Initial Evaluation Procedure (IEP) Assessment

The Engineering Assessment Guidelines – Nov. 2018 provide a technical basis for seismic assessment of existing buildings in New Zealand. This procedure is detailed in the guidelines for ISAs (Part B). 

How will the Earthquake Prone Buildings framework affect you?

This calculator is a simplified version, based on the Engineering Assessment Guidelines 2018, that provides a guide to the possible %NBS rating of your structure.


Table IEP-2: Initial Evaluation Procedure Step 2

Step 2 – Determination of (%NBS)b
2.1 Determine Nominal (%NBS)LongitudinalTransverse
a) Building Strengthening Data
Has the building been strengthened in this direction?
b) Building Information
Year of Design/Strengthening:
 
c) Soil Type
From NZS1170.5:2004, Cl 3.1.3:
d) Estimate Period, T
hn=m
Ac=m2
Moment Resisting Concrete Frames: T = max{0.09hn0.75,0.4}
Moment Resisting Steel Frames: T = max{0.14hn0.75,0.4}
Eccentrically Braced Steel Frames: T = max{0.08hn0.75,0.4}
All Other Frame Structures: T = max{0.06hn0.75,0.4}
Concrete Shear Walls: T = max{0.09hn0.75/Ac0.5,0.4}
Concrete Shear Walls: T ≤ 0.4s
User Defined (Input Period)
T=
e) Factor A:
f) Factor B:
g) Factor C:
h) Factor D:
(%NBS)nom = A*B*C*D = %%


Table IEP-2 Initial Evaluation Procedure Step 2 continued

2.2 Near Fault Scaling Factor, Factor E
If T ≤ 1.5s, Factor E = 1LongitudinalTransverse
a) Near Fault Factor, N(T,D) =
b) Factor E:
2.3 Hazard Scaling Factor, Factor F
a) Hazard Factor, Z, for siteLocation:
Z =
Z1992 =
Z2004 =
b) Factor F:
2.4 Return Period Scaling Factor, Factor G
a) Design Importance Level, I 
I =
b) Design Risk Factor, Ro 
Ro =
c) Return Period Factor, R













R =
d) Factor G:
Ductility Scaling Factor, Factor H
a) Available Displacement Ductility Within Existing Structure μ =
b) Factor Hkμkμ
For pre 1976 (maximum of 2) =
For 1976 onwards =
Factor H:
2.6 Structural Performance Scaling Factor, Factor I
a) Structural Performance Factor, Sp
Tick if light timber-framed construction in this direction
Sp =
b) Structural Performance Scaling Factor = 1/Sp
Factor I:
2.7 Baseline %NBS for Building, %NBSb
(equals (%NBS)nom x E x F x G x H x I )


Table IEP-3 Initial Evaluation Procedure Step 3 (Longitudinal)

Step 3 – Assessment of Performance Achievement Ratio (PAR)
a) Longitudinal Direction
Potential CSWsEffect on Structural PerformanceFactors
3.1 Plan Irregularity:




Factor A:
3.2 Vertical Irregularity:




Factor B:
3.3 Short Columns:




Factor C:
3.4 Pounding Potential
Factor D1: Pounding Effect
Factor D1 For Longitudinal Direction:
Table for Selection of Factor D1SevereSignificantInsignificant
Separation0<Sep<.005H.005<Sep<0.01HSep>0.01H
Alignment of Floors within 20% of Storey Height
Alignment of Floors not within 20% of Storey Height

Factor D2: Height Difference Effect

Factor D2 For Longitudinal Direction:
Table for Selection of Factor D2SevereSignificantInsignificant
Separation0<Sep<.005H.005<Sep<0.01HSep>0.01H
Height Difference > 4 Storeys
Height Difference 2 to 4 Storeys
Height Difference < 2 Storeys
    Factor D:
3.5 Site Characteristics
Effect on Structural Performance Factor E:
3.6 Other Factors –
     Factor F:
3.7 Performance Achievement Ratio (PAR) (equals A * B * C * D * E * F)
     Longitudinal:

Table IEP-3 Initial Evaluation Procedure Step 3 (Transverse)

Step 3 – Assessment of Performance Achievement Ratio (PAR)
a) Transverse Direction
Potential CSWsEffect on Structural PerformanceFactors
3.1 Plan Irregularity:




Factor A:
3.2 Vertical Irregularity:




Factor B:
3.3 Short Columns:




Factor C:
3.4 Pounding Potential
Factor D1: Pounding Effect
Factor D1 For Transverse Direction:
Table for Selection of Factor D1SevereSignificantInsignificant
Separation0<Sep<.005H.005<Sep<0.01HSep>0.01H
Alignment of Floors within 20% of Storey Height
Alignment of Floors not within 20% of Storey Height

Factor D2: Height Difference Effect

Factor D2 For Transverse Direction:
Table for Selection of Factor D2SevereSignificantInsignificant
Separation0<Sep<.005H.005<Sep<0.01HSep>0.01H
Height Difference > 4 Storeys
Height Difference 2 to 4 Storeys
Height Difference < 2 Storeys
    Factor D:
3.5 Site Characteristics
Effect on Structural Performance Factor E:
3.6 Other Factors –
     Factor F:
3.7 Performance Achievement Ratio (PAR) (equals A * B * C * D * E * F)
     Transverse:

Table IEP-4 Initial Evaluation Procedure Steps 4, 5, 6 and 7

Step 4 – Percentage of New Building Standard (%NBS)LongitudinalTransverse
4.1 Assessed Baseline %NBS (NBS)b
Performance Achievement Ratio (PAR)
PAR * Baseline (%NBS)b
4.4 Percentage New Building Standard (%NBS) – Seismic Rating 
Step 5 – Is %NBS < 34? 
Step 6 – Potential Earthquake Risk (is %NBS < 67)? 
Step 7 – Provisional Grading for Seismic Risk based on IEP
 Seismic Grade: