For readers unfamiliar with the program, a detailed description of BSSC's purpose and activities concludes the commentary volume.). This task was carried out with the cooperation of the USGS (under a Memorandum of Understanding signed by the BSSC and the USGS) and under the direction of a five-member Managing Committee (MC).
PURPOSE
SCOPE AND APPLICATION
- Scope
- Additions
- Change of Use
- Alterations
- Alternate Materials and Alternate Means and Methods of Construction
The addition does not reduce the seismic resistance of any structural element of the existing structure to less than that required for a new structure. Exception: When a change of use results in a structure being reclassified from Seismic Use Group I to Seismic Use Group II, compliance with these provisions is not required if the structure is located where the SDS is less than 0.3.
SEISMIC USE GROUPS
- Seismic Use Group III
- Seismic Use Group II
- Seismic Use Group I
- Multiple Use
- Seismic Use Group III Structure Access Protection
Medical facilities with more than 50 disabled resident patients not otherwise designated a Seismic Use Group III facility. Where operational access is less than 10 ft (3 m) from an interior lot line or less than 10 ft (3 m) from another structure, protection of the access from potential falling debris shall be provided by the owner of the structure of Group III of Seismic Use.
OCCUPANCY IMPORTANCE FACTOR
GLOSSARY
Design displacement: The design earthquake lateral displacement, excluding the additional displacement due to actual and accidental twisting, required for the design of the isolation system. Hold-Down: A device used to resist the uplift of shear wall chords.
NOTATIONS
Fxm The portion of the seismic base shear, Vm, induced at level x, as determined in Sec. L The total length of the building (ft or m) at the base in the analyzed direction.
QUALITY ASSURANCE
SCOPE
QUALITY ASSURANCE
- Details of Quality Assurance Plan
- Contractor Responsibility
The seismic force-resistant systems and the seismic systems designated in accordance with this chapter that are subject to quality assurance. Identification and qualifications of the person(s) exercising such control and their position(s) in the organization.
SPECIAL INSPECTION
- Piers, Piles, Caissons
- Reinforcing Steel
- Structural Concrete
- Prestressed Concrete
- Structural Masonry
- Structural Steel
- Structural Wood
- Cold–Formed Steel Framing
- Architectural Components
- Mechanical and Electrical Components
Periodic special inspections during installation of anchorages of all other electrical equipment in seismic design categories E and F;. Regular special inspections during installation of HVAC ducts that will contain hazardous materials in Seismic Construction Categories C, D, E, and F.
TESTING
- Reinforcing and Prestressing Steel
- Structural Concrete
- Structural Masonry
- Mechanical and Electrical Equipment
- Seismically Isolated Structures
The Special Inspector(s) is/are responsible for verifying that testing requirements are performed by an approved testing agency for compliance with the following: Masonry quality assurance testing shall be in accordance with the requirements of Ref. in accordance with the requirements of ref.
STRUCTURAL OBSERVATIONS
The testing necessary to prove that construction conforms to these Provisions shall be included in a quality assurance plan. Deficiencies observed must be reported in writing to the owner and the authority having jurisdiction.
REPORTING AND COMPLIANCE PROCEDURES
PROCEDURES FOR DETERMINING MAXIMUM CONSIDERED EARTHQUAKE
- Maximum Considered Earthquake Ground Motions
- General Procedure for Determining Maximum Considered Earthquake and
- Site-Specific Procedure for Determining Ground Motion Accelerations
Map Earthquake Spectral Acceleration Location Class, Considered Short Period of Maximum Earthquake Spectral Response. The considered maximum acceleration of the earthquake spectral response, SaM, at each period, T, will be obtained from that spectrum.
SEISMIC DESIGN CATEGORY
- Determination of Seismic Design Category
- Site Limitation for Seismic Design Categories E and F
Seismic Use Group I and II structures located at locations with a mapped maximum considered earthquake spectral response acceleration with a period of 1 second, S1, equal to or greater than 0.75g, shall be assigned to Seismic Design Category E and Seismic Use Group III structures located in such locations are assigned to seismic design category F.
DESIGN BASIS
- General
- Basic Seismic-Force-Resisting Systems
- Structure Configuration
- Redundancy
- Analysis Procedures
- Design, Detailing Requirements, and Structural Component Load Effects
- Combination of Load Effects
- Deflection and Drift Limits
Ordinary reinforced concrete moment frames are not permitted as part of the seismic system in Seismika. A vertical geometric irregularity 5.2.5.3 D, E and F is considered to exist where the horizontal dimension of the lateral force-.
EQUIVALENT LATERAL FORCE PROCEDURE
- General
- Seismic Base Shear
- Period Determination
- Overturning
- Drift Determination and P-Delta Effects
The design history drift, ), shall be calculated as the difference between the deflections at the center of mass at the top and bottom of the considered floor. The elastic analysis of the seismic force-resisting system shall be performed using the prescribed seismic design forces in Sec.
MODAL ANALYSIS PROCEDURE
- General
- Modeling
- Modes
- Modal Properties
- Modal Base Shear
- Modal Forces, Deflections, and Drifts
- Modal Story Shears and Moments
- Design Values
- Horizontal Shear Distribution
- Foundation Overturning
- P-Delta Effects
1.4, and Tm = the modal vibration period (in seconds) of the structure's mth mode. Nim = the displacement amplitude at the ith level of the structure when vibrating in its mth mode.
SOIL-STRUCTURE INTERACTION EFFECTS
- General
- Equivalent Lateral Force Procedure
- Modal Analysis Procedure
5.3.2.1-1 using the fundamental natural period of the fixed base structure (T or Ta) as specified in Sec. Mo1 = the overturning base moment for the fundamental mode of the fixed base structure, as determined in Sec.
GENERAL
- References and Standards
- Component Force Transfer
- Seismic Forces
- Seismic Relative Displacements
- Component Importance Factor
- Component Anchorage
- Construction Documents
The force (Fp) must be independently applied longitudinally and laterally in combination with service loads associated with the component. The effects of seismic relative displacements shall be considered in combination with displacements caused by other loads as appropriate.
ARCHITECTURAL COMPONENT DESIGN
- General
- Architectural Component Forces and Displacements
- Architectural Component Deformation
- Exterior Nonstructural Wall Elements and Connections
- Out-of-Plane Bending
- Suspended Ceilings
- Access Floors
- Partitions
- Steel Storage Racks
In each perpendicular horizontal direction, one end of the ceiling grid must be attached to the closing angle. The earthquake force, Fp, is transmitted from the upper surface of the access floor to the supporting structure.
MECHANICAL AND ELECTRICAL COMPONENT DESIGN
- General
- Mechanical and Electrical Component Forces and Displacements
- Mechanical and Electrical Component Period
- Mechanical and Electrical Component Attachments
- Component Supports
- Component Certification
- Utility and Service Lines at Structure Interfaces
- Site-Specific Considerations
- Storage Tanks
- HVAC Ductwork
- Piping Systems
- Boilers and Pressure Vessels
- Mechanical Equipment, Attachments, and Supports
- Electrical Equipment, Attachments, and Supports
- Alternative Seismic Qualification Methods
- Elevator Design Requirements
GENERAL
In addition to their attachments and supports, duct systems designated as having an Ip greater than 1.0 must be designed to meet the strength and displacement requirements of Sec. In addition, mechanical equipment designated as an Ip greater than 1.0 must be designed to meet the power and displacement requirements of Art.
STRENGTH OF COMPONENTS AND FOUNDATIONS
- Structural Materials
- Soil Capacities
These requirements include, but are not limited to, requirements regarding the extent of the foundation investigation, the presence or placement of fills in the area of the structure, the stability of the slope, subsurface drainage and settlement control.
SEISMIC DESIGN CATEGORIES A AND B
SEISMIC DESIGN CATEGORY C
- Investigation
- Pole-Type Structures
- Foundation Ties
- Special Pile Requirements
The post cap connection can be done using field set pins anchored into the concrete pile. The connection of the pile cap is permitted to be made by means of pins as required in Sec.
