Page 459 - Advanced Design Examples of Seismic Retrofit of Structures

Examples of Nonengineered Buildings Chapter 6 405

TABLE 6.2 Standardized Damage States

Damage Commentary on Damage to
State EERI Description Adobe Buildings
A No damage, but room contents No damage or evidence of new
could be shifted. Only incidental cracking
None
hazard
B Minor damage to nonstructural Preexisting cracks have opened
elements slightly. New hairline cracking
Slight
Building may be temporarily may have begun to develop at
closed but could probably be the corners of doors and
reopened after minor cleanup in windows or the intersection of
less than one week. Only perpendicular walls
incidental hazard
C Primarily nonstructural damage; Cracking damage throughout
there also could be minor but the building
Moderate
nonthreatening structural damage; Cracks at the expected locations
building probably closed for (opening, wall intersections,
2–12weeks
slippage between framing and
walls). Offsets at cracks are small.
None of the wall sections is
unstable
D Extensive structural and Extensive crack damage
nonstructural damage. Long-term throughout the building. Crack
Extensive
closure should be expected due offsets are large in many areas,
either to amount of repair work or cracked wall sections are
uncertainty of economic unstable, vertical support for the
feasibility of repair. Localized, floor and roof framing is
life-threatening situations would hazardous
be common
E Complete collapse or damage that Very extensive damage.
is not economically repairable. Collapse or partial collapse of
Complete
Life-threatening situations in every much of the structure. Due to
building of this category extensive wall collapse, repair
of the building requires
reconstruction of many of the
walls
(Adapted from E.L. Tolles, F.A. Webster, A. Crosby, E.E. Kimbro, Survey of Damage to Historic Adobe
Buildings After the January 1994 Northridge Earthquake, Getty Conservation Institute, 1996.)

Retrofit Measures
The retrofit measures on the model buildings included horizontal elements and,
usually, vertical elements. The horizontal elements were nylon straps, a bond
beam, or a partial wood diaphragm. The vertical elements were nylon straps,
center-core rods, or local ties.