Chapter 7B — EARTHQUAKE HAZARD REDUCTION IN EXISTING BUILDINGS

The purpose of this chapter is to promote public safety and welfare by reducing the risk of death or injury that may result from the effects of earthquakes on unreinforced masonry buildings. The provisions of this chapter are intended as minimum standards for structural seismic resistance and are established primarily to reduce the risk of loss of life or injury. Compliance with these standards will not necessarily prevent all loss of life or injury or prevent earthquake damage to strengthened buildings. However, this will provide a reasonable level of public safety while being sensitive to the financial needs and the preservation of Brawley's building stock.

(Ord. No. 93-10 § 1.)

(a)

The provisions of this chapter shall apply to all buildings having at least one unreinforced masonry bearing wall.

(b)

This chapter pertains only to buildings that have load bearing walls of unreinforced masonry. Buildings are exempt from this ordinance if the building owner shows or does any of the following:

That the building contains no unreinforced masonry. Example-several older buildings are of poured, reinforced concrete;

That the masonry on the building is reinforced;

That the building has, through the years, been sufficiently reinforced to meet the ordinance requirements;

That the unreinforced masonry, although present, is not load bearing. Example-Some buildings have steel and/or poured reinforced concrete columns and beams supporting the building loads with unreinforced masonry filling the space between the columns;

Alter the building to comply with the required strengthening;

The building owner and building official observe the building and agree that there is no unreinforced masonry bearing wall.

(c)

It is recognized that strengthening was done to many unreinforced masonry buildings following the 1940 and 1979 Imperial County earthquakes. The engineer or architect, retained by the building owner, and the city building official shall give full consideration to any strengthening done when analyzing the existing condition of the building as required by this chapter. Where strengthening was done which may not fully comply with the provisions of this chapter, approval may be granted by the building official if the building's condition complies with the intent of this chapter.

(d)

Nothing in this chapter shall prevent the building owner or his architect or engineer from employing accepted alternative methods to prove the minimum seismic safety of a building. The building owner's architect or engineer may submit an alternative which may be based on the UCBC, Appendix 1A (current edition) which also meets the minimum seismic standards established by the voluntary provisions of this chapter, but this is an alternative method and shall not be interpreted as a requirement. In the event an alternative method is employed by the building owner, or his architect or engineer which is not accepted by the city building official, the building owner shall have the right to appeal that decision to the board of building appeals.

(e)

Exceptions: This chapter shall not apply to the following:

Buildings classified as essential facilities in Table No. 23-K;

Buildings classified as hazardous facilities in Table No. 23-K;

Detached dwellings;

Detached apartment houses containing less than five dwelling units which are used solely for residential pruposes;

A building having no unreinforced masonry bearing wall except foundations, basements, and retaining walls constructed of masonry below the first floor level of the building;

Single story warehouse buildings used for storage purposes and occupied less than three hours per day.

(Ord. No. 93-10 § 1.)

For the purposes of this chapter, certain terms used in this chapter shall have the following meanings:

(a)

"Crosswall" means an interior wall of masonry or wood stud construction. In order to be considered a cross-wall within the intent of this chapter, crosswalls shall: be not more than forty feet apart in each story; shall be full story height between diaphragms; an existing wood stud crosswall shall have a minimum length of one and one-half times the story height and shall be sheathed with one of the following:

Wood lath and plaster;

One-half inch thick gypsum wall board two sides;

Solid 1x mimimum diagonal wood board sheathing two sides;

Solid 1x minimum diagonal wood board sheathing.

New crosswalls shall have a rational shear path to the ground and shall be constructed of materials that are assigned allowable shear values in chapter 25 or chapter 47 of the Uniform Building Code and shall have a total shear capacity equal to that of a wall that is one and one-half times the story height that is sheathed with a material that has an allowable shear value of at least one hundred fifty pounds per foot.

(b)

"Unreinforced masonry (URM)" means masonry constructed without reinforcement.

(c)

"Unreinforced masonry bearing wall" means a wall having all the following characteristics:

It provides vertical support for a floor or roof.

The total superimposed load is over one hundred pounds per linear foot.

It is constructed of unreinforced masonry (URM).

