Technical Report - EcoSmart Concrete

READ JONES CHRISTOFFERSEN LTD. 500, 144 Front Street West, Toronto, ON M5J 2L7 Phone (416) 977-5335 Š Fax (416) 977-1427 Web site: www.rjc.ca Š email: [email protected]

HIGH-RISE EARLY DESIGN STUDY STAGE 2 Prepared For: EcoSmart CONCRETE PROJECT 504-999 Canada Place Vancouver, B.C. V6C 3E1 Prepared By: READ JONES CHRISTOFFERSEN LTD. 1285 W. Broadway 3rd Floor Vancouver, B.C. V6H 3X8 and READ JONES CHRISTOFFERSEN LTD. 500 – 144 Front Street West Toronto, Ontario M5J 2L7 RJC#: 38647.02 February 6, 2004

Vancouver • Victoria • Calgary • Edmonton • Toronto

High-Rise Early Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

Page i

TABLE OF CONTENTS Page 1.0

INTRODUCTION

1

2.0

SCOPE OF STUDY

5

3.0

DESCRIPTION OF SYSTEMS 3.1 Lift Slab Construction Description 3.2 Hybrid Precast Description 3.3 Bubble Deck Slab System

7 7 9 10

4.0

CONSTRUCTION COST COMPARISON 4.1 Lift Slab Construction 4.2 Hybrid Precast Scheme Cost 4.3 Cost Impact of Schedule 4.4 Cost Impact of Exterior Cladding

11 12 14 16 17

5.0

CONSTRUCTION SCHEDULE COMPARISON 5.1 Lift Slab Construction Schedule 5.2 Hybrid Precast System Construction Schedule

21 21 24

6.0

ENVIRONMENTAL PERFORMANCE COMPARISON 6.1 Lift Slab Construction 6.2 Hybrid Precast System

27 28 29

7.0

CEMENT USAGE COMPARISON

32

8.0

SUMMARY OF FINDINGS 8.1 Construction Cost Comparison 8.2 Construction Schedule Comparison 8.3 Environmental Performance Comparison 8.4 Cement Usage Comparison

34 34 34 35 35

APPENDIX A APPENDIX B APPENDIX C APPENDIX D APPENDIX E

Lift Slab Floor Plate and Construction Sequence and Schedule Hybrid Concrete Slab Floor Plate and Details and Schedule Bubble Deck System An Environmental Assessment of Alternative High Rise Structural Systems Report By Athena Sustained Materials Institute. Yolles Cast-in-Place Flat Plate Base System

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Page 1

INTRODUCTION Read Jones Christoffersen Ltd. was one of two consulting structural engineering firms retained by the EcoSmartTM Concrete Project to participate in the High Rise Early Design Study. Stage 1 of the study was completed in October 2003. This report outlines the findings of Stage 2. The other firm selected to undertake this review was Yolles Partnership Inc. of Toronto. Read Jones Christoffersen Ltd. met with Yolles prior to commencing Stage 1 in order to divide the structural systems to be reviewed to avoid duplication in this study and, therefore, maximize the number of systems reviewed on behalf of EcoSmart. The objective of the EcoSmart Concrete Project is to minimize greenhouse gas emissions to the atmosphere by replacing Portland Cement in the concrete mix with Supplementary Cementing Materials (SCM) to the greatest extent possible while maintaining and improving cost, performance and constructability. Previous reports prepared by Fast + Epp Structural Engineers,1 and Busby + Associates Architects,2 had indicated that the increased use of supplementary cementing materials on the slab portions of high-rise residential construction was problematic due to the extended cure time required for such concrete. This extended cure time meant that in normal cast-in-place reinforced concrete construction the formwork could not be stripped as quickly as with a normal concrete mix. This delay in the formwork stripping extended the construction schedule to a point that the use of SCM’s was no longer economically viable in this form of construction.

1

High volume fly-ash concrete usage for high-rise construction by Fast + Epp Structural Engineers dated November 2000 2

Use of EcoSmart concrete in the Bayview high-rise apartment, Vancouver, B.C., prepared by Busby + Associates Architects, November 2002.

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This is particularly frustrating in the use of SCM’s as studies indicate that twothirds of all building concrete comprises the horizontal elements and that the tower slabs comprise of 40% of the total concrete in the project.1 An inability to utilize SCM’s in these components of a typical high-rise building severely limits its application to the construction industry. The objective of this High-Rise Early Design Study is to investigate alternative structural slab systems for use in a typical high-rise residential building in Vancouver that could use increased levels of SCM’s to replace normal Portland Cement in slab construction as outlined in the Terms of Reference of this study, is to produce the required knowledge for understanding the relationship between the selection of a high-rise building structural system and its environmental performance, cost and constructability (i.e. the principles of EcoSmart). “The goal of this study is not to design new systems for high-rise construction; instead it is to compare available proven technology based on the principles of EcoSmart.” The Terms of Reference of the EcoSmart Project is that it addresses three desired outcomes: Early Stage: Develop design methodologies that take EcoSmart concrete properties into consideration at the time the structure is designed. De-Materialization: Identify material reduction opportunities by using a smaller amount of better performance concrete or by using precast elements when possible.

1

Reference – High Volume Fly Ash Concrete Usage for High Rise construction report by Fast + Epp, November 2000, prepared for the Greater Vancouver Regional District, Air 2000 Program

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High-Rise Construction: The fast setting requirements associated with high-rise construction make it very challenging to apply EcoSmart Concrete to this important market. The project will search solutions to this issue, both by looking at traditional cast-in-place methods and by investigating novel approaches such as hybrid steel/concrete system. The project will invest in the additional research and design work necessary to produce a real case study using three innovative building design methods. Stage 1 Study As part of the Stage 1 Study at least three floor framing systems, one from each of the following three groups, were to be evaluated: .1

Traditional cast-in-place concrete.

.2

Conventional precast or hybrid concrete precast.

.3

Steel, or hybrid concrete steel, or other systems as proposed by the consultant.

A particular building floor plate was created and utilized as the case study. The floor plate originally proposed was revised to conform more closely to a typical Vancouver residential tower. This building is to represent a typical high-rise condominium project located in downtown Vancouver. It is 22-storeys in height with a floor plate as indicated in the attached Appendices A and B. The building height is specified in terms of a clear interior room height of 2,400mm. The exterior envelope is assumed to be a full height double-glazed window wall cladding system commonly used in this type of building construction in Vancouver. Alternative comparable building cladding systems can be suggested as part of the study in order to ensure compatibility with selected structural systems. There is a requirement that mechanical ducts be incorporated into the floor system with an average area of 8,000 mm2 in cross section. There is also a

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requirement that the acoustical sound transmission rating be a minimum of 52 STC for the floor and the floor to have a minimum 2-hour fire-rating. The Stage 1 part of the project, as outlined in our previous report dated October 24, 2003, documents a description of the structural system with schematic drawings of the floor slab for one system of each of the three categories required. The systems selected by Read Jones Christoffersen Ltd. for the Stage 1 Study were: .1

Cast-in-Place Concrete (a) (b)

.2

Precast Concrete (a) (b)

.3

Lift Slab Construction Post-Tensioned Construction

Hybrid Precast /Cast-in-Place Concrete Deck PRESSS

Hybrid Steel and Concrete System (a)

Hambro Joist System

In each of the three studies reviewed, the primary system reviewed was the system (a) in each of the categories. System (b) was reviewed in less detail and with a general description of its potential and limitations in each of the sections. Upon review of the Stage 1 Report, the Ecosmart Steering Committee decided to carry the Lift Slab Construction and the Hybrid Precast/Cast-in-place concrete schemes into the Stage 2 Study. The work was undertaken in both Read Jones Christoffersen Ltd.’s Toronto and Vancouver offices under the direction of Ronald Mazza, P. Eng., a Principal in our Toronto office, Diana Klein a project engineer in our Vancouver office, and Ralf Altenkirch a design engineer in our Toronto office.

