combined errata

8/13/2019 Combined Errata

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ERRATA FOR THE 2003 NEHRP RECOMMENDED PROVISIONS FOR

SEISMIC REGULATIONS FOR NEW BUILDINGS AND OTHER STRUCTURES

June 2006

Table of Contents, pages XIV XV, Change the page numbers of Sec. 14.2.5

through 14.4.7 to read as follows:

14.2.5 Structural analysis procedure selection ..................................................241

14.2.6 Seismic weight ........................................................................................241

14.2.7 Rigid nonbuilding structures ...................................................................241

14.2.8 Minimum base shear ..............................................................................241

14.2.9 Fundamental period.................................................................................241

14.2.10 Vertical distribution of seismic forces ..................................................242

14.2.11 Deformation requirements ....................................................................242

14.2.12 Nonbuilding structure classification .....................................................24214.3 NONBUILDING STRUCTUTRES SIMILAR TO BUILDINGS .....................242

14.3.1 Electrical power generating facilities ......................................................242

14.3.2 Structural towers for tanks and vessels ...................................................242

14.3.3 Piers and wharves....................................................................................243

14.3.4 Pipe racks ................................................................................................243

14.3.5 Steel storage tanks ...................................................................................243

14.4 NONBUILDING STRUCTURES NOT SIMILAR TO BUILDINGS................244

14.4.1 General ....................................................................................................244

14.4.2 Earth retaining structures.........................................................................244

14.4.3 Stacks and chimneys ...............................................................................244

14.4.4 Amusement structures .............................................................................244

14.4.5 Special hydraulic structures ....................................................................24514.4.6 Secondary containment systems .............................................................245

14.4.7 Tanks and vessels ....................................................................................245

Chapter 4Sec. 4.3.3.2, page 66, Add the word not to the last sentence after item No. 4

4.3.3.2 Seismic Design Categories D, E, and F. For structures assigned to Seismic Design

Category D, E, or F, shall be permitted to be taken as 1.0, provided that at each story resisting

more than 35 percent of the base shear in the direction of interest the seismic-force-resistingsystem meets the following redundancy requirements:

1. Systems with braced frames: Removal of an individual brace, or connection thereto, would

not result in more than a 33 percent reduction in story strength, nor create an extreme

torsional irregularity (plan structural irregularity Type 1b).

2. Systems with moment frames: Loss of moment resistance at the beam-to-column connections

at both ends of a single beam would not result in more than a 33 percent reduction in story

strength, nor create an extreme torsional irregularity (plan structural irregularity Type 1b).


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3. Systems with shear walls or wall piers: Removal of a shear wall or wall pier with a height-to-

length-ratio greater than 1.0 within any story, or collector connections thereto, would not

result in more that a 33 percent reduction in story strength, nor create an extreme torsional

irregularity (plan structural irregularity Type 1b).

4. All other systems: No requirements.

For structures not meeting items 1,2,3, and 4 above permitting equal to 1.0,shall be taken as1.3.

Exception: The structure shall be permitted to be designed using ataken as 1.0,

provided that at each story that resists more than 35 percent of the base shear the seismic

force-resisting system is regular in plan with at least two bays of primary seismic force-

resisting elements located at the perimeter framing on each side of the structure in each

orthogonal direction. The number of bays for a shear wall shall be calculated as the

length of wall divided by the story height.

Chapter 6Sec. 6.1.1, page 111, Add the following qualifiers.

6.1.1 Scope. This chapter establishes minimum design criteria for nonstructural components that are

permanently attached to structures and for their supports and attachments

Exception: The following nonstructural components are exempt from the requirements of this section:

1. Architectural components in Seismic Design Category B other than parapets supported by bearing

walls or shear walls provided that the component importance factor (Ip) is equal to 1.0.

2. Mechanical and electrical components in Seismic Design Category B.

3. Mechanical and electrical components in Seismic Design Category C provided that the componentimportance factor (Ip) is equal to 1.0.

4. Mechanical and electrical components inSeismic Design Categories D, E, and F where thecomponent importance factor (Ip) is equal to 1.0 and either both of the following conditions apply:

a. Flexible connections between the components and associated ductwork, piping, and conduitare provided, or and

b. Components are mounted at 4 ft (1.22 m) or less above a floor level and weigh 400 lb (1780 N)

or less.

5. Mechanical and electrical components in Seismic Design Categories D, E, and F where thecomponent importance factor (Ip) is equal to 1.0 andboth of the following conditions apply:

a. Flexible connections between the components and associated ductwork, piping, and conduitare provided, and

b. The components weigh 20 lb (95N) or less or, for distribution systems, weighing 5 lb/ft (7N/m) or less.

Design..


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Chapter 14

Sec. 14.4.7.1 , Page 245, Remove the Importance Factor (I) from , paragraph 3. a, b

(Equation 14.4-1), and c.

14.4.7.1 Design basis. Tanks and vessels storing liquids, gases, or granular solids shall satisfy

the analysis and design requirements set forth in the applicable references as indicated in Table

14.1-1 and the additional requirements of theseProvisionsincluding the following:

1. Damping for the convective (sloshing) force component shall be taken as 0.5 percent unless

otherwise define in an adopted reference or other approved standard.

2. Impulsive and convective components may be combined by taking the square root of the sum

of the squares of the components.

3. Vertical earthquake effects shall be considered in accordance with the applicable approved

standard. If the approved standard permits the user the option of including or excluding the

vertical earthquake effects, to comply with theseProvisions, they shall be included. For

tanks and vessels not covered by an approved standard, the forces due to the vertical

acceleration shall be defined as follows:a. Hydrodynamic vertical and lateral forces in tank walls: The increase in

hydrostatic pressures due to the vertical excitation of the contained liquid shall

correspond to an effective increase in density, L, of the stored liquid equal to

0.2SDSI L.

b. Hydrodynamic hoopforces in cylindrical tank walls: In a cylindrical tank wall,

the hoopforce per unit height, Nh, at level yfrom the base, associated with the

vertical excitation of the contained liquid, shall be computed in accordance with

Eq. 14.4-1

0.2h DSN S I=

( )( )2L iLy

H D . (14.4-1)

where:

Di= inside tank diameter (ft)

HL= liquid height inside the tank (ft).

y = distance from base of the tank to level being investigated (ft).

L= unit weight of stored liquid (lb/ft3)

c. Vertical inertia forces in cylindrical and rectangular tank walls: Vertical inertia

forces associated with the vertical acceleration of the structure itself shall be

taken equal to 0.2SDSIW.

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