3.6 / (TC x TD)) / q | Constant |
| TC ≤ T ≤ TD | ((2 x π)2 x γl x SDR(1.5TS) x 3.6 / (T x TD)) / q | Constant/T |
| TD ≤ T ≤ 4s | ((2 x π)2 / T2 x [λl x SDR(1.5TS) x 3.6 + γl x mr x (T - TD))] / q | Constant/T2 |
EN 1998-1 site specific spectra - user defined (Malaysia)
Parameters
- SDRuser(0) – units g
- SDRuser(TBuser) – units g
- TBuser – units sec
- TCuser – units sec
- TDuser – units sec
- TEuser – units sec, default = 4s
Input limits
- SDRuser(0) > 0
- SDRuser(TBuser) > 0
- 0s ≤ TBuser < TCuser < TDuser ≤ TEuser
Curve Equations
Elastic Response Spectrum curves for Se/agare defined by
Note: same curve for both Dir1 and Dir2
| Line | Limits | Equation |
|---|---|---|
| (1) – straight line | 0 ≤ T ≤ TBuser | Se/ag(T) =SDRuser(0) + ((SDRuser(TBuser) - SDRuser(0)) x T / TBuser) |
| (2) – straight line | TBuser ≤ T ≤ TCuser | Se/ag(T) = SDRuser(TBuser) |
| (3) – curve | TCuser ≤ T ≤ TDuser | Se/ag(T) = SDRuser(TBuser) x TCuser / T |
| (4) – curve | TDuser ≤ T ≤ TEuser | Se/ag(T) = SDRuser(TBuser) x TCuser x TDuser / T2 |
| (5) – straight line continued from (4) |
Design Spectrum for Elastic Analysis curves for Sd/ag are defined by
Note: same curve for both Dir1 and Dir2
| Line | Limits | Equation |
|---|---|---|
| (1) – straight line | 0 ≤ T ≤ TBuser | Sd/ag(T) = [SDRuser(0) + ((SDRuser(TBuser) - SDRuser(0)) x T / TBuser)] / q |
| (2) – straight line | TBuser ≤ T ≤ TCuser | Sd/ag(T) = SDRuser(TBuser) / q |
| (3) – curve | TCuser ≤ T ≤ TDuser | Sd/ag(T) = SDRuser(TBuser) x TCuser / T / q |
| (4) – curve | TDuser ≤ T ≤ TEuser | Sd/ag(T) = SDRuser(TBuser) x TCuser x TDuser / T2 / q |
| (5) – straight line continued from (4) |
Note:
If TBuser = 0, then no line (1) exists(as in the example above)
If TDuser = TEuser then no line (4) exists
Note:
The above by default does not quite equate to Line (4) in the Malaysian NA because there is an extra term (2 x π)2 / T2 x γl x mr x (T - TD) that tweaks the 1/T2 curve slightly. In Sarawak, this term is non-existent, in Peninsular Malaysia it does not exist for Flexible soils. In the Tekla Structural Designer User defined spectrum it is also non-existent.