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SCOPE OF STUDY - STAGE 2 The objective of the Stage 2 - High Rise Design Study is to produce more indepth data and a comparison of selected structural schemes with respect to constructability, economics and environmental performance. As outlined in Stage 1- High Rise Early Design Study, a typical Vancouver floor plate was created and served as a base for the structural schemes investigated. The building is 22 storeys in height and for simplicity any transfer slab at ground level and underground parking has been deleted from the study to achieve a clear comparison between the selected schemes. The clear interior room height was specified as 2400mm. The exterior envelope is assumed to be a full height double glazed window wall typical for the Vancouver region. All mechanical ducts were to be incorporated into the floor system. A 2 hour fire rating and a minimum of 52 STC sound transmission for the floor system was specified. From the three schemes produced by RJC and the three developed by Yolles in Stage 1-High Rise Design Study, four schemes were selected by the EcoSmart Steering Committee for further in-depth study as part of the Stage 2 Study. RJC undertook and developed their Lift Slab and Hybrid Precast Concrete schemes and Yolles were to pursue the Cast-In-Place concrete Flat Plate scheme and the structural steel with metal deck and concrete topping scheme. This Stage 2 Study presents a detailed cost analysis of the schemes with a material summary. Furthermore the environmental impact of each scheme will be investigated in depth and compared to each other. A construction schedule will also be developed and compared. In order to obtain a detailed environmental assessment Read Jones Christoffersen Ltd. and Yolles Partnership Inc. engaged the services of the AthenaTM Sustainable Material Institute. Under the direction of Jamie Meil, the AthenaTM Sustainable

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Material Institute provided both firms with an Environmental Assessment of Alternative High Rise Structural Systems. Read Jones Christoffersen Ltd. and Yolles Partnership Inc. provided the Athena with spreadsheets detailing a per floor summary of materials for the four different structural systems. Further information with respect to method of construction and sequencing, particularly for the unusual systems such as Lift Slab and Hybrid Precast, was discussed with Athena in a meeting in Ottawa.

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3.0

DESCRIPTION OF STRUCTURAL SYSTEMS

3.1

Lift Slab Construction Description

Page 7

The Lift Slab System is comprised of cast on site post-tensioned concrete slabs supported on steel columns. The post-tensioned concrete slabs are cast on top of each other on the ground or podium floor with plastic sheets or a chemical separator compound dividing them. The lowest level slab is cast first, with subsequent slabs poured directly on top of the preceding one. Steel shear heads are embedded within the slab around the columns to form an opening to facilitate the lifting process as well as a lifting attachment point and a welded connection point to the steel columns. Some earlier projects utilized conventional reinforced concrete flat plates as well as beam and slab configurations. However, currently post-tensioned slabs are normally used for better lifting performance and also have the advantage of reduced concrete thickness. In Vancouver the minimum slab thickness is usually 7½” due to mechanical ducts located within the slab. Though this was originally a requirement of the original Terms of Reference for this study, in order to take full advantage of the efficiency of post-tensioned construction to reduce the required slab thickness, we have reduced the slab thickness to 6½” for this particular project and assumed the mechanical ducts are placed beneath the slab in a bulk head against a partition wall which is commonly done in other parts of North America. A 6½” slab thickness was assumed for this study. (See Appendix A for details of a typical floor plate). Lift slab construction has historically been used on projects in the 4 to 8 storey range. The tallest lift slab structure we are aware of is 18 storeys. This 22 storey is therefore taller than any other previous project and is therefore certainly “pushing the envelope”.

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Before the lifting process commences all concrete slabs are tensioned at ground level. This has the advantage of eliminating the awkwardness of performing tensioning above-grade. The post tensioning increases the slabs spanning capabilities relative to thickness and thus can reduce the number of columns and, therefore, the number of jacking points. Furthermore, most of the concrete creep and shrinkage takes place on the ground and the restraint induced cracking of the floor slab is reduced. However, the post-tensioned strands must be protected from moisture ingress both during and after construction to ensure a long lasting, durable structural system. After all slabs are poured at grade and cured, mechanical jacks mounted on steel castings that are supported on top of the steel columns lift the floor slabs at a rate of a few centimeters an hour sequentially into their respective positions. The steel columns are designed as cantilever columns above the slab that serves as a working platform to limit the unbraced length of columns and ensure temporary stability. The number of slabs lifted at one time varies between 2-5 depending on the jack capacity and floor configuration. While the slabs are parked in temporary positions they are supported by wedges and tack welds to the steel columns. The lowest slab is parked in its final position and new sections of steel columns are spliced on top of existing columns (usually 2-storeys above working platform). The lifting process carries on while workers continue to work below finishing the permanent connections between columns and slabs. Structural components such as cross bracing or shearwalls providing lateral stability for the building are installed at lower levels while lifting is proceeding above. (See Appendix A for a description of the detailed lifting sequence proposed for this building).

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3.2

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Hybrid Precast Description This hybrid composite system consists of precast / prestressed concrete elements that are shop manufactured combined with field cast concrete topping. The precast elements in this example consist of inverted channel elements for the typical slab portions which are supported on precast concrete ‘U’ shaped beam forms. Column forms can also be similarly fabricated or normally constructed cast-in-place columns could be used. See Appendix B for the proposed typical floor slab of this building. The precast forms could be cast in a certified precast concrete plant with as much SCM’s as possible or they could be field cast on site, depending on site configuration and weather. Our initial findings indicate a possible range of 20%-25% SCM’s. These forms need to reach sufficient strength to be lifted out of the mould after 24 hours in order to maintain an economical viable production cycle for a precast plant. This time constraint governs the SCM content. The in deck mechanical ducts are assumed to be cast into the field poured concrete topping as shown in Section 2A of Appendix B. The precast column and beam forms are shipped to site and erected and temporarily shored and secured by steel clamps or normal cast-in-place concrete columns could be formed and poured. The floor channels are placed onto the precast concrete beam forms and additional steel reinforcement is placed and tied. A high SCM content concrete mix is then field poured into the beam and column forms, as well as the channel forms to finish the floor slab. The beam shores are left in place until the field cast concrete has reached sufficient strength. Temporary shoring could be reduced if the precast panels were designed to span further under the weight of wet concrete. This would produce thicker precast elements, however, resulting in greater shipment costs and reduced use of field cast high SCM concrete. An economical balance also has to be established

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between shoring cost and floor thickness. The use of temporary shoring allows reduced total floor thicknesses and reduced precast concrete thickness. 3.3

Bubble Deck Slab System In the course of our research for this study we came across a hybrid precast/castin-place concrete system that has been developed in Europe and is being used in the construction of high rise buildings in Holland. Additional information about this system is contained in Appendix C. In general principal, the system is very similar to the Hybrid Precast system developed for this study. It also consists of a thin shop fabricated concrete panel shipped to site, lifted into a place with a cast-in-place concrete topping added. However, the thin concrete bottom layer is stiffened by a top and bottom grid of heavy welded wire mesh tied together by vertical shear steel. The space between the top and bottom grid of steel is filled with large plastic spheres which both reduces the final structural weight and reduces the final volume of concrete used. The panel is shipped to site with the bottom layer of concrete, top and bottom steel grid and plastic spheres in place. The field poured concrete fills the spaces between the spheres. This system is now being licensed to fabricators in Canada and should soon be available for use.

