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 Member Size (in mm)

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

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

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.

SUPPORT CONDITION

• A FIXED support has restraints

against all directions of

movement.

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

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

Typical floor

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

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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