BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM

Transcription

1 DEPARTMENT OF BUILDING INSPECTION City & County of San Francisco 1660 Mission Street, San Francisco, California BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM After a major earthquake involving damage to San Francisco buildings, it is important that local buildings can be inspected and reoccupied and that business can resume operations as soon as it is safely possible. The Department of Building Inspection (DBI) and volunteer inspectors will be utilizing standard emergency inspection and posting procedures with priorities geared toward public safety rather than expeditious business resumption. Some building owners may wish to develop programs of private inspection for their buildings to permit rapid, individualized emergency response. A program of private emergency building inspection, including precertification of building owners engineers or architects, is outlined below. In order to assist DBI emergency management and assure public safety, it is necessary for such private response to follow the same general format and procedures as public response. PURPOSE The purpose of a precertified emergency inspection program is to allow a quick and thorough evaluation of possible damage to a structure by qualified persons familiar with the structural design and life-safety systems of the building. This private emergency inspection could facilitate rapid decisions regarding the closure or reoccupancy of building areas. Prearranged emergency inspection could reduce inspection delays, as City inspection personnel typically are dispatched first to areas of greatest damage or public hazard which may not include the building in question. PREPARATION Building owners or their authorized representatives may request participation in this program at any time except during the aftermath of an earthquake resulting in a declared state of emergency. A building designated as having met the requirements outlined below in preparing for emergency response shall be placed on a list of buildings which are accepted for private emergency inspection. There is no charge for participation in this program. The following steps should be taken by building owners who wish to participate in the program: Select emergency inspection team Obtain building plans Write inspection plan Develop building information, evacuation plan, inspector response requirements, equipment and drawing locations, and other pertinent information

2 Prepare precertification documentation Submit written building emergency inspection program, including inspection plan Obtain and store emergency earthquake safety and inspection equipment and supplies Establish and maintain emergency inspection program Update inspection plan, supplies, personnel changes and training as necessary Submit Annual Update form by October 17 of each year (Appendix D) EMERGENCY INSPECTOR REQUIREMENTS A minimum of one primary and one alternate inspector shall be retained by the building owner for each applicable inspection discipline. The costs of training shall be borne by the building owner or emergency inspector. Few architects consider structural inspections within their purview; however, architects can add expertise to an inspection team to address nonstructural hazards such as blockage of exits, façade and ceiling assembly hazards and life safety system performance. Architects/engineers experienced with historical structures should be considered for the emergency inspection of historic buildings. Approved emergency inspectors for this program will be deputized by the City and County of San Francisco to give them authorization to perform inspections and post buildings which are on the precertified list with official City placards. The extent of responsibility and liability is governed by the agreement between the owner and inspector(s). A. Minimum Qualifications 1. Structural Inspectors a. Current California license as a professional civil or structural engineer or architect b. Relevant experience in the structural design and/or inspection of similar buildings c. Proficiency in ATC-20 Detailed Evaluation Procedures plus additional and/or refresher training as necessary for readiness d. Familiarity with DBI administrative, posting, and reporting guidelines for post-earthquake emergency inspection 2. Elevator Inspectors (not required if structural inspector assumes responsibility for elevators) a. Employment by a firm engaged in elevator maintenance and installation as their primary business. b. Familiarity with the building elevator installation

3 3. Life-safety System Inspectors (required for high-rise buildings) a. Current California license as a mechanical or electrical engineer b. Familiarity with building life-safety system B. Required Documents, Equipment and Supplies 1. Copy of building Emergency Inspection Program including evacuation plan and other pertinent information 2. Structural, architectural, and/or life-safety system drawings; or [If building is so old that structural drawings do not exist or are not clear enough to allow a good understanding of the actual structural system] As-built drawings or a clear description of the structural system and any known weaknesses and unique features 3. Personal safety equipment including hardhat, protective clothing, respirator, etc. 4. Inspection equipment including flashlights, measuring devices, ladders, and other applicable items 5. ATC-20 Detailed Evaluation forms (latest edition) for reporting inspection findings to DBI 6. Sufficient green, yellow, and red official City safety assessment placards to provide one of each color for each entrance to the building 7. Caution tape and barricades 8. Walkie-talkies or other emergency communication equipment for large buildings, if applicable. EMERGENCY INSPECTION PROGRAM The program shall include the following information: A. List of primary and alternate emergency inspectors for this building with addresses and phone numbers: 1. Licensed engineers/architects retained for structural inspection 2. Staff building engineers 3. Elevator firm, if elevator inspection required 4. Life-safety system mechanical and electrical engineers, if required B. Building information 1. Photograph of building 2. Address 3. Description of building including age, number of stories, size, materials