(d)

"External hazard" means an object attached to or forming the exterior facade of a building which may fall onto pedestrians or occupants of adjacent buildings. Examples of this type of hazards include, but are not limited to, the following:

Nonstructural exterior wall panels, such as masonry infill or decorative precast concrete;

Parapets;

Marquees, awnings, or other roof-like projections from a building;

Masonry or stone wall veneer and wall ornamentation, including cornices or other decorative appendages;

Masonry chimneys;

Tile roofing;

Wall signs and exterior lighting fixtures hung from a building exterior;

Fire escapes or balconies;

Deteriorated portions of structures such as loose or weak masonry in unreinforced bearing walls adjoining public rights-of- way;

Unbraced equipment.

(Ord. No. 93-10 § 1.)

For the purpose of this chapter, the applicable symbols and notations in the Building Code, and the following shall apply.

(Ord. No. 93-10 § 1.)

(a)

Existing Materials. All materials utilized as part of the lateral force resisting system shall be in sound condition or shall be removed and replaced with new materials.

(b)

Existing Unreinforced Masonry.

General. Unreinforced masonry walls shall be tested as specified in this subsection. Masonry that does not meet or exceed the minimum standards established by this chapter shall be removed and replaced by new materials or anchored to supporting elements; design of anchorage shall comply with requirements for anchorage of masonry veneer of section 7B.8.

Exception. Testing may be omitted providing:

a.

The architect or engineer determines that the mortar is in sound condition; or

b.

The architect or engineer determines that, except where local repairs are needed, the mortar is in sound condition; and the architect or engineer submits to the building official a report in accordance with section 7B.6(d) that designates the location and description of local repairs required (if any) to provide sound quality mortar throughout the building.

Lay-up of Walls. The facing and backing shall be bonded so that not less than four percent of the wall surface of each face is composed of solid headers extending not less than four inches into the backing. The distance between adjacent full- length headers shall not exceed twenty-four inches either vertically or horizontally. In walls in which a single header does not extend through the wall, headers from opposite sides shall overlap at least four inches, or headers from opposite sides shall be covered with another header course overlapping the header below at least four inches. Wythes of walls not bonded as described above shall not be included in the effective thickness used in calculating the height-to-thickness ratio of the wall unless it is bonded and anchored to the backing in a manner acceptable to the building official.

Mortar. a. Tests. The quality of mortar in unreinforced masonry walls shall be determined by performing in place shear tests in accordance with Uniform Building Code Standard (24-7). Alternate methods of testing to establish compliance with the minimum requirements of section 7B.5(B)(3)(d)(iv) may be approved by the building official.

b.

Location of Tests. Shear tests shall be taken at locations representative of the mortar conditions throughout the entire building. The exact test location shall be determined at the building site by the engineer or architect in responsible charge of structural design work. An accurate record of such tests and their location in the building shall be recorded and these results shall be submitted to the building official for approval as part of the structural analysis.

c.

Number of Tests. The minimum number of tests per wall or line of wall elements providing a common line of resistance to lateral forces shall be as follows: Two tests per wall with a minimum total number of eight tests or one test per one thousand five hundred square feet of wall area, whichever results in greater number of tests.

d.

Minimum Quality Mortar.

(i)

Mortar shear test values, V to , shall be obtained for each in-place shear test in accordance with the following equation:

V to = V test /A;sub\sub; − P D+L /A W . . . . . . . . (5-1)

(ii)

An individual unreinforced masonry wall in which V to at all tests is less than thirty psi shall be pointed prior to retesting.

(iii)

The mortar shear strength, V T is the value in psi that is exceeded by eighty percent of all of the mortar shear test values, V to .

(iv)

Unreinforced masonry with mortar shear strength, V T less than thirty psi shall be removed or pointed and retested.

e.

Pointing. All deteriorated mortar joints in unreinforced masonry walls shall be pointed in accordance with Standard No. 24- 9. Nothing shall prevent pointing with mortar of all masonry wall joints before tests are made.

(Ord. No. 93-10 § 1.)

(a)

Pointing. Special inspection shall be provided during preparation and mortar pointing.

Exception: Pointing may be performed without special inspection where approved by the engineer.

(b)

Existing Floor or Roof Level Wall Anchors.

