Detail Analysis and Structural Design examples

PROJECT: VENT-SLAB DETAIL

LIVING SHANGRI LA BUILDING

PORJECT TEAM

Design Architect: James KM Cheng Architects

Project Architects: Hariri Pontarini Architects

Young + Wright / IBI Group Architects ERA Architects Inc. Landscape Architect:

Phillips Farevaag Smallenberg Inc.

Developer:

Westbank & Peterson Group

Electrical Engineer:

Nemetz (S/A) & Associates Ltd.

Structural Engineer:

Jones Kwong Kishi, Adjeleian Allen Rubeli Ltd.

Real Estate Agent:

Rennie Marketing Systems

Formwork supplier: Doka Industrie GmbH Hardrock Forming Company Concrete Supplier: Innocon Inc. Toronto Redi-Mix Ltd. Ontario Redimix Ltd

Dufferin Concrete Steel Supplier:

Salit Steel Ltd.

Shoring Contractor:

Anchor Shoring & Caissons Ltd.

Wind Surveyor:

RWDI

Demolition Company:

Greenspoon Specialty Contracting

Excavation Company:

Aro Excavating Ltd.

Traffic Consultant:

BA Group

Consultantcy: LMDG Building Code Consultants

Brook Van Dalen & Associates

John W. Gunn Consultants Inc. Terraprobe Ltd. Mortgage Bank:

Caisse de dépôt et placement du Québec

address:

180 University Ave

city:

Toronto, ON

country:

Canada

year completed:

2012

gross floor area:

81,192.38 m²

architectural height:

214.50 m

top floor:

207.30 m

floors above ground:

66

floors below ground:

5

hotel: Shangri-La Worldwide 1-17 Floor 222 Units residences: Living Shangri-La 18-49 287 Residences estates: 50-66 83 Private Estates (incl. 2 Penthouses)

LIVING SHANGRI LA BUILDING

Curtain walls are popular non-structural systems used for building envelopes. Often made of lightweight materials, the curtain wall is non-load bearing and transfers any horizontal loads directly to the structure through connections at the floor slabs. The curtain wall system found on the Living Shangri La building is fairly straight-forwarded with the introduction of smaller design details that display a creative solution to structural and mechanical needs.

CONTEXT

The Living Shangri-La project found neatly situated on University Avenue between Richmond St. W. and Adelaide St. W. adds a distinguishing element to Toronto’s skyline. At 66-storeys tall, the building is cladded in a beautiful glass façade with subtle details that reflect the elegance of the Shangri La brand of hotels. Nestled in between the Entertainment District and Fashion District, this iconic tower is home to luxurious hotel rooms, residences, private estates, and penthouse homes. The ability to encapsulate all these uses within a uniform building envelope is both challenging and innovative. Of the many interesting details found throughout the envelope, the detail being highlighted in this report is the in-slab vent that is seamlessly integrated into the curtain wall system.

LIVING SHANGRI LA BUILDING

CONTEXT

mechanical vents

19mm wood sil 13mm gypsum board

15.9mm gypsum board (acoustic) spandrel glazing with insulated back panel fire stopping & smoke seal

continuous heating pipe 230mm concrete slab eccoduct in-slab ducting

wall vent 50mm srpay poly urethane insulation curtain wall system joint components 16mm ply blocking

mechanical duct 41mm steel studs at 600mm o/c

painted mdf valance soffit window glazing

13mm gypsum board

LIVING SHANGRI LA BUILDING

curtain wall system joint components

DETAIL COMPONENTS

window glazing

LIVING SHANGRI LA BUILDING

HEAT

HEAT LOSS ANALYSIS

fire stopping and smoke seal

continuous heating pipe concrete slab spandrel insulation

The greatest challenge to envelope design is heat leakage through conductive elements such as window mullions, and slab edges. To minimize the thermal bridging between these elements, the most effective method is to spec high quality glass panes and apply thermal breaks in the mullion so that the mullion unit does not conduct from the inside to the outside. Since the Shangri-La hotel is located in Toronto, ON where there is a difference of 40 degrees Celsius between interior design temperature and exterior design temperature, it is interesting to review how they’ve minimize the effects of thermal heat transfer. The building predominantly utilizes a curtain wall system with the exception of some lower level podium masonry elements. As a result, energy consumption in heating and cooling during different times of the year is critical.

Concrete floor slabs are typical in this type of construction. One of the primary thermal concerns to concrete slabs is thermal bridging to the exterior. In this specific detail, we notice that the vent/ soffit module is found within the concrete floor slab and adds an additional conducting path to the exterior that is unique. To address this issue, the vent is insulated with 50 mm spray poly urethane insulation and sealed with caulking as it meets the concrete slab. By applying the 50 mm spray poly urethane, it drastically minimizes the heat transfer and thermal bridging effect. 16 mm ply blocking is continuous between the spray poly urethane and the gypsum board finish on the underside of the slab. Air and vapour barriers complete the system by preventing any possible short circuiting through vapour diffusion or air leakages.

spray poly-urethane foam

As spandrel glazing doesn’t provide significant insulation, the possibility of thermal bridging through the concrete slab edge is high. Thus the system includes an insulated back panel between the spandrel glazing and the adjacent concrete slab edge. Firestopping and smoke seals are found between the insulated back spandrel panel and the concrete slab edge. Although not a vital component to insulating the slab edge, it inevitably reduces heat transfer between the slab edge and the spandrel panel system.

