1. Introduction 2. Codes & References Governing Structural...

1. Introduction

2. Codes & References Governing Structural Design

3. Limitations of Codes

4. Other Challenges

5. Alternative Systems & Method of Analysis

6. Motivation for PBD

7. What is PBD?

8. Why PBD?

9. Notable PBD Projects

10. Concluding Remarks

Metro Manila Skyline

Philippine Statistics Authority

Philippines’ Tallest Buildings – Top 20

70% Designed by Sy^2

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



NSCP 2010 AISCACI - 318

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



Structural Systems Pure frames Pure Shearwall buildings are limited to 75 meters Dual system

Seismic Provisions UBC 1997 (Replaced by IBC in USA)

Developed for buildings less than 50 meters Permit a limited number of structural systems No provisions for framing system appropriate for tall buildings Based on Elastic Method of Analysis Prescriptive in nature, no explicit check on outcome Enforce uniform detailing rules on all members Enforce unreasonable demand distribution Doesn't take advantage of recent powerful computing tools

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



UBC 1997 – Response Spectrum Curve

Cannot adopt IBC due to absence of spectral map available

Map Showing Fault Lines

Top 10 Strongest Earthquakes to hit the Philippines

LOCATION DATE MAGNITUDE

1. Mindanao August 17, 1976 8.0

2. Northern and Central Luzon July 16, 1990 7.80

3. Luzon November 3, 1645 7.50

4. Ilocos Norte August 17, 1983 7.50

5. Casiguran August 2, 1968 7.30

6. Bohol October 15, 2013 7.20

7. Mindoro November 15, 1994 7.10

8. Eastern Samar August 31, 2012 7.00

9. Central Visaya February 6, 2012 6.90

10. Central and Southern Mindanao March 5, 2002 6.80

*Average Number of Earthquakes Per Year : 500

The Devastating Effect of a Typhoon

Average Number of Typhoons Per Year : 24

ACI – 318, 21.5.2.4 (C)

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



With the limited structural systems with specific provisions, the code allows for alternative systems.

Alternative Procedure208.4.8.4.1

Section 101.4System

Nonlinear Time History Analysis208.5.3.6.3.1

Section 101.4System

Metro Manila Seismic Mapper

Seismic mapper Soli Type Sc Distance to Near Source 5.0 Km


Seismic mapper Soil Type Sd Distance to Near Source 10 Km


Seismic mapper Soil Type Sd Distance to Near Source 2.5 Km

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



Motivation for PBD

Lack of explicit performance in design codes

Requires the designer to assess building performance under heavy shaking

to identify unsafe designs

Enable to lift code restrictions to ensure safe and cost-effective design

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



Checks performance of buildings under multiple seismic events

Assess the building performance using seven (7) ground motions

Non-linear analysis to investigate explicitly at least two performance objectives

1. Service Level Assessment

Negligible damage in once in a lifetime earthquake having a return period of 50 years.

2. Collapse Level Assessment

Collapse prevention under the maximum considered earthquake with a return period of 2,500 years.

Concepts Multiple performance levels are checked.

Multiple seismic events are applied.

May utilize nonlinear analysis.

Detailed local acceptance criteria

For structural elements

For nonstructural elements

Detailed local acceptance criteria indicates element-by-element checking,

rather than an overall system R factor such as is used in the conventional

design of new buildings.

Seismic Performance Objectives

Level of Earthquake Performance Objective

Frequent/Service: 50% probability of

exceedance in 50 years (72-year return)

Serviceability: Negligible damage in once-in-a-

lifetime earthquake. Structure to remain essentially

elastic with minor damage to structural and non-

structural elements

Design Basis Earthquake (DBE): 10%

probability of exceedance in 50 years (475-

year return)

Code Level: Moderate structural damage; extensive

repairs may be required

Maximum Considered Earthquake (MCE):

2% probability of exceedance in 50

years(2500-year return)

Collapse Prevention: Extensive structural damage;

repairs are required and may not be economically

feasible

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



Buildings are getting taller.

Emerald The Suites West Gallery Place

Spire

Buildings are getting more complicated.

Buildings are getting more complex.

Ayala Triangle DiamondProscenium The Finance Center

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



PARK TERRACES

Perspective Typical Floor Plan

Performance Based Seismic Design(Figure showing location of BRBs)

BRB

PARK TERRACES

Perspective Cladding Axometric

SPIRE

SPIRE

Vertical IrregularitiesFraming System of the Crown

Vertical IrregularitiesMushrooming Column Diagonally Outward at Different

Levels

WEST SUPERBLOCK

Perspective The Suites

WEST SUPERBLOCK

Framing Plans (Typical Residential Floor)

Elevation Showing Flagwalls and BRBs

EMERALD TOWER

Perspective

Typical Floor Plan

EMERALD TOWER

Section Showing VCDs

EMERALD TOWER

Pictures of VCDs

NOVA


NOVA

Sloping Columns

NOVA

Transverse View Longitudinal View

GARDEN TOWERS

Perspective

GARDEN TOWERS

Typical Floor Plan

SONATA


SONATA

Elevation Showing Flagwalls and BRBsPodium Floor Framing Plan

EAST GALLERY


EAST GALLERY

Elevation Showing BRBs

1. Introduction



4. Other Challenges



7. What is PBD?

8. Why PBD?



The Philippines has the same earthquake risk as California, Japan, New Zealand, Haiti,

etc. However, our practice of earthquake engineering is not at par with theirs.

Sy^2 takes it as a challenge to elevate the practice of earthquake engineering and it

already pioneered in:

Performance Based Design Approach

Use of Energy Dissipating Devices

Buckling Restrained Braces

Viscous Coupling Dampers

Tuned Liquid Column Dampers

We believe that we should not be bounded by the limitations of the codes.

We believe that we should take advantage of available powerful hardware and software

in doing alternative approaches to ensure better performing buildings against

earthquakes.

Code compliance is not enough.

Innovative approach is a must.

DO NOT GET OBSOLETE LIKE AN OLD TECHNOLOGY, KEEP INNOVATING YOURSELF.

- S U K A N T R A T N A K A R

THANK YOU!

1. Introduction 2. Codes & References Governing Structural...

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