4 4. Estimated current building valuation 5. Listing of occupancy type(s) 6. Description of structural system 7. Description of life-safety system including location of emergency power generator 8. Description of building fire detection and suppression systems 9. Location, type, and handling instructions for any hazardous material C. Emergency response requirements and information including: 1. Procedures for automatic activation of emergency response 2. Access procedures and/or keys for entrance to the site and all building areas 3. Location of equipment and supplies 4. Location of Emergency Inspection Plan and on-site drawings D. Emergency Inspection Plan, including: 1. Inspection guidelines consistent with ATC-20 Procedures for Postearthquake Safety Evaluation of Buildings including Detailed Evaluation Procedure. Note: Recommended methodology for welded steel joint inspection is SAC Detailed instructions regarding where to look, what to look for, and how to obtain access to inspection areas. 3. Detailed instructions regarding how to inspect specific structural and nonstructural elements and how to interpret observed damage. 4. Detailed instructions regarding additional inspection procedures to be performed following aftershocks. 5. [Optional] Placement of accelerometers. Instrumentation is recommended as part of an Emergency Inspection Program for all highrise buildings in San Francisco. Correct placement of accelerometers can provide valuable postearthquake information about the performance of a building. This option may be considered in certain cases as an alternative to inspection of welded joints. E. List of required documents, equipment and supplies and their location. PRECERTIFICATION DOCUMENTATION Precertification must occur before the earthquake. No documentation will be accepted for a period of at least three months after a declared state of emergency. Submit two (2) copies each of the following to the Department of Building Inspection: A. Request for Precertification form signed by building owner or authorized representative (Appendix B) B. Evidence of emergency inspector qualifications for each individual:

5 1. Copy of current California license as a professional civil or structural engineer or architect 2. Resume showing relevant experience in the structural design and/or inspection of similar buildings 3. Signed Emergency Inspector Authorization form (Appendix C) C. Copy of written Emergency Inspection Program (see content requirements and Appendix E) D. Completed Emergency Inspection Program Checklist (Appendix A) PRECERTIFICATION ACCEPTANCE DBI will add the building to the list of buildings approved for the Building Occupancy Resumption Emergency Inspection Program and provide the following upon acceptance of precertification documentation: A. DBI-signed copy of Request for Precertification form B. DBI-signed copy of each Emergency Inspector Authorization form C. The accepted Emergency Inspection Program D. Number of official City posting placards requested IMPLEMENTATION A. Upon notification of an earthquake resulting in a declared state of emergency, initiate emergency inspection program within 8 hours of daylight access to building. B. Contact DBI immediately if building or area (including sidewalk, street, or parking area) presents a public safety hazard or if emergency demolition or shoring permit is needed. C. Arrange for barricading of all unsafe areas. Contact the Department of Public Works immediately if areas barricaded including a City street or otherwise adversely affect City services, or if barricades provided by the building owner are insufficient. D. Complete detailed evaluation as soon as reasonably possible. E. Post building (green, yellow, or red) at the main entry of the building or at all entrances of multi-entrance buildings. F. Take preventive measures regarding gas leaks, release of hazardous materials, or other life-safety mitigation. G. At owner s and inspector s discretion, non-structural hazards may be mitigated without a building permit. H. Submit ATC-20 Detailed Evaluation report (Appendix G) signed and dated by prequalified engineer(s)/architect to DBI within 72 hours of the declared state of emergency. If reports are not received by that time, an inspection may be made by City inspectors or deputized volunteer inspectors using standard City-wide inspection criteria.

6 DBI VERIFICATION The Department of Building Inspection may perform inspection of a building accepted for the Building Occupancy Resumption Emergency Inspection Program under any of the following conditions: A. The emergency inspector has reported the building unsafe and has posted it with a red placard. B. There is no reason to believe that unsafe conditions exist. C. Building owners, tenants, other City agencies, or members of the general public have expressed specific concerns.

