BEHRENS, ANA TERESA | ONOZAWA, ARISA | SURTIDA, FRANCIS

TANTUICO, RAISA | VILLA, MA. EDISA

ARCH 134 - TABAFUNDA

ST. FRANCIS TOWERS SHANGRI-LA PLACE

BUILDING CASE STUDY

TABLE OF CONTENTS

Introduction

Background: St. Francis Towers Shangri-la Place

Building Facts

Architectural | Technical Specifications

Structure

Structural Strategy

Conjecture and Structural Diagrams

Structural Computations

Environment

Climate Data

Environmental Responses: Daylighting

Environmental Responses: Ventilation

Construction

Foundation

Cladding

Fire Protection System

Plumbing and Drainage System

Reference

BACKGROUND

The St. Francis Towers Shangri-La Place is located at

Mandaluyong City in Metro Manila. It is the tallest residential

high-rise building in the country. This landmark development

comprises two towers, each rising 60 floors to 217m high and

providing a total of 1,200 units.

The towers are the 6th and 7th-tallest buildings in the country and are currently the tallest twin

towers in the Philippines surpassing Pacific Plaza Towers with a height of 212.88 meters from

the ground to its architectural spire. It also has two of the most number of floors in the

Philippines. The buildings have 60 floors above ground, including a podium which connects the

two towers, and 5 basement levels for parking, and are considered as one of the most

prestigious residential buildings in the Philippines.

The St. Francis Shangri-La Place was master planned and designed by Wong Tung International

Ltd., in cooperation with local architectural firm Recio + Casas Architects. Structural design for

the building was provided by Arup, and reviewed by international engineering firm Magnusson

Klemencic Associates. The buildings mechanical, electrical, and sanitary engineering works

were designed by WSP Hong Kong Ltd. Interior design was made by Brennan Beer Gorman

Monk Architects (Interior Design). The construction team is composed of Jose Aliling &

Associates (Project / Construction Management); Davis Langdon & Seah Philippines Inc.

(Quantity Surveying); and EEI Corporation (General Constractor).

EXTERIOR PODIUM

LOBBY

ENTRANCE

NORTHEAST VIEW

NORTHWEST VIEW

SOUTHWEST VIEW

SOUTHEAST VIEW

BUILDING FACTS

Project Team Owner Kuok Group

Architect Wong Tung International Ltd., in cooperation

with Recio + Casas Architects

Developer Shang Properties, Inc.

Structural engineer Ove Arup & Partners Hong Kong Ltd. in

cooperation with Magnusson Klemencic

Associates

Main contractor EEI Corporation

Project Floor Area (sq.m) Tower 1: 107,473 m²Tower 2: 214946 m²

Occupant Load 1200-3600 occupants

Cost Php 3,000,000,000

Program 60 story High Rise Residential Building

Site Site Description 6,172 m²

Site Type urban, rural, etc. urban

Parking Spaces 7 podium parking levels, 1 basement parking

Structure Foundation Type

Gravity Force Systems

Secondary structure/

Backup

Viscous Damping System

Envelope Glazing Types 10mm thick, heat strenghtened, fully

tempered glass

Cladding Type

Passive System Day lighting

Cooling

HVAC Equipment List

Cooling System Type

Duct yes/no yes

Vertical Chases yes/no no

The building is located on Shaw Boulevard corner in Ortigas center and has a direct link to the

Edsa Shangri-La Hotel and Plaza mall which means easy access to the Metro Rail Transit. This

location is described as the Business Center which makes it a strategic spot and thus creates

high expectations for buildings in that site, hence this particular building. Being surrounded by

San Miguel Corporation, Asian Development Bank, Meralco , the Philippine Stock Exchange, he

New Medical City Hospital and the Wack Wack Golf and Country Club, and a number of other

educational and business attractions, affects the form of the building immensely to make it fit

within the context. And thus, the building takes the very professional, modern, static shape that

it does.

The building, being as high as 60 floors and being in an area that is prone to earthquakes

creates a critical challenge considering the structural system. the structural system must be

strong enough to support the building against reacting to all the loads (dead or live) exerted on

it. The use of dampers is to protect the building from the earthquake forces.

The building is located in a relatively warm zone area which has a big influence on the HVAC

systems installed in the building. In a warm atmosphere ventilation as well as air conditioning

are necessary, and keeping in mind that the building is one of the tallest residential building in

Philippines, installing the most convenient and efficient HVAC is not an easy task.