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4.0

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CONSTRUCTION COST ESTIMATES Due to the competitive nature of property development, especially in the high rise condominium market, the initial construction cost of a building is one of the primary driving factors in private construction in North America. More often than not it dictates other design criteria and short term financial gains are viewed more important than longer life cycles and better design of the building. Therefore any structural system that is potentially more sustainable than commonly used construction methods must at least be initially as financially viable as the common base scheme. The comparative base scheme is the cast-inplace concrete flat plate scheme with minimum fly ash content. This is presently the most commonly used system in high rise residential construction both in Vancouver and across Canada. The structural schemes were broken down into their respective elements and the calculated quantities of materials were multiplied by unit costs to arrive at a total cost of construction. The unit costs are based on Hanscomb’s Yardsticks for Costing 2003 with some variations based on Read Jones Christoffersen Ltd. experience which reflects current cost fluctuations within the Vancouver market. For example, formwork in the Vancouver market is currently more expensive than usual due to a current shortage of plywood. Additionally, Read Jones Christoffersen Ltd. contacted specialist contractors for their unique expert input. RJC and Yolles agreed between themselves on the value of unit costs issued in order to make comparisons between the two studies possible. The unit costs used are shown in Table 1. Only the cost of the structural elements above the ground floor or podium deck is included in this comparison. For the purpose of this study, it has been assumed that the structural systems below the alternative typical floor systems would be identical, and therefore assumed to have the same cost.

Any variation in

foundation cost resulting from lighter weight systems was noted to be relatively

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small, well within the likely margin of error of this study and therefore not included. Curtain wall costs are included to the extent that differing floor-to-floor height influence that cost. The costs calculated in the following tables for the construction of the structure of the building represents our opinion of the probable cost of construction based on the limited information obtained during this study. They are based on unit costs generally recognised in the industry as representative and our estimate of construction time and schedule. Some of the schemes, reviewed are not commonly used in this type of construction. Therefore a good body of costing information simply is not available. Final costs cannot be determined until such time that the work is designed in detail, tendered and the final quantities and methods of construction are defined. It is not possible to accurately forecast the final unit prices that may be tendered for the work as they are directly related to the construction climate at the time of tendering. The cost estimates should therefore be treated as “ball park” figures only for comparison use and cannot be guaranteed. A helpful assessment tool for comparison is the sub total that summarizes the cost of the major elements alone. This allows for a more detailed comparison and future combination of the most efficient and most sustainable elements of the various structural schemes which have been studied. 4.1

Lift Slab Construction Cost The cost estimate break down and calculation for this scheme are shown in Table 2. the total calculated estimated cost for this scheme is $1,716,048.00 or $226.10/m2 ($21.00/sq foot). This cost is based on our estimate of construction cost of the structure only and does not include the economic impact of schedule. This cost compares with an estimated $1,703,774 or $224.48 per m2 ($20.85/sq ft) for the base flat plate scheme.

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In summary, the materials and costs for this system break down as follows: Quantity

Total Costs

Cost $/m2

%

1447 m3

$197,419

$26.00

11.5

451 m2

$39,691

$5.20

2.3

Mild Rebar

58.5 tonne

$76,011

$10.00

4.4

P/T Reinforced

40.7 tonne

$224,092

$29.50

13.1

Structural Steel

158.1 tonne

$399,852

$52.70

23.3

10 stages

$660,000

$87.00

38.4

54.24m3

$54,581

$7.20

3.2

Drywall

2

3726 m

$54,402

$7.20

3.2

Wet Curing

7590m2

$10,000

$1.30

0.6

$1,716,048

$226.10

100

Concrete Formwork

Slab Lifting Fire Protection

Total

An estimate of $10,000.00 has been added to the cost to account for the need to wet cure the high fly ash content slab for the relatively short period between their casting, setting, and covering by the new slab poured on top.

This curing

requirement is in accordance with the proposed new CSA A23.1 Standard, Concrete Materials and Methods of Concrete Construction (Committee Draft). This proposed revision to the existing standard will require a 7-day wet cure for concrete with a fly ash content in excess of 35% or 40% for slag. This scheme is affected by the very low formwork cost which is offset by the cost of slab lifting and the higher cost of post-tensioning steel. The breakdown on a per floor basis indicates that the steel cross braced core framing accounts for approximately 20 % and the concrete floor plate for are approximately 30% of the total construction cost. The perimeter columns do not have a significant impact on the overall per floor cost and present approximately

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10% of the total. The largest contribution is the lifting and steel erection cost with almost 39%. 4.2

Hybrid Precast Scheme Cost The cost estimates and breakdown for this section is shown in Table 3. the total calculated estimated cost for this scheme is $1,876,365.00 or $247.1/m2 ($17.90/sq ft). This cost is based on our estimate of the construction cost of the structure only and does not include the economic impact of schedule. This cost compares with a cost of $1,703,774 or $224.48 per m2 ($20.85/sq ft) for the base flat plate scheme. In summary, the materials and costs for this system break down as follows: Quantity

Total Costs

Cost $/m2

%

Cast-in-place Concrete Precast Concrete

1855m3

$264,962

$34.90

14.12

610m3

$609,312

$80.30

32.5

Wet Curing

9090 m2

$200,000

$26.30

10.6

Mild Rebar

90.6 tonne

$117,780

$15.60

6.3

Prestressed Rebar

68.2 tonne

$272,800

$35.90

14.5

1805 m2

$361,511

$47.60

19.3

$50,000

$6.60

2.7

$1,876,365

$247.20

100

Formwork/PC Shoring Total

This scheme also has a relatively low form work cost which is partially offset by the higher unit rate for the precast concrete forms and cost of the precast concrete elements.

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Customized forms for the precast elements, which are constructed of steel with a special plastic coating have a significantly higher unit cost than normal slab formwork but are more than offset by their much smaller quantity and extent of reuse. The estimated fabrication cost for these forms which ensure a faster curing and quality finished concrete are approximately $970.00 per square metre ($90.00 per square foot) for first time production but can be reused up to 500 times. After such extensive usage the forms will need to be overhauled to maintain their quality. To overhaul a used form, which usually consists of replacing the inside liner of the form, costs approximately $485.00 per square metre ($45.00 per square foot). As there are typical planks on this floor plate it was assumed that 10 forms would be required which will be overhauled at least once for an average cost of $750.00 per square metre ($70.00 per square foot). This appears to be a high unit cost but accounts for only 9% of the cost with the floor system alone, due to the repetitive production cycle of precast construction. The foundation costs are higher than the other reviewed structural systems due to the increased overall building weight due to the thicker floor slab required. However this does not contribute significantly to the overall cost as foundations only amount to 4% of the overall cost, and have therefore not been included in the comparison of costs. A cost estimate of $200,000.00 has been included for wet curing of the high SCM content cast-in-place concrete topping as required by the new CSA A23.1 Standard Concrete Materials and Methods of Concrete Construction (Committee Draft). This is the same cost carried in the Yolles base flat plate system comparator. The greatest cost benefit for the Hybrid Precast System is that on site formwork is almost eliminated. Even though the material cost is higher for precast formwork than ordinary formwork the repetitive nature of precast fabrication saves costs. For the cast-in-place base scheme the formwork for the slabs accounts for