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8 BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM APPENDIX A CHECKLIST Building Address: List of primary and alternate emergency inspectors for this building with addresses and phone numbers: 1. Licensed engineers/architects retained for structural inspection 2. Staff building engineers 3. Elevator firm, if elevator inspection required 4. Life-safety system mechanical and electrical engineers, if required Building information 1. Photograph of building 2. Address 3. Description of building including age, number of stories, size, materials 4. Estimated current building valuation 5. Listing of occupancy type(s) 6. Description of structural system 7. Description of life-safety system including location of emergency power generator 8. Description of building fire detection and suppression systems 9. Location, type, and handling instructions for any hazardous material Emergency response requirements and information including: 1. Procedures for automatic activation of emergency response 2. Access procedures and/or keys for entrance to the site and all building areas 3. Location of equipment and supplies 4. Location of Emergency Inspection Plan and on-site drawings Emergency Inspection Plan, including: 1. Inspection guidelines consistent with ATC-20 Procedures for Postearthquake Safety Evaluation of Buildings including Detailed Evaluation Procedure. Note: Recommended methodology for welded steel joint inspection is SAC Detailed instructions regarding where to look, what to look for, and how to obtain access to inspection areas. 3. Detailed instructions regarding how to inspect specific structural and non-structural elements and how to interpret observed damage. 4. Detailed instructions regarding additional inspection procedures to be performed following aftershocks. 5. [Optional] Placement of accelerometers. This option may be considered in certain cases as an alternative to inspection of welded joints. List of required documents, equipment and supplies and their location. 1. Copy of building Emergency Inspection Program including evacuation plan and other pertinent info. 2. Structural, architectural, and/or life-safety system drawings; or [If building is so old that structural drawings do not exist or are not clear enough to allow a good understanding of the actual structural system] As-built drawings or a clear description of the structural system and any known weaknesses and unique features 3. Personal safety equipment including hardhat, protective clothing, respirator, etc. 4. Inspection equipment including flashlights, measuring devices, ladders, and other applicable items 5. ATC-20 Detailed Evaluation forms (latest edition) for reporting inspection findings to DBI 6. Sufficient green, yellow, and red official City safety assessment placards to provide one of each color for each entrance to the building 7. Caution tape and barricades 8. Walkie-talkies or other emergency communication equipment for large buildings, if applicable. Reviewed & Accepted for DBI by: Date: RETURN ONE COPY OF THIS FORM TO BUILDING OWNER AFTER REVIEW & ACCEPTANCE

9 BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM APPENDIX B REQUEST FOR PRECERTIFICATION Precertification of the building at (address), San Francisco, California, is requested for acceptance in the Department of Building Inspection Business Resumption Emergency Inspection Program. I certify that: 1. I am the [ ] owner [ ] owner s authorized representative; letter of authorization from the building owner is enclosed. 2. The enclosed precertification documentation and written emergency inspection program complies with the minimum requirements of the DBI Business Resumption Emergency Inspection Program. 3. Emergency inspectors have been given a copy of the Emergency Inspection Program for the building at the address listed above. 4. Emergency inspectors have been given means of access to all areas of the building at all times of day and night or have been given instructions regarding obtaining accompanied access. 5. Emergency inspectors have access to the most recent accurate copies of all relevant structural, architectural, and life-saving drawings at all times. 6. All emergency inspectors will receive immediate notification of any changes in factors affecting the emergency inspection program (e.g., changes to structural or life-safety systems, access to buildings, etc.). 7. The number of building entrances to be posted with City placards is. (signature) Phone Date (typed name) The precertification documentation for this building has been accepted by the Department of Building Inspection. The building will be placed on the list of buildings for the Business Resumption Emergency Inspection Program. Accepted by: Date: RETURN ONE COPY OF THIS FORM TO BUILDING OWNER AFTER REVIEW & ACCEPTANCE

10 BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM APPENDIX C EMERGENCY INSPECTOR AUTHORIZATION I request precertification as an emergency inspector for the building at, San Francisco, California, for the following the of emergency inspection: A. [ ] Structural Inspector (enclosed is a copy of my current license I am a California licensed [ ] engineer [ ] architect Lic. No. Exp. Date I certify that: 1. I have relevant experience in the design and/or inspection of similar buildings which is described in the enclosed resume. 2. I am proficient in ATC-20 Detailed Evaluation Procedures and will complete any additional and/or refresher training in a manner consistent with maintaining readiness. 3. I am familiar with the emergency inspection plan and relevant drawings for this building. B. [ ] Elevator Inspection Firm I certify that: 1. Employees of my firm are authorized as qualified elevator technicians by the owner; authorization is enclosed. 2. My firm is familiar with the building elevator equipment, installation, and operation. 3. I will report findings to the structural inspector for inclusion in emergency inspection reports. C. [ ] Life-safety System Inspector I certify that: 1. I am familiar with the building life-safety system and have access to relevant drawings. 2. I will report inspection findings to the structural inspector for inclusion in emergency inspection reports. D. [X] All Inspectors I certify that: 1. I will follow the procedures in the Emergency Inspection Program for this building. 2. I will accept authorization as an emergency inspector by the City & County of San Francisco Department of Building Inspection and will display this form upon request. (signature) (typed/printed name) Date The structural engineers shown above are deputized as emergency inspectors for the above-listed building by the City & County of San Francisco Department of Building Inspection and are authorized to post this building with official City post-earthquake safety evaluation placards. Accepted by: Date: RETURN ONE COPY OF THIS FORM TO BUILDING OWNER AFTER REVIEW & ACCEPTANCE BUILDING OWNER TO GIVE ORIGINAL TO INSPECTOR FOR IDENTIFICATION PURPOSES

11 BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM APPENDIX D ANNUAL PROGRAM UPDATE TO BE SUBMITTED BEFORE OCTOBER 17 EACH YEAR Building Address:, San Francisco, California Estimated current building valuation is $. [ ] No change has been made in the building or any element of emergency inspection program. [ ] All emergency equipment and supplies for the program have been checked and updated as necessary. [ ] The building own has changed. The new owner is. A Request for Precertification form signed by the new owner is enclosed. [ ] The following emergency inspectors have been deleted from the program. Resumes and Emergency Inspector Authorization forms for new inspectors are enclosed. has been replaced by has been replaced by Emergency inspectors have been given revised drawings for any relevant changes to the building. [ ] The following pages of the Emergency Inspection Program have been revised:. Emergency inspectors have been given a copy of the revised program. A copy of the revised program, with changes highlighted, is enclosed. (signature) (typed name) Date The updated documentation for this building has been accepted by the Department of Building Inspection. The building will remain on the list of buildings for the Building Occupancy Resumption Emergency Inspection Program. Accepted by: Date: RETURN ONE COPY OF THIS FORM TO BUILDING OWNER AFTER REVIEW & ACCEPTANCE

12 BUILDING OCCUPANCY RESUMPTION EMERGENCY INSPECTION PROGRAM APPENDIX E PROGRAM FORMAT A. Emergency Inspectors 1. Licensed engineers/architects retained for Structural Inspection: Name Address Work Phone Home Phone Primary: Alternate: 2. Staff building engineers: Name Address Work Phone Home Phone 3. Elevator firm, if elevator inspection required: Firm address: Name Address Work Phone Home Phone Primary: Alternate: 4. Life-safety system mechanical and electrical engineers, if required: Name Address Work Phone Home Phone Mechanical: Electrical:

13 B. Building Information (photo enclosed) 1. Address: 2. Description of building: a. Date of original construction: b. No. of stories beginning at ground floor: c. No. of levels below ground: d. Building height: e. Dimension of ground floor footprint: or Sketch: f. Description & locations of non-structural materials: 3. Listing of occupancy type(s): 4. Description of structural system & materials: 5. Description of life-safety system including location of emergency power generator:

14 6. Description of building fire detection and suppression systems: 7. Information about hazardous material, including known friable asbestoscontaining materials: a. Location: Type: Handling instructions: b. Location: Type: Handling instructions: c. Location: Type: Handling instructions: C. Emergency response requirements and information: 1. Procedures for automatic activation of emergency response: 2. Access procedures and/or keys for entrance to the site and all building areas: 3. Location of equipment and supplies: a. Drawings (structural, architectural, life-safety); Emergency Inspection Plan; evacuation plan; green, yellow & red official City safety assessment placards (one of each color for each building entrance); inspection report forms for owner, ATC-20 Detailed Evaluation forms:

15 b. Hard hats, gloves, safety glasses, respirators, flashlights, tape measures, micrometer, hammer, screwdriver, and walkie-talkies or other emergency communication equipment (if needed): c. Ladders or other equipment needed for inspection access: d. Caution tape, barricades: e. Other necessary equipment or supplies: D. Emergency Inspection Plan Please attach inspection guidelines for the building which are consistent with ATC-20 Procedures for Postearthquake Safety Evaluation of Buildings including Detailed Evaluation Procedure (Appendix F). Note: Recommended methodology for welded steel joint inspection is SAC 3. The emergency inspection plan must include: 1. A detailed evaluation procedure. 2. Detailed instructions regarding where to look, what to look for, and how to obtain access to inspect specific structural and non-structural elements. 3. Detailed instructions regarding how to inspect specific structural and nonstructural elements and how to interpret observed damage. 4. Detailed instructions regarding additional inspection procedures to be performed following aftershocks. 5. [Optional] Placement of accelerometers. (This option may be considered in certain cases as an alternative to inspection of welded joints.) ATTACH AS MANY SHEETS AS REQUIRED.

16 Procedures for Postearthquake Safety Evaluation of Buildings Governor s Office of Emergency Services State of California ATC 20

17 5. Detailed Evaluation Method 5.1 Overview This method is primarily used to evaluate the safety of buildings posted Limited Entry after a Rapid Evaluation. Normally this will be done by having engineers familiar with building design observe the damage and assess its impact on life safety. Ideally, this evaluation will be carried out by a team of at least two structural engineers, both of whom have experience in the seismic design of buildings similar to those being inspected. In the aftermath of a large quake, however, this ideal may be impossible, and alternative teams will probably have to be used. One such alternative is the use of a team consisting of one structural engineer and one building inspector. The inspection team should closely examine the entire building, inside and out, particularly its structural system (.e., whatever parts are exposed and viewable). Ordinarily, they will not perform destructive exploration such as removal of plaster or gypsum walls to view the structural system, although in many cases this may be required of the owner before a full assessment can be made. The overall purpose of a Detailed Evaluation is to evaluate safety and recommend a posting classification. The Detailed Evaluation is intended to provide reasonable assurance that the structural system, as well as elements of the building that could cause falling hazards, are sufficiently safe before the building is put back into service. Considerable use of judgment by the inspection team will generally be required since it is very difficult, if not impossible, to develop damage evaluation procedures and guidelines that can be used without judgment. 5.2 Qualifications of Damage Inspectors Ideally, Detailed Evaluation should be conducted by damage investigators with experience in structural design and insight into the earthquake behavior of buildings. As previously mentioned, in the aftermath of a great quake, it may not be possible to have sufficient numbers of experienced engineers available, and officials in charge may have to make do with available resources. Normally, structural engineers, structural plan checkers, and other engineers with structural design expertise will be excellent choices for this task. Additional desirable qualifications include 5 to 10 years or more of experience, previous postevent inspection experience, and knowledge of earthquake effects on buildings. Certain items of concern are probably best evaluated by specialists. For example, a reinforced concrete highrise with substantial cracking in frames or walls is probably best visually assessed by a team of structural engineers experienced in the design of such structures. Similarly, suspected geotechnical hazards need to be assessed by geotechnical engineers or geologists, and elevator safety questions by elevator engineers and specialists. The makeup of the damage inspection team for the Detailed Evaluation of either a single large building or an area of several questionably damaged building or an area of several questionably damaged buildings needs attention from those coordinating and directing the overall event. 5.3 California OES Volunteer Engineer Program One way to obtain structural engineers to perform Detailed Evaluations is to use

18 volunteers. The State of California s Office of Emergency Services (OES) has developed such a plan in conjunction with the Structural Engineers Association of California (SEAOC). Under this plan, volunteer SEAOC engineers are brought in from outside the damaged area to help with the safety evaluations. These volunteer structural engineers are used to supplement the staff of the local building department. A similar program has also been sponsored by the California State Council of the American Society of Civil Engineers (ASCE). The ASCE volunteer engineer program provides assistance for evaluations of lifelines, such as airports, roads, bridges, dams, water treatment and wastewater treatment plants, and pipelines. ASCE also has volunteer geotechnical engineers available to assist with slope stability and other kinds of geotechnical evaluations needed for buildings. OES volunteer engineers are considered to be temporary, uncompensated disaster service workers. As such, they will enjoy the same immunities as officers and employees of the state and receive workman s compensation for injuries sustained on the job as provided by state law (California Government Code Sections 8580; 8657(a) and Labor Code Sections ). During their service, volunteer engineers will evaluate the safety of damaged structures using their best professional judgment. Under state law, no disaster service worker who is performing disaster services ordered by lawful authority during a State of War Emergency, State of Emergency, or a Local Emergency is liable for civil damages on account of personal injury to or death of any person or damage to property resulting from an act or omission in the line of duty, except one that is willful (California Civil Code, Section ). 5.4 Detailed Evaluation Objectives and Approach For most buildings, the principal objectives of the Detailed Evaluation are to establish whether there is a possibility of either (1) structural collapse or (2) falling hazards and to then post the structure. These are the two primary lifesafety concerns to consider when evaluating a damaged structure. Structural collapse, of course, can come from either the damaged structure itself or from outside sources, such as slope failure or collapse of an adjacent structure. In some instances, there may be concerns for other hazards such as toxic chemical spills, gas leaks, or inoperable exit doors. A fundamental assumption in the evaluation process is to consider that the structure must be capable of withstanding at least a repetition of the event that caused the initial damage without collapse and without additional risk from falling (or other) hazards. It should be emphasized, however, that this is a minimum requirement. The structural system of every building can be thought of as consisting of two systems: 1. Vertical-load-carrying system 2. Lateral-load-carrying system For a structure to be considered safe, both systems must be functional, and neither can be seriously degraded (e.g., badly spalled concrete columns, plywood diaphragm with separated sheets). This can be established either by inspecting the structural system directly, which may require removal of ceilings, walls and other architectural finishes to permit viewing, or by careful inspection of cladding, full-height plaster and gypsum board walls, and other architectural

19 finishes to verify that destructive story drifts have not taken place. The latter approach is best used when serious structural damage is not suspected. 5.5 General Detailed Evaluation Criteria General Items Inspection List. Given below are guidelines for rating damaged buildings. These are factors of concern common to many different types of buildings, such as 2-story wood frame apartments, tilt-up industrial structures, and multistory office buildings. In addition, more structure- or situationspecific guidelines covering where to look for damage, how to rate its life-safety significance, and what posting category to use (i.e., Inspected, Limited Entry, or Unsafe) are given in Chapters 6 through 10, respectively, for wood frame, masonry, tilt-up, concrete, and steel frame structures. Geotechnical hazards are covered in Chapter 11 and nonstructural hazards in Chapter 12. The damage inspection guidelines given below require the use of judgment. Under some circumstances, the posting actions recommended (e.g., Unsafe) may not be warranted, and use of a less restrictive posting (e.g., Limited Entry, Area Unsafe) or other action may be appropriate. 1. Overall Damage. This is perhaps the best indicator of the severity of the damage to the structural system. Severely racked walls, whole stories out of plumb, leaning buildings, broken foundations, and the like are excellent indicators of major structural distress. If a Rapid Evaluation is begun by examining the entire building, inside and out, for the unsafe conditions listed below. Collapse or Partial Collapse... UNSAFE Building or Individual Story Noticeably Leaning... UNSAFE Fractured Foundations... UNSAFE 2. Vertical Load System. Inspect the vertical load system. No structure must be allowed to remain in service if there are any real doubts about its ability to safely carry vertical loads (i.e., its own weight and the weight of any people and contents). Failure of the vertical load system either globally (e.g., partial collapse) or locally (e.g., buckled columns, failed corbel) is generally considered grounds for posting the entire structure unsafe. Columns Noticeably out of Plumb... UNSAFE Buckled or Failed Columns... UNSAFE Roof or Floor Framing Separation from Walls or Other Vertical Supports... UNSAFE Bearing Wall, Plaster, or Corbel Cracking Which Jeopardizes Vertical Support... UNSAFE Other Failure or Incipient Failure of Significant Vertical-Load-Carrying Element or Connection... UNSAFE 3. Lateral Load System. First identify and then inspect the lateral-load-resisting system. For a damaged structure to be permitted to remain in use, it must have a functioning lateral-loadresisting system. Broken X- bracing, severely cracked shear walls, hinging and massive spalling in concrete columns, badly damaged diaphragms, and the like are strong evidence that the lateral

20 load system may not be viable. Under these conditions, the structure should be considered unsafe until shown otherwise. Broken, Leaning, or Seriously Degraded Moment Frames... UNSAFE Severely Cracked Shear Walls... UNSAFE Broken or Buckled Vertical Braces... UNSAFE Broken or Seriously Damaged Diaphragms or Horizontal Bracing... UNSAFE Other Failure or Incipient Failure of Significant Lateral-Load- Carrying Element or Connection... UNSAFE 4. P-Delta Effects. For tall frame structures, particularly high-rise buildings, any residual story drift is generally quite serious. The weight of the portion of the structure above the deflected story results in additional moment on the columns, and attached girders, due to the P-delta effect. Any frame structure, particularly very tall structures, showing a significant residual drift in one or more stories should be considered unsafe until shown otherwise. More story drift can be tolerated in lightweight one- and two-story wood frame structures than heavy, non-ductile concrete or unreinforced masonry. Multistory Frame Building with Residual Drift... UNSAFE 5. Degradation of the Structural System. It is important to examine the structural system to determine that the entire system, or its major components, has not been so degraded that its strength and stiffness have been reduced to unsafe levels. This is a particular concern for concrete and masonry structural systems. For example, concrete frames that experience cracking, spalling, and local crushing of concrete, may still carry some vertical and lateral loads, but their overall strength can be greatly degraded even without the presence of other failure symptoms (e.g., buckled or out-of-plumb columns). Seriously Degraded Structural System... UNSAFE 6. Falling Hazards. Parapets, cladding, ornamentation, signs, joists and beams ending on ledgers, interior partitions, ceilings, and light fixtures are examples of items found in or on buildings that may become falling hazards. While many of these items may be damaged and fall due to the initial shock, the postevent hazard is that damaged items may fall as a result of static forces or an after shock. Areas within striking distance of potential falling objects must be placed off limits and barricaded to prevent access. Falling Hazard Present... UNSAFE 7. Slope or Foundation Distress. Examine the ground in the immediate area of the building for evidence of mass ground displacements. Liquefaction, slope movements, surface fault rupture and associated ground distortions, or other earthquake-related ground movements can result in damage to buildings. These vertical or horizontal ground displacements may fracture

21 foundations and cause severe structural distress to building superstructures. Once such foundation distress is observed or is suspected, or if there are new 1 inch or wider cracks in the foundation, or new differential settlements in excess of 1 inch, or if there are fissures more than several inches wide in the vicinity of buildings, a geotechnical engineer or engineering geologist should examine the site and assist with the safety evaluation. Often, geotechnical hazards cover areas larger than a single structure. For instance, large hillside slope failures may cover one or more city blocks. Base of Building Pulled Apart or Differentially Settled, with Fractured Foundations, Walls, Floors, or Roof... UNSAFE Building in Zone of Faulting or Suspected Major Slope Movement... UNSAFE Building in Danger of Being Impacted by Sliding or Falling Landslide Debris from Upslope... UNSAFE 8. Other Hazards. If unsafe conditions such as a friable asbestos release, broken fuel line, or chemical spill are observed, entry to the unsafe area should be restricted. Spill of Unknown or Suspected Dangerous Materials... UNSAFE Other Hazard (e.g., downed power line)... UNSAFE Additional Factors to Consider. The Detailed Evaluation procedure is designed to make maximum use of visual damage information. This is done by having the building thoroughly examined, inside and out, by the inspection team, using the above procedures. The net result of this inspection is to be a decision regarding the posting of the building (i.e., Inspected, Limited Entry, Unsafe). To do this, the inspectors must consider all the appropriate factors and aggregate these. Because the use of judgment is essential in virtually every case involving structural damage, the inspector should also keep in mind the following factors: 1. Intensity of Shaking Experienced. If the structure has sustained obvious damage in moderate or slight shaking, this has far more significance than if the same degree of damage was sustained under very strong shaking. 2. Preexisting Conditions. It is important to know what damage has occurred before the earthquake. For instance, cracking in concrete and masonry due to foundation settlement or shrinkage needs to be considered. 3. Basic Ductility of the Structural System. This is a very important factor when assessing the probable performance of a damaged structure in an aftershock. Unreinforced masonry and nonductile concrete structures generally have little ductility and, when damaged, often exhibit little capacity for resisting additional shaking. A well proportioned ductile steel frame or wellreinforced shear wall can often absorb additional energy with visible signs of distress, but without serious loss of function.

22 5.6 When the Structural System is not Viewable If it were not for the fact that architectural elements, such as walls and ceilings, conceal the structural system of most buildings, it would be a relatively easy matter to make postevent inspections and determine the extent of any structural damage. Unfortunately, this is not the case in most buildings, and the damage evaluation task is much more difficult. For the typical building, the damage inspector must usually examine the architectural walls, on both the interior and the exterior of the building, to gauge the amount of racking or story drift sustained as well as any overall building torsion or horizontal diaphragm distress. This information can be supplemented by observations of the structural system, wherever it is exposed, such as in basements, stairwells, or mechanical equipment rooms or at various other points on the interior or exterior of the building. When serious damage is suspected and not enough of the structural system is viewable to permit a reliable evaluation, the building should be posted Limited Entry or Unsafe and the occupants informed that they must evacuate the premises. The owner must be informed that he or she must do one of the following: (1) Arrange for demolition or removal of walls, plaster ceilings, etc. to permit completion of the evaluation; or (2) Arrange for an Engineering Evaluation. 2. In hillside areas, examine the area for landslide displacement or debris encroaching onto the site. 3. When geotechnical hazards are suspected, the Detailed Evaluation must be made by a team including a geotechnical engineer or geologist. 4. Since geotechnical hazards can extend in area to include several or more buildings, undamaged buildings in an unstable area may be posted Limited Entry or Unsafe. For example, if an embankment on which an undamaged structure is located has the potential to move further under static loading, the structure should be considered unsafe. Step 3: Inspect the Structural System from Inside the Building 1. Before entering the building, look for falling hazards and consider the danger of collapse. Do not enter obviously unsafe buildings. 2. Enter building. 3. Ordinarily, the structural system is concealed by walls, ceilings, and other architectural elements. The damage inspector may remove ceiling panels to better view the structural system, but destructive exploration of walls by the damage inspector is ordinarily not done. If the owner is willing, indicate where gypsum or plaster walls and other architectural elements should be removed to facilitate examination of the structural system. Any destructive exploration must be done only by the owner. 4. Look in stairwells, basements, mechanical rooms, and other exposed areas to view the structural system if it is covered elsewhere.

