Chapter 23
SEISMIC SAFETY

Contents

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23.1 Policy

It is Laboratory policy to design and construct its physical plant and program facilities to prevent the loss of life and to minimize the risk of personal injury, program interruption, and property damage due to earthquakes.  It is the further policy that furnishings and equipment in buildings be secured in accordance with the requirements of this chapter.

23.2 New Buildings and Other Structures, Including Programmatic Equipment

All new Laboratory buildings and other structures, including program equipment and heavy shielding, will be designed and constructed to resist a magnitude-7+ earthquake on the Hayward Fault or a magnitude-8.3 earthquake on the San Andreas Fault without collapse.  The determination that the buildings and other structures will survive without collapse will be made by qualified structural engineers under the supervision of the Facilities Division Chief Structural Engineer.  Note that the occurrence of some structural and nonstructural damage is anticipated and is unavoidable in an area with the seismic risks that are present in Northern California.

23.2.1 Physical Plant Facilities

All buildings and other structures must be structurally designed and constructed in accordance with CCR, Title 24, California Building Code by, or under the supervision of, a structural engineer registered in the state of California.

All building projects must be designed on the basis of geological and geotechnical investigations used to establish foundation design values and to assess hazards from fault movement (e.g., landslides and ground motion). No building may be constructed over an active fault, and the proposed location of a building relative to an active fault must be reviewed and approved by the Facilities Division.

Calculations, drawings, and specifications for buildings must be submitted to the Facilities Division for review before construction, and drawings must be signed and stamped with the registered engineer’s seal.

In accordance with the University Seismic Safety Policy dated January 15, 1995, all drawings and calculations for buildings must be formally peer-reviewed by an independent, structural engineer licensed in California.

23.2.2 Design Criteria for Programmatic Facilities

The following equipment and structures must be constructed and/or seismically secured in a manner that ensures life safety and is acceptable to the Facilities Division Chief Structural Engineer:

1. Any structure that personnel can enter, such as radiation hutches, shielding structures, or environmental test chambers.
2. Any structure that supports personnel, such as mezzanines and personnel platforms more than 4 feet high.
3. Any equipment or tool that weighs 500 lbs or more.  Examples are machine tools and granite tables.  Note: Even for equipment of lesser weight, verify that the floor load limit is not exceeded.

In addition to seismic considerations, the Chief Structural Engineer’s review will also address Building Code issues and floor loading concerns. 

All programmatic facilities that are beyond the scope of the California Building Code shall be designed and constructed to ensure life safety in the event of the design basis earthquake.  The following design criteria shall be incorporated.

• If personnel can be exposed to a life-threatening injury by being struck or trapped by the lateral movement or upset (toppling, overturning) of any object from a seismic disturbance, the movement or overturning of the object must be prevented under horizontal accelerations of up to 0.7 g. If the object is provided with adjustments, it must resist 0.7 g when the adjustments are in the most unfavorable positions. In severe earthquakes, simultaneous vertical accelerations can occur, and the nearby Hayward Fault is known to have a strong vertical component; therefore, on the LBNL site, only 75% of the object's weight acting at the center of gravity may be considered effective against overturning, and friction due to gravity cannot be relied on to resist movement. For locations away from the LBNL site, the percentage of the object's weight acting at the center of gravity that is considered effective against overturning is specified by the California Building Code. The use of mechanically induced friction to resist movement must be reviewed on a case-by-case basis with the Facilities Division Design and Construction Department. Secure structural connections to the floor or to the building are needed to resist horizontal accelerations.
• Where the maximum allowable stress and displacement in seismic restraining systems are not specified below, these criteria must be established by the Project Engineer and must be such that life-threatening lateral movement (relative to the support) or overturning will not occur during a horizontal acceleration of 0.7 g.
• For equipment or other objects mounted on resilient stands or on floors of resilient buildings, the dynamic load during an earthquake may be amplified and may greatly exceed the maximum ground acceleration. Stands must have sufficient strength and ductility to withstand dynamic loads. Spectral analyses, using the LBNL Design Basis Earthquake, must be used to determine the seismic horizontal acceleration.