SEISMIC DESIGN CATEGORIES D, E, AND F
- Investigation
- Foundation Ties
- Liquefaction Potential and Soil Strength Loss
- Special Pile Requirements
The connection of the pile cap is allowed to be done by the development of the reinforcing strand of the piles if a ductile connection is provided. 14 gauge may be considered to provide concrete insulation equivalent to the closed joints or equivalent coils required in an uncapped concrete pile, provided the metal layer is adequately protected against possible damaging action due to soil constituents , changing water levels or other factors indicated by boring records of site conditions.
SEISMIC REQUIREMENTS FOR STEEL STRUCTURES
SEISMIC DESIGN CATEGORIES A, B, AND C
SEISMIC DESIGN CATEGORIES D, E, AND F
COLD-FORMED STEEL SEISMIC REQUIREMENTS
- Modifications to Ref. 8.4
- Modifications to Ref. 8.5
The reference to section and paragraph numbers has been changed to that of the specific specification.
LIGHT-FRAMED WALLS
- Boundary Members
- Connections
Nominal shear values shall be multiplied by the appropriate strength reduction factor N to determine a design strength as specified in Sec. Both studs and tracks shall have a minimum uncoated base metal thickness of 0.033 inch and shall be ASTM A446 Grade A (or ASTM A653 SQ Grade 33 [new designation]).
SEISMIC REQUIREMENTS FOR STEEL DECK DIAPHRAGMS
Wall studs and track shall have a minimum exposed base thickness of not less than 0.033 inch (0.84 mm) and shall not have an exposed base metal thickness greater than 0.048 inch (1.22 mm). Panel end supports and their uplift anchorage must have the design strength to withstand the forces determined by the seismic loads determined by Eq.
STEEL CABLES
- Modifications to Ref. 9-1
It is assumed to extend for a distance of not less than h/2 on either side of the non-linear action location. The contribution of the diagonal reinforcement to the nominal flexural strength of the coupling beam surface must be taken into account.
BOLTS AND HEADED STUD ANCHORS IN CONCRETE
- Load Factor Multipliers
- Strength of Anchors
- Strength Based on Tests
- Strength Based on Calculations
As = area (in. ) of the assumed failure surface, taken as a truncated cone inclined2 at an angle of 45 degrees from the anchor head to the concrete surface as shown in Figure 9.2.4.1a;. If any anchors are closer to the free edge of the concrete than the anchor embedment length, the structural tensile strength of those anchors is reduced in proportion to the edge distance divided by the embedment length.
CLASSIFICATION OF SEISMIC-FORCE-RESISTING SYSTEMS
- Classification of Moment Frames
- Classification of Shear Walls
At the bottom of load-bearing walls or at the top of foundations when attached to a wall, and c. Reinforcement at the top and bottom of openings, when used to determine the maximum spacing specified in c above, shall be continuous in the wall.
SEISMIC DESIGN CATEGORY A
SEISMIC DESIGN CATEGORY B
- Moment Frames
The footing, footing, or other walls below the footing shall be reinforced as required by Sec.
SEISMIC DESIGN CATEGORY C
- Seismic-Force-Resisting Systems
- Discontinuous Members
- Plain Concrete
- Seismic-Force-Resisting Systems
- Frame Members Not Proportioned to Resist Forces Induced by Earthquake Motions
- Plain Concrete
The probable strength, Spr, of the connector should be determined using an N value of unity and a steel stress of at least 1.25fy. The connector must be anchored on either side of the interface for capacities that are at least 1.6 times the Spr value for that connector.
REQUIREMENTS
GENERAL
- Scope
- Reference Documents
- Definitions
- Notations
Av = cross-sectional area of shear reinforcement, in. mm)2 2 a = length of compressive stress block, in. Ma = maximum moment in the member due to the applied load for which the deflection is calculated, in.-lb (N- mm).
CONSTRUCTION REQUIREMENTS
- General
- Quality Assurance
DE = ratio of the reinforcement area to the net cross-sectional area of masonry in a plane perpendicular to the reinforcement.
GENERAL REQUIREMENTS
- Scope
- Empirical Masonry Design
- Plain (Unreinforced) Masonry Design
- Reinforced Masonry Design
- Seismic Design Category A
- Seismic Design Category B
- Seismic Design Category C
- Seismic Design Category D
- Seismic Design Categories E and F
- Properties of Materials
- Section Properties
If open end members are used and solid jointed, the minimum amount of horizontal reinforcement shall be 0.0007 times the gross cross-sectional area of the wall. The minimum effective embedment length of curved bar anchor bolts that can withstand axial forces shall be 4 bolt diameters or 2 inches.
DETAILS OF REINFORCEMENT
- General
- Size of Reinforcement
- Placement Limits for Reinforcement
- Cover for Reinforcement
- Development of Reinforcement
The effective embedment of a stirrup leg should be taken as the distance between the mid-depth of the member, and the start of the hook (point of contact). The ld/3 embedment of a stirrup leg should be taken as the distance between mid-depth of member, and the start of the hook (point of contact).
STRENGTH AND DEFORMATION REQUIREMENTS
- General
- Strength
- Design Strength
- Deformation Requirements
The width of the keys must be at least equal to the width of the space for the injection mass b. The distance between the keys must be at least equal to the length of the key.
FLEXURE AND AXIAL LOADS
- Scope
- Design Requirements of Reinforced Masonry Members
- Design of Plain (Unreinforced) Masonry Members
SHEAR
- Scope
- Shear Strength
- Design of Reinforced Masonry Members
- Design of Plain (Unreinforced) Masonry Members
An = net cross-sectional area of the masonry, in. specified compressive strength of the masonry, psi; and. Av = area of shear reinforcement, in. dv = length of element in direction of shear force, in. mm) s = distance between shear reinforcement, in.
SPECIAL REQUIREMENTS FOR BEAMS
SPECIAL REQUIREMENTS FOR COLUMNS
Side ties shall be so arranged that each corner and alternate longitudinal bar shall have lateral support provided by the corner of a side tie having an included angle of not more than 135 degrees and no bar shall be beyond 6 inches. Side joints shall be located vertically not more than one-half lateral bond spacing above the top of footing or slab in any story and shall be spaced as herein provided to not more than one-half lateral bond spacing below the lowest horizontal reinforcement in beam, girder, plate or drop panel above.
SPECIAL REQUIREMENTS FOR WALLS
Vertical spacing of lateral ties shall not exceed 16 longitudinal bar diameters, 48 lateral tie diameters, nor the least diameter dimension of the column. Where beams or brackets frame from four directions in a column, side joints may not terminate more than 3 inches.
SPECIAL REQUIREMENTS FOR SHEAR WALLS
- Ordinary Plain Masonry Shear Walls
- Detailed Plain Masonry Shear Walls
- Ordinary Reinforced Masonry Shear Walls
- Intermediate Reinforced Masonry Shear Walls
- Special Reinforced Masonry Shear Walls
- Flanged Shear Walls
- Coupled Shear Walls
- Flexural Yielding
- Reinforcement
- Wall Frame Beams
- Wall Frame Columns
- Wall Frame Beam-Column Intersection
The cumulative length of all keys must be at least 20% of the length of the shear wall. The spacing of transverse reinforcement shall not exceed 1/4 of the nominal dimension of the column parallel to the plane of the wall frame.
GLASS-UNIT MASONRY AND MASONRY VENEER
- Design Lateral Forces and Displacements
- Glass-Unit Masonry Design
- Masonry Veneer Design
The R-coefficients of Table 5.2.2 for detailed plain masonry shear walls shall apply to walls constructed in accordance with Chapter 6 and Art. The R-coefficients of Table 5.2.2 for ordinary plain masonry shear walls shall apply to walls designed in accordance with Chapter 6 of Ref.
GENERAL
- Scope
- Reference Documents
- Notations
The maximum clearance from the foundation to the bottom of the floor or roof frame above or. The maximum clearance from the top of the floor or roof frame to the bottom of the floor or roof frame above.
DESIGN METHODS
- Engineered Wood Design
- Conventional Light-Frame Construction
The dimensions for wood products and related products listed in this section are nominal dimensions, and the actual dimensions must not be less than those prescribed by the reference standards. For open front designs, l is the length from the edge of the diaphragm at the open front to the vertical resisting elements parallel to the direction of the applied force.
ENGINEERED WOOD CONSTRUCTION
- General
- Framing Requirements
- Deformation Compatibility Requirements
- Design Limitations
Rigid wood diaphragms shall be permitted to overhang beyond the outer supporting shear wall (or other vertical resisting member) a length, l, of not more than 25 feet (7620 mm) or two-thirds of the diaphragm width, w, whichever is smaller. . Alternatively, for walls sheathed at both levels, the bolts should be placed in the center of the foundation sill with the edge of the plate washer within ½ inch.
DIAPHRAGMS AND SHEAR WALLS
- Diaphragm and Shear Wall Aspect Ratios
- Shear Resistance Based on Principles of Mechanics
- Sheathing Requirements
One additional nail should be placed in each panel at the boundaries of the diaphragm and shear wall. Double diagonally paneled timber diaphragms and shear walls should be lined with two layers of diagonal panels placed at right angles to each other on the same side of the girders.
CONVENTIONAL LIGHT-FRAME CONSTRUCTION
- Scope
- Braced Walls
- Detailing Requirements
12.5.1.1.5 A construction shall be considered to have an irregularity when braced wall lines are not perpendicular to each other. Foundation for braced wall connections shall be made at each foundation supporting a braced wall panel.
SEISMIC DESIGN CATEGORY A
For openings with a dimension greater than 4 feet. 1220 mm), or openings in structures in seismic design categories D and E, the following minimum details must be provided.
SEISMIC DESIGN CATEGORIES B, C, AND D
- Conventional Light-Frame Construction
- Engineered Construction
SEISMIC DESIGN CATEGORIES E AND F
- Limitations
Fasteners Blocked Diaphragms Unblocked Diaphragms Panel Grade Type Minimum Minimum Minimum Lines parallel to load (Cases 3 and 4) and at all panel edges (Cases 5 and 6) 6 in.
GENERAL
CRITERIA SELECTION
- Basis for Design
- Stability of the Isolation System
- Seismic Use Group
- Configuration Requirements
- Selection of Lateral Response Procedure
EQUIVALENT LATERAL FORCE PROCEDURE
- General
- Deformation Characteristics of the Isolation System
- Minimum Lateral Displacements
- Minimum Lateral Forces
- Vertical Distribution of Force
- Drift Limits
DYNAMIC LATERAL RESPONSE PROCEDURE
- General
- Isolation System and Structural Elements Below the Isolation System
- Structural Elements Above the Isolation System
- Ground Motion
- Mathematical Model
- Description of Analysis Procedures
- Design Lateral Force
LATERAL LOAD ON ELEMENTS OF STRUCTURES AND NONSTRUCTURAL
- General
- Forces and Displacements
DETAILED SYSTEM REQUIREMENTS
- General
- Isolation System
- Structural System
FOUNDATIONS
DESIGN AND CONSTRUCTION REVIEW
- General
- Isolation System
REQUIRED TESTS OF THE ISOLATION SYSTEM
- General
- Prototype Tests
- Determination of Force-Deflection Characteristics
- Test Specimen Adequacy
- Design Properties of the Isolation System
GENERAL
- Scope
- Nonbuilding Structures Supported by Other Structures
- Architectural, Mechanical, and Electrical Components
- Loads
- Fundamental Period
- Drift Limitations
- Materials Requirements
STRUCTURAL DESIGN REQUIREMENTS
- Design Basis
- Rigid Nonbuilding Structures
- Deflection Limits and Structure Separation
NONBUILDING STRUCTURES SIMILAR TO BUILDINGS
- General
- Pipe Racks
- Steel Storage Racks
- Electrical Power Generating Facilities
- Structural Towers for Tanks and Vessels
- Piers and Wharves
NONBUILDING STRUCTURES NOT SIMILAR TO BUILDINGS
- General
- Earth Retaining Structures
- Tanks and Vessels
- Electrical Transmission, Substation, and Distribution Structures
- Telecommunication Towers
- Stacks and Chimneys
- Amusement Structures
- Special Hydraulic Structures
- Buried Structures
- Inverted Pendulums
