Ce - 522 - Staad - Earthquake Loads

STRUCTURAL ANALYSIS AND DESIGN USING STAAD PRO SOFTWARE GENERAL PROCESS FLOW STRUCTURE MODELING DETERMINE PRIMARY LOADS APPLY LOAD COMBINATIONS

ANALYSIS AND DESIGN

STRUCTURE MODELING

FOUR – STOREY REINFORCED CONCRETE BUILDING

Typical Floor Framing Plan

MEMBER SIZES/PROPERTY Member Description

Interior Columns: Ground floor to third floor level Third floor to roof deck level corner Columns: Ground floor to third floor level Third floor to roof deck level

Member Size (in mm) 400 x 400 350 x 350

300 x 500 300 x 450

Girders Longitudinal (x direction) Transverse (z direction)

300 x 450 300 x 400

Intermediate beams Stair beam

250 x 400 250 x 350

SUPPORT CONDITION • A FIXED support has restraints against all directions of movement.

BETA ANGLE • BETA ANGLE - is the angle through which the local z – axis has been rotated about the local x – axis from the position of being parallel and in the same positive direction of the global z – axis.

Application: without beta angle

Application: with beta angle

Application: beta angle – step 1



MEMBER RELEASE Specification This set of commands may be used to fully release specific degrees of freedom at the ends of frame members. They may also be used to describe a mode of attachment where the member end is connected to the joint for specific degrees of freedom through the means of springs.

MEMBER RELEASE Specification

Application: step – 1



MEMBER OFFSET Specification This command can be used for any member whose starting or ending point is not concurrent with the given incident joint. This command enables the user to account for the secondary forces, which are induced due to the eccentricity of the member. Member offsets can be specified in any direction, including the direction that may coincide with the member x-axis.

MEMBER OFFSET Specification






MASTER/SLAVE Specification The master-slave option enables us to specify rigid links or specialized linkages in the structure. This facility can be used to model special structural elements such as ties or a floor diaphragm which makes the floor rigid for in-plane movements.

MASTER/SLAVE Specification

MASTER/SLAVE Specification





CREATING A GROUPINGS FOR FLOOR





PRIMARY LOADINGS

UBC 1997 LOAD GENERATION

EQUIVALENT LATERAL FORCE PROCEDURE

EXAMPLE:

EQUIVALENT LATERAL FORCE PROCEDURE • NOTES: The UBC load cases should be provided as the first set of load cases. Non – UBC primary load case specified before a UBC load case is not acceptable. Additional loads such as member loads and joint loads may be specified along with the UBC load under the same load case.

EXAMPLE:

SEISMIC PARAMETERS  Preliminary Data Occupancy Category Type IV Importance Factor I = 1.0 Soil Profile Type SD Seismic Zone Zone 4 Seismic Zone Factor Z = 0.40  Near-Source Factors Na = 1.0 Nv = 1.0 Note: location of structure > 10 km from known seismic source

SEISMIC PARAMETERS  Seismic Response Coefficients Ca = 0.44 Na Ca = 0.44 (1.0) = 0.44 Cv = 0.64 Nv Cv = 0.64 (1.0) = 0.64  Response Modification Factor Structural System

Concrete SMRF

Response Mod. Factor

R = 8.5

DEADLOADS Dead Loads on Typical Floor

Total Floor Slab Load

6.49 kPa

On floor area

Loading from ext. walls

11.55 kN/m On beams supp. walls

Stair Beam Loading

9.50 kN/m

DEADLOADS Dead Loads on Roof Deck

Total Floor Slab Load

3.89 kPa

On floor area

Loading from ext. walls

2.93 kN/m On beams supp. walls

Stair Beam Loading

9.50 kN/m

LIVE LOADS LIVE LOADS

Load

Remarks

Office

2.4 kPa

On floor area

Commercial Assembly

4.8 kPa

On floor area

Residential/Dormitory

2.04 kPa

On floor area

Typical floor








Application: step – 8 – assign all the loads in the structure



Application: step – 11 • NOTE:

REPEAT STEP 10 FOR LOAD CASE NUMBER 2, but the seismic is in z – direction


Ce - 522 - Staad - Earthquake Loads

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