Discontinuous Shear Walls - The Analysis of Irregular Shaped Structures - page 406

F i g u r e 11.1 In-plane offset segmented shear walls.
the upper wall section act as a collector which transfers the upper wall overturning
force out to the hold-downs at each end of wall section C. The first-floor wall sheathing
is nailed to the collector with special nailing that has a capacity that is equal to the over-
turning force of section A. The basic wall shears of section C have to be combined with
the transfer diaphragm shears. The disadvantage with this option is that special detail-
ing and structural observations must be made to ensure that the walls are properly
constructed in accordance with the intended design. The special nailing can easily be
overlooked by the contractor and inspector if the nailing and detailing are not clearly
defined in the drawings. The photograph in Fig. 11.2 shows this exact condition. The
double studs at the first floor and the tie strap at the second floor were properly installed.
However, the nailing of the first floor wall sheathing to the multiple studs was accom-
plished with only one row of nails at 12″ o.c. (field nailing), which in most cases will not
provide enough capacity to resist the overturning transferred into the wall. Each of the
double 2× studs should have had special nailing as required by the overturning force.
There was no hold-down installed at the bottom of the multiple-stud location for a tie
to the foundation.