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approximately 20% of the overall cost and on this precast building the precast forms of the slab elements account for 2%. 4.3

Cost Impact of Schedule In addition to the direct construction cost for each structural system reviewed there is a secondary cost affect related to construction schedule. This cost has two principal components, contractor cost and financing costs. Based on discussions with residential contractors and developers we have assumed the contracting costs, made up of insurance and bonding costs, head office costs, site staffing costs, and equipment rental to be $50,000.00/week. We have assumed cost of financing of the building at a 5% interest rate based on a total carrying cost of two times the total construction cost of the building to account for land costs and soft costs. We have assumed a total building cost of $110/sq ft and a total building area of 81,700.00 sq ft. this works out to a carrying cost of approximately $17,300.00 per wk. We have, therefore, assumed a total cost implication of $70,000.00/wk for construction schedule differentials. The estimated construction schedule for the Lift Slab Scheme is shown in Appendix A and is estimated to be 28 weeks. The estimated construction schedule for the Hybrid Precast concrete scheme is shown in Appendix B and is estimated to be 21 weeks. The base building scheme of a normally reinforced concrete flat plate as outlined in the Yolles report is estimated to be 22 weeks. Therefore the cost impact for the lift slab system is +$445,500.00 (+$58.7/m2) and the Hybrid system is -$70,000.00 (-$9.2/m2).

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4.4

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Cost Impact of Exterior Cladding This Stage 2 High Rise Early Design Study primarily focuses on the comparison of

structural

systems

only.

All

other

building

systems,

such

as

mechanical/electrical systems, interior finishes, elevators, and cladding etc. are assumed equal for all alternative structural schemes. The only exception to this, included in this review is the relative cost of the exterior cladding affected by the differential floor-to-floor height of the various schemes. The floor and ceiling height of all schemes has been set at 2,400mm, therefore, due to different structural thicknesses for different floor plates the floor-to-floor heights will vary and thus affect the overall height of the building. The exterior cladding is the most cost intensive system affected by this change in height, and therefore has been included both in the cost comparison and the primary energy and greenhouse gas emission study. The total building height for the lift slab scheme would be 56.43 meters. The total height for the Precast Hybrid system would be 56.76 meters. This compares with a total building height of the base building scheme of normally reinforced concrete flat plate construction of 56.65 metres. Assuming a building perimeter of 85 meters and a curtain wall cost of $420/m2 this works out to the following additional costs of the base building: Height of Building

Height Difference to Base Building

Cost Difference to Base Building

Cost Difference to Base Building in $/m2 of Floor Area

Base Building

56.65 m

0.0

$0.0

$0.0

Lift Slab

56.43m

-0.22

-$3927

-$0.53

Hybrid Precast

56.76m

+0.11

+$7854

+$1.05

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UNIT COSTS Vancouver Market 2003 Material

Unit

Cost in $

Unit

Cost in $

CY CY CY CY

13.00 13.00 17.60 19.10

m3 m3 m3 m3

17.0 17.0 23.0 25.0

CY CY SF CY CY

12.25 16.80 16.25 13.00 92.00

m3 m3 m2 m3 m3

16.0 22.0 175 17.0 120.3

lbs

0.59

kg

1.3

Concrete (Cast in place) Footings Foundation Walls Walls Columns Slabs Flat Slab Concrete on Metall Deck Precast (8”) Slab with incorp. Beams Concrete Supply(3000 psi)

Rebar

Formwork Footings

SF

7.50

m2

80.7

Foundation Walls

SF

16.50

m2

177.6

Walls

SF

16.50

m2

177.6

Slabs

SF

8.50

m2

91.5

Precast

SF

75

m2

750

Structural Steel Core walls + Bracing

ton (Imp)

3110

Beams + columns

ton

2550

tonnes

tonnes

3425.0

22 GA deck

SF

2.00

m2

21.5

16 GA deck

SF

2.65

m2

28.5

2810.9

Steel Decking

Post tensioning + Pretensioning Pretensioning

lbs

2

kg

4

Unbonded P/T

lbs

2.50

kg

5.5

Steel columns + beams

SF

1.40

m2

15.1

Steel deck

SF

1.20

m2

12.9

Supply Only

SF

0.60

m2

6.5

Fire proofing

Gypsum Wall board

Installation Only

Cladding system assuming Curtain wall with thermal insulation

SF

Table 1

39.00

m2

8

m2

419.8

Page 19

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

Scheme Lift Slab Construction Cost Estimate

Table 2

Agreed dimensions Floor area =

345 m2

Floor perimeter =

85 m

Core wall perimeter =

33 m

Core wall openings =

11 m2

Varied Dimension Floor to Floor height

2.565

Element

Sub-element

Sub-sub element

Dimensions

Foundations

Concrete

50% Fly Ash (30MPa)

Volume/m3

193

193

Concrete

Tonnage Area/ m2

7.9

7.87

Reinforcement

142.0

142

Formwork/footing

Reinforcement Formwork

Quantities/Floor

Total

Sub-element

Quantity cost 137 1,300 81

Sub-Total Core Framing

Steel Fire protection

Promat type H

Tonnage/ tonne Volume/m3 Area/ m2 Area/ m2

Formwork drywall

48,189

15,325

246,600

15

1,782

39,200

0 3000.8 drywall

15

0.0 136.4

1,978

43,512

19,084

329,311

0.0

0

3.1

68.1

Structural steel *

0.7 33.0

15.3 726

Fire protection drywall

Fire protection drywall

Promat type H

Tonnage/tonne Volume/m3 Area/ m2

2,250

6,966

153,252

15 15

699 495

15,381 10,890

Concrete

50% Fly Ash modified (30MPa)

Volume/m3

57.0

1254

Concrete

Tonnage/tonne Area/ m2

2.3

50.6

Reinforcement

14.0 1.9

308.6 Formwork 40.7 Post Tensioning

8,160

179,523

136

7,769

170,920

1,300

2,990

65,780

92 5,500

1,283 10,186

28,232 224,092

22,228

489,025

30,000

660,000

With Foundation

79,573

1,716,048

Without Foundation

79,473

Sub-Total Wet Curing

10,000

Lifting of Slab

Total Lifting Cost*

660,000

With Concrete Core Cladding

11,459

2,740

Structural steel

Tonnage/tonne

2,190

10,231

38.94 Fire protection

Area/ m2

Formwork Post Tensioning

26,499

90.00 Steel *

Formwork

Reinforcement

1,204 465 521

1.8

Sub-Total Structural Floor system

Total cost

5.6

Sub-Total Columns

Cost per floor

Total area

Perimeter x Height

Percentage viewable glazing

Percentage 40%

Percentage spandral panel

Percentage 40%

Percentage opaque glazing With insulated backpan (yes/no)

Percentage 20% Yes

*= The unit costs for steel were reduced by 20% as the erection and plumbing of the structural frame is included in lifting cost

218.0

4796.6 Total area

Total

60,802 420

91,527

2,013,592

3,729,640

Page 20

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

Precast Hybrid Cost Estimate

Table 3

Agreed dimensions Floor area =

345 m2

Floor perimeter =

85 m

Core wall perimeter =

33 m

Core wall openings =

11 m2

Varied Dimension Floor to Floor height

2.58

Element

Sub-element

Sub-sub element

Foundations

Concrete

50% Fly Ash 30MPa)

Reinforcement Formwork

Dimensions

Quantities/Floor

Total

Sub-element

Cost

Concrete

50% Fly Ash (30MPa)

