When using the UBC 97 option, a frame is assigned to one of the following five Seismic Zones (UBC 2213, 2214):

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1 COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001 CONCRETE FRAME DESIGN UBC97 Technical Note The Concrete Frame Design UBC 97 series of Technical Notes describes in detail the various aspects of the concrete design procedure that is used by this program when the user selects the UBC 97 Design Code (ICBO 1997). The various notations used in this series are listed herein. The design is based on user-specified loading combinations. The program provides a set of default load combinations that should satisfy requirements for the design of most building type structures. See Technical Note Design Load Combinations Concrete Frame Design UBC97 for more information. When using the UBC 97 option, a frame is assigned to one of the following five Seismic Zones (UBC 2213, 2214):! Zone 0! Zone 1! Zone 2! Zone 3! Zone 4 By default the Seismic Zone is taken as Zone 4 in the program. However, the Seismic Zone can be overwritten in the Preference form to change the default. See Technical Note Preferences Concrete Frame Design UBC97 for more information. When using the UBC 97 option, the following Framing Systems are recognized and designed according to the UBC design provisions (UBC 1627, 1921):! Ordinary Moment-Resisting Frame (OMF)! Intermediate Moment-Resisting Frame (IMRF) Page 1 of 5

2 ! Special Moment-Resisting Frame (SMRF) The Ordinary Moment-Resisting Frame (OMF) is appropriate in minimal seismic risk areas, especially in Seismic Zones 0 and 1. The Intermediate Moment-Resisting Frame (IMRF) is appropriate in moderate seismic risk areas, specially in Seismic Zone 2. The Special Moment-Resisting Frame (SMRF) is appropriate in high seismic risk areas, specially in Seismic Zones 3 and 4. The UBC seismic design provisions are considered in the program. The details of the design criteria used for the different framing systems are described in Notes Strength Reduction Factors Concrete Frame Design UBC 97, Column Design Concrete Frame Design UBC97, Beam Design Concrete Frame Design UBC97, and Joint Design Concrete Frame Design UBC 97. By default the frame type is taken in the program as OMRF in Seismic Zone 0 and 1, as IMRF in Seismic Zone 2, and as SMRF in Seismic Zone 3 and 4. However, the frame type can be overwritten in the Overwrites form on a member-by-member basis. See Technical Note Overwrites Concrete Frame Design UBC 97 for more information. If any member is assigned with a frame type, the change of the Seismic Zone in the Preferences will not modify the frame type of an individual member that has been assigned a frame type. The program also provides input and output data summaries, which are described in Technical Notes Input Data Concrete Frame Design UBC97 and Output Details Concrete Frame Design UBC97. English as well as SI and MKS metric units can be used for input. The code is based on Inch-Pound-Second units. For simplicity, all equations and descriptions presented in this Technical Note correspond to Inch-Pound-Second units unless otherwise noted. Notation A cv Area of concrete used to determine shear stress, sq-in A g A s ' As Gross area of concrete, sq-in Area of tension reinforcement, sq-in Area of compression reinforcement, sq-in Notation Page 2 of 5

3 A s(required) A st A v C m D' E c E s I g I se L M 1 M 2 M c M ns M s M u M ux M uy P b P c Area of steel required for tension reinforcement, sq-in Total area of column longitudinal reinforcement, sq-in Area of shear reinforcement, sq-in Coefficient, dependent upon column curvature, used to calculate moment magnification factor Diameter of hoop, in Modulus of elasticity of concrete, psi Modulus of elasticity of reinforcement, assumed as 29,000,000 psi (UBC ) Moment of inertia of gross concrete section about centroidal axis, neglecting reinforcement, in 4 Moment of inertia of reinforcement about centroidal axis of member cross section, in 4 Clear unsupported length, in Smaller factored end moment in a column, lb-in Larger factored end moment in a column, lb-in Factored moment to be used in design, lb-in Nonsway component of factored end moment, lb-in Sway component of factored end moment, lb-in Factored moment at section, lb-in Factored moment at section about X-axis, lb-in Factored moment at section about Y-axis, lb-in Axial load capacity at balanced strain conditions, lb Critical buckling strength of column, lb Notation Page 3 of 5

4 P max P 0 P u V c V E V D+L V u V p a a b b b f b w c c b d d' d s ' fc Maximum axial load strength allowed, lb Acial load capacity at zero eccentricity, lb Factored axial load at section, lb Shear resisted by concrete, lb Shear force caused by earthquake loads, lb Shear force from span loading, lb Factored shear force at a section, lb Shear force computed from probable moment capacity, lb Depth of compression block, in Depth of compression block at balanced condition, in Width of member, in Effective width of flange (T-Beam section), in Width of web (T-Beam section), in Depth to neutral axis, in Depth to neutral axis at balanced conditions, in Distance from compression face to tension reinforcement, in Concrete cover to center of reinforcing, in Thickness of slab (T-Beam section), in Specified compressive strength of concrete, psi f y f ys Specified yield strength of flexural reinforcement, psi f y 80,000 psi (UBC ) Specified yield strength of flexural reinforcement, psi Notation Page 4 of 5

5 h k r α β 1 β d δ s δ ns ε c ε s ϕ Dimension of column, in Effective length factor Radius of gyration of column section, in Reinforcing steel overstrength factor Factor for obtaining depth of compression block in concrete Absolute value of ratio of maximum factored axial dead load to maximum factored axial total load Moment magnification factor for sway moments Moment magnification factor for nonsway moments Strain in concrete Strain in reinforcing steel Strength reduction factor Notation Page 5 of 5