Nonductile Structures

Structures constructed of components or materials that fail in a brittle manner [i.e., are susceptible to sudden failure resulting from elastic (nonlinear) behavior] and that do not exhibit ample reserve strain-energy capacity are considered nonductile structures. One example is a structure made of nonductile reinforced concrete blocks held together with ductile metal attachments that are not configured, or do not have enough mass, to safely absorb the seismic strain energy in the structure. For nonductile structures and bracing systems, the design must be based on the following:

• The base shear must not be less than 0.7 g.
• In severe earthquakes, simultaneous vertical accelerations can occur, and the nearby Hayward Fault is known to have a strong vertical component; therefore, on the LBNL site, only 65% of the object's weight acting at the center of gravity may be considered effective against overturning, and friction due to gravity cannot be relied on to resist movement. The use of mechanically induced friction to resist movement must be reviewed on a case-by-case basis with the Facilities Division Design and Construction Department.
• The maximum allowable stress in ductile structural elements must not exceed the following:
• 75% of the ultimate compressive strength, or the stresses permitted by the CBC, for concrete in bearing or compression. Requirements for reinforced concrete in shear, torsion, or flexure are given in Building Code Requirements for Reinforced Concrete.
• 50% of the ultimate strength for welds.
• 75% of the manufacturer’s recommended ultimate load values, which have been established by testing, for proprietary anchor bolts or expansion anchors that depend on the concrete for their ultimate load capacities.
-     75% of the ultimate strength for other structural elements.

Ductile Structures

Structures and their attachments and bracing constructed of materials that exhibit ductile inelastic (nonlinear) behavior at stresses beyond their yield points, and that have ample reserve strain-energy capacity beyond their yield points, are considered ductile structures; an example is a structure and its attachments made of structural steel having a configuration and mass of ductile metal sufficient to safely absorb the seismic strain energy in the structure. The designer should be aware that a ductile material can be configured in such a way as to result in a nonductile structure or attachment, and should seek guidance from the Facilities Division Chief Structural Engineer early in the design process. For ductile bracing systems, the design must be based on the following requirements:

• The base shear must not be less than 0.5 g.
• The dead load assumed for calculating the resisting moment about the center of gravity must not exceed 75% of the weight.
• The maximum allowable stress in ductile structural elements must not exceed the elements’ yield strengths at 0.5 g.
• The design of bolts and concrete anchors shall be in accordance with "Strength Design of Anchorage to Concrete," Portland Cement Association, 1999, to assure ductile behavior.

23.3 New and Existing Special Facilities

The determination that special facilities meet the following criteria will be made by qualified structural engineers under the supervision of the Facilities Division Chief Structural Engineer. 

23.3.1 Critical Emergency Facilities

Critical emergency facilities will be designed to remain functional during and after the design basis earthquakes specified above.

23.3.2 Enclosures and Systems Containing Radioactive and Other Hazardous Dispersible Materials

Enclosures and systems containing radioactive or other hazardous, dispersible materials (e.g., toxic, flammable, or infectious substances) will be designed and constructed to ensure confinement during and after the design earthquake specified above and to ensure that the acceptable risk, established during the AHD determination by the division, is not exceeded.  These enclosures must be inspected by EH&S before any use.

23.4 Existing Buildings and Other Structures

23.4.1 Rating of Buildings and Other Structures

All Laboratory buildings and other occupied structures will be reviewed by qualified structural engineers to determine their rating in accordance with the requirements of the UC Seismic Safety Policy.  One of the following UC mandated ratings will be assigned to each building or other structure:

A "Good" seismic performance rating would apply to buildings and other structures whose performance during a major seismic disturbance "is anticipated to result in some structural and/or nonstructural damage and/or falling hazards" that would not significantly jeopardize life. Buildings and other structures with a "Good" rating would have a level of seismic resistance such that funds need not be spent to improve their seismic resistance to gain greater life safety, and would represent an acceptable level of earthquake safety.

A "Fair" seismic performance rating would apply to buildings and other structures whose performance during a major seismic disturbance is anticipated to result in structural and nonstructural damage and/or falling hazards that would represent low life hazards. Buildings and other structures with a "Fair" seismic performance rating would be given a low priority for expenditures to improve their seismic resistance and/or to reduce falling hazards so that the building could be reclassified "Good."

A "Poor" seismic performance rating would apply to buildings and other structures whose performance during a major seismic disturbance is anticipated to result in significant structural and nonstructural damage and/or falling hazards that would represent appreciable life hazards. Either such buildings or structures would be given a high priority for expenditures to improve their seismic resistance and/or to reduce falling hazards so that the building could be reclassified as "Good," or would be considered for other abatement programs, such as reduction of occupancy.

A "Very Poor" seismic performance rating would apply to buildings and other structures whose performance during a major seismic disturbance is anticipated to result in extensive structural and nonstructural damage, potential structural collapse, and/or falling hazards that would represent high life hazards. Such buildings or structures either would be given the highest priority for expenditures to improve their seismic resistance and/or to reduce falling hazards so that the building could be reclassified "Good," or would be considered for other abatement programs such as reduction of occupancy.

23.4.2 Use Restrictions for Buildings and Other Structures with Seismic Ratings of “Poor” and “Very Poor”

The use of each building or other structure with a rating of “Poor” or “Very Poor” will be reviewed by the Laboratory managers responsible for the building or structure for the purpose of determining what seismic risk-reduction strategy will be implemented.  The determination will be based on recommendations from the Facilities Division Structural Engineer and from the EH&S Division Seismic Safety Subject Matter Expert.  See Section 23.5.

23.4.3 Posting of Seismic Information for Buildings and Other Structures

The seismic rating of buildings and any use restrictions or limitations will be posted on the Laboratory’s Seismic Status Web Page.  The structural rating of buildings will be maintained by the Facilities Division Chief Structural Engineer; and the use limitations and restrictions will be maintained by the EH&S Division Seismic Subject Matter Expert, based on the risk mitigation measures adopted by management as described in the next section.  See http://fac.lbl.gov/Facilities/DandC/CivStr/

23.5 Process for Determining Use Restrictions for Buildings and Other Structures with “Poor” and “Very Poor” Seismic Ratings

The Facilities Chief Structural Engineer will advise Laboratory managers of the seismic rating of each building that has been evaluated, and will provide a summary of the issues that cause buildings to have a “Poor” or “Very Poor” rating.  Based on this information and on a review of the present use of the building with the occupying divisions’ safety coordinators, the EH&S Division Seismic Subject Matter Expert shall make seismic risk mitigation recommendations to the responsible division directors and the Laboratory’s Chief Operating Officer concerning appropriate risk-reduction measures for buildings that have a seismic rating of “Poor” or “Very Poor.”

These recommendations shall incorporate the following guidance:

For seismically “Very Poor” buildings, the following applies:

• No new or additional operations that result in personnel exposure to the seismic hazard may be located in buildings with a “Very Poor” seismic rating.
• Funding must be requested to upgrade the building to a seismic rating of “Good” or to replace or remove the building.  Alternatively, the building may be vacated and abandoned in place until a plan has been developed.
• Activities that bring additional personnel into the building will be curtailed; for example, conference rooms will be closed.
• Every effort will be made to relocate personnel who spend most of their time in the building to other, safer facilities; for example, occupants of continually occupied offices will be moved in a specified period of time.
• Laboratory and experimental facilities that cannot be moved will only be used for essential activities, and where possible, personnel working in these spaces shall be assigned other, safer spaces for office work and other activities that can be performed elsewhere.
• Personnel remaining in the building shall be briefed on the hazards and use restrictions by the Chief Structural Engineer and the EH&S Seismic Subject Matter Expert, and the use restrictions shall be posted on the Laboratory’s Seismic Status Web page.