Reinforcement Formwork

Volume/m3

307

307

Concrete

137

1,916

42,151

12.5 200

12.5 200

Reinforcement Formwork

1300 81

739 734

16,250 16,140

3,388

74,541

Volume/m3

26.6

585.2

Concrete

143

3,812

83,859

Tonnage/ m3 Area/m2

2.1 68.2

46.2 1500.4

Reinforcement Formwork

1300 178

2,730 12,112

60,060 266,471

18,654

410,390

Sub- Total Columns

Concrete (topping)

50%Fly Ash (30MPa)

Volume/m3

2.04

44.88

Concrete (topping)

144

294

6,476

Concrete (precast)

60MPa 9% Silica fume

Volume/m3

3.96

87.12

Concrete (precast)

1000

3,960

87,120

Reinforcement (mild rebar)

Tonnage/tonne

0.6

13.2

Reinforcement (mild rebar)

1300

780

17,160

Reinforcement (pretensioned) Formwork

Assume 5 reused steel forms

Tonnage/tonne Area/m2

0.2 30

4.4 30

Reinforcement (pretensioned) Formwork

4000 750

800 1,023

17,600 22,500

6,857

150,856

Concrete (topping)

50% Fly Ash (30MPa)

Volume/m3

41.73

918.06

144

6,022

132,476

Precast

60MPa 9% Silica fume

Volume/m3

23.736

522.192 Precast

522,192

Sub- Total Structural Floor system

Concrete (topping)

1000

23,736

Reinforcement (mild rebar)

Tonnage/tonne

0.85

18.7

Reinforcement (mild rebar)

1300

1,105

24,310

Reinforcement (pretensioned) Formwork

Tonnage/tonne Area/m2

2.9 75.2

63.8 75.2

Reinforcement (pretensioned) Formwork

4000 750

11,600 2,564

255,200 56,400

assume 10 reused steel forms

Sub- Total Wet Curing

22 floors + Core walls

Shoring

5 floors

45,026

990,578 200,000 50,000

With Foundation Without Foundation Cladding

Total cost

Tonnage/tonne Area/m2

Sub- Total Core walls

Cost per floor

Total area

Perimeter x Height

Percentage viewable glazing

Percentage 40%

Percentage spandral panel

Percentage 40%

Percentage opaque glazing

Percentage 20%

With insulated backpan (yes/no)

Yes

219.3

4824.6

Total area

Total

420

73,926

1,876,366

70,537

1,801,824

92,062

2,025,367

3,901,733

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5.0

Page 21

CONSTRUCTION SCHEDULE COMPARISON In addition to a cost estimate we have also undertaken an estimated construction schedule for each of the two schemes reviewed as part of this Stage 2 Study, as speed of construction has a direct relation to the construction cost of the project. The base schedule used as a comparative is the normally reinforced cast-in-place concrete flat plate scheme with 9% SCM as reviewed n the Yolles report. Based on the review of this system undertaken by Yolles we have taken this base construction schedule as 22 weeks for the typical floors above the podium deck. It was agreed between RJC and Yolles that only the construction schedule for the typical floor tower portion of the project would be compared. It was assumed that the foundations, below grade portion, and any grade level or podium structure would have the same construction schedule and cost for all schemes. The estimated construction schedule for both of the lift slab scheme and the Hybrid concrete scheme was developed from first principals by RJC personnel based on specialist input from contractors. These systems are not in common usage in Canada for this type of structure, so there is not a good track record in the construction industry on the time requirements for their construction. Therefore these schedules should be viewed as approximate estimates only with a possible margin of error.

5.1

Lift Slab Construction Schedule The construction of the lift slab system comprises of two main phases. Initially, the floor slab is constructed at ground level with each slab poured on top of the previous slab, separated by a release agent. The slab edge is formed, the mild and post-tensioning steel placed, the concrete poured, the surface finished, and once cured the release agent is applied to the top surface, then the process is repeated

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Page 22

and each slab poured on top of the one below. Once the concrete reaches sufficient strength the post-tensioned strands are tightened. We estimate this phase to take 10 weeks for this project based on a 2 day casting cycle as indicated in Table 4. The second phase is the lifting process itself.

The lifting process cannot

commence until all 22 floor plates are poured and the post tensioning is completed. The post tensioning will be done on the lower slabs while the upper slabs are still being constructed. The lifting process is shown graphically in Appendix A. Only two levels of steel columns are initially erected. All the slabs are then sequentially lifted (up to five at a time) above the second floor and temporarily parked. The second floor slab (the lowest of the lifted stack of slabs) is then permanently attached by welding the embedded shear heads to the steel columns at its final location. New column extensions are then added and the process is repeated. The placement of the lower level floors take longer than the upper level floors due to the increased number of floors that need to be handled and parked. Steel cross bracing, or concrete core walls is added as the floors are lifted to maintain structural stability. We estimate approximately 11 weeks for this lifting phase for this building. Once the 2nd and 3rd floors are locked in place the other trades can now access these levels to complete their work. However, the slower pace of lifting at the lower levels may create some delays in completing these levels. The total estimated construction time for the Lift Slab system is 28 weeks.

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Page 23

Table 4 Lift Slab Construction Schedule for Slab Construction of 22 Floors Total

Days

Time

Action FIRST FLOOR 3 DAY CYCLE

1st day

1 day

3/4 day

st

Placing of 1 set of steel columns 32’ long 1/4 day Construction of Jump form around slab edge Installation of lower level reinforcement of 1st slab 1/2 day Installation and preparation of shear heads & collars @ 20 column locations

2nd day

1 day

3rd day

1 day

(note: shear heads are prefabricated of site)

Installation upper layer reinforcement of 1st slab 1/2 day Installation of P/T layout in slab Installation of mechanical and electrical sleeves Finishing any mechanical electrical sleeves and Reinforcement works 1/2 day Placing concrete late morning 1/2 day Finish slab after 4-5 hour setting time START TYPICAL 2 DAY CYCLE 1/2 day

4th day

1 day 1/2 day

5th day

1 day

1/2 day 1/2 day

Move up form work for 2nd slab Spray seperating compound on previous slab Layout and preperation of shear heads @ column locations Installation of lower level reinforcement of 2nd slab Installation upper layer reinforcement of 2nd slab Installation of P/T layout in slab Installation of mechanical and electrical sleeves Finishing any mechanical electrical sleeves and Reinforcement works Placing concrete late morning Finish slab after 4-5 hour setting time CONTINUE 2 DAY CYCLE

6th day

7th day

1 day

1 day

45th day 9 weeks 50th day 10 weeks

Move up form work for next slab Spray seperating compound on previous slab 1/2 day Layout and preperation of shear heads @ column locations Installation of lower level reinforcement of next slab Installation upper layer reinforcement of next slab 1/2 day Installation of P/T layout in slab Installation of mechanical and electrical sleeves Finishing any mechanical electrical sleeves and Reinforcement works 1/2 day Placing concrete late morning 1/2 day Finish slab after 4-5 hour setting time REPEAT FOR REMAINING 19 SLABS Finish 22nd floor slab

