When can nonstructural archaic materials remain in place and what hazards must be mitigated?

Grounded in the retrieved California Historical Building Code — click a citation to read the verbatim passage:

• CHBC § 8-801 High relevance — show source text

  SECTION 8-801 — PURPOSE, INTENT AND SCOPE

  8-801.1 Purpose. The purpose of the CHBC is to provide regulations for the use of historical methods and materials of construction that are at variance with regular code requirements or are not otherwise codified, in buildings or structures designated as qualified historical buildings or properties. The CHBC require enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

  8-801.2 Intent. It is the intent of the CHBC to provide for the use of historical methods and materials of construction that are at variance with specific code requirements or are not otherwise codified.

  8-801.3 Scope. Any construction type or material that is, or was, part of the historical fabric of a structure is covered by this chapter. Archaic materials and methods of construction present in a historical structure may remain or be reinstalled or be installed with new materials of the same class to match existing conditions.

  SECTION 8-802 — GENERAL ENGINEERING APPROACHES

  Strength values for archaic materials shall be assigned based upon similar conventional codified materials, or on tests as hereinafter indicated. The archaic materials and methods of construction shall be thoroughly investigated for their details of construction in accordance with Section 8-703. Testing shall be performed when applicable to evaluate existing conditions. The architect or structural engineer in responsible charge of the project shall assign allowable stresses or strength levels to archaic materials. Such assigned strength values shall not be greater than those provided for in the following sections without adequate testing, and shall be subject to the concurrence of the enforcing agency.

  SECTION 8-803 — NONSTRUCTURAL ARCHAIC MATERIALS

  Where nonstructural historical materials exist in uses which do not meet the requirements of the regular code, their continued use is allowed by this code, provided that any public health and life safety hazards are mitigated subject to the concurrence of the enforcing agency.

  SECTION 8-804 — ALLOWABLE CONDITIONS FOR SPECIFIC MATERIALS

  Archaic materials which exist and are to remain in qualified historical buildings or structures shall be evaluated for their condition and for loads required by this code. The structural survey required in Section 8-703 of the CHBC shall document existing conditions, reinforcement, anchorage, deterioration and other factors pertinent to establishing allowable stresses, strength levels and adequacy of the archaic materials. The remaining portion of this chapter provides additional specific requirements for commonly encountered archaic materials.

  SECTION 8-805 — MASONRY

  For adobe, see Section 8-806.

  8-805.1 Existing solid masonry. Existing solid masonry walls of any type, except adobe, may be allowed, without testing, a maximum ultimate strength of 9 pounds per square inch (62.1 kPa) in shear where there is a qualifying statement by the architect or engineer that an inspection has been made, that mortar joints are filled and that both brick and mortar are reasonably good. The shear stress above applies to unreinforced masonry, except adobe, where the maximum ratio of unsupported height or length to thickness does not exceed 13, and where minimum quality mortar is used or exists. Wall height or length is measured to supporting or resisting elements that are at least twice as stiff as the tributary wall. Stiffness is based on the gross section. Shear stress may be increased by the addition of 10 percent of the axial direct stress due to the weight of the wall directly above.

• CHBC § 8-6 High relevance — show source text

  CHAPTER 8-6 ACCESSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . 11

  Section

  8-601 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 11

  8-602 Basic Provisions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

  8-603 Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

  8-604 Equivalent Facilitation. . . . . . . . . . . . . . . . . . . . . . . . . . 12

  CHAPTER 8-7 STRUCTURAL REGULATIONS. . . . . . . . . . . . . 13

  Section

  8-701 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 13 8-702 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

  8-703 Structural Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8-704 Nonhistorical Additions and

  Nonhistorical Alterations . . . . . . . . . . . . . . . . . . . . . . . 13

  8-705 Structural Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8-706 Lateral Load Regulations. . . . . . . . . . . . . . . . . . . . . . . . 14

  CHAPTER 8-8 ARCHAIC MATERIALS AND METHODS OF

  CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . 15

  Section

  8-801 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 15 8-802 General Engineering Approaches. . . . . . . . . . . . . . . . . 15 8-803 Nonstructural Archaic Materials. . . . . . . . . . . . . . . . . . 15

  8-804 Allowable Conditions for Specific Materials . . . . . . . 15 8-805 Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8-806 Adobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

  8-807 Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

  8-808 Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

• CHBC § 8-706.3 High relevance — show source text

  8-706.3 Load path. A complete and continuous load path, including connections, from every part or portion of the structure to the ground shall be provided for the required forces. It shall be verified that the structure is adequately tied together to perform as a unit when subjected to earthquake forces.

