Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 16 - Structural Design › Section 1614 - STRUCTURAL INTEGRITY › Subsection 1614.4 - Bearing wall structures

Current through Register 1525, July 5, 2024
Bearing wall structures shall have vertical ties in all
				  load-bearing walls and longitudinal ties, transverse ties and perimeter ties at
				  each floor level in accordance with this section and as shown in Figure
				  1614.4.
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FIGURE 1614.4 LONGITUDINAL, PERIMETER, TRANSVERSE AND
				  VERTICAL TIES
1614.4.1
Concrete wall structures.
Precast bearing wall structures constructed
				solely of reinforced or prestressed concrete, or combinations of these shall
				conform to the requirements of Sections 7.13, 13.3.8.5 and 16.5 of ACI
				318.
1614.4.2
Other bearing
				wall structures.
Ties in bearing wall structures other than those
				covered in Section 1614.4.1 shall conform to this section.
1614.4.2.1
Longitudinal ties.
Longitudinal ties shall consist of continuous reinforcement in slabs;
				continuous or spliced decks or sheathing; continuous or spliced members framing
				to, within or across walls; or connections of continuous framing members to
				walls. Longitudinal ties shall extend across interior load-bearing walls and
				shall connect to exterior load-bearing walls and shall be spaced at not greater
				than 10 feet (3038 mm) on center. Ties shall have a minimum nominal tensile
				strength,
T
T, given by Equation 16-46.
				For ASD the minimum nominal tensile strength shall be permitted to be taken as
				1.5 times the allowable tensile stress times the area of the tie.
T
T =
wLS
<= T
S
(Equation 16-46)
where:
L
= The span of the horizontal element in
				  the direction of the tie, between bearing walls, feet (m).
w
= The weight per unit area of the floor or
				  roof in the span being tied to or across the wall, psf
				  (N/m2).
S
= The spacing between ties, feet
				  (m).
[ALPHA]T = A coefficient with a value
				  of 1,500 pounds per foot (2.25 kN/m) for masonry bearing wall structures and a
				  value of 375 pounds per foot (0.6 kN/m) for structures with bearing walls of
				  cold-formed steel light-frame construction.
1614.4.2.2
Transverse ties.
Transverse ties shall consist of continuous reinforcement in slabs; continuous
				or spliced decks or sheathing; continuous or spliced members framing to, within
				or across walls; or connections of continuous framing members to walls.
				Transverse ties shall be placed no farther apart than the spacing of load-
				bearing walls. Transverse ties shall have minimum nominal tensile strength
T
T, given by Equation 16-46. For ASD
				the minimum nominal tensile strength shall be permitted to be taken as 1.5
				times the allowable tensile stress times the area of the tie.
1614.4.2.3
Perimeter ties.
Perimeter ties shall consist of continuous reinforcement in slabs; continuous
				or spliced decks or sheathing; continuous or spliced members framing to, within
				or across walls; or connections of continuous framing members to walls. Ties
				around the perimeter of each floor and roof shall be located within 4 feet
				(1219 mm) of the edge and shall provide a nominal strength in tension not less
				than
T
p, given by Equation 16-47. For
				ASD the minimum nominal tensile strength shall be permitted to be taken as 1.5
				times the allowable tensile stress times the area of the tie.
T
p =
							 200
w
<= ßT
(Equation 16-47)
For SI:
T
p =
				  90.7
w
<= ßT
where:
w
= As defined in Section 1614.4.2.1.
ßT = A coefficient with a value
				  of 16,000 pounds (7200 kN) for structures with masonry bearing walls and a
				  value of 4,000 pounds (1300 kN) for structures with bearing walls of
				  cold-formed steel light-frame construction.
1614.4.2.4
Vertical ties.
Vertical ties shall consist of continuous or spliced reinforcing, continuous or
				spliced members, wall sheathing or other engineered systems. Vertical tension
				ties shall be provided in bearing walls and shall be continuous over the height
				of the building. The minimum nominal tensile strength for vertical ties within
				a bearing wall shall be equal to the weight of the wall within that
story
plus the weight of the diaphragm tributary to the wall
				in the
story
below. No fewer than two ties shall be provided
				for each wall. The strength of each tie need not exceed 3,000 pounds per foot
				(450 kN/m) of wall tributary to the tie for walls of masonry construction or
				750 pounds per foot (140 kN/m) of wall tributary to the tie for walls of
				cold-formed steel light-frame construction.