Floor level tension anchors embedded in brick. If existing tension anchors embedded in brick are to be utilized as all or part of the required wall anchorage system at the floor level, not less than five percent of such existing tension anchors shall be tested by an approved testing laboratory or under the supervision of the architect or engineer. The minimum number of anchors tested shall be four per floor, with two tests at walls with joists framing into the wall and two tests at walls with joists parallel to the wall but not less than five percent of the total number of existing tension anchors at each level. The test apparatus shall be supported on the masonry wall at a minimum distance of the wall thickness from the anchor tested. The tension anchor shall be given a preload of three hundred pounds prior to establishing a datum for recording elongation. The tension test load reported shall be recorded at one-eighth inch relative movement of the anchor and the adjacent masonry

surface. Results of all tests shall be reported. The report shall include the test results as related to the wall thickness and joist orientation. Ends of existing anchors shall be secured into the wood framing by a positive mechanical attachment.

Floor or roof level anchors embedded in concrete. Existing tension anchors at floor or roof levels that are embedded in existing concrete or in gunite applied to the opposite side of the wall need not be tested provided such embedment is verified by observation and report by an approved testing agency or the architect or engineer for at least one anchor (and for all anchors observed) in each level for which such anchors are to be utilized as all or part of the required wall anchorage system. Other evidence of such embedment may be approved by the building official.

(c)

Testing of Bolts. One-fourth of new embedded bolts in unreinforced masonry walls shall be tested by a testing laboratory or engineer using the procedure of UBC Standard No. 24-8.

Exception: Special inspection in accordance with the building code or continuous observation by the architect or engineer may be provided during installation in lieu of testing.

(d)

Required Reports. The architect, engineer, or testing agency shall submit a signed report to the building official for each test, observation, or inspection required by this section. The report shall state the test, observation, or inspection performed; the date; the results of each individual test, observation, or inspection (including those that fail to satisfy the intent of this ordinance); and whether, to the best of the knowledge of the preparer of the report, the results indicate compliance with this chapter.

(Ord. No. 93-10 § 1.)

(a)

Tension Anchors. Allowable values for tension anchors are given in Table No. 1-A. A one-third increase is not allowed for values listed in this table.

(b)

Other Materials. Allowable values not specified in this chapter shall be as specified elsewhere in the 1991 Uniform Building Code.

(Ord. No. 93-10 § 1.)

(a)

Lateral Force on Elements of Structures and Nonstructural Components. Parts or portions of structures, nonstructural components, and their anchorage to the main structural system shall be designed for lateral forces in accordance with the following formula:

F p = C p W p . . . . . . . . . .(8-1)

(b)

Height-to-Thickness Limitations. Unreinforced masonry wall height-to-thickness ratios shall not exceed the ratios set forth in Table No. 1C. If a wall height-to-thickness ratio exceeds the specified limits, the wall shall be laterally supported by

bracing members complying with subsection (c)(1) or with subsection (c)(2). Bracing systems shall be designed in accordance with section 7B.8A. The wall thickness may include the thickness of plaster, stucco, or concrete that is determined by the engineer to be bonded to the full height of the wall between wall anchors.

(c)

Bracing Methods.

Vertical Bracing Members. Vertical bracing members shall be attached to the wall and at each end to floor and roof construction. Attachments shall have capacities for their design loads independent of required wall anchors. Horizontal spacing of vertical bracing memebers shall not exceed one-half the unsupported height of the wall nor ten feet. Deflection of such bracing members at design loads, shall not exceed one-tenth of the wall thickness.

Wall Bracing. The wall height may be measured to tension anchors and bracing elements other than at a floor or roof level. Horizontal spacing of the tension anchors and bracing elements shall not exceed six feet on center or six times the wall thickness, whichever is less. Bracing elements shall be detailed to minimize the horizontal displacement of the wall by the vertical displacement of the floor or roof.

(d)

Wall Anchorage.

Anchor Locations. Unreinforced masonry walls shall be anchored to the roof and floor levels above grade in order to resist the forces specified in this section.