  8-706.4 Parapets. Parapets and exterior decoration shall be investigated for conformance with regular code requirements for anchorage and ability to resist prescribed seismic forces.

  An exception to regular code requirements shall be permitted for those parapets and decorations which are judged not to be a hazard to life safety.

  8-706.5 Nonstructural features. Nonstructural features of historical structure, such as exterior veneer, cornices and decorations, which might fall and create a life safety hazard in an earthquake, shall be evaluated. Their ability to resist seismic forces shall be verified, or the feature shall be strengthened with improved anchorage when appropriate.

  8-706.5.1 Partitions and ceilings of corridors and stairways serving an occupant load of 30 or more shall be investigated to determine their ability to remain in place when the building is subjected to earthquake forces.

  8-706.5.2 Seismic forces used to evaluate and improve nonstructural components and their anchorage, where required, shall comply with ASCE 41 or need not exceed 0.75 times the seismic forces prescribed by the requirements of the regular code.

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  8-8 ARCHAIC MATERIALS AND METHODS OF CONSTRUCTION

  SECTION 8-801 — PURPOSE, INTENT AND SCOPE

  8-801.1 Purpose. The purpose of the CHBC is to provide regulations for the use of historical methods and materials of construction that are at variance with regular code requirements or are not otherwise codified, in buildings or structures designated as qualified historical buildings or properties. The CHBC require enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

  8-801.2 Intent. It is the intent of the CHBC to provide for the use of historical methods and materials of construction that are at variance with specific code requirements or are not otherwise codified.

  8-801.3 Scope. Any construction type or material that is, or was, part of the historical fabric of a structure is covered by this chapter. Archaic materials and methods of construction present in a historical structure may remain or be reinstalled or be installed with new materials of the same class to match existing conditions.

  SECTION 8-802 — GENERAL ENGINEERING APPROACHES

  Strength values for archaic materials shall be assigned based upon similar conventional codified materials, or on tests as hereinafter indicated. The archaic materials and methods of construction shall be thoroughly investigated for their details of construction in accordance with Section 8-703. Testing shall be performed when applicable to evaluate existing conditions. The architect or structural engineer in responsible charge of the project shall assign allowable stresses or strength levels to archaic materials. Such assigned strength values shall not be greater than those provided for in the following sections without adequate testing, and shall be subject to the concurrence of the enforcing agency.

  SECTION 8-803 — NONSTRUCTURAL ARCHAIC MATERIALS

• CHBC § 8-807.3 High relevance — show source text

  8-807.3 Existing wood framing. Existing wood framing members may be assigned allowable stresses consistent with codes in effect at the time of construction. Existing or new replacement wood framing may be of archaic types originally used if properly researched, such as balloon and single wall. Wood joints such as dovetail and mortise and tenon types may be used structurally, provided they are well made. Lumber selected for use and type need not bear grade marks, and greater or lesser species such as low-level pine and fir, boxwood and indigenous hardwoods and other variations may be used for specific conditions where they were or would have been used.

  Wood fasteners such as square or cut nails may be used with a maximum increase of 50 percent over wire nails for shear.

  SECTION 8-808 — CONCRETE

  8-808.1 Materials. Natural cement concrete, unreinforced rubble concrete and similar materials may be utilized wherever that material is used historically. Concrete of low strength and with less reinforcement than required by the regular code may remain in place. The architect or engineer shall assign appropriate values of strength based on testing of samples of the materials. Bond and development lengths shall be determined based on historical information or tests.

  8-808.2 Detailing. The architect or engineer shall carefully evaluate all detailing provisions of the regular code which are not met and shall consider the implications of these variations on the ultimate performance of the structure, giving due consideration to ductility and reserve strength.

