---
title: "Modeling a Building at an International Site"
canonical: "https://support.sp3risk.com/space/KnowledgeBase/2203779073/Modeling%20a%20Building%20at%20an%20International%20Site"
format: markdown
---
# Overview

For sites outside of the United States and Japan, an equivalent United States building code, a level of seismicity for that building code, and a level of seismicity for the shaking hazard are specified to approximate the risk assessment.

![image](media://de2ec981-e15f-423a-a7d2-3c37bb106263)

- **Equivalent Design Code**: Select a US design code that best represents the design practice used for the construction of the building.
- **Design Code Level of Seismicity**: The level of seismicity associated with the design code to determine which design code parameters to use.
  - *Example 1*: ASCE 7-10 designed in a “high” seismicity region will use ASCE 7-10 requirements with S<sub>s</sub> and S<sub>1</sub> values of 1.2g and 0.48g, respectively, to approximate the building and component properties (see the conversion table below).
  - *Example 2*: UBC 1997 designed in a “high” seismicity region will use UBC 1997 requirements for Zone 3 buildings to approximate the building and component properties (see the conversion table below).
- **Shaking Level of Seismicity**: To approximate the shaking intensity at the site, the 475 year hazard will be approximately consistent with the S<sub>s</sub> and S<sub>1</sub> values in the ASCE 7 conversion table below. The hazard can be manually overridden if that information is available to the user.

# Site Specific Parameters and Design

A specific site (latitude/longitude) provides three key parameters in the risk assessment that SP3 does not explicitly support outside of the US and Japan.  Below is how each of those are addressed for international sites.

- **Site Class (Vs30)**
  - International sites are defaulted to be site class D (Vs30 ≈ 259 m/s).
  - This can be overridden by the user to reflect more detailed information at the actual international site.
- **Building Design and Performance Model**
  - The user is required to specify an equivalent US building code and level of seismicity that corresponds to the international building. The mappings to the UBC zone and ASCE 7 parameters are shown in the tables below. This code is then used for the default structural and non-structural design properties of the building.
  - The building strength and stiffness may be directly overridden if that information is available. Any equivalent code parameters (e.g. detailing level) may also be overridden.
- **Shaking Hazard**
  - For each level of seismicity, a US site is selected to reasonably match the shaking for which the 475 year return period shaking is consistent with the Ss and S1 values in the ASCE 7 conversion table below.  The USGS hazard from this site is then used as an approximate shaking hazard at the international site. The vulnerability curve (intensity vs loss) will be accurate with this method, but the actual return period of the shaking (the frequency at which a given shaking would occur) is not necessarily accurate.
  - The shaking hazard may be overridden by the user if that information is available. This is recommended if the shaking frequency is important for the analysis being performed (see previous bullet point).

#  Proxy Building Design Code Mapping

Mapping of the level of seismicity to S<sub>s</sub> and S<sub>1</sub> for ASCE 7 (7-02, 7-05, 7-10, 7-16). These values are consistent with the seismicities specified in FEMA P-155 Table 5-4.

|  |  |
| --- | --- |
|  | **Level of Seismicity** |
| **Parameter** | **Low** | **Moderate** | **Moderately High** | **High** | **Very High** |
| S<sub>s</sub> | 0.2 | 0.4 | 0.8 | 1.2 | 2.25 |
| S<sub>1</sub> | 0.08 | 0.16 | 0.32 | 0.48 | 0.9 |

Mapping of the level of seismicity and year to the UBC zone is shown in the table below.

|  |  |
| --- | --- |
|  | **Level of Seismicity** |
| **UBC Code Year** | **Low** | **Moderate** | **Moderately High** | **High** | **Very High** |
| 1927* | No | No | Yes | Yes | Yes |
| 1935 | 0 | 1 | 2 | 3 | 3 |
| 1937 | 0 | 1 | 2 | 3 | 3 |
| 1940 | 0 | 1 | 2 | 3 | 3 |
| 1943 | 0 | 1 | 2 | 3 | 3 |
| 1946 | 0 | 1 | 2 | 3 | 3 |
| 1949 | 0 | 1 | 2 | 3 | 3 |
| 1952 | 0 | 1 | 2 | 3 | 3 |
| 1955 | 0 | 1 | 2 | 3 | 3 |
| 1958 | 0 | 1 | 2 | 3 | 3 |
| 1961 | 0 | 1 | 2 | 3 | 3 |
| 1964 | 0 | 1 | 2 | 3 | 3 |
| 1967 | 0 | 1 | 2 | 3 | 3 |
| 1973 | 0 | 1 | 2 | 3 | 3 |
| 1976 | 0 | 1 | 2 | 3 | 4 |
| 1979 | 0 | 1 | 2 | 3 | 4 |
| 1982 | 0 | 1 | 2 | 3 | 4 |
| 1985 | 0 | 1 | 2 | 3 | 4 |
| 1988 | 0 | 1 | 2B | 3 | 4 |
| 1991 | 0 | 1 | 2B | 3 | 4 |
| 1994 | 0 | 1 | 2B | 3 | 4 |
| 1997 | 0 | 1 | 2B | 3 | 4 |

*1927 only distinguishes seismic requirements for “cities subjected to seismic shock”