Seismic and Wind Design and Evaluation of Structures and Facilities

DOE-HDBK-1129-99

loading at corners, eaves, and ridges. Extreme windstorms can produce missiles from debris near

the facility or from nearby facilities. These missiles can strike walls and roofs and their effects

should be evaluated. During tornadoes, in addition to pressure effects and windborne missiles,

there will be an atmospheric pressure change or a pressure drop below ambient pressure as the

tornado passes over a facility. This can affect wall and roof openings and ventilation system filters.

An approach used at SRS is to store resources in a Highly Invulnerable Encased Safe (HIVES).

HIVES are metal cabinets designed to store tritium reservoirs and Hydride Storage Vessels (HSV).

The HIVES are designed to be capable of protecting the pressure boundary integrity of stored

reservoirs or HSV against impact of structural elements free falling from the collapse of Building

234-H and the adjacent 296-H stack caused by credible NPH Design Bases Accidents. The

HIVES are constructed of hardened T-1 steel, primarily from 1-inch plate. The overall dimensions

are approximately 22"Wx39"Dx68"H, which includes both a cabinet and a matching bonnet

assembly bolted to the cabinet top plate. This bonnet contains an aluminum hexcall honeycomb

material designed to absorb the impact loading stated above.

The following should be considered when designing or evaluating structures or facilities for

earthquakes and windstorms:

The Performance Category (PC) of the structure or facility should be determined. It is not

necessary for the entire facility to have the same PC; that is, different parts of a facility could be

in different performance categories. For example the office portion of a Tritium Handling

Facility may be PC1 while the laboratory portion may be PC3.

Judgment should be exercised to ensure that various parts of the facility have been

categorized in a rational manner. For example, a PC1 facility does not physically support a

PC3 facility.

In addition to the vertical load carrying system, a lateral force resisting system should carry the

seismic and wind loads. This may be a frame or shear wall system or separate bracing

system. Attention to connection details is very important in ensuring adequate structural

integrity to resist the limited energy input motion produced by earthquakes and the longer

duration wind loading.

An understanding of the type of loading that earthquakes and extreme winds produce on the

overall structure is essential during the design and evaluation process.

An adequate load path must be ensured throughout the structure

Roof and wall connection details to structural system

Overall roof-to-wall connections

Wall-to-foundation connections

Foundation adequacy

Innovative technologies, such as base isolation and passive energy dissipation devices, should

be considered during design of new facilities and for upgrading of existing facilities to reduce

seismic loads to systems and equipment within the structure. These approaches have been

used in many projects throughout the world during the last 10 years.

Avoid the type of details and structural features that have performed poorly during past

earthquakes. These are as follows: