SOW Attachment 5 -Northampton VAMC Memo Non Structural Components Seismic Requiremen.pdf

October 25, 2023

October 27, 2023, Rev1

VA Central Western Mass Health Care System MS 138

421 North Main Street

Leeds MA 01053

Re: Seismic Restraints for Nonstructural Components in Existing Buildings

Ms. Josee Goldin:

This memorandum is intended to state the seismic restraint requirements within existing buildings for work that includes the addition or replacement of existing nonstructural components at the Central Western Massachusetts VAMC.

Acela Architects and Engineers has concluded that the requirement for seismic restraint bracing related to the addition or replacement of nonstructural components in our opinion is not required for any of the existing buildings at this facility. This conclusion is based on two site specific factors. The first factor is the Site Classification which describes the site geological and geotechnical characteristics. The second factor is the site-specific Design Spectral Response

Acceleration (Sds). These two site-specific characteristics are used to determine the Seismic

Design Category (SDC) for the building(s). The Basic Performance Objectives of Existing Buildings

(BPOE) as outlined in the RP-8 and ASCE-41 Standards, also as referenced in the VA H-18-8

Seismic Design Requirement Manual, determine the requirements for seismic restraint bracing for this campus either by determining the SDC or the Design Spectral Response Acceleration(Sds).

Specifically, the Northampton campus Site Classification has been determined using two (2) of the most recent geotechnical investigations conducted at various locations across the campus that both identify this area to be Site Classification equal to “C”. This Site Classification describes the subsurface conditions as a very dense soil and soft rock composition. The site-specific area Design Spectral Response Acceleration (Sds) for this campus has been determined to have a value of 0.13g. This was determined through the ASCE 7 Spectral Response

Acceleration maps. Per the ASCE 7-41 Standard, this value is considered to have a Seismicity

Level rating of “Very Low” when considering the ground shaking intensity. Therefore, when using these (2) two pieces of site-specific data, the Seismic Design Category (SDC) for the buildings on this campus has been determined to be SDC “A” regardless of Risk Category.

A Seismic Design Category of either A or B exempts nonstructural components from having to meet the seismic restraint requirements in the VA H-18-8 or as simply stated in the RP-8, is exempt based solely on Design Spectral Response Acceleration (Sds) of the RP-8 Standards.

Northampton VAMC

Seismic Restraints

October 25, 2023

October 27, 2023 Rev1

Additionally, VA H-18-8 manual, Table 3 Section 2.6 states the Basic Performance Objective

(BPOE) for nonstructural components in both the Critical and Essential Risk Categories shall only need to meet the BPOE of “Position Retention Nonstructural Performance”. This also indicates the Importance Factor (Ip) noted in section 4.2 of the VA H18-8 Manual of 1.5 need not apply when determining the horizontal forces per Chapter 13 of the ASCE 7 for non-structural components.

In conclusion, the Northampton campus currently has buildings that identify in all four (4) of the risk categories and this memorandum will apply to all of those categories. This site is a very low seismic region and regardless of risk categories the exemptions will still be applicable. This is specifically due to the SDC of “A” or “B” selected for the building(s) on this campus are excluded from those listed in the H-18-8. New or additional nonstructural components for the existing buildings need not comply with the seismic bracing restraint regulations in the VA H-18-8 for this site. Additionally, the Design Spectral Response Acceleration (Sds) is less than specified in the RP-

8 Standard, these buildings are exempt from the requirements stated in this Standard. Lastly, as noted in ASCE 7, nonstructural components in a Seismic Design Category of “A” are exempt from seismic design requirements.

Please note, that while this document states exemptions from the minimum required by design manuals and standards, assignments of mission critical objective are left to the discretions of this campus. Northampton VAMC at its own discretion, may require additional requirements not covered in these Standards.

If you should have any questions please feel free to contact me.

Respectfully, Gavin T. McManaman, PE

Director of Structural Engineering

Acela Architects + Engineers, PC

Reference Documents:

1. ICSSC Recommend Practice 8 (RP-8)

“Standards of Seismic Safety for Existing Federally Owned and Leased Buildings”

2. U.S.Department of Veteran Affairs

“Seismic Design Requirements (H-18-8”)

3. American Society of Civil Engineers ASCE 41-17

“Seismic Evaluation and Retrofit of Existing Buildings”

4. American Society of Civil Engineers ASCE 7

“Minimum Design Loads for Buildings and Other Structures” cc: file