TECHNICAL SPECIFICTATIONS

At 60 stories high, with each tower St. Francis Shangri-La Place housing 600 units, seven

podium parking levels, and one basement parking level, the numbers give the impression of

density, but looking closer, it’s in the planning and details that the design shines through.

Floor density determines the tower’s four zones: the 16 unit per floor Low Zone, the nine unit

per floor High Zone, two levels of four Simplex Penthouse units per tower on the 57th and 58th

floors, and four three-level Grand penthouses topping off each tower.

Security and access is controlled by zone-specific high speed elevators with the Low Zone lifts

servicing the lobbies and basement parking levels, the Ground to the thirty-third floor, while the

High Zone lifts run from the second to seventh level podium lobbies, and to the thirty-fourth to

sixtieth floor.

Figure 3. Ground Floor Plan

Figure 2. Site Development Plan

Figure 4. Tower 1 Low Zone (Typical 11th -14th and 26th – 28th Floor Plan)

Figure 5. Tower 1 High Zone (Typical 46th – 58th Floor Plan)

Figure 5. Tower 2 Low Zone (Typical 11th-33rd Plan)

Figure 5. Tower 2 High Zone (Typical46th-58th Plan)

STRUCTURE

The location of the towers subjected it to high

levels of seismic activity due to the nearby active

fault line, and high winds due to typhoon winds.

In order to design a safe, cost effective building,

the engineers at Ove Arup & Partners came up

with an idea that was the first of its kind in

buildings. They came up with a revolutionary

damping system that was not only cheaper than

traditional methods of damping, it is arguably

much better as well.

This landmark development comprises two

towers, each rising 60 floors to 217m high and

providing a total of 1,200 units. Arup provided

civil and structural engineering services for the

project. The firm’s trademark damped-outrigger

system, for which patents have been applied, will

help to reduce the motion of the towers in windy

weather and will result in construction cost

savings. A total of 32 dampers were installed, 16

for each of the twin towers.

For buildings of about 40 storeys and more like

St. Francis Towers, the dynamic resonance in

wind starts to have a significant effect on the

design. A building’s dynamic resonance is

similar to that of a tuning fork – the higher the

building, the lower the frequency. Unfortunately

the lower the frequency, the more the building

is “excited” or “resonated” by the wind, which

has two effects: The occupants start to feel the

movement potentially leading to complaints or

even panic and the design loading due to wind

needs to be increased.

Figure 7. How overturning moment varies with damping in St Francis Towers

Figure 6. Construction of St. Francis Towers

The dynamic response of a tall building is governed by several factors, including shape, stiffness,

mass, and the damping. While engineers can predict with reasonable certainty the effect of the

first three, it is more difficult to do this for the level of damping. Damping is the degree of energy

dissipation that a structure can provide, helping to reduce build-up of the resonant response. It

comes from two main sources: intrinsic and supplementary. All buildings have intrinsic

damping - from the structural materials, the foundations, the cladding, etc - but it is very

difficult to predict as it depends on so many factors. Supplementary damping is added by the

engineer and is only currently used in a small minority of buildings. As it is engineered,

however, predicting it is much easier. The degree to which damping affects structural loading

can be seen in Fig 7, which shows the global overturning load in a 400m high building. By

increasing the level of damping from a typical intrinsic level of 1%, it I possible to reduce this

overturning load by a factor of three.

Due to the tower's location being close to an active fault in a highly seismic region and also

subjected to typhoon winds, the St. Francis Shangri-La Place was the first building in the world

to feature a revolutionary ‘damping’ system designed by international engineering company

Ove Arup & Partners. The new system, which minimizes the standard wobble in high-rise

buildings, employs the same technology used to strengthen the Millennium Bridge in London.

This makes the St. Francis Shangri-La Place one of the safest buildings.

The usual methods employed to strengthen buildings are to reinforce it with significant extra

structure or to install tuned mass dampers. Both methods are not only expensive, but also make

the building stiffer and heavier while consuming valuable space. The Arup solution works by

inserting Viscous Dampers into the St. Francis Shangri-La Place to act as energy absorbers and

damp out vibrations. Viscous dampers connect deep reinforced concrete outriggers from the

central core of each building to the perimeter columns at one level. The added damping so

Figure 8. Intrinsic Damping of tall Building

Figure 9. Floor Framing Layout

derived, in excess of 6% of critical controls wind-induced motions, achieving occupant comfort

objectives, and reduces the design wind overturning moment by a factor of 1.7. Not only is this a

lower-cost solution, it is also more sustainable as it uses less material, and leaves more valuable

space inside the building.

