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HomeMy WebLinkAboutNS-1518CTD/fm 1/10/80 ORDINANCE NO. NS-15t8 AN ORDINANCE OF THE CITY OF SANTA ANA AMENDING THE SANTA ANA MUNICIPAL CODE BY ADDING ARTICLE XI CONSISTING OF NEW SECTIONS 8-2000 THROUGH 8-2007, INCLUSIVE, TO CHAPTER 8, PROVIDING FOR EARTHQUAKE HAZARD REDUCTION IN EXISTING BUILDINGS. THE CITY COUNCIL OF THE CITY OF SANTA ANA DOES ORDAIN AS FOLLOWS: That the Santa Ana Municipal Code is hereby amended by adding Article XI consisting of sections 8-2000 through 8-2007, inclusive, to Chapter 8, which said Article shall read as follows: ARTICLE XI. EARTHQUAKE HAZARD REDUCTION IN EXISTING BUILDINGS. Sec. 8-2000. PURPOSE The purpose of this Article is to promote public health, safety and welfare by reducing the risk of death or injury that may result from the effects of earthquakes on unreinforced masonry buildings. Such buildings have caused substantial damage and danger when they have collapsed during past moderate to strong earthquakes. The provisions of this Article establish minimum standards for structural seismic resistance primarily to reduce the risk of death or injury but cannot prevent all loss of life or injury or prevent earthquake damage to an existing building even though it complies with these standards. This Article shall not require existing electrical, plumbing, mechanical or fire safety systems to be altered unless they consitute a hazard to life or property. This Article provides systematic procedures and standards for identification and classification of unrein- forced masonry buildings based on their present use. Priorities and standards are also established under which these buildings are required to be structurally analyzed. Where the analysis or testing determines deficiencies, this Article requires the building to be strengthened to minimum levels required for compliance or to be demolished. SEC. 8-2001. SCOPE The provisions of this Article shall apply to all existing buildings constructed with unreinforced masonry walls as defined herein. EXCEPTION: This Article shall not apply to detached dwellings or apartment houses containing fewer than 5 dwelling units. SEC. 8-2002. DEFINITIONS For the purpose of this Article, the following terms shall be construed as follows: A. ESSENTIAL BUILDINGS: Those structures or buildings which are used for emergency purposes after an earthquake in order to preserve the peace, health and safety of the general public. Such facilities shall include the following: hospitals and other medical facilities having surgery or emergency treatment areas; fire and police stations; municipal government disaster operation centers; and public utility and communication buildings deemed to be vital in emergencies. ORDINANCE NO. NS-15t8 Page Two B. HIGH RISK BUILDINGS: Any building, other than an essential building, having an occupant load of 100 occupants or more as determined pursuant to Chapter 33 of the Uniform Building Code and which said building is occupied for its intended use for more than 20 hours per week. EXCEPTION: High risk buildings shall not include buildings having exterior walls braced with masonry cross walls or wood frame cross walls spaced less than 40 feet apart in each story. C. LOW RISK BUILDINGS: Any building, other than an essential building, having a capacity of less than 20 occupants determined pursuant to Chapter 33 of the Uniform Building Code. D. MEDIUM RISK BUILDINGS: Any building having an occupant load of 20 occupants or more as determined pursuant to Chapter 33 of the Uniform Building Code that is not classified as a high risk building or an essential building. E. UNREINFORCED MASONRY WALL: A masonry wall contain- ing less than one-half the reinforcing steel required for reinforced masonry walls in accordance with Chapter 24 of the Uniform Building Code. Safety. DEPARTMENT: Shall mean Department of Building G. DIRECTOR: Shall mean the Director of Building Safety or h--~ designated representative. SEC. 8-2003. RATING CLASSIFICATION A. CLASSIFICATION: The rating classifications as exhibited in Table A are hereby established and each building within the scope of this Article shall be placed in one such rating classification by the Director. TABLE A RATING CLASSIFICATIONS GENERAL USE OF BUILDING RATING CLASSIFICATION Essential Buildings High Risk Buildings Medium Risk Buildings Low Risk Buildings I II III IV For the purpose of this Article, portions of buildings constructed to act independently when resisting seismic forces may be placed in separate rating classifications. B. MULTIPLE CLASSIFICATIONS. For the purpose of determining a