Tension Anchor Requirements. Tension anchors shall have a maximum spacing of six feet or six times the wall thickness, whichever is less, and shall comply with the requirements set forth in Table No. 1-A. Tension anchors used to resist required forces may be assumed to develop the allowable values listed in Table No. 1-A. If access to the exterior face of a masonry wall is prevented by proximity of an existing building or when the appearance of through the wall tension anchors will affect the architectural appearance of the building, embedded bolts conforming to Table No. 1-A may be used. Wall anchors shall be secured to the rafters or joists to transfer the required forces into the roof or floor diaphragm. Combination tension-and- shear bolts shall be secured to the framing to develop into the diaphragm, a shear force of at least one hundred pounds per foot.

Minimum Wall Anchorage Force. Anchorage of masonry walls to each floor or roof shall resist a minimum force determined by Formula (8-1) or two hundred pounds per linear foot, whichever is greater, acting normal to the wall at the level of the floor or roof. Existing wall anchors installed under previous permits must meet or must be upgraded to meet the requirements of this chapter.

Anchors at Corners. If new tension anchors are installed at the roof or floor level, to meet the requirements of this section, combination tension-and-shear anchors shall be provided within two feet horizontally from the inside of masonry wall intersections.

(e)

Parapets. Parapets and exterior wall appendages not capable of resisting the forces specified in this section shall be removed, stabilized, or braced.

The maximum height of an unbraced unreinforced masonry parapet above the level of tension anchors shall not exceed one and one-half times the thickness of the parapet wall. If the required parapet height exceeds this maximum height, a bracing system designed for the force determined by formula (8-1) shall be installed to brace the parapet.

The minimum height of a parapet above the wall anchor shall be twelve inches.

Exception: If a reinforced concrete beam is provided at the top of the wall, the minimum height above the wall anchor may be six inches.

(f)

Mortar Joints. All deteriorated mortar joints in unreinforced masonry walls shall be pointed with Type S or N mortar. Masonry cements shall not be used. Prior to any pointing, the wall surface must be raked and cleaned to remove loose and deteriorated mortar. All preparation for pointing shall be inspected by the architect, engineer, or his representative.

(g)

Masonry Veneer.

Veneer shall be anchored to the structure of the building with approved anchor ties conforming to the required design capacity specified in the Building Code and placed at a maximum spacing of twenty-four inches with a maximum supported area of two square feet.

Exception:

a.

Existing masonry veneer anchor ties may be acceptable provided the ties are in sound condition and conform to the following minimum size, maximum spacing and material requirements:

b.

Existing masonry veneer anchor ties shall be corrugated galvanized iron strips not less than one inch in width, eight inches in length and one-sixteenth inch in thickness and shall be located and laid in every alternate course in the vertical height of the wall at a spacing not to exceed seventeen inches on center horizontally. As an alternate, such ties may be laid in every fourth course vertically at a spacing not to exceed nine inches on center horizontally.

c.

Masonry veneer, no portion of which is six feet above grade need not be anchored.

The location and condition of existing veneer anchor ties shall be verified and reported to the building official as follows:

a.

The architect or engineer shall determine the location and spacing of ties.

b.

Under the direction of the engineer, a portion of the veneer shall be removed from a designated location to expose a representative sample of ties (not less than four) for evaluation. The engineer's evaluation shall be included in the report to

the building official.

Unreinforced masonry walls which carry no loads other than their own weight may be considered as veneer if they are adequately anchored to new supporting elements in compliance with this section.

(Ord. No. 93-10 § 1.)

(a)

General. An unreinforced masonry bearing wall building shall have a seismic resisting system conforming with this chapter.

(b)

Requirements for Plans. The following construction information shall be included on plans prepared or approved by a California licensed architect or civil or structural engineer to bring a building into compliance with this chapter.

Floor and roof plans showing existing masonry walls, crosswalls, roof and floor framing members, and sheathing materials, and structural elements that are not in sound condition.

Wall elevations showing diaphragm levels, parapet heights, wall and parapet thickness, masonry veneer that includes portions more than six feet above grade, openings, and locations of damaged masonry to be repointed or repaired.

Wall anchors and parapet anchors used in the seismic resisting system.

Vertical bracing members or wall braces required to satisfy the wall height-to-thickness ratio requirements of this chapter.

Sections and details required to delineate the work to bring the building into compliance with this chapter and restore structural elements to their original strength.

(Ord. No. 93-10 § 1.)

(a)

Except as required by this section, the provisions of this chapter are voluntary.