Finish upper slab Post Tensioning with 7 days delay for strength gain

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

5.2

Page 24

Hybrid Precast System Construction Schedule Our analysis indicates that a 4 day per floor construction cycle, equal to the castin-place concrete flat plate base system, can be achieved for this system (see Table 5). The schedule of the precast scheme is driven mainly by the cranage time required to lift the precast planks, beams and column halves into their respective positions. The column and beam sections require more lifting time due to the extra time required to plum the elements and tack weld them into position. Precast Contractors indicated that an average of 30 minutes for these elements should suffice. For the typical precast planks that only need to be lifted into place and are supported by the core walls and the perimeter beams the lifting time is estimated to be an average of 15 minutes per element. The reinforcement cages can be tied by the rebar crews concurrently with the precast lifting and then only need to be dropped into the columns and beams. The rebar at the balconies and the welded wire mesh in the slab do not amount to significant amount of work with respect to the schedule. The cast-in-place concrete slab topping also fills the columns and beams to form a monolithic structure and is placed during the late morning to give the finishers all afternoon to finish the slab. The next morning lifting of formwork for the core wall can commence. The option of slip forming the core in advance was explored but no benefit was found. It appears that the initial set up of the slip form would delay rather than accelerate the schedule. Another approach worth considering would be to replace the precast concrete perimeter columns with cast-in-place columns. The lifting time would be reduced as the column forms can be lifted and set plum more quickly by the forming crew. Placing of the concrete would be at the same time as for the core walls. Therefore, all horizontal elements would be precast with concrete topping and all

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vertical elements could be cast in place. From an environmental and cost point of view this would result in no significant change as the perimeter columns only account for a low amount of greenhouse gases and costs. Based on our analysis and schedule assumptions as indicated on the Hybrid Precast Construction schedule in Appendix B, the construction time of this system is 21 weeks. This is virtually identical to the 22-week schedule of the base concrete flat plate system. The 1-week difference is due to the initial construction time required for the fly forms for the flat plate system.

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Table 5

Hybrid Precast Construction Schedule Total

Days

Time 3/4day

1st day

Erect Formwork for core walls (2.5 Hours) Erect Precast 6 Columns =12 pieces at 15min each = 3 hours

1day

2nd day

1 day

3rd day

1 day

Parallel Rebar Crews tie reinforcement cages for colums and core walls + Installation 1day 1/4 day Pour core walls late afternoon Strip formwork for core wall (1 hour) 1day Finish Remaining 6 Precast Columns 3 hours Start Erection of Precast Beams + Planks (56 Pieces x 15min=14 hours) (3.5 Hours) Parallel Rebar Crews tie reinforcement cages for next columns and core walls 1day Parallel Rebar Crews start placing slab reinforcement mesh and bars at cantilever balconies Continue Erection of Precast Planks 7.5 Hours 1 day

1 day

4th day

Action

Rebar Crews continue layout of rebar in Perimeter beams and on top of erected planks

1 day

Finish Remaining 12 Precast Planks 3 hours Finish Remaining Rebar and mesh layout

1 day

Pour concrete around late morning Finish concrete topping late afternoon

1 day

REPEAT 3 DAY CYCLE 22 TIMES

88 DAYS=17.6 WEEKS

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

6.0

Page 27

ENVIRONMENTAL PERFORMANCE COMPARISON RJC and Yolles jointly engaged AthenaTM Sustainable Materials Institute to undertake the comparative environmental impact of the various structural systems reviewed as part of this study. Their report is contained in Appendix D, An Environmental Assessment of Alternative High Rise Structural Systems. Yolles Partnership Inc. and Read Jones Christoffersen Ltd prepared quantity take off sheets for the 4 structural schemes and the AthenaTM Sustainable Materials Institute used them to prepare their environmental assessment. Due to the complexity of the analysis and limitations of the material database of the AthenaTM software, AthenaTM Sustainable Materials Institute were required to make some assumptions and substitutions in their analysis. Thus the results are to be viewed as “ball park” comparative figures in the approximate order of magnitude. For example, the precast concrete mix used for the analysis of the Hybrid Precast system is based on a hollow core concrete mix rather than the mix desired by Read Jones Christoffersen Ltd. The implications of this is discussed in Section 6.2. The results of the Athena analysis indicate the following comparative results of the environmental assessment of the structural systems reviewed:

1. Flat Plate 50% FA

Primary Global Energy Warming (Gj) Ratio Tonne Ratio 12,896 0.93 879 0.87

Total Concrete Volume m3 Ratio 2300 1.0

2. Flat Plate 35%FA

13,332

0.96

932

0.92

2300

1.0

3. Flat Plate 9% FA *

13,868

1.00

1007

1.00

2300

1.0

4. Hybrid Precast Concrete

13,947

1.005

987

0.98

2465

1.07

5. Lift Slab Concrete

16,770

1.21

1096

1.09

1447

0.63

6. Structural Steel and Metal Deck

22,656

1.63

1391

1.38

1482

0.64

* Base System for Comparison

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Page 28

Based on the above comparative figures, it appears that the Hybrid Precast structured system is virtually identical with the base system of Flat Plate with 9% F.A. and the Lift Slab system exceeds the base system both in Primary Energy (1.21), and Global Warning (1.09). 6.1

Lift Slab Construction The environmental assessment concluded that the lift slab system consumes approximately 20% more primary energy than the base system and also contributes 9% more to the Global warming effect. The main contributor to these higher numbers for this system appears to be due to the manufacturing process of the structural steel columns and core cross bracing. According to the AthenaTM Sustainable Materials Institute report (Appendix D), the structural steel “primarily comes from integrated or virgin steel mills as opposed to concrete reinforcing steel and steel wire strands which are manufactured in mini-mills using almost entirely recycled steel as their primary furnish. Typically, these mini-mills use about a third less energy to produce a given quantity of steel and they are more abundant across the country. The integrated producers are concentrated in Ontario and hence, transportation to Vancouver is also factored into the profile results.” A significant reduction in both primary energy and global warning could be achieved by replacing the steel core with a cast-in-place concrete core. The overall Energy consumption and GHG-emission would reduce drastically and bring the Lift slab system closer to the Flat Plate and Hybrid Precast systems. The Lift Slab System did not receive any beneficial accounting for the minimized amount of formwork. The fly forms for the flat plate base scheme need to lifted into place and the concrete bucket needs to travel a great number of times over a long distance. On the lift slab system, however, the concrete is poured on the

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Page 29

ground and the finished slab only travels once to its permanent position. As it is very difficult to determine the impact of this it was not taken into account. Concrete when compared to steel appears to be more efficient with respect to primary energy use and greenhouse gas emissions for this particular floor layout based on the Athena analysis. It should be noted, however, that the Athena energy analysis included only the embodied energy of materials from extraction, manufacture, and construction and did not consider the full life cycle of the materials. Therefore, the advantage of steel’s greater ease of demolition and its better reuse or recycleability was not included in the analysis. Steel also becomes more structurally efficient for larger floor spans, than used in this residential floor plate as does post tensioning. Therefore, for residential construction with the current structural floor spans and load criteria, concrete appears to be a more suitable building material with respect to energy use and greenhouse gas emissions. 6.2

Hybrid Precast System The environmental performance of the Hybrid Precast System is within 5% of the Flat Plate base system with 9% fly ash on greenhouse gas emissions and virtually identical on Primary Energy use. This can be improved by having the columns also cast-in-place concrete. The floor system is the main contributor to the primary energy at almost 40% of the total. The precast and concrete topping components contribute each almost the same amount to GHG-emissions and primary energy use. This is due to the higher volume of concrete topping which has a lower embodied energy per volume than the precast concrete.

