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EFCOG Best Practice #64
(12/17/08)
PDF
Version
Title:
Rebar and Dowel Placement
Facility:
Los Alamos National Laboratory, West Valley Demonstration
Project
Point of Contact:
Tim J. McEvoy, 505-667-8172,
mcevoytj@lanl.gov; or Bob Carter, 509-377-3220,
bob.carter@wch-rcc.com
Brief Description of Best Practice:
Successful efforts to prevent reoccurrence
include: engineered checklists, training and in-place
evaluation. Implementation for each of the three phases is
described below:
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Procurement/Storage
-
Checklists are utilized to verify
procurement requests prior to purchase. Targeted
mistakes include proper size, proper grade,
validated fabrication drawings, epoxy coating
requirement.
-
Training and clearly written
inspection acceptance criteria are provided to
inspection personnel for proper receipt inspection
and handling and storage of rebar. Targeted mistakes
include commingling of safety significant/safety
class and commercial grade, improper material,
excessive rust and improper use of dunnage.
-
Rebar Placement
-
Work Plan development utilizes a
validation process for technical specifications and
shop drawing generation.
-
Shop drawing development and
constructability reviews.
-
Pre-Activity training for all craft
and supervision focuses on requirements and
inspection acceptance criteria.
-
Routine inspections utilizing
tailored checklist ensure early detection of
improper practices. Targeted mistakes include
inadequate concrete coverage, improper lap/splice
length and inadequate tie percentage.
-
Self-mandated hold points prior to
commencement of the pour ensures that formwork,
rebar placement and inserts are dimensionally
correct.
-
Insert / Dowel Placement
-
All shop drawings or transfer of
dimensions requires a two-party verification of
dimensions.
-
Likewise, actual placement is
verified and documented as a part of the pre-pour
checklist.
Why the best practice was used:
Improper rebar, dowel and insert placement
results in increased production cost due to
rework/remediation efforts and potential schedule impact.
Errors have been categorized into three phases:
procurement/storage, rebar placement, and insert/dowel
placement.
What are the benefits of the best practice:
To reduce cost or schedule overruns due to
unacceptable products getting through receipt inspections,
improper coverage, lap splicing, spacing, or dowel and
insert placement.
What problems/issues were associated with the
best practice:
Discovering these type issues to late in the
process to prevent rework.
How the
success of the Best Practice was measured:
Less work delays, fewer nonconforming
conditions generated due to improper or unknown material
issues or placement and spacing requirements. Changes in
clearly defining the acceptance criteria and work planning
documents increase field placement and final inspection
processes.
Description of process experience using the
Best Practice:
Increased confidence in material received and
used during construction. Raised awareness of where in the
construction to address potential problems that could cause
delays due to rework to achieve final inspection and
approval to poor concrete. Customer satisfaction that the
finished product will function as required. |
