Structural Design Practices In The Philippines

Structural Design Practices in the PhilippinesLooking Back and Looking Beyond.Engr. Jose A. SySysquared & Associates, Inc.President/Ceo

AGENDA01. Marcos Regime02. August 21, 1983 : Ninoy Aquino’s Assassination03. EDSA People Power Revolution04. 1987 : Key Projects05. 1990 – 1997 : Construction on the Rise06. 1997 : Asian Financial Crisis07. 2000 Onwards : Moving Forward08. Look Ahead

Marcos RegimeThat time, no structuraldesign code is availablein the Philippines.Seismic lateral designforce is proportional tothe building weight.V 0.10 WThe collapse of Ruby Tower, a six-storycondominium building, in the magnitude 7.3 1968earthquake started the call for better design andconstruction practice in the Philippines

Marcos RegimeNational Structural Code for Buildings, 1st Edition Based on the Uniform Building Code (UBC1970) Divided the Philippines into 3 zones withcorresponding seismic zone factorsV ZKCW Ductility requirements are still not includedfrom 1971 San Fernando EarthquakeNSCB 1972

Marcos RegimeCultural Center of the Philippines (CCP)Philippine International Convention Center (PICC)Folk Arts TheatrePhilippine Heart Center

AUGUST 21, 1983Ninoy Aquino Assassination Economic Status“The period shortlyafter the AquinoAssassination inAugust 1983 and theDebt Moratorium inOctober 1983 sawthe severesteconomiccontractions in thePhilippines since afterWorld War II.”

AUGUST 21, 1983Ninoy Aquino Assassination Dollar Exchange Rate The Philippines Peso to US DollarExchange rate was already sufferingdue to increasing debt, but it trulytook a downfall almost immediatelyafter the assassination. The peso plunged 30% in 1983, and afurther 50% in 1984, 1USD 27 PHP

AUGUST 21, 1983Ninoy Aquino Assassination Rampant Protests and Rallies165 rallies, marches, and other demonstrations took place between August21 and September 30, 1983. Protest demonstrations continued into thefollowing year, with more than 100 held between October 1983 andFebruary 1984.

AUGUST 21, 1983Ninoy Aquino Assassination As a result, no construction activities were carried out Decrease in overall government spending Restrictive monetary policies became detrimental, especially in theindustrial sector Majority of government led programs gave focus to the agriculturalsectors only, failing to address the needs of other industries In effect, construction activities were at a standstill

AUGUST 21, 1983Ninoy Aquino AssassinationPacific Star (Nauru Building) Tallest building in the Philippinesduring the revolution 112.5 meters 29 stories with 4 basement levels

EDSA People Power Revolution

EDSA People Power Revolution

EDSA People Power Revolution

1987 : Key ProjectsPacific Plaza Tallest building to be after therevolution 43 stories Designed using NSCP 1987 (based onUBC 1985) Wind pressure, P CeCqqsI Earthquake force, V ZIKCSW First building in the Philippines to use6000 psi concrete Dual system

1987 : Key ProjectsSM Megamall Largest shopping mall in Asia in 1991330,000 square meters total floor areaAlso designed using NSCP 1987Utilized post-tensioning for long spanbeams

1990 - 1997The Magnitude 7.7 Luzon Earthquake in 1990 reminded us to further improvethe structural design practice in the Philippines

1990 - 1997National Structural Code for Buildings, 4th Edition Based on the Uniform Building Code (UBC1988) Inclusion of Seismic Zone Maps (Zone 2 and 4) Introduction of response modification factorsor “R-Factors”V (ZIC/Rw)W

1990 - 1997Construction On the RiseThe country saw a boom in construction projects from the early to mid-90s

1990 - 1997Construction On the RisePBCom Tower-Tallest building in the Philippines 259 meters 52 storeysGT International Tower 217 meters 47 storeysProjects by the

1990 - 1997Construction On the RiseLKG Tower 180 meters 38 storeysAyala Tower One 160 meters 35 storeysProjects by the

1997 : Asian Financial Crisis The Peso dropped from 26.2 Pesosper US Dollar at the start of the crisisto 43.173 Pesos. in 1998, it was downto 54 Pesos per US Dollar. Investment in the Philippinesdeclined as a result of the limitationsof investors to accessing capital. In June 1997, office vacancy ratesfor Makati were extremely low at0.9%, but by September 1998, theMakati area then had a vacancyrate of 5.8%.