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  ARCHAIC MATERIALS AND METHODS OF CONSTRUCTION

  SECTION 8-809 — STEEL AND IRON

  The hand-built, untested use of wrought or black iron, the use of cast iron or grey iron, and the myriad of joining methods that are not specifically allowed by code may be used wherever applicable and wherever they have proven their worth under the considerable span of years involved with most qualified historical buildings or structures. Uplift capacity should be evaluated and strengthened where necessary. Fixed conditions or midheight lateral loads on cast iron columns that could cause failure should be taken into account. Existing structural wrought, forged steel or grey iron may be assigned the maximum working stress prevalent at the time of original construction.

  SECTION 8-810 — HOLLOW CLAY TILE

  The historical performance of hollow clay tile in past earthquakes shall be carefully considered in evaluating walls of hollow clay tile construction. Hollow clay tile bearing walls shall be evaluated and strengthened as appropriate for lateral loads and their ability to maintain support of gravity loads. Suitable protective measures shall be provided to prevent blockage of exit stairways, stairway enclosures, exit ways and public ways as a result of an earthquake.

  SECTION 8-811 — VENEERS

  8-811.1 Terra cotta and stone. Terra cotta, cast stone and natural stone veneers shall be investigated for the presence of suitable anchorage. Steel anchors shall be investigated for deterioration or corrosion. New or supplemental anchorage shall be provided as appropriate.

  8-811.2 Anchorage. Brick veneer with mechanical anchorage at spacings greater than required by the regular code may remain, provided the anchorages have not corroded. Nail strength in withdrawal in wood sheathing may be utilized to its capacity in accordance with code values.

  SECTION 8-812 — GLASS AND GLAZING

• CHBC § 8-706.1.3 High relevance — show source text

  Exceptions:

  1. Alternative standards may be used on a case-by-case basis when approved by the authority having jurisdiction. It shall be permitted to exceed the strength limitation of 100 psi in Section A108.2 of the CEBC when test data and building configuration supports higher values subject to the approval of the authority having jurisdiction.
  2. CEBC Section A102.2 shall not apply to Qualified Historical Buildings in Risk Category III buildings and other structures whose primary occupancies are public assembly with an occupancy load greater than 300.

  8-706.1.3 All deviations from the detailing provisions of the lateral-force-resisting systems shall be evaluated for stability and the ability to maintain load-carrying capacity at the expected inelastic deformations.

  8-706.2 Existing building performance. The seismic resistance may be based upon the ultimate capacity of the structure to perform, giving due consideration to ductility and reserve strength of the lateral-force-resisting system and materials while maintaining a reasonable factor of safety. Broad judgment may be exercised regarding the strength and performance of materials not recognized by regular code requirements. (See Chapter 8-8, Archaic Materials and Methods of Construction.)

  8-706.2.1 All structural materials or members that do not comply with detailing and proportioning requirements of the regular code shall be evaluated for potential seismic performance and the consequence of non-compliance. All members that would be reasonably expected to fail and lead to collapse or life threatening injury when subjected to seismic demands shall be judged unacceptable, and appropriate structural strengthening shall be developed.

  8-706.3 Load path. A complete and continuous load path, including connections, from every part or portion of the structure to the ground shall be provided for the required forces. It shall be verified that the structure is adequately tied together to perform as a unit when subjected to earthquake forces.

  8-706.4 Parapets. Parapets and exterior decoration shall be investigated for conformance with regular code requirements for anchorage and ability to resist prescribed seismic forces.

  An exception to regular code requirements shall be permitted for those parapets and decorations which are judged not to be a hazard to life safety.

  8-706.5 Nonstructural features. Nonstructural features of historical structure, such as exterior veneer, cornices and decorations, which might fall and create a life safety hazard in an earthquake, shall be evaluated. Their ability to resist seismic forces shall be verified, or the feature shall be strengthened with improved anchorage when appropriate.

  8-706.5.1 Partitions and ceilings of corridors and stairways serving an occupant load of 30 or more shall be investigated to determine their ability to remain in place when the building is subjected to earthquake forces.

  8-706.5.2 Seismic forces used to evaluate and improve nonstructural components and their anchorage, where required, shall comply with ASCE 41 or need not exceed 0.75 times the seismic forces prescribed by the requirements of the regular code.