The image above shows a typical floor plan of the towers. The thick black lines and boxes

represent the thick concrete core walls and perimeter columns. The towers are technically

considered to be of a bearing wall system since a majority of the gravity load is supported by the

building core. The lines closer to the perimeter of the building represent shear walls which act

as the laterally resisting components of the building. Both the walls increase in size towards the

base of the building due to the obvious increase in gravity loads. The floors are a concrete slab-

on-beam design.

Figure 10. Concrete Outriggers and Structural Damping System

Viscous dampers connect deep reinforced concrete outriggers from the central core of each

building to the perimeter columns at one level. The added damping so derived, in excess of 6%

of critical controls wind-induced motions, achieving occupant comfort objectives, and reduces

the design wind overturning moment by a factor of 1.7. Not only is this a lower-cost solution, it

is also more sustainable as it uses less material, and leaves more valuable space inside the

building.

Reductions in the quantities of concrete and reinforcing steel in the St Francis Towers structure

due to the incorporation of the Arup damping system and performance based seismic design

saved the building's developer in excess of $5 million in construction cost and more net floor

space (through smaller columns and core walls, and no need for space for TMDs).

One of the most interesting features of the towers is their structural damping system. Half-way

up each building there is a large concrete mass that seems to be "floating" and not directly

attached to the core of the building. This concrete mass spans two floors and has outriggers

that connect to the perimeter columns where it is supported. At each outrigger-to-column

connection there are two viscous dampers which support the mass, but allow it to move in high

wind situations, such as typhoons, and during earthquakes. This movement helped absorb a lot

of the energy of the building and dissipates it as heat.

Figure11. Detail of Viscous Damper Connection

Figure12. Installation of Viscous Dampers Figure13. Dramatic Representation of

Wind/Seismic Load Deflection

As shown in Figure 10, the concrete outriggers and core mass hang from the columns by the

viscous connectors. The picture below shows just how massive each one of these connectors is.

The diagram on Figure 12 shows a building section while the building is experiencing deflection

due to seismic of wind loads. The mass in the middle represents the concrete outriggers and

viscous damper connections moving up and down to absorb the energy from the high loads.

Figure 14. Installation of the Dampers

STUCTURAL COMPUTATIONS FOR ST. FRANCIS TOWERS

8" thick concrete slabs for each floor, and 12" thick slabs for the parking levels underground.

LOADS

Area of Average Floor 18658.5 SQF/ 1734.06

Number of Floors 60/building above ground 5/building underground parking

Height of Building 212.88 m/ 698.9 ft

Average Horizontal Area of Concrete in Core

1300 square feet

Density of Major Materials

Steel=490 PCF Concrete=145 PCF Reinforced Concrete=150 PCF Glass=185 PCF

DEAD LOAD

CONCRETE

Floor Weight: (# of floors)x(floor area)x(floor thickness)x(unit weight of reinforced concrete)=(60) x (18658.5 sf) x (0.667 feet) x (150 PCF)= 112,006,975.5 lbs = 112,000,000 lbs

Parking Floor Weight: (# of floors)x(floor area)x(floor thickness)x(unit weight of reinforced concrete)=(5) x (18658.5 sf) x (1 ft.) x (150 PCF)= 13,993,875 lbs = 13,900,000 lbs

Building Core Weight: (Height of Building) x (Area of Concrete in Core) x (Unit Weight of Concrete)=(698 ft.) x (1300 sf) x (150 PCF) = 136,110,000 lbs = 136,000,000 lbs

Vertical Load: (1.5%)x(Floor Area)x(Height of Building)x(Unit Weight of Concrete)=(1.5%) x (18658.5 sf) x (698 ft.) x (150 PCF) = 29,303,174.25 lbs =29,300,000 lbs

GLASS LOAD (Glass Area)x(Glass Thickness)x(Unit Weight of Glass) = (381,376.4 sf) x (1 in) x (185 PCF) = 5,879,552.8 lbs = 5,880,000 lbs