Rating Classification, a building with more than one rating classification shall be classified in the Rating Classification which is the most restrictive. C. MULTIPLE OCCUPANCIES. For the purpose of de- termining rating classifications the total occupant load as determined pursuant to Chapter 33 of the Uniform Building Code of all occupancies in the building shall be used. ORDINANCE NO. NS-I~8~ Page Three SEC. 8-2004. ADMINISTRATION A. PRIORITY OF NOTIFICATION. The Director shall notify owners of buildings within the scope of this Article in accordance with the rating classifications as set forth in Table A. In general, buildings having a rating classification of I shall be notified first; buildings having a rating classification of II shall be notified second, but not earlier than six months after the effective date of this Article; buildings having a rating classification of III shall be notified third, but not earlier than 18 months after the effective date of this Article; and buildings having a rating classification of IV shall be notified last, but not earlier than five years after the effective date of this Article. Within each separate Rating Classification, the notification shall normally be based on the occupant load of the building, with the buildings housing larger occupant loads being notified first. Upon receipt of a written request from the owner, the Director shall serve notification ordering a building into compliance with this Article prior to the normal notification date set forth in this Section. B. NOTIFICATION. Following the priorities listed in Subsection 8-2004 (A), the Director shall serve notice ordering the owner of each building within the scope of this Article to cause a structural analysis to be made of the building by a licensed civil or structural engineer or licensed architect. If the building is found to be deficient under the standards established by this Article, the owner shall cause said building to be structurally altered so as to conform to those standards or cause it to be demolished. The notice or order shall be in writing and shall be served either personally or by first class mail, return receipt requested, upon the owner as shown in the last equalized assessment roll, and upon the person, if any, in apparent charge or control of the building. The aforesaid order shall direct that the structural analysis together with the necessary plans and calculations be submitted to the Department for review within 270 days after service of the order. The order shall specify that permits required to accomplish the necessary structural alterations shall be obtained not later than one year after the service of the order, and that the building be corrected to meet the minimum requirements of this Article, or be demolished, not later than three years after such service. The necessary alterations, however, must commence within 180 days of the date that the permit was issued. C. APPEAL FROM ORDER. The owner or person in apparent charge or control of the building may appeal the Director's initial order and determination within 180 days of the service of the aforesaid order, pursuant to the procedure established by Chapter 3 of the Santa Ana Municipal Code. Any such appeal shall be decided by the Hearing Officer no later than 60 days after the date when the appeal is filed. The order for demolition can be upheld only if, based upon complete evidence, the Hearing Officer finds that the subject property constitutes a nuisance and that there is no other way reasonably to correct the nuisance. D. RECORDATION. At the time when he serves the ORDINANCE NO. NS-1518 Page Four aforesaid order, the Director shall file with the Office of the County Recorder a certificate stating that the subject building is within the scope of Santa Ana Municipal Code, Articte XI of Chapter 8, "Earthquake Hazard Reduction in Existing Buildings." The certificate shall also state that the owner thereof has been notified and ordered to structurally analyze the building and to structurally strengthen or demolish it where Compliance within ArticleXI is not exhibited. If the building is either demolished, found not to be within the scope of this Article, or is found to be structurally capable of resisting minimum seismic forces required by this Article, the Director shall file with the Office of the County Recorder a certificate terminating the status of the subject building as being classified within the scope of Santa Ana Municipal Code, Article XI of Chapter 8, "Earthquake Hazard Reduction in Existing Buildings." E. ENFORCEMENT. If the owner or other person in charge and