23 5. Examine the vertical-load-carrying system. Look for situations where a column may show signs of failure, where the floor or roof framing has begun to pull away from its vertical supports, or where the slab or beam has failed or begun to fail. 6. Examine the lateral-load-carrying system. Any residual story drift means some structural damage has been experienced. 7. Use guidance provided in the following chapters for hints on how to inspect various kinds of structures: Building Type Chapter Wood Frame 6 Masonry 7 Tilt-up 8 Concrete 9 Steel Frame 10 Remember that these are only guidelines and that judgment must be exercised to avoid imposing unwarranted hardship on owners and occupants of damaged buildings, but always avoid exposing occupants to unnecessary risk. 8. Inspect exposed components of the foundation system and the basement or lowest level floors for fractured components and uneven settlement. Also inspect basement floors and exterior walls for cracks and bulges. 9. Examine every floor, including basement, roof, and penthouse. 10. Remember that severe wall damage and broken glass are evidence of large story drifts. Step 4: Inspect for Nonstructural Hazards 1. Once inside the building, look for damage to the following: Cladding connections (if visible) Masonry partitions, particularly in older buildings where these may be unreinforced Demountable partitions Ceilings and light fixtures Rooftop water tanks Other appendages If cladding damage is suspected, inspect representative connections. Guidance on evaluating these and other nonstructural items is given in Chapter Severe damage to a nonstructural element does not in itself necessitate posting the entire structure unsafe. Only the unsafe area (e.g., rooms with damaged partitions) should be restricted if the building is otherwise safe. Step 5: Inspect for Other Hazards 1. Elevators should not be restarted without inspection. Refer to Chapter 12 for inspection procedure. 2. Look for spills or leaks in areas of stored chemicals or other hazardous materials. Refer to Chapter 16 for guidance. 3. If damage to fire protection and detection equipment is observed, it may be necessary to restrict

24 building use. Refer to Chapter 12 for guidance. 4. Inspect stairs for structural safety and exits for jammed doors and obstructions. Step 6: Complete Checklist and Post Building 1. Evaluate the structure and complete the Detailed Evaluation form (Appendix C). Indicate if shoring or bracing or other action is needed. of the three placards (Inspected, Limited Entry, or Unsafe). Post every entrance to a building classified as Limited Entry or Unsafe. 3. Explain the significance of Unsafe and Limited Entry postings to building occupants, and advise them to leave immediately. Areas designated Area Unsafe must also be evacuated. 2. Post the structure according to the results of the evaluation. Use one Table 5.1 Age Indicators of Construction Materials Age Indicator Material Older Construction Newer Construction Reinforced Concrete Straight sheathing form marks Plywood form marks Wood Framing Bowstring trusses Straight or diagonal sheathing Glulams Plywood sheathing Steel Framing Masonry Tilt-up Fire-resistant Partitions Riveted construction Common bolts Weak mortar Exposed wall anchors Header joints Plywood nailed to ledger, no roof anchors Hollow tile Wood lath and plaster Welded construction High-strength bolts Open-web joints Tapered girders Strong mortar Roof framing members anchored to wall Gypsum board

25 Figure 5.1 Structural systems with vertical discontinuities or irregularities.

26 Figure 5.2 Buildings with irregular configurations in plan.

27 ATC-20 Detailed Evaluation Safety Assessment Form Inspection Inspector ID: Affiliation: Inspection date and time: AM PM Final Posting from page 2 Inspected Restricted Use Unsafe Building Description Building name: Address: Building contact/phone Number of stories above ground: below ground: Approx. Footprint area (square feet): Number of residential units: Number of residential units not habitable: Type of Construction Wood frame Steel frame Tilt-up concrete Concrete frame Primary Occupancy Dwelling Other residential Public assembly Emergency services Concrete shear wall Unreinforced masonry Reinforced masonry Other: Primary Occupancy Commercial Government Offices Industrial Historic School Other: Evaluation Investigate the building for the conditions below and check the appropriate column. There is room on the second page for a sketch. Minor/None Moderate Severe Comments Overall hazards: Collapse or partial collapse Building or story leaning Other Structural hazards: Foundations Roofs, floors (vertical loads) Columns, pilasters, corbels Diaphragms, horizontal bracing Walls, vertical bracing Precast connections Other Nonstructural hazards: Parapets, ornamentation Cladding, glazing Ceilings, light fixtures Interior walls, partitions Elevators Stairs, exits Electric, gas Other Geotechnical hazards: Slope failure, debris Ground movement, fissures Other General Comments: Continue on page 2

28 ATC-20 Detailed Evaluation Safety Assessment Form Page 2 Building name: Inspector ID: Sketch (optional) Provide a sketch of the building or damaged portions. Indicate damage points Estimated Building Damage If requested by the jurisdiction, estimate building damage (repair cost replacement cost, excluding contents). None 0-1% 1-10% 10-30% 30-60% % 100% Posting If there is an existing posting from a previous evaluation, check the appropriate box. Previous posting: INSPECTED RESTRICTED USE UNSAFE Inspector ID: Date: If necessary, revise the posting based on the new evaluation and team judgment. Severe conditions endangering the overall building are grounds for an Unsafe posting. Severe and overall Moderate conditions may allow a Restricted Use posting. Indicate the current posting below and at the top of page one. INSPECTED (Green placard) RESTRICTED USE (Yellow placard) UNSAFE (Red placard) Record any use and entry restrictions exactly as written on placard: Further Actions Check the boxes below only if further actions are needed. Barricades needed in the following areas Engineering Evaluation recommended: Structural Geotechnical Other Other recommendations: Comments: