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7/27/2019 FVN Presentation2 Eng
http://slidepdf.com/reader/full/fvn-presentation2-eng 1/18
RECOMMENDATION FOR COST EFFECTIVE PT SOLUTION& ENSURE QUALITY OF PT WORK.
U-SILK CITY, HANOIKeangNam landmark, HANOICity Garden, HCM
7/27/2019 FVN Presentation2 Eng
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CONTENTS :
Economic advantages
Ensure quality & durability of project
Recommendation & Action of Freyssinet
Discussion & Experience exchange for better control quality of PT slabin Vietnam
POSTENSIONED (PT) SLAB
7/27/2019 FVN Presentation2 Eng
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PT SLAB SYSTEM
SCOPE OF APPLICATION
8m 9m 10m7m 11m6m
PT
RC
Cost
RC: Reinforced Concrete Slab
PT: Postensioned Slab
Span
ECONOMY
Cost Comparison Exponential saving for spans > 7.3m
7/27/2019 FVN Presentation2 Eng
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Reduce height of storey
3.1m instead of 3.3 or 3.5m
Reduce concrete, rebar quantity
for column, RC wall, partition
wall, finishing.
Reduce foundation’s materialdue to less gravity loading, less
lateral load : wind, seism
Flat slab give aesthetics, moreflexibility of space dividing.
Reduce M&E fee
Save energy
PT SLAB SYSTEM
TECHNICAL & ECONOMIC ADVANTAGES :
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Formwork, rebar : simple toinstall
Faster to build
Cheaper
PT SLAB SYSTEM
TECHNICAL & ECONOMIC ADVANTAGES :
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In term of law, we haven’t considered it as conditioned business yet like for
example : construction of basement and underground work.
In term of contractor’s capacity : because PT slab is just recently popular in
Vietnam, so there are only few professional contractors who can guarantee quality
and sustainability of PT slab.
Regarding design & build’s capacity : there is no certificate of sufficient design &build’s capacity as in other developed countries
Regarding design code : there is no Vietnamese code for PT design, we normally
use foreign code : AS, ACI, BS, EC2
There is no certified anchorage system. Any anchorage proposed by contractor can
be used so price decide the choice of contractor.
Quality control depend totally to PT contractors
HOW WE ARE CONTROLING QUALITY OF PT SLAB ?
PT SLAB SYSTEM
Status of use in Vietnam :
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-Thi Nai Bridge(Binh Dinh province)inaugurated in 2006.
On 19-Nov-2011, 04 tendons were broken, so
they must limit weight of truck less than 15
tons during reparation
REASON : Quality control is no good:
contractor buy material, install tendon
without strictly surveillance
PT SLAB SYSTEM
Situation in Vietnam :
EXPERIENCE OF BRIDGE IN VIETNAM (Applied post tensioned more than 20 years)
-Rao bridge in Haiphong collapsed in 1988 due to tendon break.
- Project of rebuild of 148 weak bridges along National Road 1A (with funding from
JICA) among which there are many bridges built less than 20 years. One important
reason is the corrosion of tendon.
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Experiences in the past In 70 - 80s of last century, there are problems in many bridges due to corrosion of
tendons. Even Ministry of transportation in England prohibited the use of PT
structures in 1992. the ban only be removed in 1996 after serious investigation/
study in all aspect to have preventive measure such as revising of design code,execution criteria, certified PT systems and PT contractor...
Requirement to control quality
& durability of project
Reports of FIB (International
Federation for Structural Concrete)
over view of global situation, thecase of Germany, United State,
France, England, Japan, Canada
PT SLAB SYSTEM
Durability problem
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What does leading Organizations of postensioned structure do for durable of PT
structural( EOTA,FIB,PTI).
Review all aspect from :
Design : multi protective layers (Design code)
Materials :
9 Tensile element (strand,wire...by material code)
9 Anchorage system & accessories ( The system must be pre- certified) Execution ( Specification/Method statement)
9 Packing, Transportation, Storage, handling
9 Equipment, Installation, Stressing
9 Grouting
Personnel, workers for PT work must have certificate
PT SLAB SYSTEM
Durability problem
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Recommendation & Action of Freyssinet
PT SLAB SYSTEM
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Point of view
Pt-tendons are structural elements decisive for the functioning of pt-structures
It need strict quality control of design, material & personnel.
It should be executed by specialist contractor
PT SLAB SYSTEM
Recommendation & Action of Freyssinet
7/27/2019 FVN Presentation2 Eng
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Authority Management
Should consider PT structure is conditional business which require capacity,
experience :
9 Design capacity
9 Specialist equipments, machines, personnel
9 Professional liability insurance
9Anchorage system is recommended by international organizations of PT structure(such as PTI, FIP, EOTA) or approved by similar tests.
PT SLAB SYSTEM
Recommendation & Action of Freyssinet
7/27/2019 FVN Presentation2 Eng
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Design code:
Should have Vietnamese design code for PT structure.
It should use foreign code and revise. We propose to use Eurocode (similar to using
AASHTO and transform to Vietnamese standard for infrastructure design)
PT SLAB SYSTEM
Recommendation & Action of Freyssinet
7/27/2019 FVN Presentation2 Eng
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Material criteria:
Tendon is conformed to ASTM A416, BS5896
Anchorage system: It should be certified and
tested system not only separated items as we are
doing
We recommend to use ETAG 013 which guide
detail and require strictly quality.
PT SLAB SYSTEM
Recommendation & Action of Freyssinet
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Source: Post-Tensioning Institute of Australia (PTIA) http://www.ptia.org.au
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Annually organize seminar about design & build PT structure with design consultant,
contractor, client to improve PT technique knowledge
Continue convincing people to consider PT slab is special item which need specialist
contractor.
Convince client to choose Design & Build contractor for PT slab
Share experience about longterm durability of PT structure.
We can support technical specification which show detail of work and requirement to
control durability of project
PT SLAB SYSTEM
Action of Freyssinet
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LET’S SHARE YOUR IDEA TO CONTROL BETTER QUALITY OF POSTENSIONEDSTRUCTURE
THANK YOU!