Performance Strengths: - The slab edge being the largest potential thermal bridge is well insulated - Heating under the window will prevent convection currents Performance Weaknesses: - Although insulated near the envelope exterior, the aluminum duct can act as a conductor to bridge the concrete to the outside causing cold spots on the floor - Being a curtain wall, the walls generally don’t provide a significant amount of thermal resistance

Curtain walls are inherently designed to resist water penetration due the low permeability of glass which functions both as a rain screen and a vapour barrier. As the vast majority of the surface area of a curtain wall comprises of glazing, the points that need the most attention with respect to water leakage are the joints and mullions. The seams and edge conditions where the curtain wall glazing meets the mullions need to be sufficiently sealed. As a second layer of defence, a vapour barrier is placed inside the mullion to catch any unwanted moisture that may have penetrated through the seal. The water is collected along this membrane and drained back to the exterior through the weep holes located at the bottom of the mullions.

Over time, expansion and contraction as a direct result of weather can cause deterioration over time and leave the system susceptible to water penetration. Deterioration of the seals and joints can cause a decrease in performance, regular maintenance will ensure the caulking and seals are functional and minimize any water penetration into the curtain wall system.

Performance Strengths: - Since the curtain wall surface area is primarily glazing, vapour diffusion is largely reduced - Continuous vapour barrier along the vertical length of the mullion.

- Outwards sloping wall vent prevents water collection in ducts.

Performance Weaknesses: - A disconnect in vapour barrier at the bottom of the spandrel pannel to the top of the window assembly below adds a potential infiltration point.

WATER

Another potential point of entry through the curtain wall system is through the wall vent.

Hydrostatic pressure could potentially draw water through the mesh and into the duct. To prevent this the mouth of the vent is sloped downwards towards the exterior to drain out any water.

vapour barrier

glazing panels

weep holes

wall vent

vapour barrier

LIVING SHANGRI LA BUILDING

WATER LEAKAGE ANALYSIS

LIVING SHANGRI LA BUILDING

AIR

AIR LEAKAGE ANALYSIS

air barrier

window joints glazing panels

To prevent air infiltration, a continuous air barrier must be in place so that air currents can’t short circuit insulation or vapour barriers. In a curtain wall system, the primary vulnerabilities are at the edges of the glazing panels. Specifically, the window joints, mullions and weep holes must be sufficiently sealed so that air can’t penetrate the envelope. This is especially true since this curtain wall contains openable windows just above the spandrels.

It is unclear in the detail drawings for the Shangri-La hotel if there is a continuous air barrier, but they suggest that the vapour barrier doubles as an air barrier. However, the discontinuity of the air barrier with the glazing panels underneath the wall vent could compromise the system.

The particular placement of the wall vent across the façade of the building also adds a potential air leakage point potentially drawing up water vapour into the ductwork. This is mitigated by the placement of a backdraft damper at the mouth of the vent.

Proper maintenance is important with regards to air leakage as the seals and caulking could deteriorate over time through temperature swings. Thus reducing the overall effectiveness of the envelope system.

weep holes

Performance Strengths: - Wall system is sealed above the spandrel glazing.

- Wall vent mitigates back draft

backdraft damper

air barrier

Performance Weaknesses: - Potential discontinuity in air barrier system underneath wall vent may compromise air-tightness

An interesting element to the vent and soffit design is that the mechanism travels through the concrete floor slab. This is a product of ECCODUCT, a company specializing in creating systems that are encased (in the case of the Living Shangri La building, in concrete). The soffit exits the floor slab and is connected to a Metal Plenum that is insulated by 50 mm spray poly urethane foam to prevent any thermal bridging.

Performance Strengths: - Having the structural steel component positioned around the heating pipe could potentially reduce thermal bridging through the system.

aluminum curtain wall mullion

curtain wall anchor

STRUCTURE

Curtain wall systems function as a non-structural component of a building. It bears no structural load and only carries its own dead load. As a building envelope, it can be lightweight and versatile. In the case of the Living Shangri La building, the curtain walls are designed to transfer any horizontal wind loads it receives directly into the structural floor slab that it is connected to. The mullion system is fairly complex and includes an aluminum curtain wall sill mullion, a curtain wall anchor poured into the concrete slab, and various metal studs. These components ensure that the curtain wall is secured and fastened to the floor slab.

LIVING SHANGRI LA BUILDING

STRUCTURAL ANALYSIS

LIVING SHANGRI LA BUILDING

MODEL PHOTOS

LIVING SHANGRI LA BUILDING

MODEL PHOTOS

LIVING SHANGRI LA BUILDING

TECHNICAL DRAWINGS

SKY BRIDGE Straddling a path that links two ski runs (site map), Sky Bridge is a timber structure that offers itself as a shelter and viewing platform for Ski Rangers and recreational visitors alike.

