(a) 
Anchor locations. All URM walls shall be anchored at the roof and floor levels as required in subsection 9-12.603(b) of this chapter. Ceilings with substantial rigidity and abutting masonry walls shall be connected to walls with tension bolts at a maximum anchor spacing of six feet. Ceiling systems with substantial mass shall be braced at the perimeter to diaphragms.
(b) 
Anchor requirements. Anchors shall be tension bolts through the wall as specified in Table 12-D of this chapter or by an equivalent approved by the Building Official at a maximum anchor spacing of six feet. All existing wall anchors shall be secured to the joists to develop the required forces.
(c) 
Minimum wall anchorage. Anchorage of masonry walls to each floor or roof shall resist a minimum force determined by:
Fp = ZCpWp.
or 200 pounds per linear foot, whichever is greater, acting normal to the wall at the level of the floor or roof. Existing floor wall anchors must meet or must be upgraded to meet the requirements of this chapter if utilized in the design. Existing roof anchors shall not be utilized in the design.
(d) 
Anchors at corners. At the roof and all floor levels, both shear and tension anchors shall be provided within two feet horizontally from the inside of the corners of the walls.
(e) 
Anchors with limited access. When access to the exterior face of the masonry wall is prevented by proximity of an existing building, wall anchors conforming to Item 5b in Table 12-D of this chapter may be used.
(§ 1, Ord. 678, eff. July 12, 1991)
Collector elements shall be provided which are capable of transferring the seismic forces originating in other portions of the building to the element providing the resistance to those forces.
(§ 1, Ord. 678, eff. July 12, 1991)
Ties and continuity shall conform to Section 2312(h)2E of the Uniform Building Code.
(§ 1, Ord. 678, eff. July 12, 1991)
(a) 
General. Where a wall height-thickness ratio exceeds the specified limits, the wall may be laterally supported by vertical bracing members in accordance with the provisions of subsection (b) of this section or by reducing the wall height by bracing in accordance with the provisions of subsection (c) of this section.
(b) 
Vertical bracing members. Vertical bracing members shall be attached to floor and roof construction for their design loads independently of required wall anchors. Horizontal spacing of vertical bracing members shall not exceed one-half (½) the unsupported height of the wall nor 10 feet. Deflection of such bracing members at design loads shall not exceed one-tenth of the wall thickness.
(c) 
Wall height bracing. The wall height may be reduced by bracing elements connected to the floor or roof. Horizontal spacing of the bracing elements and wall anchors shall be as required by design but shall not exceed six feet on center. Bracing elements shall be detailed to minimize the horizontal displacement of the wall by the vertical displacement of the floor or roof.
(§ 1, Ord. 678, eff. July 12, 1991)
Parapets and exterior wall appendages not conforming to this chapter shall be removed or stabilized or braced to ensure that the parapets and appendages remain in their original position.
The maximum height of an unbraced URM parapet above the lower of either the level of tension anchors or roof sheathing shall not exceed two times the thickness of the parapet wall. If the required parapet height exceeds this maximum height, a bracing system designed for the force factors specified in Table 23-P of the Uniform Building Code for walls shall support the top of the parapet. Parapet corrective work must be performed in conjunction with the installation of tension roof anchors.
The minimum height of a parapet above the wall anchor shall be 12 inches; provided, however, that, if a reinforced concrete beam is provided at the top of the wall, the minimum height above the wall anchor may be six inches.
(§ 1, Ord. 678, eff. July 12, 1991)
(a) 
URM walls which carry no design load other than their own weight may be considered as veneer if they are adequately anchored to new supporting elements.
(b) 
Veneer shall be anchored with approved anchor ties conforming to the required design capacity specified in the Uniform Building Code and placed at a maximum spacing of 24 inches with a maximum supported area of two square feet; provided, however, that existing veneer anchor ties may be acceptable provided the ties are in good condition and conform to the following minimum size, maximum spacing and material requirements:
(1) 
Existing veneer anchor ties shall be corrugated galvanized iron strips not less than one inch in width, eight inches in length and one-sixteenth (1/16) of an inch in thickness or equal and shall be located and laid in every alternate course in the vertical height of the wall at a spacing not to exceed 17 inches on centers horizontally.
(2) 
As an alternate, such ties may be laid in every fourth course vertically at a spacing not to exceed nine inches on centers horizontally.
(c) 
The location and condition of existing veneer anchor ties shall be verified as follows:
(1) 
An approved testing laboratory shall verify the location and spacing of the ties and shall submit a report to the Building Official for appeal as a part of the structural analysis.
(2) 
The veneer in a selected area shall be removed to expose a representative sample of ties (not less than four) for inspection by the Building Official.
(§ 1, Ord. 678, eff. July 12, 1991)
Where trusses and beams other than rafters or joists are supported on masonry, independent secondary columns shall be installed to support vertical loads of the roof or floor members. The loads shall be transmitted down to adequate support.
(§ 1, Ord. 678, eff. July 12, 1991)