The use of seismically “Very Poor” buildings for unattended storage of material and equipment is permitted.

For seismically “Poor” buildings, the following applies:

• No additional operations that result in personnel exposure to the seismic hazard may be located in buildings with a “Poor” seismic rating.  Replacement of activities with like activities may be acceptable, depending on specific circumstances.
• Funding must be requested to upgrade the facility to a seismic rating of “Good” or to replace or remove the facility.
• Personnel remaining in the building shall be briefed on the hazards and use restrictions by the Chief Structural Engineer and the EH&S Seismic Subject Matter Expert, and the use restrictions shall be posted on the Laboratory’s Seismic Status Web page
• Post a hard copy of the briefing of Hazards and Use Restrictions, in a prominent and central location, for review by building occupants, particularly those who become occupants after the initial briefing. It is the responsibility of division line management to inform new building occupants of the location of the posted briefing. It is the building occupants' responsibility to review the posting and to contact the Chief Structural Engineer, or EH&S Seismic Subject Matter Expert, if they have any questions. 

23.6 Programmatic Equipment and Structures

The following equipment and structures must be constructed and/or seismically secured in a manner that is acceptable to the Facilities Division Chief Structural Engineer:

• Any structure that personnel can enter, such as radiation hutches, shielding structures, or environmental test chambers.
• Any structure that supports personnel, such as mezzanines and personnel platforms more than 4 feet high.
• Any equipment or tool that weighs 1,000 lbs or more; examples are machine tools and granite tables.  Note: Even for equipment of lesser weight, verify that the floor load limit is not exceeded.

In addition to seismic considerations, the Chief Structural Engineer’s review will also address Building Code issues and floor loading concerns. 

23.7 Non-Structural Earthquake Safety Measures

Seismic anchoring of furnishings and equipment is required where it may prevent blocking of exit passages, and where items may topple and crush personnel in case of an earthquake.  Note that the seismic anchoring that is typically possible will provide protection in cases of minor earthquakes, but may fail during a design basis earthquake, depending on the direction of the ground motion. 

Where equipment is anchored, it must be bolted to structural elements, such as studs in walls, or secured to concrete with approved anchors.  Seismic anchoring may require Facilities Division Penetration permits, depending on the depth of the anchors and the location.  Contact the Facilities Division Work Request Center for seismic anchoring.  Facilities Division carpenters have been instructed on acceptable methods of anchoring typical furnishings.

Where the contents of shelves or cabinets may fall and pose hazards during an earthquake, they must be secured in the cabinet or shelf by doors or other restraining mechanisms such as 3/4-inch-tall lips at the front of shelves, or elastic cords on bookshelves.

The following items are required to be secured against toppling or emptying of contents:

• Any item weighing 500 lbs or more.
• Bookcases, file cabinets, storage cabinets, electronics racks, and other furnishings that are more than 4 feet high.
• Bookcases and other furnishings regardless of height where they might block doors or exit passages.
• 160-liter dewars and compressed gas cylinders.
• Heavy items on shelves where they might fall down on personnel below.

23.8 Orders and Standards

• DOE Order 420.1A, Facility Safety, Chapter IV,  “Natural Phenomena Hazard Mitigation.” See http://www.directives.doe.gov/cgi-bin/explhcgi?qry1445232542;doe-146. 
• Executive Order 12941, "Seismic Safety of Existing Federally Owned or Leased Buildings." See http://www.gsa.gov/Portal/gsa/ep/contentView.do?contentType=GSA_BASIC&contentId=12394&noc=T.
• University Policy on Seismic Safety, January 17, 1995. See http://www.ucop.edu/ucophome/coordrev/policy/1-17-95att.html.
• CAC Title 24 Building Standards