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  8-8 ARCHAIC MATERIALS AND METHODS OF CONSTRUCTION

  SECTION 8-801 — PURPOSE, INTENT AND SCOPE

• CHBC § 8-804 High relevance — show source text

  SECTION 8-804 — ALLOWABLE CONDITIONS FOR SPECIFIC MATERIALS

  Archaic materials which exist and are to remain in qualified historical buildings or structures shall be evaluated for their condition and for loads required by this code. The structural survey required in Section 8-703 of the CHBC shall document existing conditions, reinforcement, anchorage, deterioration and other factors pertinent to establishing allowable stresses, strength levels and adequacy of the archaic materials. The remaining portion of this chapter provides additional specific requirements for commonly encountered archaic materials.

  SECTION 8-805 — MASONRY

  For adobe, see Section 8-806.

  8-805.1 Existing solid masonry. Existing solid masonry walls of any type, except adobe, may be allowed, without testing, a maximum ultimate strength of 9 pounds per square inch (62.1 kPa) in shear where there is a qualifying statement by the architect or engineer that an inspection has been made, that mortar joints are filled and that both brick and mortar are reasonably good. The shear stress above applies to unreinforced masonry, except adobe, where the maximum ratio of unsupported height or length to thickness does not exceed 13, and where minimum quality mortar is used or exists. Wall height or length is measured to supporting or resisting elements that are at least twice as stiff as the tributary wall. Stiffness is based on the gross section. Shear stress may be increased by the addition of 10 percent of the axial direct stress due to the weight of the wall directly above. Higher-quality mortar may provide a greater shear value and shall be tested in accordance with Appendix A, Chapter A1 of the California Existing Building Code (CEBC) 2010 edition, and as modified by the CHBC.

  8-805.2 Stone masonry.

  8-805.2.1 Solid-backed stone masonry. Stone masonry solidly backed with brick masonry shall be treated as solid brick masonry as described in Section 8-805.1 and in the 2009 International Existing Building Code [®] (IEBC [®] ), provided representative testing and inspection verifies solid collar joints between stone and brick and that a reasonable number of stones lap with the brick wythes as headers or that steel anchors are present. Solid stone masonry where the wythes of stone effectively overlap to provide the equivalent header courses may also be treated as solid brick masonry.

  8-805.2.2 Independent wythe stone masonry. Stone masonry with independent face wythes may be treated as solid brick masonry as described in Section 8-805.1 and the CEBC, provided representative testing and inspection verify that the core is essentially solid in the masonry wall and that steel ties are epoxied in drilled holes between outer stone wythes at floors, roof and not to exceed 4 feet (1219 mm) on center in each direction, between floors and roof. A reinforcing element shall exist or be provided at or near the top of all stone masonry walls.

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  ARCHAIC MATERIALS AND METHODS OF CONSTRUCTION

  8-805.2.3 Testing of stone masonry. Testing of stone masonry shall be similar to the 2010 CEBC requirements for brick masonry, except that representative stones which are not interlocked shall be pulled outward from the wall and shear area appropriately calculated after the test.

• CHBC § 8-903.3 High relevance — show source text

  8-903.3 Materials. New nonhistorical materials shall comply with the regular code requirements. The enforcing agency shall accept alternative materials which do not create a safety hazard where their use is necessary to maintain the historical integrity of the building.

  8-903.4 Drainage and vent systems. Plumbing fixtures shall be connected to an adequate drainage and vent system. The enforcing agency may require operational tests for drainage and vent systems which do not comply with applicable requirements of the regular code. Vent terminations may be installed in any location which, in the opinion of the enforcing agency, does not create a safety hazard.

  8-903.5 Indirect and special wastes. Indirect and special waste systems shall be installed so that no safety hazard is created. Chemical or industrial liquid wastes which may detrimentally affect the sanitary sewer system shall be pretreated to render them safe prior to discharge.

  8-903.6 Traps and interceptors. Traps and interceptors shall comply with the regular code requirements except that the enforcing agency shall accept solutions which do not increase the safety hazard. Properly maintained “S” and drum traps may remain in use.