control of the subject building fails to comply with the order within any of the time periods set forth in Section 8-2004 (B), the Director shall order that the entire building be vacated and that the building remain vacated until all required analyses and structural alterations have been completed. Whenever compliance with the aforementioned order issued pursuant to the provisions of this Article has not been accomplished within 90 days after the date the building has been ordered vacated, or such additional time as may have been granted by the Board, the Director may order demolition of any such building in accordance with Chapter 17 of the Santa Ana Municipal Code. SEC. 8-2005. ANALYSIS AND DESIGN A. GENERAL. Every structure within the scope of this Article shall be analyzed and constructed to resist minimum total lateral seismic forces assumed to act nonconcurrently in the direction of each of the main axes of the structure in accordance with the following equation: V = IKCSW The value of "IKCS" need not exceed the values set forth in Table B based on the appropriate priority rating. TABLE B HORIZONTAL FORCE FACTORS BASED ON RATING CLASSIFICATION RATING CLASSIFICATION IKCS I 0.186 II 0.133 III & IV 0.100 B. LATERAL FORCES ON ELEMENTS OF STRUCTURES. Parts or portions of structures shall be analyzed and designed for lateral loads in accordance with Chapter 23 of the Uniform Building Code but no less than the value from the following equation: Fp = ICpSWp For the provision of this subsection, the product of "IS" need not exceed the values as set forth in Table C. ORDINANCE NO. NS-15{8~ Page Five EXCEPTION: Unreinforced masonry walls in buildings not having a rating classification of I may be analyzed in accordance with Section 8-2006. C. ANCHORAGE AND INTERCONNECTION. Anchorage and interconnection of all parts, portions and elements of the structure shall be analyzed and designed for lateral forces in accordance with the equation F~ = IC~SW~ as modified by Table C. Minimum anchorage of masonry ~al{s to each floor or roof shall resist a minimum force of 200 pounds per lineal foot acting normal to the wall at the level of the floor or roof. TABLE C HORIZONTAL FORCE FACTORS "IS" FOR PARTS OR PORTIONS OF STRUCTURES RATING CLASSIFICATION IS I 1.50 II 1.00 III & IV 0.75 D. LEVEL OF REQUIRED REPAIR. Alterations and repairs required to meet the provisions of this Article shall comply with all other applicable requirements of this Code unless specifically excluded elsewhere in this Article. E. REQUIRED ANALYSIS. 1. CONTINUOUS STRESS PATH. A complete, continuous stress path from every part or portion of the structure to the ground shall be provided for the required horizontal forces. 2. POSITIVE CONNECTIONS. Ail parts, portions or elements of the structure shall be interconnected by positive means. F. ANALYSIS PROCEDURE. (1) GENERAL. Stresses in materials and existing construction utilized to transfer seismic forces from the ground to parts or portions of the structure shall conform to those permitted by the Uniform Building Code and those materials and types of construction specified in Section 8-2006. (2) CONNECTIONS. Materials and connectors used for interconnection of parts and portions of the structure shall conform to the Uniform Building Code. (3) UNREINFORCED MASONRY WALLS. Unreinforced masonry walls shall be analyzed to insure their capability of resisting superimposed vertical loads in addition to the seismic forces required by this Article. Allowable stresses in such walls shall be obtained by tests utilizing values established by laboratory testing as specified in Section 8-2006E. However, no allowable tension stress will be permitted. Walls not capable of resisisting the applied loads shall be strengthened to resist the forces specified in this Article or shall be removed and replaced. ORDINANCE NO. NS Page Six EXCEPTIONS: 1. Unreinforced masonry walls in buildings not classified as a Classification Rating I may be analyzed in accordance with the provisions of Section 8-2006. 