(b)

Seismic Preliminary Report. The owner of each unreinforced masonry building shall obtain a preliminary seismic report. The building official shall prepare a seismic preliminary report form.

Notification. The building official shall send notice of the requirements set forth in this section, by certified mail to the owner of record as shown on the latest equalized assessment roll of the county of Imperial, of each building on the city's unreinforced masonry list.

The Owner's Responsibilities. Each owner, as shown on the latest equalized assessment roll of the county of Imperial, of an unreinforced masonry building shall obtain a seismic preliminary report of the building, as defined by subsection (b)(6) of this section.

The report shall be completed and submitted to the building official within twenty-four months of receipt of notice from the building official.

The building owner shall meet with building department staff and shall comply with removal of finishes or veneers as reasonably required by the building department in order to expose building construction. Such requirements may include drilling into existing walls to establish type of construction.

Group Basis Preliminary Reports. A request for proposal shall be made to hire an engineer on a group basis for the seismic preliminary reports. The selection of the engineer shall be made by a committee composed of URM building owners, tenants, and city staff. Based upon proposals submitted by various architects and engineers, the selection committee shall evaluate and determine the architect or engineer who will provide reports on a group basis. An owner need not hire the engineer selected, but in not hiring the selected engineer, the owner will forfeit the city funding established to pay a portion of the cost for the seismic preliminary report.

Funding of Group Basis Seismic Preliminary Reports. The city or community redevelopment agency will provide funds to pay for fifty percent of the engineering report required by subsection (a) of this section for each building that is served with a notice. The fifty percent cost shall be based on the group rate established by the engineer hired on a group basis.

Preparation of seismic preliminary report shall be by a California licensed architect or civil or structural engineer using forms provided by the city.

Contents of the Seismic Preliminary Report. The seismic prliminary report shall indicate findings of whether the building complies with the provisions of this chapter, and for a building determined not in compliance, general recommendations for providing compliance. No formal drawings are required for the report, however, the preparer's field notes may be requested by the building official. The findings and recommendations shall be itemized to provide an evaluation of each of the following elements:

a.

Whether the building is within the scope of this chapter. If there is no URM bearing wall in the building, or if the building is otherwise found not within the scope of this chapter, the building shall be removed from the list and the survey need not be completed. (See section 7B.2);

b.

Structural materials that are part of the lateral load resisting system: Whether they are in sound condition. (See section 7B.5(a));

c.

Mortar: Whether testing is required to establish mortar quality or the mortar is in sound condition, or repairs are required to provide sound quality mortar throughout the building. (See section 7B.5(b)(1));

d.

Lay-up of walls: Whether the walls are adequately bonded. (See section 7B.5(a)(2));

e.

Height-to-thickness limitations: Whether, based on measurements of wall thicknesses and distances between wall anchorage levels, the height-to-thickness ratios comply with Table No. 1-C. (See section 7B.8(b));

f.

Wall anchorage: Whether wall anchorage system is adequate. This evaluation shall be based on determination of wall anchor forces for each wall at each diaphragm level in accordance with Section 7B.8(d) and formula 8-1, and wall anchor capacities as specified in Table No. 1A. Existing anchors embedded in brick may be considered as part of an adequate anchorage system only at floor levels, and only with testing in accordance with section 7B.6.(b)(1); such testing is not to be included in the seismic preliminary report. (See section 7B.8.(d));

g.

Parapets: Whether the parapets of each wall are capable of resisting the specified forces or must be removed, stabilized, or braced. (See section 7B.8.(e));

h.

Mortar joints: Whether there are deteriorated mortar joints that need to be repointed. (See section 7B.8.f);

i.

Masonry veneer: Whether there is masonry veneer any portion of which is more than six feet above grade. Masonry veneer must be removed or tested to determine whether existing veneer anchor ties are adequate; such testing is not to be included in the seismic preliminary report. (See Section 7B.8.(g));

j.

Whether there are external hazards and a description of each identified external hazard. (See Section 7B.3.(d));

k.

A sketched plan of the building indicating adjacent streets and walkways and other pedestrian ways, the locations of the URM bearing walls, and location of each identified external hazard and its relationship to adjacent pedestrian ways;

l.

Whether any portion of the seismic preliminary report is incomplete because of lack of access for evaluation and recommendations for completing the evaluation.