  8-903.7 Joints and connections.

  8-903.7.1 Joints and connections in new plumbing systems shall comply with applicable requirements of the regular code.

  8-903.7.2 Joints and connections in existing or restored systems may be of any type that does not create a safety hazard.

  8-903.8 Water distribution. Plumbing fixtures shall be connected to an adequate water distribution system. The enforcing agency may require operational tests for water distribution systems which do not comply with applicable requirements of the regular code. Prohibited (unlawful) connections and cross connections shall not be permitted.

  8-903.9 Building sewers and private sewage disposal systems. New building sewers and new private sewage disposal systems shall comply with applicable requirements of the regular code.

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  MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS

  8-903.10 Fuel-gas piping. Fuel-gas piping shall comply with the regular code requirements except that the enforcing agency shall accept solutions which do not increase the safety hazard.

  SECTION 8-904 — ELECTRICAL

  8-904.1 General. Electrical systems shall comply with the regular code unless otherwise permitted by this code, or approved by the authority having jurisdiction.

  8-904.1.1 The provisions of the CHBC shall apply to the acceptance, location, installation, alteration, repair, relocation, replacement or addition of any electrical system or portion thereof, the premise wiring, or equipment fixed in place as related to restoration within or attached to a qualified historical building or property.

  8-904.1.2 Existing systems, wiring methods and electrical equipment which do not, in the opinion of the enforcing agency, constitute a safety hazard may remain in use.

  8-904.1.3 The enforcing agency may approve any alternative to the CHBC which achieves equivalent safety.

  8-904.1.4 Archaic methods that do not appear in present codes may remain and may be extended if, in the opinion of the enforcing agency, they constitute a safe installation.

  8-904.2 Wiring methods.

• CHBC § 8-8 Medium relevance — show source text

  CHAPTER 8-8 ARCHAIC MATERIALS AND METHODS OF

  CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . 15

  Section

  8-801 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 15 8-802 General Engineering Approaches. . . . . . . . . . . . . . . . . 15 8-803 Nonstructural Archaic Materials. . . . . . . . . . . . . . . . . . 15

  8-804 Allowable Conditions for Specific Materials . . . . . . . 15 8-805 Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8-806 Adobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

  8-807 Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

  8-808 Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

  8-809 Steel and Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

  8-810 Hollow Clay Tile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

  8-811 Veneers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

  8-812 Glass and Glazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

  CHAPTER 8-9 MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . 19

  Section

  8-901 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 19 8-902 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

  8-903 Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8-904 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

  CHAPTER 8-10 QUALIFIED HISTORICAL DISTRICTS,

  SITES AND OPEN SPACES . . . . . . . . . . . . . . . 23

  Section

• CHBC § 6.850 Medium relevance — show source text

  850|6.850| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|<75|≤0.6421
  FL
  ≤0.5789
  IPLV.IP|≤0.7316
  FL
  ≤0.4632
  IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|AHRI
  550/590| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|<75|≤0.6421
  FL
  ≤0.5789
  IPLV.IP|≤0.7316
  FL
  ≤0.4632
  IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|≥75
  and
  <150|≤0.5895
  FL
  ≤0.5474
  IPLV.IP|≤0.6684
  FL
  ≤0.4211
  IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|≥75
  and
  <150|≤0.5895
  FL
  ≤0.5474
  IPLV.IP|≤0.6684
  FL
  ≤0.4211
  IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|≥150
  and
  <300|≤0.5895
  FL
  ≤0.5263
  IPLV.IP|≤0.6263
  FL
  ≤0.4105
  IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
  source
  electri-
  cally
  operated
  centrifu-
  gal|≥150
  and
  <300|≤0.5895
  FL
  ≤0.5263
  IPLV.IP|≤0.6263
  FL
  ≤0.4105
  IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|≥6.150|≥6.150|

• CHBC § 8-104.3 Medium relevance — show source text

  ENFORCING AGENCY, Authority Having Jurisdiction, Local Agency with Jurisdiction. An entity with the responsibility for regulating, enforcing, reviewing or otherwise that exerts control of or administration over the process of granting permits, approvals, decisions, variances, appeals for qualified historical buildings or properties.