2. Unreinforced masonry walls which carry no design loads other than their own weight may be considered as veneer if they are adequately anchored to new supporting elements. G. COMBINATION OF LOAD EFFECTS. (1) NEW MATERIALS. Combination of load effects shall conform to the Uniform Building Code for all new materials introduced into the building structure to meet the requirements of this Section. (2) EXISTING MATERIALS. When stress in existing lateral force resisting elements is due to a combination of dead loads plus live loads plus seismic loads, the allowable working stress specified in the Code may be increased 100%. However, no increase shall be permitted in the stresses allowed in Section 8-2006 of this Article and the stresses in members due only to seismic and dead loads shall not exceed the values permitted by Chapter 23 of the Uniform Building Code. (3) ALLOWABLE REDUCTION OF BENDING STRESS BY VERTICAL LOAD. In calculating maximum tensile stress due to earthquake forces, the maximum tensile fiber stresses may be reduced by not more than 50 percent of the direct stress due to vertical dead loads. SEC. 8-2006. MATERIALS OF CONSTRUCTION A. GENERAL. Ail materials permitted by this Code including their appropriate allowable stresses and those existing configurations of materials specified herein may be utilized to meet the requirements of this Article. B. EXISTING MATERIALS. (1) UNREINFORCED MASONRY WALLS. Unreinforced masonry walls analyzed in accordance with this Section may provide vertical support for roof and floor construction and resistance to lateral loads. Tension stresses due to seismic forces normal to the wall may be neglected if the wall does not exceed the height or length to thickness ratio and the in-plane shear stresses due to seismic loads as set forth in Table D. ORDINANCE NO. NS ~518 Page Seven TABLE D ALLOWABLE VALUE OF UNREINFORCED MASONRY WALL~I~ WITH MINIMUM QUALITY MORTAR'-' RATING CLASSIFICATION MAXIMUM RATIO UNSUPPORTED HEIGHT OR LENGTH TO THICKNESS SEISMIC IN-PLANE SHEAR STRESS BASED ON GROSS AREA I NOt applicable(2) Not applicable(2) II 9 3 psi(3) III 10 3 psi(3) IV 12 3 psi(3) FOOTNOTES: (1) Minimum quality mortar shall be determined by laboratory testing in accordance with Section 8-2005 F. (2) Walls of buildings within rating classification I shall be analyzed in accordance with Section 8-2005 F. (3) Allowable shear stress may be increased by the addition of 10% of the direct stress due to the weight of the wall directly above. The wall height or length may be measured horizontally to supporting elements providing the stiffness of the supporting member is at least twice as stiff as the tributary wall. Stiffness shall be based on the gross section. (2) EXISTING ROOF, FLOORS, WALLS, FOOTINGS, AND WOOD FRAMING. Existing materials utilized in the described configuration may be used as part of the lateral load resisting system, provided that the stresses in these materials do not exceed the values shown in Table E. TABLE E VALUES FOR EXISTING MATERIALS MATERIALS(2) ALLOWABLE VALUES HORIZONTAL DIAPHRAGMS (a) Roofs with straight sheathing and roofing applied directly to the sheathing. 150 lbs. per foot for seismic shear. (b) Roofs with diagonal sheathing and roofing applied directly to the sheathing. 400 lbs. per foot for seismic shear. (c) Floors with straight tongue and groove sheathing 150 lbs. per foot for seismic shear. (d) Floors with straight sheathing and finished wood flooring. 300 lbs. per foot for seismic shear. (e) Floors with diagonal sheathing and finished wood flooring. 400 lbs. per foot for seismic shear. (f) Floors or roofs with straight sheathing and plaster applied t~l~he joist or rafters. Add 50 lbs. per foot to materials la and lc. ORDINANCE NO. NS~1518 Page Eight 2. SHEAR WALLS (a) Wood stud walls with wood lath and plaster. 50 lbs. per foot each side for seismic shear. (b) Wood stud walls with plaster and lath other than wood lath. 100 lbs. per foot each side for seismic shear. PLAIN CONCRETE FOOTINGS f' = 1500 psi unless otherwise shown by tests. 4. DOUGLAS FIR WOOD Allowable stress same as No. 1 (d)- (f) REINFORCING STEEL f. = 20f000 lbs per s~uare ~nch maximum. STRUCTURAL STEEL f~ = 20,000 lbs. per s~uare inch maximum. FOOTNOTES: (1) The wood lath and plaster must be reattached to existing joists or rafters in a manner approved by the Department. (2) Material must be sound and in good condition. C. STRENGTHENING OF EXISTING MATERIALS. New materials may be utilized to strengthen portions of the existing seismic resisting system in the described configurations provided that the stresses do not exceed the values shown in Table F. TABLE F ALLOWABLE VALUES OF NEW MATERIALS USED IN CONJUNCTION WITH EXISTING CONSTRUCTION NEW MATERIALS ALLOWABLE VALUES Plywood sheathing applied directly over existing straight sheathing with ends of plywood sheets bearing on joists or rafters and edges of plywood located on center of individual sheathing boards. Same as specified in U.B.C. Table 25-J for blocked diaphragms. 