The bridge or pier slides through a pine stand and offers up 3 tiers of experience and views to the valley below: Main Platform; Secondary Viewing Deck; Lower Access stairs/ramp.

The structure is composed of solid hewn, light wood frame and heavy timber.

A light wood frame deck is suspended between 2 heavy timber trusses that project horizontally 30 meters from the hillside. Cross-tensioning rods provide lateral stability to the pier.

At the end of the pier, a heated volume (100 sq. ft) is nested beneath a secondary viewing platform.

A beam extends across the width of the structure, receiving primary loads from the three trusses and a secondary set of loads from the stairs and raised viewing platform. 3 timber columns transfer their load to concrete caissons embedded in the hillside. Two smaller concrete bearing piers take the load at the entry to the pier entry and at the lower level stairs.

Articulated steel joints connect the muscular, timber structure revealing pinned and fixed connections.

A lightweight skin of timber slats runs diagonally across major structural members (truss and post/beam) acting as tension and compression members and offering degrees of enclosure and view.

Après-ski on the Sky Bridge, Ranger at the edge, Poised for a breathtaking departure, A ramp to a path to the hills below.

Diagonal Sheathing on Truss

Long Span Timber Truss Diagonal Frame/Truss

Timber Compression & Steel Tension Members for lateral stability

ASSEMBLY DIAGRAM

Conditioned Space

Timber Deck Supported by Secondary Beams & Joist

Compression Timber Member Resisting Lateral Force Cantilever Timber Beam Supporting Stair Landing

Sheathing on Timber Truss Frame

Deep Timber Beam Load Bearing Timber Columns

GRAVITY LOAD DIAGRAM

terminates in grounded footings

LATERAL LOAD DIAGRAM

terminates in grounded footings

5319 800

1900

1100

3000

1900

Level 2 - Observation (+12.45m)

Column Beyond

EAST ELEVATION Bridge Truss 1a 1:100

View Opening

Level 1 - Bridge (+09.00m)

Column Beyond

Grade - Lowest Point (+/- 00.00m)

Stair Below

38 17

Open to Below

Brace Above Enclosed Space (Below)

1645

45

41

8 Risers @ 150 mm

8600 Bench (Below)

LEVEL 2 PLAN Observation 1:100

Bridge (Below)

Lowered Beams (Joist Bearing on Top)

61

40

00

69

25 @ ? Ris 15 ers 0m m

(TY 30 85 ME PIC MB AL ER VER SP TIC AC INGAL )

18

94

LEVEL 1.5 PLAN

52

71

27950 1025

Open to Below

15 @ Rise 15 rs 0m m

1:100

10 NUMBER

2150

10 NUMBER

(TYPICAL)

2344

4000

Enclosed Space (Glass Box)

25800

10750

(CANTILEVER) Lowered Beams (Joist Bearing on Top)

LEVEL 1 PLAN

Bridge / Porch / Box / Outlook 1:100

Landing

40

00

Truss(es) Joist(s) Secondary Beam(s) Primary Beam Primary Column(s) Primary Beam 10 NUMBER

27950

10 NUMBER

Secondary Beam - Mid-Height Stair Support / Truss Brace

10 NUMBER

Secondary Beam - Stair Support / Truss Brace Cantilever Enclosed Space (Above)

Secondary Column

4000

Secondary Beam - Outlook Support Cantilever

10 NUMBER

10 NUMBER

10 NUMBER

Stair Stringer

Stair Riser Decking

25800 Truss Brace

LEVEL 0 PLAN Understory

1:100

Level 2 - Observation (+12.45m)

1100

Level 1.5 - Landing (+11.25m)

800

Level 1 - Bridge (+09.00m)

Enclosed Space

Column Beyond

Grade - Lowest Point (+/- 00.00m)

WEST ELEVATION

Bridge Truss 1b 1:100

Level 2 - Observation (+12.45m)

Level 1.5 - Landing (+11.25m)

1100

Level 1 - Bridge (+09.00m)

Column (Beyond)

Column (Beyond)

Grade - Lowest Point (+/- 00.00m)

Cantilevered Stair Stringer

Grade - Lowest Point (+/- 00.00m)

WEST ELEVATION

Stair Truss 1:100

5316

Truss Brace

Level 2 - Observation (+12.45m)

1900

Level 2 - Observation (+12.45m)

Level 1.5 - Landing (+11.25m)

Level 1.5 - Landing (+11.25m)

1900

Enclosed Space (Beyond)

Level 1 - Bridge (+09.00m)

Level 1 - Bridge (+09.00m)

Enclosed Space

Column (Beyond)

Column (Beyond)

Column (Beyond)

Grade - Lowest Point (+/- 00.00m)

SOUTH ELEVATION Face Truss / Outlook

1:100

NORTH ELEVATION

Braced Frame 1:100

At the summit of Blue Mountain, a timber sphinx stretches out, tucked in a pine stand, hovering in a white sea.