How to evaluate gravity-load capacity and when may the structure be assumed adequate?

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

• CHBC § 8-702.2 High 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

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  STRUCTURAL REGULATIONS

• CHBC § 8-705.1 High relevance — show source text

  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

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  STRUCTURAL REGULATIONS

  SECTION 8-706 — LATERAL LOAD REGULATIONS

  8-706.1 Seismic forces. Strength-level seismic forces used to evaluate the structure for resistance to seismic loads shall be based on the R -values tabulated in the regular code for similar lateral-force-resisting systems including consideration of the structural detailing of the members where such R -values exist. Where such R -values do not exist, an appropriate R -value shall be rationally assigned considering the structural detailing of the members.

  Exceptions:

  1. The forces need not exceed 0.75 times the seismic forces prescribed by the regular code requirements.
  2. For Risk Category I, II or III structures, near-fault increases in ground motion (maximum considered earthquake ground motion of 0.2 second spectral response greater than 150 percent at 5 percent damping) need not be considered when the fundamental period of the building is 0.5 seconds in the direction under consideration.
  3. For Risk Category I or II structures, the seismic base shear need not exceed 0.30W.
  4. For Risk Category III or IV structures, the seismic base shear need not exceed 0.40W.

  8-706.1.1 When a building is to be strengthened with the addition of a new lateral force resisting system, the R -value of the new system can be used when the new lateral force resisting system resists at least 75 percent of the building’s base shear regardless of its relative rigidity.

  8-706.1.2 Evaluation and seismic improvement of unreinforced masonry bearing wall buildings shall comply with the California Existing Building Code (CEBC), Appendix Chapter A1 2013 Edition, and as modified by the CHBC.

  Exceptions:

• CHBC § 4-17 High relevance — show source text

  where:

  δ d = δ x + δ y

  Equation 4-17 δ x = δ xy + 0.3 δ xx

  and

  Equation 4-18 δ y = 0.3 δ yx + δ yy

  OR

  Equation 4-19 δ y = δ yx + 0.3 δ yy

  and

  Equation 4-20 δ x = 0.3 δ xy + δ xx whichever results in the greater design displacement demand.

  31F-40 2025 CALIFORNIA BUILDING CODE

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

  MARINE OIL TERMINALS

  FIGURE 31F-4-7 — PLAN VIEW OF WHARF SEGMENT UNDER X AND Y SEISMIC EXCITATIONS

  3104F.4.3 P- Δ Effects. The P- Δ effect (i.e., the additional moment induced by the total vertical load multiplied by the lateral deck deflection) shall be considered unless the following relationship is satisfied (see Figure 31F-4-8):

  Equation 4-21

  V ≥ 4 [Δ] [d] W [--] [-] [-----] H

  where:

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

  W = dead load of the frame

  Δ d = displacement demand

  H = distance from the location of maximum in-ground moment to center of gravity of the deck

  FIGURE 31F-4-8 — P- Δ EFFECT

  For wharf structures where the lateral displacement is limited by almost fully embedded piles, P- Δ effects may be ignored; however, the individual stability of the piles shall be checked in accordance with Section 3107F.2.5.2.

  If the landside batter piles are allowed to fail in a Level 2 evaluation, the remaining portion of the wharf shall be checked for P- Δ effects.

  3104F.4.4 Expansion joints. The effect of expansion joints shall be considered in the seismic analysis.

  3104F.4.5 Shear key forces. Shear force across shear keys connecting adjacent wharf segments, V sk , (approximate upper bound to the shear key force [4.7]) shall be calculated as follows:

  Equation 4-22 V sk = 1.5(e/L l )V ΔT

  where:

  V Δ T = total segment lateral force found from a push-over analysis

  L l = segment length

  e = eccentricity between the center of rigidity and the center of mass

  3104F.4.6 Connections. For an existing wharf, the deteriorated conditions at the junction between the pile top and pile cap shall be considered in evaluating the moment capacity. Connection detail between the vertical pile and pile cap shall be evaluated to deter- mine whether full or partial moment capacity can be developed under seismic action.

  For new MOTs, the connection details shall develop the full moment capacities.

• CHBC § 8-810 Medium relevance — show source text

  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

  8-812.1 Glazing subject to human impact. Historical glazing material located in areas subject to human impact may be approved subject to the concurrence of the enforcing agency when alternative protective measures are provided. These measures may include, but not be limited to, additional glazing panels, protective film, protective guards or systems, and devices or signs which would provide adequate public safety.

  8-812.2 Glazing in fire-rated systems. See Section 8-402.3.