2. SHEAR WALLS ' a. Plywood sheathing applied directly over existing wood studs. No value shall be given to plywood applied over existing plaster or wood sheathing. Same as specified in U.B.C. Table 25-K for shear walls. b. Dry wall or plaster applied directly over existing wood studs. Same as specified in U.B.C. Table 47-I. c. Dry wall or plaster applied to plywood sheathing over existing wood studs. 33 1/3 per cent of the values specified in U.B.C. Table 47-I. e Shear bolts and shear dowels embedded a minimum of 8 inches into unreinforced masonry walls. Bolt centered in a 2 1/2 inch diameter hole with dry-pack or non- shrink grout around circumference of bolt or dowel. (1) Same as value given for solid masonry in U.B.C Table 24-G. Max. 750 lbs. ORDIN~/qCE NO. NS-15'18 Page Nine 4e Se Tension bolts and tension dowels ex- tending entirely through unreinforced masonry walls secured with bearing plates on far side of wall with at least 30 sq. inches of area.(2) 1200 lbs. per bolt. Reinforced masonry infilled openings in existing unreinforced masonry walls with dowels to match reinforcing. Same value as for un- reinforced masonry walls. e e Masonry piers and walls reinforced per U.B.C. SectiOn 2418 and designed for tributary loads. Concrete footings, walls and piers reinforced as specified in Chapter 26 and designed for tributary loads. Foundation pressures for structures exhibiting no evidence of settlement. FOOTNOTES: in Section 8-2006. minimum in diameter. (1) Bolts and dowels to be tested as (2) Same values as speci- fied in U.B.C. Table 24-H. same values as speci, fied in U.B.C. Chapter 26. Calculated existing foundation pressure due to max dead load plus live load may be increased 25% for dead load, and may be in- creased 50% for dead ~ load plus seismic load. specified Bolts and dowels to be 1/2 inch D. ALTERNATE MATERIALS. Alternate materials and methods of construction may be approved by the Department in accordance with the provisions of Section 106 of the Uniform Building Code. ("U.B.C.") E. MINIMUM ACCEPTABLE QUALITY OF EXISTING UNREINFORCED MASONRY WALLS. (1) GENERAL PROVISIONS. Ail unreinforced masonry walls utilized to carry vertical loads and seismic forces parallel and perpendicular to the wall plans shall be tested as specified in this Section. All masonry quality shall equal or exceed the minimum standards established herein or shall be removed and replaced by new materials. Alternate methods of testing approved by the Department may be used. Nothing shall prevent point with cement mortar of all the masonry wall joints before the tests are first made. If the exterior joints are pointed then the inside face must also be pointed. Prior to any pointing, the wall surface must be sand or water blasted to remove loose and deteriorating mortar. All preparation and cement mortar pointing shall be done under the continuous inspection of the Director with a subsequent written report to the Department. All testing shall be performed by an approved testing agency in accordance with the requirements specified in this Subsection. EXCEPTION: Unreinforced masonry walls which carry no design horizontal or vertical loads other than their own weight may be considered as veneer if they are adequately anchored to new supporting elements. (2) NUMBER AND LOCATION OF TESTS. The quality of mortar in all masonry walls shall be determined by performing in place shear tests or by testing eight inch diameter ORDINANCE NO. NS-1518 Page Ten cores. The minimum number of tests shall be two per wall or line of wall elements resisting a common seismic force, 1 per 1500 square foot of wall surface, or eight minimum whichever requires the largest number of tests or cores. The exact test or core location shall be determined at the building site by the licensed engineer or architect responsible for the seismic analysis of the subject building. The results of all tests or coring shall be recorded and reported. (3) IN PLACE SHEAR TESTS. The bed joints of the outer wythe of the masonry shall be tested in shear by laterally displaying a single brick relative to the adjacent bricks in that wythe. The opposite head joint of the brick to be tested shall be removed and cleaned prior to testing. The minimum quality mortar in 80 percent of the shear tests shall not be less than the total of 30 psi plus the axial stress in the wall at the point of the test. The shear stress shall be based on the gross area of both bed joints and shall be that at which movement of the brick is first observed. (4) CORE TESTS. A minimum number of mortar test specimens equal to the number of required cores shall be prepared from the cores and tested as specified herein. The mortar joint of the outer wythe of the masonry core shall be tested in shear by placing the circular core section in a compression testing