Distribution of the Seismic Preliminary Report. One copy of the report shall be provided to the owner; five copies shall be submitted to the building official.

Enforcement-Appeal of Seismic Safety Report.

a.

When, after the prescribed time limits, the building official finds that any building subject to the provisions of this chapter has not had a report prepared as outlined in this chapter, the official shall commence proceedings to cause such a report to be prepared of such building.

The building official shall serve upon the record owner of the building as shown on the latest equalized assessment roll of the county of Imperial, by certified mail, a notice and order containing the following information:

(i)

The street address and legal description sufficient for identification of the premises upon which the building is located.

(ii)

That the building has unreinforced masonry bearing walls falling within the scope of section 7B.2 and that no report as required by this chapter has been submitted to the city within the prescribed time limits.

(iii)

A statement that the report must be completed and submitted to the building official within thirty days of service of the notice and order; and that if the analysis is not completed within that time, the city will have the report conducted and the costs thereof assessed against the property.

(iv)

A statement of the appeal procedure: Any building owner who is served with a notice and order to comply as provided for in this chapter may file an appeal of such order with the board of building appeals. Such appeal must be filed with the city clerk not more than thirty days after service of order.

b.

Upon the filing of an appeal, the city clerk shall set the matter for hearing upon notice to the building owner, the owners of adjacent property and the board of building appeals. Such notice shall be sent by mail no less than ten days prior to the hearing date.

The hearing shall be held within sixty days after the date of filing the appeal.

The board of building appeals may sustain, modify, reject, or overrule any recommendation, finding or ruling of the building official and shall make appropriate findings. The board shall render its decision on the appeal within ten days following the conclusion of the hearing.

c.

If, thirty days after service of the notice and order, no seismic preliminary report approved by the building official has been conducted, and no appeal has been filed, the city shall have such seismic preliminary report conducted.

d.

When the seismic preliminary report has been caused to be done by the city, the building official shall keep an account of the cost of such report. Such account shall be placed in a report and assessment list to the council for confirmation and filed with the city clerk. The report and assessment list shall refer to each separate building by a description sufficient to identify it and state separately the cost of abtaining the seismic safety preliminary report of each building, including any administrative charges relating to such report.

e.

The council shall conduct a hearing prior to confirmation of the report and assessment list. Notice of such hearing shall be mailed not less than ten days prior to the scheduled hearing to the owners of buildings against which such costs are

proposed to be assessed. Any interested person may appear before the council at said hearing. Following the close of the hearing, the council may remedy and correct any error and revise and correct any act or determination of the building official relating to the analysis; and may amend, alter, modify or correct the assessment in such manner as shall seem just. All decisions and determinations of the council shall be final and conclusive.

f.

Unless the amount assessed has been paid within ten days of council action confirming such assessment, the building official shall cause to be filed in the office of the recorder of the county of Imperial a notice of lien.

g.

Liens shall be collected at the time of sale or remodel in excess of fifty percent of the market value of the building.

(c)

Mitigation of External Hazards.

Within sixty days of acceptance of the preliminary seismic report the building official shall issue an order as provided in this section. The order shall require that external hazards identified in the seismic preliminary report be mitigated. The building owner shall submit plans for the mitigation to the building department, obtain building permits, and commence and complete the repairs within twenty-four months after receipt of the order. Mitigation of parapets and veneer shall be in compliance with this chapter.

Where a significant financial hardship can be shown to be caused by the time limits specified in this section the property owner may appeal to the council for a one-year extension. No more than one extension shall be approved on each building.

Hardship appeals shall be submitted prior to the expiration of the time limit being appealed.

To ensure consistent interpretation, the council shall publish minimum financial data submittal requirements and guidelines for review and approval of such appeals prior to consideration of any such appeal.

Enforcement Mitigation of External Hazards. If the owner in charge or control of the subject building fails to comply with the order issued by the building official pursuant to this section within any of the time limits set forth in this section, the building official shall verify that the record owner of this building has been properly served. If the order has been served on the record owner, the building official shall order that the entire building be vacated and that the building remain vacated until such order has been complied with. If compliance with such order has not been accomplished within ninety days after the date the building has been ordered vacated or such additional time as may have been granted by the board of appeals, the building official may order its demolition in accordance with the provisions of section 203 of the Building Code.