2000 OnwardsThe National Structural Code of the Philippinescontinued to develop.Provisions of UBC 1997 are still being adopted.NSCP 2001NSCP 2010NSCP 2015

2000 OnwardsMeanwhile, international practice alsoadvanced at a rapid pace.Seismic design is now based on mappedspectral accelerations.IBC 2000IBC 2009IBC 2018

2000 OnwardsBuilding codes are intended to establish minimum requirements for providing safety to lifeand property from hazards.– Specification of a Prescriptive Criteria Acceptable materials for construction Approved structural and nonstructural systems Required minimum levels of strength and stiffness Details of how a building is to be put together– A certain level of performance is implied without assessing the actual performancecapability of the buildingCode Compliance or Achievement of Performance Objective?Is code compliance enough?

2000 OnwardsThe development of seismic design criteria is a continuous process.1933 Long Beach Earthquake1971 San Fernando Earthquake1994 Northridge EarthquakebuildingsMinimum levels of lateral strengthAbility to deform without failure (Ductility)Damage can occur in code-compliant7.1M Mexico Earthquake

2000 OnwardsConfining Reinforcement of ColumnsThe Code Approach for Columns of Special Moment FramesSpecify ductility requirements at yield zones.Specify maximum spacing of ties, say 100.Intent is confinement for adequate ductilityand hysteretic behaviour.If we provide 125, our design is not code compliant.Does this mean failure?Will this specific column yield?Do we need to provide the same ductility for all columns?

2000 OnwardsPerformance is not guaranteed by code conformance.Performance can be achieved without code conformance.Explicit verification of performance is a must.M9 Great TohokuEQChanges in the state of knowledge and developmentof new analytical tools should translate to evolutionin structural design practice.

2000 OnwardsAlternative Systems and Methods of Analysis

2000 OnwardsAlternative Systems and Methods of AnalysisNo provisions for other structural systems appropriate for tall buildingsOutriggersBase IsolatorsViscous DampersTuned-mass DampersViscoelastic DampersDiagrids

2000 OnwardsAlternative Systems and Methods of AnalysisTime-history analysis provides an evaluationof dynamic structural response underloading which may vary according to thespecified time function.The nonlinearity comes from material andgeometric nonlinearity, including P-deltaand large-displacement effects.

2000 OnwardsThe performance-based seismic design process explicitlyevaluates how a building is likely to perform given thepotential hazard it is likely to experience.Select Performance ObjectiveDevelop Preliminary BuildingDesignAssess performance of buildings under multipleseismic eventsProvide higher performance for critical structuresthan intended by the building code.Assess PerformanceRevise DesignDeliver standard performance at a reduced costNoCan be applied to both new and existing buildingsAre PerformanceObjectives Met?YesPeer Review Process

2000 OnwardsFor Risk Category II tall buildings, two performance objectives are investigated explicitly:Level of EarthquakePerformance ObjectiveService Level Earthquake (SLE):50% probability of exceedance in 30 years(43-year return ake. Structure to remain essentially elasticwith minor damage to structural and non-structuralelements.Maximum Considered Earthquake(MCE): 2% probability of exceedance in 50years (2,475-year return period)Response without loss gravity-load-carrying capacity;without inelastic straining of important lateral-forceresisting elements; and without experiencingexcessive permanent lateral drift or development ofglobal structural instability.

2000 OnwardsStandard Structural Performance Objectives

2000 OnwardsPEER TBILATBSDCASCE 41

2000 OnwardsWhy PBD?Integrating Aesthetics, Integrity, and EconomyAestheticsThe art that exist within the built environmentIntegrityThe backbone of structural engineeringStability, Strength, and StiffnessEconomyEnhancing the quality without sacrificing cost