machine with the mortar bed joint rotated 15 degrees from the axis of the applied load. The mortar joint tested in shear shall have an average ultimate stress based on the gross area of 20 psi. The average shall be made from the total number of cores made. If test specimens cannot be made from the total taken the shear value shall be reported as zero. The results of all coring and shear testing shall be reported. F. TESTING OF SHEAR BOLTS. One-fourth of all new shear bolts and dowels embedded in unreinforced masonry walls shall be tested by the Director using a torque calibrated wrench to the following minimum torques: 1/2" diameter bolts or dowels = 40 foot-lbs. 5/8" diameter bolts or dowels = 50 foot-lbs. 3/4" diameter bolts or dowels = 60 foot-lbs. No bolts exceeding 3/4' shall be used. Ail nuts shall be installed over malleable iron or plate washers when bearing on wood and heavy cut washers when bearing on steel. G. DETERMINATION OF ALLOWABLE STRESSES FOR DESIGN METHODS BASED ON TEST RESULTS. (1) DESIGN SHEAR VALUES. Design seismic in-plane shear stresses greater than permitted in Table D shall be substantiated by tests performed as specified in Section 8-2006 E (3) and (4). Design stresses shall be related to test results obtained as noted in Table G. Intermediate values below the maximum may be interpolated. ORDINANCE NO. NS &I518 Page Eleven TABLE G ALLOWABLE SHEAR STRESS FOR TESTED UNREINFORCED MASONRY WALLS Eighty percent by test results in psi not less than Average test results cores in psi 30 plus axial stress 40 plus axial stress 50 plus axial stress or more FOOTNOTE: (1)Allowable addition of 10% of the axial wall directly above. Seismic in-plane shear based on gross area 20 2.6.7 33.3 or more -si(1) 3 ~ . (1) 4 ~ps .~ (1) 5 ps~- - shear stress may be increased by stress due to the weight of the (2) DESIGN COMPRESSION AND TENSION VALUES. Design compressive stresses of analysis specified in this section shall be 100 psi. Design tension values for unrein- forced masonry shall be assumed equal to zero. SEC. 8-2007. INFORMATION REQUIRED ON PLANS A. GENERAL. In addition to the seismic analysis required elsewhere in this Division, the licensed engineer or architect responsible for the seismic analysis of the subject building shall determine and record the information required by this Section on the approved plans. B. CONSTRUCTION DETAILS. The following construction details shall be made part of the approved plans: (1) Ail unreinforced masonry walls shall be anchored with tension bolts through the wall or by existing rod anchors at a maximum anchor spacing of six feet to all floors and roofs. Ail existing rod anchors shall be secured to joists or rafters by bolting to develop the required forces. The Department may require testing to verify adequacy of embedded ends of existing rod anchors. (2) Diaphragm chord stresses of horizontal dia- phragms shall be developed in existing materials or by addition of new materials. (3) Where wood roof or floor members other than rafters or joists are supported in masonry pockets, ledgers or columns shall be installed to support vertical loads of the roof or floor members. (4) Parapets and exterior wall appendages not capable of resisting the forces specified in this Article shall be removed, stabilized or braced to insure that the parapets and appendages remain in their original position. (5) All deteriorated mortar joints in unreinforced masonry walls shall be pointed with cement mortar. Prior to any pointing, the wall surface must be sand or water blasted to remove loose and deteriorated mortar. All preparation and pointing shall be done under the continuous inspection of the Director with a subsequent written report to the Department. ORDINANCE NO. NS-151~ Page Twelve C. EXISTING CONSTRUCTION. The following existing construction information shall be made part of the approved plans: (1) The approximate age of building. (2) The typical footing width, depth and maximum soil bearing for dead plus live loads. (3) The type and dimensions of existing walls and the size and spacing of floor and roof members. (4) The extent and type of existing wall anchorage to floors and roof. (5) Accurately dimensioned floor plans and masonry wall elevations showing dimensioned openings, piers, wall thickness and heights. (6) The type of interior wall surfaces and if reinstalling or anchoring of ceiling plaster is necessary. ADOPTED this 19th 1980, by the following vote: day of February , AYES: COUNCILMEN: Bricken, Griset, Luxembourger, Markel, Serrato, Ward, Yamamoto NOES: COUNCILMEN: None ABSENT: COUNCILMEN: None ATTEST: CITY ATTORNEY