SAMPLE DESIGN PROBLEM SAMPLE DESIGN PROBLEM FOR A FOUR (4) STOREY FOR A FOUR (4) STOREY STEEL BUILDING USING STEEL BUILDING USING NSCP-5 NSCP-5 TH TH EDITION EDITION PIMENTEL & ASSOCIATES Presented by: ENGR. TONY C. PIMENTEL Engineering Consultants INCLUDES : INCLUDES : 1. 1. DESIGN CONCEPTS DESIGN CONCEPTS 2. CALCULATION OF BASE SHEAR 2. CALCULATION OF BASE SHEAR 3. PRELIMINARY SIZING – USING MODIFIED ENERGY 3. PRELIMINARY SIZING – USING MODIFIED ENERGY APPROACH APPROACH 4. PUSH-OVER ANALYSIS – VERIFICATION OF 4. PUSH-OVER ANALYSIS – VERIFICATION OF RESULTS RESULTS ASSOCIATION OF STRUCTURAL ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES ENGINEERS OF THE PHILIPPINES INC. INC. Continuing Professional Development
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SAMPLE DESIGN SAMPLE DESIGN PROBLEM FOR A FOUR PROBLEM FOR A FOUR (4) STOREY STEEL (4) STOREY STEEL BUILDING USING BUILDING USING NSCP-5NSCP-5THTH EDITION EDITION
SAMPLE DESIGN SAMPLE DESIGN PROBLEM FOR A FOUR PROBLEM FOR A FOUR (4) STOREY STEEL (4) STOREY STEEL BUILDING USING BUILDING USING NSCP-5NSCP-5THTH EDITION EDITION
PIMENTEL & ASSOCIATES
Presented by:
ENGR. TONY C. PIMENTELEngineering Consultants
INCLUDES :INCLUDES :
1.1. DESIGN CONCEPTSDESIGN CONCEPTS
2. CALCULATION OF BASE SHEAR2. CALCULATION OF BASE SHEAR
3. PRELIMINARY SIZING – USING MODIFIED ENERGY 3. PRELIMINARY SIZING – USING MODIFIED ENERGY APPROACHAPPROACH
4. PUSH-OVER ANALYSIS – VERIFICATION OF RESULTS4. PUSH-OVER ANALYSIS – VERIFICATION OF RESULTS
ASSOCIATION OF STRUCTURAL ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES INC. ENGINEERS OF THE PHILIPPINES INC.
Continuing Professional Development
Design of a Four (4) Storey Steel BuildingDesign ConceptsDesign ConceptsGiven a Building Area as Follows :
60 m
40
mEconomy / Optimization
1. Material Optimization
2. Framing System Optimization
3. Member Design Optimization
4. Connection Optimization
General Objectives :
1. Material Optimization1. Material Optimization
Materials Allowed for Seismic Regions (NSCP- Section 515.4.1)
5. Near Source Factor Acceleration Na = 1.0 [NSCP Table 208-7 & 8]
Velocity Nv = 1.0
6. Seismic Coefficient Acceleration Ca = 0.36 Na = 0.36 (1.0) = 0.36
Velocity Cv = 0.36
There are 2 Base Shear used in design practiceThere are 2 Base Shear used in design practice
2. Base Shear due to Drift Requirements2. Base Shear due to Drift Requirements2. Base Shear due to Drift Requirements2. Base Shear due to Drift Requirements1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements
Base Shear ParametersBase Shear Parameters
Design of a Four (4) Storey Steel BuildingPreliminary SizingPreliminary SizingChoosing The Lateral Resisting Choosing The Lateral Resisting
SystemSystem
Three (3) Accepted Steel Framing SystemThree (3) Accepted Steel Framing System
Moment Resisting Space Frame R = 8.5Moment Resisting Space Frame R = 8.5
Eccentric Braced Frame R = 7.0Eccentric Braced Frame R = 7.0
Concentric Braced Frame R = 6.4Concentric Braced Frame R = 6.4
Choose – Moment Resisting Choose – Moment Resisting Space FrameSpace Frame
Design of a Four (4) Storey Steel BuildingPreliminary SizingPreliminary SizingCalculation of Base ShearCalculation of Base Shear
1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements1. Base Shear due to Strength Requirements
This Base shear is used for final design. The minimum base shear This Base shear is used for final design. The minimum base shear coefficient is set to 3% of the Effective Seismic Weightcoefficient is set to 3% of the Effective Seismic Weight
Strength Requirements
• Total Height from base ( hn ) = 4.0 x 4 = 16.0m
• Period Calculation – Method A [NSCP Eq. 208-9]
Ct = 0.853 (Special Moment Resisting Space Frame)
TA = 0.682 secs
TA Ct hn 3
4
V1Cv I RT( )
W
Velocity Velocity
V1 = 0.166 WV1 = 0.166 W
V22.5 Ca I( )
R
W
AccelerationAcceleration
V2 = 0.106 WV2 = 0.106 W
Design of a Four (4) Storey Steel BuildingPreliminary SizingPreliminary SizingMinimum Base ShearMinimum Base Shear
V4 0.11( ) Ca( ) I( )[ ] W V4 = 0.0396 WV4 = 0.0396 W
Design of a Four (4) Storey Steel BuildingPreliminary SizingPreliminary Sizing
1. Base Shear due to Drift Requirements1. Base Shear due to Drift Requirements1. Base Shear due to Drift Requirements1. Base Shear due to Drift Requirements
Calculation of Base ShearCalculation of Base Shear
Using a simplified period calculation ( METHOD B) by Teal 1975 & Using a simplified period calculation ( METHOD B) by Teal 1975 & Method by Baker 1997Method by Baker 1997
The Fundamental period can be estimated using a Rayleigh FormulaThe Fundamental period can be estimated using a Rayleigh Formula
TB 0.25( )R Cs
Where : Where : ΔΔR = Allowable roof deflectionR = Allowable roof deflection
Cs = V / W base Shear CoefficientCs = V / W base Shear Coefficient
Design of a Four (4) Storey Steel BuildingPreliminary SizingPreliminary Sizing
Calculating Calculating ΔΔR = Maximum Inelastic Response Displacement R = Maximum Inelastic Response Displacement [NSCP 208.5.9][NSCP 208.5.9]
M 0.7( ) R( ) s[ ]
s0.02( ) H( )[ ]
0.7( ) R( )
Calculating Calculating CSCS
CsCv( ) I( )[ ]
R( ) T( )
1.05( )
ΔΔs = 60.95 mm or (2.4 inches)s = 60.95 mm or (2.4 inches)
Beam Gr 36 / Column Gr 36Beam Gr 36 / Column Gr 36
Beam Gr 36 / Column Gr 50Beam Gr 36 / Column Gr 50
5% Damping5% Damping
7% Damping7% Damping
3% Damping3% Damping
Design of a Four (4) Storey Steel BuildingVerification of ResultsVerification of ResultsSummary :Summary :
1.1.Preliminary Analysis – Using Modified Preliminary Analysis – Using Modified Energy MethodEnergy Method
2.2.Verification of Section Capacities – Verification of Section Capacities – STAAD Pro 2003 , ETABS 8, etcSTAAD Pro 2003 , ETABS 8, etc
3.3.Final Verification Using Push Over Final Verification Using Push Over Analysis for Performance Based Analysis for Performance Based EngineeringEngineering
THANK YOU VERY MUCH !!!THANK YOU VERY MUCH !!!
ASSOCIATION OF STRUCTURAL ASSOCIATION OF STRUCTURAL ENGINEERS OF THE PHILIPPINES INC. ENGINEERS OF THE PHILIPPINES INC.