PARTITION LOAD (Partition Weight per Unit Floor Area)x(Total Floor Area) = (5 PSF) x (1119510 SF) = 5,597,550 lbs = 5,500,000 lbs

EQUIPMENT LOAD (Equipment Weight per Unit Floor Area)x(Total Floor Area) = (5 PSF) x (1119510 SF) = 5,597,550 lbs = 5,500,000 lbs

CEILING LOAD (Ceiling Weight per Unit Floor Area)x(Total Floor Area) = (2 PSF) x (1119510 SF) = 2,239,020 lbs = 2,200,000 lbs

TOTAL DEAD LOAD 310,280,000 lbs

The building used a load bearing wall system due to the fact that the central concrete core takes

most of the gravity load of the building. The massive loads of this building made the structure of

the building massive, causing a need for a very strong, and effective lateral resisting system.

Like any high rise design, wind load and seismic loads are a significant factor in how the

building will be designed. The typhoon-force winds and the high seismic activity of the area

made the design of the structure all that more challenging for the engineers at Arup. Their

challenge was to find a way to make the building safe, being able to resist high seismic and wind

loads, and also making it cheaper. Their Patent pending viscous damper connection system was

what they came up with. They were able to design this system to absorb enough of the energy

that they did not have to beef up their members and connections throughout the building. Even

after the cost of design and construction of the dampers and concrete outriggers the engineers

saved the owner about five million dollars in construction costs.

The dead load alone of the building would be enough to cause it to need extremely large

concrete foundations. The high lateral loads caused by the seismic activity and wind coupled

with the height of the building caused the need for extremely stable foundations that could

resist overturning.

LOADS

LIVE LOAD

Residential

(Residential weight per unit floor area)x(Total Floor Area) = (40 PSF) x (1119510 SF) = 44,780,400 lbs = 45,000,000 lbs

LOAD ON FOUNDATION

(Dead Load) + (Live Load) = (310,280,000 lbs) + (45,000,000 lbs) = 355,280,000 lbs

LOAD ON BUILDING FOOTPRINT

(Total Load on Building Foundation)/(Area of Land Coverage) = (355,280,000 lbs)/(18658.5 SF) = 19,041 PSF

Maximum Horizontal Wind Load

Design wind speed for Mandaluyong City, Philippines is 124 mph, which equals 28.9 PSF. (horizontal load per square foot)

(Elevation Area)x(Horizontal Wind Load per Unit Area) = (13,023,633 SF) x (28.9 PSF) = 376,382,994 PSF = 376,000,000 PSF

ENVIRONMENT

CLIMATE DATA AND ENVIRONMENTAL RESPONSE

Average Minimum and Maximum Temperature of Mandaluyong City Monthly mean minimum and maximum daily temperature.

Indoor and outdoor air temperature can be modified through a combination of “passive” or active design strategies. Daily average temperatures remain pleasant in Mandaluyong City, Philippines for a good portion of the year, However, temperature is only part of the equation when considering occupancy comfort as relative humidity is also a contributing factor.

Average Monthly Precipitation over the year (rainfall, snow) This is the mean monthly precipitation, including rain, snow, hail etc

Average Monthly Hours of Sunshine in the Philippines

The building is mainly composed of glass material on

all four facades and thus, it is highly exposed to direct

sunlight. This has a major effect on the cooling system,

especially regarding the fact that this building falls in a

hot climate zone.

The building is mostly cooled through air conditioning and not through natural ventilation.

Each of the 1200 units has its own separate air conditioning system.

Air conditioning diagram is illustrated below:

Ventilation

The arrows below indicate the motion of the air

(cool air in blue, and hot air in red).

As mentioned before, the building relies mainly

on air conditioning, but wen natural ventilation

could be used depending on the weather and the

prevailing wind, the cool air comes in from one

side of the building and then it escapes as warm

air from the other side. That happens as a cycle

that keeps the indoor air refreshed.

CONSTRUCTION

STRAIGHT TO FINISH SLAB

SLAB OF POER TROWEL

SHEAR WALL RETROFITTING

Installation of Formworks for

Beams, Girders & Slab

FIRE PROTECTION SYSTEM

SPRINKLER

FPS CROSS MAIN LOBBY

PLUMBING AND DRAINAGE SYSTEM

DOWNFEED WATER LINE

RISER

VENT AND POTABLE WATER LINES

SEWER LINE