(Ord. No. 93-10 § 1.)

Should the building owner comply with the voluntary requirements of this ordinance, in addition to the requirements of Section 7B.10 of this chapter, the building will be removed from the unreinforced masonry list. Notice of removal shall be recorded with the county recorder.

(Ord. No. 93-10 § 1.)

TABLE NO. 1-A

Section 15.40.050(d).

---

(1) A one-third increase in allowable stresses is not allowed for the tabulated values. The allowable capacity shall not be greater than the capacity of the connection to the floor or roof framing.

(2) Bolts to be ½ inch minimum in diameter.

(3) Drilling for bolts and dowels shall be done with an electric rotary drill. Impact tools shall not be used for drilling holes or tightening anchors and shear bolt nuts.

TABLE NO. 1-B HORIZONTAL FORCE FACTOR "CP" FOR PARTS OR PORTIONS OF BUILDINGS OR OTHER STRUCTURES

PART OR PORTION OF BUILDINGS DIRECTION OF FORCE VALUE OF C P

Exterior bearing and non-bearing walls; Normal-to-flat 0.3 interior surface bearing walls and partitions; interior non- bearing walls and partitions over 10 feet in height.

Cantilever parapet and other cantilever Normal-to-flat 1.00 walls, surface except retaining walls.

Exterior and interior ornamentations Any direction 1.00 and appendages.

TABLE NO. 1-C ALLOWABLE VALUE OF HEIGHT-THICKNESS RATIO OF UNREINFORCED MASONRY WALLS WITH MINIMUM QUALITY MORTAR

(a)

Pointing. The Uniform Building Code Standard No. 24-9 for the pointing of unreinforced masonry walls is adopted.

The old mortar should be cut out, by means of toothing chisel or a special painter's grinder, to a uniform depth of not less than three-fourths inches, or until sound mortar is reached. Care must be taken not to damage the brick edges. All dust and debris must be removed from the joint by brushing, blowing air, or rinsing with water.

Mortar mix shall be Type "S" or "N" proportions as called for in the construction specifications. The tuck-pointing mortar should be pre-hydrated to reduce excessive shrinkage. The proper pre-hydration process is as follows:

a.

All dry ingredients should be thoroughly mixed. Only enough clean water should be added to the dry mix to produce a damp, workable consistency which will retain its shape when formed into a ball. The mortar should stand in this dampened condition for one to one-and- one-half hours;

b.

The joints to be tuck-pointed should be dampened, but to ensure a good bond, the brickwork must absorb all surface water. Water should be added to the pre-hydrated mortar to bring it to a workable consistency (somewhat drier than conventional mortar). The mortar should be packed tightly into the joints in thin layers (one-fourth inch maximum). Each layer should become "thumbprint hard" before applying the next layer. The joints should be tooled to match the original profile after the last layer of mortar is "thumbprint hard".

(b)

Relaying of Brick. Replacement bricks must match the originals with respect to size, color, and texture where exposed. A tuck-pointing toothing chisel should be used to cut out the mortar which surrounds the affected units. Power driven impact tools are not allowed. Once the units are removed, all of the old mortar shall be carefully chiseled out and all dust and debris shall be swept out with a brush.

If used brick is to be relayed, it shall be cleaned of all old mortar. The brick surfaces in the wall shall be dampened before new units are placed, but the masonry should absorb all surface moisture to ensure a good bond. The appropriate surfaces of the surrounding brickwork and the replacement brick should be buttered with mortar. The replacement brick should be centered in the opening and pressed into position. The excess mortar should be removed with a trowel. Pointing around the replacement brick will help to ensure full head and bed joints. When the mortar becomes "thumbprint hard," the joints shall be tooled to match the original profile.

(Ord. No. 93-10 § 1.)

Any building falling within the scope of this chapter and any other masonry building which is modified, repaired, retrofitted, strengthened, or reconstructed and is thereby brought into compliance with and maintained in accordance with the voluntary provisions of this chapter shall not within a period of fifteen years thereafter be identified as a seismic hazard to life requiring further strengthening or reconstruction pursuant to any local building standards adopted after the date of such repair, retrofit, strengthening, or reconstruction.

(Ord. No. 93-10 § 1.)