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STRUCTURES TEAM
April 4, 2002 Mid-Atlantic States PCEF Meeting Minutes
Approval of Minutes from October 31, 2002 Meeting in Manassas, VA
Minutes from October 31, 2001 meeting approved.
A) Subcommittee Status Reports by Chairmen
1. Production/Construction (P/C)
Group was advised that a Chairman for the Production/Construction
Subcommittee was needed.
Former Chairman developed a ballot on acceptable cracking in
prestressed concrete members. PCI is developing a Manual for repair of
prestressed concrete members. Five sections have been developed that include
identifying defects and how to repair a defect. The Manual should be available
within a year. Ed Wasserman of the Tennessee DOT is chairing the effort to
produce the Manual. PCI should make the Manual available for review before its
publication. Acceptable cracking in prestressed concrete members should be
included therein. The New England PCI group is also working toward the same
goal.
The PCEF subcommittee was also addressing other issues that
included: allowable strand sizes, use of draped or debonded strands, practices
on development lengths, concrete properties, ultimate and de-tensioning values,
minimum release hours, and maximum w/c ratio. Also, corrosion protection efforts
(additives, reinforcement, clearances), inspection level of State inspectors,
use of Consultants to conduct plant & on-site inspections, inspection
reciprocity by States, inspection certifications, handling, storing and erecting
members. Other possible issues included use of self consolidated concrete, beam
sweep, use of SIP forms, tolerances and inspection guidelines.
To date, no results of the Subcommittee's work are available.
After the entire PCEF group evaluated the Subcommittee's efforts toward
prioritizing issues, it was decided to eliminate the strand size criteria study
and that tolerances were part of the QA/QC subcommittee's work. Inspection
criteria study will remain as part of the P/C subcommittee's work, along with
handling, storage and erection issues. Since transportation issues are
controlled by States' permitting regulations, it was decided to also delete
those aspects from being part of the Subcommittee's work.
2. Materials & QC/QA
Draft 4 of the Specification Guidelines for Precast/Prestressed
Concrete Bridge Products had been distributed and discussed during the Manassas,
VA meeting. Sections 4.4 to 4.7 have been added into the Draft version,
including PCI requirements where appropriate. Committee members were asked to
review the Draft 5 distributed on this date, and to submit any comments to the
co-chairmen before the next Subcommittee meeting, which will be held at the end
of May. QA/QC issues will be addressed as a separate effort.
Sections 4.4 to 4.7 include criteria on forming, finishing,
stripping, handling and storage. A discussion as to use of corrosion inhibitors
in grout mixes developed. This is especially true when dealing with post
tensioning and filling ducts with grout. There should be awareness when dealing
with grout mix specifications. It was suggested that grout mix criteria should
be a part of the guidelines.
An updated ballot taking into account the new sections 4.4 to 4.7,
and any pertinent discussions at the subcommittee's May meeting, will be
distributed to appropriate State DOT personnel for formal voting later this
summer.
Status Report by Each State DOT on Implementation of High Performance
Concrete (HPC) and PCEF
MDSHA - no action yet on use of PCEF Bulb T; however, will
continue to investigate appropriate project with the State Bridge Engineer..
Studying a completed construction project, an HPC deck slab and use of a 7000
HPC psi mix for fabrication of AASHTO Type 4 girders.
DELDOT - no action on use of PCEF Bulb T; have one deck project
under design that will utilize HPC.
NYSDOT - use the New England Bulb T shape; will allow use of the
PCEF Bulb T as an alternate or re-design by the Contractor. 5 bridges built last
year with HPC - 8 bridge projects underway - have ongoing effort to pre-approve
HPC mix designs.
VDOT - have several projects in design using PCEF Bulb T. Some
aspects of HPC have been used. Bayshore Concrete Products still needs forms, and
is pushing for narrower width bottom flange.
PennDOT - allowing Producers to use PCEF Bulb T, but no response
yet from Industry. HPC - have used up to an 8000 psi prestressed concrete HPC
mix design. 2 HPC decks built that resulted in extensive cracking.
WVDOT - no action on use of PCEF Bulb T. HPC being studied - have
formed task group to study the use of HPC and PCEF bulb-T.
NJ DOT - have included, in its Design Manual, guidance on the
availability of the PCEF Bulb T shape. 6 to 8 projects underway on use of HPC
for deck slabs. HPC will be primary deck slab type. Question was raised on the
Abrasion testing specification that is stated in the FHWA HPC guidelines. ASTM
C944, specified in FHWA guidelines, is not a test method performed by most labs.
Suggested that ASTM C779 should be adopted as labs can more readily perform the
ASTM C779 test. NJIT is researching deck cracking for the DOT.
FLDOT - looking at major projects to make form acquisition
worthwhile.
NCDOT - looking at deck cracking. Now use 54" and 72" PCI bulb-Ts.
Have built 2 HPC decks with AASHTO Type V girders.
The issue of deck cracking is still receiving much attention. In
addition to references from the States at this meeting, a national pooled fund
study is being solicited, with the KSDOT taking the lead. Purpose of the effort
will be to implement the most cost-effective techniques for improving bridge
deck life through reducing cracking. Contact Dick McReynolds at KSDOT
(785-291-3841, or dick@ksdot.org). A 1996
NCHRP Study #380, "Transverse Cracking in Newly Constructed Bridge Decks"
produced many findings on causes. This current study will followup.
Self-Consolidated Concrete (SCC) - Presentation by Dr. Celik Ozyildirim,
VDOT
Mr. Rod Meyers of Masterbuilders gave a general presentation on
SCC, as Dr. Ozyildirim was unable to attend. (Hard copy attached)
Also, a specific example of Virginia DOT's use of SCC was
presented by Mr. Paul Ramsburg of Oldcastle Precast. Findings and results were
as follows:
- No deviations in slump test results were noted between using the slump
cone upright and using it in the inverted position
- W/c < 0.40 should be easily attained
- Do a cost comparison before using modified fine aggregate instead of a
viscosity modifying agent
- Good permeability results with SCC
- No difference in freeze-thaw durability characteristics
- Cores showed no segregation of the SCC mix
Producer benefits included: reduced cleanup efforts; faster
placements; vibrator noise eliminated; and 8 man-hours per day were eliminated.
Producer concerns included: need for training; need to maintain member
tolerances; moisture contents of concrete and aggregates need to be monitored
closely; and need to apply form release agent properly (excess form oil creates
bug holes).
Costs: Leaner mix was only $1.45/cy more than conventional
concrete mix, and $1.78/cy greater than normal concrete mix for Bebo arches. A
$4-$5 increase is seen in precast concrete prices.
NJDOT suggested that future discussions of SCC should address DOT
owners' experiences and benefits gained. States need to know that they are
getting equal or better quality at equal cost. Also, SCC looks promising for
design/build projects and for buildings.
PADOT has had positive experiences so far with initial testing of
the effects of long-term creep using SCC. MDSHA noted that control of mixing
water is critical for SCC. They and VDOT are developing specifications for SCC.
VDOT has submitted an SCC project to the FHWA Innovative Bridge Research &
Construction Program. DELDOT noted that placing and curing requirements of SCC
appear to be the same as for conventional concrete, but that drop height issues
need to be addressed. NC noted that there might be application for SCC in
drilled shafts.
D) Subcommittee Status Reports by Chairmen
1. Subcommittee on Standardization
Subcommittee developed details on use of steel diaphragms for
prestressed concrete superstructures. Status of States' use of the standard
drawing was queried. Delaware DOT no use reported - will study use steel
diaphragms. New Jersey has adopted a standard drawing that is based on the
Subcommittee's work. A proposal for the adoption of the Subcommittee's standard
drawing for use of steel intermediate diaphragm for prestressed concrete
superstructures was made. State representatives voted to adopt the PCEF standard
drawing. Representatives also voted to adopt the Subcommittee's standard drawing
for diaphragm layout.
Use of spliced girders, haunched girders and lightweight concrete
will be the next issues to be undertaken by the Subcommittee. A soon-to-be
completed NCHRP study on spliced girders will be evaluated by the group. The
group will also look at standard details for positive moment connections.
2. Subcommittee on Design Parameters (need Chairman)
Due to the lack of a Chairman for this group over the past couple of years,
it was suggested that the Subcommittee be joined with Standardization
Subcommittee.
E) Precast Concrete Elements
It was questioned whether the PCEF wished to address
standardization of precast concrete elements as part of their general efforts.
The committee had previously agreed that it would be a positive move to do so.
There are enough concerns for DOT's to look at, including noise walls, drainage
components, as well as other precast items. QA/QC is one item to look at. Survey
form will be developed to obtain input from States. Issues such as technician
certification would be an item that can be studied. Reciprocity between States
for approval of plants should be studied. Industry's input would be critical.
Delaware DOT and Virginia DOT have limited interest. New York would show
interest dependent on type of structures looked at. New Jersey cautioned
direction of proposed study so that legal implications would be avoided.
F) Other Issues
February 11, 12, 13, 2003 are dates of the next Mid-Atlantic
States Quality Assurance Workshop, at the Holiday Inn in Charleston, WV. We will
tentatively target 2/13/03 as the date of next PCEF meeting in Charlestown, West
Virginia.
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