  TABLE8-8A—STRENGTH VALUES FOR EXISTING MATERIALS	Col2
  EXISTING MATERIALS OR CONFIGURATIONS OF MATERIALS1	STRENGTH LEVEL CAPACITY x14.594 for N/m
  1. Horizontal diaphragms2 1.1. Roofs with straight sheathing and roofing applied directly to the sheathing 1.2. Roofs with diagonal sheathing and roofing applied directly to the sheathing 1.3. Floors with straight tongue-and-groove sheathing 1.4. Floors with straight sheathing and finished wood flooring with board edges offset or perpendicular 1.5. Floors with diagonal sheathing and finished	300 lbs per foot for seismic shear 750 lbs per foot for seismic shear 300 lbs per foot for seismic shear 1,500 lbs per foot for seismic shear 1,800 lbs per foot for seismic shear
  2. Crosswalls2,3 2.1. Plaster on wood or metal lath 2.2. Plaster on gypsum lath 2.3. Gypsum wallboard, unblocked edges 2.4.

• CHBC § 8-2 Medium relevance — show source text

  The vertical spring stiffness_ values may be determined either from Figure 8-2 or Equation 8-11, or as provided by the geotechnical engineer. Acceptance criteria for soil bearing shall be considered met, based on one of the following methods, either A or B: A) Soil spring reactions are limited by the ultimate soil bearing capacity, and the foundation system is stable under the applied loads. B) The resisting soil pressure distribution under the footing is triangular such that the maximum soil bearing pressure at any point of the footing is less than the ultimate soil bearing capacity. Subject to the approval of the authority having jurisdiction, higher soil pressures may be permitted when appropri- ately justified.

  The evaluation of the foundation structural element shall be considered as force controlled in accordance with the material chapters using the bearing pressure distribution under the footing from the same method used for the soil bearing acceptance criteria.

  8.4.2.3.2.2 Alternatively, superstructure pseudo force overturning demands to the foundation are permitted to be divided by the appropriate m-factors above and applied to the mathematical model representing the foundation system only, re-analyzed as a beam on Winkler springs (soil does not resist tension). Acceptance criteria for soil bearing shall be considered met, based on one of the following methods, either A or B: A) Soil spring reactions are limited by the ultimate soil bearing capacity, and the foundation system is stable under the applied loads.

  2025 CALIFORNIA EXISTING BUILDING CODE 3A-7

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  PROVISIONS FOR ALL COMPLIANCE METHODS

  B) The resisting soil pressure distribution under the footing is triangular, and the maximum soil bearing pressure at any point of the footing is less than the ultimate soil bearing capacity. Subject to the approval of the authority having jurisdiction, higher soil pressures may be permitted when appropri- ately justified.

  The evaluation of the foundation structural element shall be considered as force controlled in accordance with the material chapters using the bearing pressure distribution under the footing from the same method used for the soil bearing acceptance criteria.

  304A.3.5.11 ASCE 41-13 Section 8.5.1. Modify ASCE 41-13 Section 8.5.1 with the following:

  The product of RRS bsa x RRS e , shall not be less than 0.7.

  The combined effect of kinematic interaction and foundation damping shall meet the following:

  1. The site-specific response spectrum modified for soil-structure interaction effects shall not be taken as less than 80 percent of the spectral acceleration as determined from a site-specific response spectrum in accordance with ASCE 7 Section 21.3, or

  2. The site-specific response spectrum modified for soil-structure interaction effects shall not be taken as less than 70 percent of the spectral acceleration as determined from the design response spectrum and MCE R response spectrum in accordance with ASCE 7 Sections 11.4.5 and 11.4.6, respectively.

  Exception: For the seismic retrofit of existing nonconforming buildings, design ground motion shall be consistent with performance objectives in Section 304A.3.4.

  304A.3.5.12 ASCE 41-13 Section 8.6. Modify ASCE 41-13 Section 8.6 with the following:

• CHBC § 4.3 Medium relevance — show source text

  1805 A .4.3 Drainage discharge. The floor base and foundation perimeter drain shall discharge by gravity or mechanical means into an approved drainage system that complies with the California Plumbing Code .

  Exception: Where a site is located in well-drained gravel or sand/gravel mixture soils, a dedicated drainage system is not required.

  SECTION 1806 A —PRESUMPTIVE LOAD-BEARING VALUES OF SOILS

  1806 A .1 Load combinations. The presumptive load-bearing values provided in Table 1806 A .2 shall be used with the allowable stress design load combinations specified in ASCE 7, Section 2.4 or the alternative allowable stress design load combinations of Section 1605 A .2. The values of vertical foundation pressure and lateral bearing pressure given in Table 1806 A .2 shall be permitted to be increased by one-third where used with the alternative allowable stress design load combinations of Section 1605 A .2 that include wind or earthquake loads.

