evolution and sustainability of in-situ concrete flat in office buildings
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XXXVII IAHS WORLD CONGRESS ON HOUSING. Oct-2010TRANSCRIPT
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
Evolution and sustainability of in-situ concrete flat slabs in office buildings
Liébana, O.1; G. Pulido1, MD; Gómez Hermoso J. 2
1University of San Pablo CEU (Madrid) 2University Politécnica de Madrid
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
flat slabs in office buildings in Spain
flat plate: most common floor • Easy of construction•Simpler and quicker construction•Reduces execution timeframe •Increases construction safety
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
flat slabs in office buildings in Spain
flat plate
• Relatively light, less weight• Less foundation costs • Longer spans are economic• Excellent vibration control
waffle slab: very common floor in Spain
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
flat slabs in office buildings in Spain
flat plate
• More efficient• Thinner slabs , lighter structures• Reduction in rebar tonnage• Reduced cracking and deflections• Reduced floor to floor height •….
Post-tensioned flat plate: considerably more expensive in Spainwaffle slab
Why do PT floors compete economically with traditional floor slabs in other countries?........ LOW SPECIALIZATION - SUSTAINABILITY CRITERIA INTROD.
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
LEED rating is deficient, it does not reflect the significant contributions of PT concrete structural efficiency to real sustainability
it does not reward suitably more sustainable solutions aiming at the optimization of materials
CO2 emissions Cement manufacturing process liberates approximately 5% of the total emissions delivered in the atmosphere annually.
Introduction of sustainability criteria in construction may be a necessary evolution.
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
• Office building in Madrid• Module 50x50 meters• Three levels: Parking, Storage (high loads) and Lobby• Mesh of columns with a distance of 8x8 m• Three structural solutions: flat plate, waffle slab and PT flat slab.• Thickness of the slabs and width of the ribs variations • PT: the prestressing is bonded, flat ducts, tendons are formed by 4 or 3 strands of 0.62”, grouped in a single flat duct (70x20mm)
• The minimum thickness: EHE-08, EC-2 and ACI318-08 criteria• The minimum bonded reinforcement for crack control • Steel fiber variation• Measuring emissions from the quantities of materials (ITEC)
Floor building
Study
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
50%
25%
9%
4%4%
3%
% CO2 - PT flat slab 320 mm177.3 kgCO2/m2
cementrebartendonscombust.formworkaggregates ductwatergrouting
Measuring emissions from the quantities of materials
Tons of CO2 depending on use and type of slab
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
Waffle Slab
Flat slab
PT Flat slab
Waffle Slab
Flat slab
PT Flat slab
Waffle Slab
Flat slab
PT Flat slab
0
100
200
300
400
500
600
700
FormworkPTRebarConcrete
BASEMENT (high loads) PUBLIC FLOOR UNDERGRONUD PARKING
Ton
CO
2
Tons of CO2. Solid flat plates (Basement-high loads)
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
450 FLAT SLAB 420 FLAT SLAB 320 PT FLAT SLAB0
100
200
300
400
500
600
700
FormworkGroutingDuctTendonsRebarConcrete
Ton
CO
2
% of CO2 of flat slabs (Basement-high loads)
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
WS 40+10/200 420 FLAT SLAB 320 PT FLAT SLAB0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
FormworkGroutingDuctTendonsRebarConcrete
Flat slabs
% T
on C
O2
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINABILITY STUDY RESULTS CONCLUSIONS
1. Selection criteria
At present: design known solutions ….. No evolution of specialized techniquesNecessary: Project specialization and execution …Sustainable evolution in current
construction practice
2. EHE-08 code – Building PT slabs
At present: innovative code with respect to special concrete issues or durabilityNecessary: Sections specifically related to PT slabs should be revised urgently
3. Sustainability in the study
PT solution is always the most sustainable option, particularly for high loadingThe difference is not so important in voided options with moderate loading.Small changes in thickness, in width of the joist or in the topping slab do not significantly improve CO2 emission data.Replacement of rebar for steel fibers does not involve a decrease in emissions
REFERENCES
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINABILITY STUDY RESULTS CONCLUSIONS
1. USGBC. U. S. Green Building Council. Green Building Design and Construction Reference Guide
2. POST-TENSIONING INSTITUTE. PTI. PT-Gray is the new Green. PTI Journal. 41. Sustainability and Post-Tensioned Concrete. August 2009. V.7. nº1. 2009.
3. EHE-08. Instrucción de Hormigón Estructural. Comisión Permanente del Hormigón. 1º edición revisada. Ministerio de Fomento. Madrid. 2008
4. Isaia, G.C. and Gastaldini, A.L, G. Concrete sustainability with very high amount of fly ash and slag. Ibracon Structures and materials
5. EC-2. Eurocode 2: Design of concrete structures- Part 1:General rules and rules for buildings.
6. Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary. An ACI Standard. Reported by ACI Committee 318. Structural Building Code. American Concrete Institute. USA.2008
7. CONCRETE SOCIETY. CS. Post-tensioned concrete floors. Design Handbook. Concrete Society Technical Report nº43. 2ªed. UK. 2005
8. POST-TENSIONING INSTITUTE. PTI. Post-Tensioning Manual. 6th Edition. 9. ATEP. Recomendaciones para el proyecto y construcción de losas
postesadas con tendones no adherentes HP9.96. Manuales de la ATEP. 10. Institut de Tecnologia de la Construcció de Catalunya. ITEC. Banco estructurado
de elementos constructivos BEDEC.
XXXVII IAHS WORLD CONGRESS ON HOUSING. Santander (Spain). 26-29 October 2010II. DESIGN FOR SUSTAINABILITY AND REFURBISHMENT. Criteria of design
Evolution and sustainability of in-situ concrete flat slabs in office buildingsINTRODUCTION SUSTAINIBILITY STUDY RESULTS CONCLUSIONS
Evolution and sustainability of in-situ concrete flat slabs in office buildings
Liébana, O.1; G. Pulido1, MD; Gómez Hermoso J. 2
1University of San Pablo CEU (Madrid) 2University Politécnica de Madrid