  EXIT LADDER DEVICE. An exit ladder device is a permanently installed, fixed, folding, retractable or hinged ladder intended for use as a means of emergency egress from areas of the second or third stories. Unless approved specifically for a longer length, the ladder shall be limited to 25 feet (7620 mm) in length. Exit ladders are permitted where the area served by the ladder has an occupant load less than 10 persons.

  FIRE HAZARD. Any condition which increases or may contribute to an increase in the hazard or menace of fire to a greater degree than customarily recognized by the authority having jurisdiction, or any condition or act which could obstruct, delay, hinder or interfere with the operations of firefighting personnel or the egress of occupants in the event of fire. Section 8-104.3, SHBC appeals, remains applicable.

  HISTORICAL FABRIC OR MATERIALS. Original and later-added historically significant construction materials, architectural finishes or elements in a particular pattern or configuration which form a qualified historical property, as determined by the authority having jurisdiction.

  HISTORICAL SIGNIFICANCE. Importance for which a property has been evaluated and found to be historical, as determined by the authority having jurisdiction.

  IMMINENT THREAT. Any condition within or affecting a qualified historical building or property which, in the opinion of the authority having jurisdiction, would qualify a building or property as dangerous to the extent that the life, health, property or safety of the public, its occupants or those performing necessary repair, stabilization or shoring work are in immediate peril due to conditions affecting the building or property. Potential hazards to persons using, or improvements within, the right-of-way may not be construed to be “imminent threats” solely for that reason if the hazard can be mitigated by shoring, stabilization, barricades or temporary fences.

  INTEGRITY. Authenticity of a building or property’s historical identity, evidenced by the survival of physical characteristics that existed during the property’s historical or prehistorical period of significance.

  LIFE SAFETY EVALUATION. An evaluation of the life safety hazards of a qualified historical building or property based on procedures similar to those contained in NFPA 909, Standard for the Protection of Cultural Resources, Appendix B, Fire Risk Assessment in Heritage Premises.

  LIFE SAFETY HAZARD. See Distinct Hazard.

  PERIOD OF SIGNIFICANCE. The period of time when a qualified historical building or property was associated with important events, activities or persons, or attained the characteristics for its listing or registration.

  PRESERVATION. The act or process of applying measures necessary to sustain the existing form, integrity and materials of a qualified historical building or property. Work, including preliminary measures to protect and stabilize the property, generally focuses upon the ongoing maintenance and repair of historic materials and features rather than extensive replacement and new construction. New exterior additions are not within the scope of this treatment; however, the limited and sensitive upgrading of mechanical,

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  DEFINITIONS

  electrical and plumbing systems and other code-related work to make properties functional is appropriate within a preservation project.

• CHBC § 31F-45 Medium relevance — show source text

  m = Seismic mass

  R p = Response modification factor for nonstructural component or nonbuilding structure S A = Spectral response acceleration at T

  2025 CALIFORNIA BUILDING CODE 31F-45

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  MARINE OIL TERMINALS

  S xs = Spectral acceleration in Section 3103F.4.2.4 or Section 3103F.4.2.5

  S 1 = 1-second spectral response acceleration

  T = Fundamental period of the elastic structure

  T e = Effective elastic structural period T eff, i = Effective structural period at step i of iteration T p = Period of flexible nonstructural component or nonbuilding structure T 0 = Period at peak of the acceleration response spectrum

  V = Base shear strength of the structure obtained from a plastic analysis

  V sk = Shear force across shear keys

  V Δ T = Total segment lateral force

  W = Dead load of the frame

  W p = Weight of the nonstructural component or nonbuilding structure Δ d = Target displacement demand Δ d, i = Target displacement demand at step i of iteration Δ d, j = Target displacement demand at step j of iteration α 1 = Positive post-yield slope ratio equal to positive post-yield stiffness divided by the effective stiffness

  α 2 = Negative post-yield slope ratio equal to negative post-yield stiffness divided by the effective stiffness

  α e = Effective negative post-yield slope ratio equal to effective post-yield negative stiffness divided by the effective stiffness

  α P- Δ = Negative slope ratio caused by P- Δ effects Δ avg = Average of displacements, Δ 1 and Δ 2 , at ends of the MOT transverse to an axis Δ d = Target displacement