  1806 A .2 Presumptive load-bearing values. The load-bearing values used in design for supporting soils and rock near the surface shall not exceed the values specified in Table 1806 A .2 unless data to substantiate the use of higher values are submitted and approved. Where the building official has reason to doubt the classification, strength or compressibility of the soil or rock, the requirements of Section 1803 A .5.2 shall be satisfied.

  Presumptive load-bearing values shall apply to materials with similar physical and engineering characteristics. Mud, organic silt and organic clays (OL, OH), peat (Pt) and undocumented fill shall not be assumed to have a presumptive load-bearing capacity unless data to substantiate the use of such a value are submitted.

  Exception: A presumptive load-bearing capacity shall be permitted to be used where the building official deems the load-bearing capacity is adequate for the support of lightweight or temporary structures.

  TABLE 1806A.2—PRESUMPTIVE LOAD-BEARING VALUES	Col2	Col3	Col4	Col5
  CLASS OF MATERIALS	VERTICAL FOUNDATION PRESSURE (psf)	LATERAL BEARING PRESSURE (psf/ft below natural grade)	LATERAL SLIDING RESISTANCE	LATERAL SLIDING RESISTANCE
  CLASS OF MATERIALS	VERTICAL FOUNDATION PRESSURE (psf)	LATERAL BEARING PRESSURE (psf/ft below natural grade)	Coefficient of frictiona	Cohesion (psf)b
  1. Crystalline bedrock	12,000	1,200	0.70	—
  2. Sedimentary and foliated rock	4,000	400	0.35	—
  3. Sandy gravel and gravel (GW and GP)	3,000	200	0.35	—
  4. Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC)	2,000	150	0.25	—
  5.

• CHBC § 8-7 Medium relevance — show source text

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  8-7 STRUCTURAL REGULATIONS

  SECTION 8-701 — PURPOSE, INTENT AND SCOPE

  8-701.1 Purpose. The purpose of the CHBC is to provide alternative regulations to the regular code for the structural safety of buildings designated as qualified historical buildings or properties. The CHBC requires enforcing agencies to accept any reasonably equivalent alternatives to the regular code when dealing with qualified historical buildings or properties.

  8-701.2 Intent. The intent of this chapter is to encourage the preservation of qualified historical buildings or structures while providing standards for a minimum level of building performance with the objective of preventing partial or total structural collapse such that the overall risk of life-threatening injury as a result of structural collapse is low.

  8-701.3 Application. The alternative structural regulations provided by Section 8-705 are to be applied in conjunction with the regular code whenever a structural upgrade or reconstruction is undertaken for qualified historical buildings or properties.

  SECTION 8-702 — GENERAL

  8-702.1 The CHBC shall not be construed to allow the enforcing agency to approve or permit a lower level of safety of structural design and construction than that which is reasonably equivalent to the regular code provisions in occupancies which are critical to the safety and welfare of the public at large, including, but not limited to, public and private schools, hospitals, municipal police and fire stations and essential services facilities.

  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

• CHBC § 1603.1.7 Medium relevance — show source text

  ** The design load-bearing values of soils shall be shown on the construction documents. 1603.1.7 Flood design data. For buildings located in whole or in part in flood hazard areas as established in Section 1612.3, the documentation pertaining to design, if required in Section 1612.4, shall be included and the following information, referenced to the datum on the community’s Flood Insurance Rate Map (FIRM), shall be shown, regardless of whether flood loads govern the design of the building:

  1. Flood design class assigned according to ASCE 24.
  2. In flood hazard areas other than coastal high hazard areas or coastal A zones, the elevation of the proposed lowest floor, including the basement.
  3. In flood hazard areas other than coastal high hazard areas or coastal A zones, the elevation to which any nonresidential building will be dry floodproofed.
  4. In coastal high hazard areas and coastal A zones, the proposed elevation of the bottom of the lowest horizontal structural member of the lowest floor, including the basement.

  1603.1.8 Special loads. Special loads that are applicable to the design of the building, structure or portions thereof, including but not limited to the loads of machinery or equipment, and that are greater than specified floor and roof loads shall be specified by their descriptions and locations.

  1603.1.8.1 Photovoltaic panel systems. The dead load of rooftop-mounted photovoltaic panel systems, including rack support systems, shall be indicated on the construction documents.

  1603.1.9 Roof rain load data. Design rainfall intensity, i (in/hr) (cm/hr), and roof drain, scupper and overflow locations shall be shown regardless of whether rain loads govern the design.

  SECTION 1604—GENERAL DESIGN REQUIREMENTS

  1604.1 General. Building, structures and parts thereof shall be designed and constructed in accordance with strength design, load and resistance factor design, allowable stress design, empirical design or conventional construction methods, as permitted by the applicable material chapters and referenced standards.