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Page 30

As noted previously, however, the precast concrete component of this system was modeled using a 9% silica fume core slab concrete mix available to Athena. This mix consists of 352 kg/m3 of cement and 33 kg/m3 of silica fume for a total cementitious material content of 385 kg/m3 . In order to achieve a better representative of the energy and global warming effect of a more typical precast concrete mix design, Athena was asked to comment on the impact of using precast concrete mixes supplied by the Steering Committee of EcoSmart TM Concrete Project. Two mix designs supplied were as follows: Mix No. 1

Mix No. 2

25% Fly Ash 50 MPa at 28 days 404 kg/m3 Cement 132 kg/m3 Fly Ash 536 kg/m3 Total Cementitious

20% Fly Ash 45 MPa at 28 days 323 kg/m3 Cement 81 kg/m3 Fly Ash 404 kg/m3 Total Cementitious

Athena’s comments are as follows: Mix #1 The new 25% fly ash mix design is not a 1:1 displacement of cement by fly ash. Relative to the original report precast mix design, this mix is adding more cement (15%) and more semi-cementitious material – fly ash (300%). The net effect of this change is not favourable. Athena’s experience indicates that a 10% change in cement use would typically yield a 6% change in energy and a 9% change in GHG emissions. Thus they would expect about 9% increase in the energy and 14% increase in GHG emissions associated with this mix design relative to the original mix design. Most of the additional cement and fly ash would displace the sand component of the mix, so the transportation trade-off effect would be

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Page 31

relatively minor in the scheme of things. The analysis excludes the impact of replacing silica fume with fly ash. Mix #2 The 20% fly ash mix design is also not a straight 1:1 replacement of cement, but relative to the original study precast concrete mix design, the mix calls for less cement and adds only half as much fly ash as the 25% FA case. Using the same premise as above, Athena expects about a 5% reduction in energy use and a 7% reduction in GHG, from the original findings. An environmental benefit is also achieved by the amount of prefabrication that is achieved with the precast elements. This reduces waste on site and plywood usage.

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

7.0

Page 32

CEMENT USAGE COMPARISON The primary objective of the EcoSmart program is to reduce the amount of Greenhouse Gas emission to the atmosphere from concrete construction. As one of the principal strategies to do this is to reduce the cement content in concrete, a comparative analysis of cement content in the various systems is of primary interest. Percentage Replacement Discussion When one specifies high percentage usage of supplementary cementitious materials it is often assumed at a 1:1 replacement of cement by the SCM. This may not always be true and individual mix designs should be reviewed to determine the actual cement reduction. According to the concrete mix design information received from and used by Athena, as well as the mix design supplied by the Precast Industry, it appears that the supplementary cementing materials (SCM’s) are not always replacing cement on a 1:1 basis. This is also discussed in Section 6.2. It appears that when larger percentages of SCM’s, especially Fly Ash, are introduced into a concrete mix, additional cement is often added, apparently to offset the longer initial set time that may otherwise result. For example, based on the mix designs used by Athena (see table below), their standard 30MPa concrete mix with 9% SCM’s would contain 319 kg of cement and 349 kg of total cementitious material. Therefore, for a mix with no fly ash, one would assume a total cement content of approximately 349 kg or less, and a 35% fly ash mix should contain 227 kg of cement (65% of 349 kg), and a 50% fly ash mix should contain 175 kg of cement (50% of 349 kg).

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Page 33

However, a review of the mix designs obtained by Athena indicates that the actual cement content for this 35% fly ash mix is 250 kg versus 227 kg calculated above and the total cementitious content has increased to 385 from 349. Similarly, for the 50% fly ash mix, the cement content is 200 kg versus the 175kg calculated above, and the total cementitious content has increased to 400 kg from 349 kg. In the last column in the table below, we have indicated the actual percentage of cement reduction compared to the assumed base mix of 349 kg of cement. For the 35% fly ash mix, the actual reduction is 29% and for the 50% fly ash mix, the actual reduction is 43%. A significant reduction, but not as high as the 35% and 50% SCM content implies. Concrete Strength

Mix Design

FA Kg/m3

Cement Kg/m3

Total Kg/m3

30 MPa

9% FA

31

319

349

* % of Cement Reduction 9

30 MPa

35% FA

135

250

385

29

30 MPa

50% FA

200

200

400

43

* Compared to an assumed base of 349 kg

Therefore high percent SCM mixes can be somewhat misleading as to the assumed “displacement” of Portland cement in the concrete mix. Though some mix designs do replace cement with SCM’s on a 1:1 basis, others may not. The actual mix design needs to be reviewed in order to determine the actual cement content of a particular mix. Cement Contents for Scheme Review For comparative purposes, we have compared the total amount of cement used in each scheme to the base scheme of concrete mixes used in the 9% fly ash cast-inplace flat plate scheme.

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Page 34

Total Cement

Base 9% FA Flat Plate Hybrid Concrete Scheme Lift Slab Scheme

Ratio

Total Concrete Volume

2300 m3

Total Cement as Percentage of Total Concrete Content 13.7%

734 tonnes

1.0

586 tonnes 289 Tonnes

Global Warming

1007 tonnes

0.80

2465 m3

10.3%

987 tonnes

0.39

1447 m3

8.6%

1096 tonnes

Therefore, it appears that both alternative systems studied in this report significantly do reduce the amount of cement used in the hypothetical building. The Hybrid Concrete Scheme reduces the amount of cement even though the total quantity of concrete has increased. The large reduction in cement use for the lift slab is due to both a reduction in cement per cubic metre and a reduction in the total volume of concrete.

However, the global warming reflects the entire

building system and, therefore, does not directly correspond to the total cement tonnage.

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Page 35

8.0

SUMMARY OF FINDINGS

8.1

Construction Cost Comparison Based on our cost estimates of the Lift Slab system and the Hybrid Precast Concrete system compared with the 9% Fly Ash concrete flat plate base system from the Yolles study the following comparative study can be made. Construction Cost

8.2

Schedule Cost Premium

Base System

$1,703,774

0

Curtain Wall Cost Premium 0

Total Cost

Ratio

$1,703,774

1.0

Hybrid PC System Lift Slab System

$1,876,366

-$70,000

+$7,854

$1,814,220

1.06

$1,716,048

+$445,500

-$3,927

$2,157,621

1.26

Construction Schedule Comparison Based on an estimated construction schedule of the Lift Slab System and the Hybrid Precast Concrete System compared with the 9% Fly Ash concrete flat plate base system from the Yolles study the following comparative study can be made: Estimated Construction Schedule •

Base System

-

22 Weeks (5 working days per week)

•

Hybrid PC System

-

21 Weeks ( “

“

“

•

Lift Slab System

-

28 Weeks ( “

“

“ )

)

High-Rise Design Study – Stage 2 EcoSmart Concrete Project RJC# : 38647.02 February 6, 2004

8.3

Page 36

Environmental Performance Comparison

Primary Energy

Global Warming Ratio 0.87

Total Concrete Volume m3 Ratio 2300 1.0

1. Flat Plate 50% FA

(Gj) Ratio Tonne 12,896 0.93 879

2. Flat Plate 35%FA

13,332

0.96

932

0.92

2300

1.0

3. Flat Plate 9% FA *

13,868

1.00

1007

1.00

2300

1.0

4. Hybrid Precast Concrete

13,947

1.005

987

0.98

2465

1.07

5. Lift Slab Concrete

16,770

1.21

1096

1.09

1447

0.63

6.Structural Steel and Metal Deck

22,656

1.63

1391

1.38

1482

0.64

* Base System For Comparison

8.4

Cement Usage Comparison Total Cement Base 9% FA Flat Plate Hybrid Concrete Scheme Lift Slab Scheme

Ratio

Total Concrete Volume

734 tonnes

1.0

2300 m3

Percentage of total Concrete Content 13.7%

Global Warming

586 tonnes

0.80

2465 m3

10.3%

987 tonnes

289 Tonnes

0.39

1447 m3

8.6%

1096 tonnes

1007 tonnes

APPENDIX A LIFT SLAB FLOOR PLATE AND CONSTRUCTIVE SEQUENCE

LIFTSLAB CONSTRUCTION SCHEDULE ECOSMART CONCRETE HIGH RISE STUDY ID 1

Task Name

Duration

Start

Finish

Mobilization

0 days

Mon 1/5/04

Mon 1/5/04

2

Excavation

0 days

Mon 1/5/04

Mon 1/5/04

3

Foundation

0 days

Mon 1/5/04

Mon 1/5/04

4

Parking Garage

0 days

Mon 1/5/04

Mon 1/5/04

5

Plaza Slab

0 days

Mon 1/5/04

Mon 1/5/04

Dec 2 Jan 4 Jan 1 Jan 1 Jan 2 Feb 1 Feb 8 Feb 1 Feb 2 Feb 2 Mar 7 Mar 1 Mar 2 Mar 2 Apr 4 Apr 11 Apr 1 Apr 25 May 2 May 9 May 1 May 2 May 3 Jun 6 Jun 1 Jun 2 Jun 2 Jul 4 12/28 1/4 1/11 1/18 1/25 2/1 2/8 2/15 2/22 2/29 3/7 3/14 3/21 3/28 4/4 4/11 4/18 4/25 5/2 5/9 5/16 5/23 5/30 6/6 6/13 6/20 6/27 7/4

6 7

PLACING OF 22 CONCRETE SLABS

45 days

Mon 1/5/04

Fri 3/5/04

8

Set of 1st Set of Steel Col + 1st floor

3 days

Mon 1/5/04

Wed 1/7/04

9

Placing of remaining 21 floor slabs

42 days

Thu 1/8/04

Fri 3/5/04

Post Tensioning

35 days

Mon 1/19/04

Fri 3/5/04

10 11 12 13

55 days

Mon 3/8/04

Fri 5/21/04

14

LIFTING OF 22 FLOOR SLABS 1. LIFTING STAGE

10 days

Mon 3/8/04

Fri 3/19/04

15

2.Lifting Stage -10.Lifting Stage

40 days

Mon 3/22/04

Fri 5/14/04

16

3.Bracing +Stair

45 days

Mon 3/22/04

Fri 5/21/04

17

Construction of Curtain Wall

84 days

Mon 3/22/04

Thu 7/15/04

18

Drywall

85 days

Mon 3/22/04

Fri 7/16/04

Project: LIFT SLAB SCHEDULE Date: Thu 1/15/04

Task

Milestone

Rolled Up Task

Rolled Up Progress

External Tasks

Progress

Summary

Rolled Up Milestone

Split

Project Summary

Page 1

Group By Summary

Jul 11 Jul 18 7/11 7/18

APPENDIX B HYBRID CONCRETE SLAB FLOOR PLATE AND DETAILS

HYBRID PRECAST CONCRETE CONSTRUCTION SCHEDULE ECOSMART CONCRETE HIGH RISE STUDY ID 1

Task Name

2

Mobilization

0 days

Mon 1/5/04

Mon 1/5/04

3

Excavation

0 days

Mon 1/5/04

Mon 1/5/04

4

Foundation

0 days

Mon 1/5/04

Mon 1/5/04

5

Parking Garage

0 days

Mon 1/5/04

Mon 1/5/04

Plaza Slab

0 days

Mon 1/5/04

Mon 1/5/04

88 days

Mon 1/5/04

Wed 5/5/04

6

Duration

Start

Finish

Dec 28 12/28

Jan 4 1/4

Jan 11 1/11

Jan 18 1/18

Jan 25 1/25

Feb 1 2/1

Feb 8 2/8

Feb 15 2/15

Feb 22 2/22

Feb 29 2/29

Mar 7 3/7

Mar 14 3/14

Mar 21 3/21

Mar 28 3/28

Apr 4 4/4

Apr 11 4/11

Apr 18 4/18

Apr 25 4/25

May 2 5/2

May 9 5/9

7 8

ERECTION OF BUILDING

9

1st Floor to 5th

20 days

Mon 1/5/04

Fri 1/30/04

10

6th Floor to 10th

20 days

Mon 2/2/04

Fri 2/27/04

11

11th Floor to 15th

20 days

Mon 3/1/04

Fri 3/26/04

12

16th Floor to 20th

20 days

Mon 3/29/04

Fri 4/23/04

13

21st to Roof

8 days

Mon 4/26/04

Wed 5/5/04

14 15

Construction of Curtain Wall

84 days

Mon 2/2/04

Thu 5/27/04

16

Construction of Drywall

85 days

Mon 2/2/04

Fri 5/28/04

Project: Hybrid Precast SCHEDULE Date: Thu 1/15/04

Task

Milestone

Rolled Up Task

Rolled Up Progress

External Tasks

Progress

Summary

Rolled Up Milestone

Split

Project Summary

Page 1

Group By Summary

May 16 5/16

May 23 5/23

May 30 5/30

APPENDIX E YOLLES CAST-IN-PLACE FLAT PLATE BASE SYSTEM

Scheme A Flat Plate - Material Construction Cost Agreed dimensions Floor area = Floor perimeter = Core wall perimeter = Core wall openings = Varied dimension Floor to Floor =

345 m2 85m 33m 11 m2 2.575m

Element

Sub-element

Material

Dimensions

Foundations

Concrete Reinforcement Formwork

50% Fly Ash (30MPa)

Concrete Reinforcement Formwork

Sub-Total Core walls

Sub-Total Columns

Sub-Total Floor system

Total

Volume (m 3) Tonnage (tonne) Area (m 2)

Quantities/ Floor 257 10.5 175

Unit Cost

Cost/ Total cost Floor $35,209 $35,209 $13,650 $13,650 $14,175 $14,175 $63,034 $3,644 $80,145 $2,600 $57,200 $11,837 $260,414 $397,759 $808 $17,783 $949 $20,878 $9,612 $211,464 $250,125 $8,275 $182,046

257 10.5 175

$137 $1,300 $81

50% Fly Ash (30MPa)

Volume (m 3) Tonnage (tonne) Area (m2)

26.6 2 66.5

585 44 1463

$137 $1,300 $178

Concrete Reinforcement Formwork

50% Fly Ash (30MPa)

Volume (m 3) Tonnage (tonne) Area (m 2)

5.9 0.73 54

129.8 16.06 1188

$137 $1,300 $178

Concrete

Normal concrete (30 MPa) (Concrete with 35% or 50% Fly Ash similar)

Volume (m 3)

60.4

1328.8

$137

Reinforcement Formwork

Tonnage (tonne) Area (m 2)

4.2 345

92.4 7590

$1,300 $91

$5,460 $31,395

$120,120 $690,690 $992,856 $1,703,773

Total area Percentage viewable glazing Percentage spandrel panel Percentage opaque glazing With insulated back pan

Perimeter x Height (m 2) Percentage 40% Percentage 40% Percentage 20% Yes

219

4818

$420

$91,980

$2,023,560

Sub-Total Total Cladding

Total

Prepared by Yolles Partnership Inc. as part of Stage 2 High Rise Early Design Study

$3,727,333