  Δ m = Maximum of displacements, Δ 1 and Δ 2 , at ends of the MOT transverse to an axis Δ y = Displacement at yield strength Δ 1 , Δ 2 = Displacement at ends of the MOT transverse to an axis δ d = Design displacement demand at an element δ x = Displacement of an element in X direction δ y = Displacement of an element in Y direction δ xx = X displacement under X direction excitation δ xy = X displacement under Y direction excitation δ yx = Y displacement under X direction excitation δ yy = Y displacement under Y direction excitation λ = Near-field effect factor

  μ max = Maximum strength ratio μ strength = Ratio of elastic strength demand to yield strength μ Δ,ι = Initial ductility level ξ eff,i = Effective structural damping at step i of iteration

  3104F.7 References.

  [4.1] American Society of Civil Engineers (ASCE), 2016, ASCE/SEI 7-16 (ASCE/SEI 7), “Minimum Design Loads and Associates Criteria for Buildings and Other Structures,” Reston, VA.

• CHBC § 8-702.2 Medium relevance — show source text

  8-702.2 Nothing in these regulations shall prevent voluntary and partial seismic upgrades when it is demonstrated that such upgrades will improve life safety and when a full upgrade would not otherwise be required.

  SECTION 8-703 — STRUCTURAL SURVEY

  8-703.1 Scope. When a structure or portion of a structure is to be evaluated for structural capacity under the CHBC, it shall be surveyed for structural conditions by an architect or engineer knowledgeable in historical structures. The survey shall evaluate deterioration or signs of distress. The survey shall determine the details of the structural framing and the system for resistance of gravity and lateral loads. Details, reinforcement and anchorage of structural systems and veneers shall be determined and documented where these members are relied on for seismic lateral resistance.

  8-703.2 The results of the survey shall be utilized for evaluating the structural capacity and for designing modifications to the structural system to reach compliance with this code.

  8-703.3 Historical records. Past historical records of the structure or similar structures may be used in the evaluation, including the effects of subsequent alterations.

  SECTION 8-704 — NONHISTORICAL ADDITIONS AND NONHISTORICAL ALTERATIONS

  8-704.1 New nonhistorical additions and nonhistorical alterations which are structurally separated from an existing historical building or structure shall comply with regular code requirements.

  8-704.2 New nonhistorical additions which impose vertical or lateral loads on an existing structure shall not be permitted unless the affected part of the supporting structure is evaluated and strengthened, if necessary, to meet regular code requirements.

  Note: For use of archaic materials, see Chapter 8-8.

  SECTION 8-705 — STRUCTURAL REGULATIONS

  8-705.1 Gravity loads. The capacity of the structure to resist gravity loads shall be evaluated and the structure strengthened as necessary. The evaluation shall include all parts of the load path. Where no distress is evident, and a complete load path is present, the structure may be assumed adequate by having withstood the test of time if anticipated dead and live loads will not exceed those historically present.

  8-705.2 Wind and seismic loads. The ability of the structure to resist wind and seismic loads shall be evaluated. Wind loads shall be considered when appropriate, but need not exceed 75 percent of the wind loads prescribed by the regular code. The evaluation shall be based on the requirements of Section 8-706.

  8.705.2.1 Any unsafe conditions in the lateral-load-resisting system shall be corrected, or alternative resistance shall be provided. When strengthening is required, additional resistance shall be provided to meet the minimum requirements of the CHBC. The strengthening measures shall be selected with the intent of meeting the performance objectives set forth in Section 8-701.2. The evaluation of structural members and structural systems for seismic loads shall consider the inelastic performance of structural members and their ability to maintain load-carrying capacity during the seismic loadings prescribed by the regular code.

  8.705.2.2 The architect or engineer shall consider additional measures with minimal loss of, and impact to, historical materials which will reduce damage and needed repairs in future earthquakes to better preserve the historical structure in perpetuity. These additional measures shall be presented to the owner for consideration as part of the rehabilitation or restoration.

  2025 CALIFORNIA HISTORICAL BUILDING CODE 13

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  STRUCTURAL REGULATIONS