2000 OnwardsWhy PBD?Buildings are getting taller.Stratford ResidencesTrump TowerGramercy Residences

2000 OnwardsWhy PBD?Buildings are getting more complicated.The Spire

2000 OnwardsWhy PBD?Buildings are getting complex.The ProsceniumAyala Triangle GardensPark Central Towers

2000 Onwards80 PBD ProjectsBeacon Tower-2Beacon Tower-3Park Terraces Tower-1Park Terraces Tower-2Gramercy ResidencesMilano ResidencesNiagara TowerAnchor SkysuitesOne Shangri-la PlaceAdmiral BaysuitesStratford ResidencesBlue ResidencesAscott ResidencesDiscovery PrimeaEdades TowerOne World Place BuildingBDO TowerM Place @ OrtigasShang Salcedo PlaceKnightsbridge ResidencesGreen ResidencesSequoia at Two SerendraThe SuitesKirov TowerSakura TowerLorraine TowerLincoln TowerProscenium TowerDettifoss TowerTrump TowerSutherland TowerGarden Tower-1Garden Tower-2Spire TowerShangri-la at the FortLivingstone TowerTwo Roxas TriangleIguazu TowerThe RiseEast Gallery Place128 Nivel Hills Tower 1128 Nivel Hills Tower 2128 Nivel Hills Tower 3Air ResidencesAnchor GrandsuitesSonata Premier ResidentialTowerSonata Premier Hotel TowerOlive ResidencesAyala Triangle Garden HotelAyala Triangle Garden OfficeFame ResidencesPortico Tower 1Menarco TowerWest Gallery PlaceNova ManilaEmerald North TowerEmerald South TowerTwo Serendra BuildingAzure NorthMandani Bay Ph. 1 Tower 1Mandani Bay Ph. 1 Tower 2STRC Apartment RidgeThe ConnorGlas Office DevelopmentMandani Bay Ph. 2 Tower 1Mandani Bay Ph. 2 Tower 2Mandani Bay Ph. 2 Tower 3Mandani Bay Ph. 2 Tower 4Sixth Tower at ProsceniumProscenium Performance HallShang ResidencesLandmark BGC Office TowerNAIA Terminal IGSIS BuildingAlphaland Makati TowerVertis NorthEstanciaFrontera VerdeBenpresInnoland Makati Tower

2000 OnwardsPacific Plaza Twin Towers 179 meters 53 storeys Designed using displacement-baseddesign approach Utilized Tuned Liquid Column SloshingDampers to resist wind

2000 OnwardsDesigned more 250m using the Performance-Based Design approachShangri-La at the FortTrump TowerGramercy Residences

2000 OnwardsThe Proscenium

2000 OnwardsThe Proscenium

2000 OnwardsThe SpireVertical IrregularitiesAsymmetrical FramingSystem of the CrownVertical IrregularitiesMushrooming ColumnDiagonally Outward atDifferent LevelsCladding Axometric

2000 OnwardsNova Manila

2000 OnwardsNova Manila

2000 OnwardsStarted the application of energy-dissipating devices such as BRBsPark TerracesFirst Application of Buckling-Restrained Brace (BRB) in thePhilippines

2000 OnwardsThe SuitesSonata PremierEast Gallery Place

2000 Onwards. until Viscoelastic Coupling Damper (VCD) was introduced in 2016.Park Central Towers(Emerald) Consists of Two High-Rise Residential Towers South Tower (70-story, 235m) & North Tower (58-story, 197m) First application of Viscoelastic (VE) dampers in thePhilippines

2000 Onwards. until Viscoelastic Coupling Damper (VCD) was introduced in 2016.Park Central Towers(Emerald)First application of viscoelastic (VE) damper in thePhilippinesBRB SchemeVCD Scheme

2000 Onwards. until Viscoelastic Coupling Damper (VCD) was introduced in 2016.Park Central Towers(Emerald)

Look Ahead The Philippines has the same earthquake risk as California, Japan,New Zealand, Haiti, etc. However, our practice of earthquakeengineering is not at par with theirs. We believe that we should not be bounded by the limitationsof the codes. We believe that we should take advantage ofavailable powerful hardware and software in doingalternative approaches to ensure better performingbuildings against earthquakes. Code compliance is not enough. Innovative approach is a must.

Challenges Inspire Innovations.THANK YOUwww.sysquared.com

condominium building, in the magnitude 7.3 1968 earthquake started the call for better design and construction practice in the Philippines That time, no structural design code is available in the Philippines. Seismic lateral design