  1604.2 Strength. Buildings and other structures, and parts thereof, shall be designed and constructed to support safely the factored loads in load combinations defined in this code without exceeding the appropriate strength limit states for the materials of construction. Alternatively, buildings and other structures, and parts thereof, shall be designed and constructed to support safely the nominal loads in load combinations defined in this code without exceeding the appropriate specified allowable stresses for the materials of construction.

  Loads and forces for occupancies or uses not covered in this chapter shall be subject to the approval of the building official.

  1604.3 Serviceability. Structural systems and members thereof shall be designed to have adequate stiffness to limit deflections as indicated in Table 1604.3.

• CHBC § 503.3 Medium relevance — show source text

  [BS] 503.3 Existing structural elements carrying gravity load. Any existing gravity load-carrying structural element for which an alteration causes an increase in design dead, live or snow load, including snow drift effects, of more than 5 percent shall be replaced or altered as needed to carry the gravity loads required by the California Building Code for new structures. Any existing gravity load-carrying structural element whose gravity load-carrying capacity is decreased as part of the alteration shall be shown to have the capacity to resist the applicable design dead, live and snow loads including snow drift effects required by the California Building Code for new structures.

  Exceptions:

  1. Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes where the altered building complies with the conventional light-frame construction methods of the California Building Code or the provisions of the California Residential Code .
  2. Buildings in which the increased dead load is due entirely to the addition of a second layer of roof covering weighing 3 pounds per square foot (0.1437 kN/m [2] ) or less over an existing single layer of roof covering. [DSA-SS, DSA-SS/CC] Excep- tion 2 is not permitted.

  [BS] 503.4 Existing structural elements carrying lateral load. Except as permitted by Section 503.13, where the alteration increases design lateral loads, results in a prohibited structural irregularity as defined in ASCE 7, or decreases the capacity of any existing lateral load-carrying structural element, the lateral force-resisting system of the altered building or structure shall meet the requirements of Section 1609 of the California Building Code and Section 304.3.2 of this code.

  Exceptions:

  1. Any existing lateral load-carrying structural element whose demand-capacity ratio with the alteration considered is not more than 10 percent greater than its demand-capacity ratio with the alteration ignored shall be permitted to remain

  2025 CALIFORNIA EXISTING BUILDING CODE 5-5

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  PRESCRIPTIVE COMPLIANCE METHOD

  unaltered. For purposes of calculating demand-capacity ratios, the demand shall consider applicable load combinations with design lateral loads or forces in accordance with Section 1609 of the California Building Code and Section 304.3.1 or 304.3.2 of this code. The same methodology shall be used for the altered and unaltered structures. For purposes of this exception, comparisons of demand-capacity ratios and calculation of design lateral loads, forces and capacities shall account for the cumulative effects of additions and alterations since original construction. When calculating demandcapacity ratios for wind, the date of original construction shall be permitted to be taken as the date of completion of a prior addition, alteration or repair in compliance with Section 1609 of the California Building Code or the code wind forces in effect at the time. When calculating demand-capacity ratios for earthquake, the date of original construction shall be permitted to be taken as the date of completion of a prior addition, alteration or repair in compliance with Section 304.3.1 or Section 304.3.2, Item 1 or 3, or the full or reduced seismic forces in effect at the time.
• CHBC § 2306.2 Medium relevance — show source text

  For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c. Framing at adjoining panel edges shall be 3 inches nominal or wider.
  d. Staples shall have a minimum crown width of7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.
  e. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.
  f. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.
  g. For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c. Framing at adjoining panel edges shall be 3 inches nominal or wider.
  d. Staples shall have a minimum crown width of7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.
  e. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.
  f. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.
  g. For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c. Framing at adjoining panel edges shall be 3 inches nominal or wider.
  d.

• CHBC § 8-706.3 Medium 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 § 0.63 Medium relevance — show source text

  For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.
  g. For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c. Framing at adjoining panel edges shall be 3 inches nominal or wider.
  d. Staples shall have a minimum crown width of7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.
  e. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.
  f. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.
  g. For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c. Framing at adjoining panel edges shall be 3 inches nominal or wider.
  d. Staples shall have a minimum crown width of7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.
  e. The minimum nominal width of framing members not located at boundaries or adjoining panel edges shall be 2 inches.
  f. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.
  g. For Case 1 through 6 descriptions see Figure 2306.2(1).|For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
  a. For framing of other species: (1) Find specific gravity for species of lumber in ANSI/AWC NDS. (2) For staples find shear value from table for Structural I panels (regardless of
  actual grade) and multiply value by 0.82 for species with specific gravity of 0.42 or greater, or 0.65 for all other species.
  b. Space fasteners maximum 12 inches on center along intermediate framing members (6 inches on center where supports are spaced 48 inches on center).
  c.