ITEM 523 DYNAMIC LOAD TEST
523.01
Description
523.02 General
523.03
Equipment
523.04 Test
Report
523.05 Basis of
Payment
523.01 Description. This work consists of
establishing a driving criteria for all the piles of a specified shape,
cross-section, and ultimate bearing capacity or as specified on the plans to be
installed in the structure. This shall be accomplished by applying
dynamic loads with a pile hammer during driving of production piles to
determine driving requirements. Apply the dynamic load to the piles using
a pile hammer that is operating at its normal operating level. Perform
restrike tests when specified in the plans.
523.02 General. Perform dynamic tests on a
minimum of two piles. Perform signal matching analysis of the dynamic test data
on at least one of the two test piles. Perform the test according to ASTM D 4945 to determine
driving requirements to achieve the required ultimate bearing values for the
piles to be installed in the structure.
Perform
restrike tests after piles have been driven and a minimum time specified in the
plans has elapsed. When performing a restrike, warm the hammer before restriking the pile by applying at least 20 blows to
another pile. Each restrike consists of performing dynamic testing on two piles
and performing a signal matching analysis on one of the two piles tested.
Use
the hammer selected for driving the test piles to drive all piles represented
by the test piles. If the Contractor subsequently finds it necessary to
use a different hammer or multiple hammers to drive piles represented by
dynamic load testing, or if the hammer performance varies subsequent to the
dynamic test, complete additional tests at no additional cost to the
Department.
523.03 Equipment. Supply all required dynamic
testing equipment necessary to run the test set forth in ASTM D 4945. Supply
personnel with an Advanced Master, or Expert Level Certification in High Strain
Dynamic Pile Testing (HSDPT) from either Foundation QA
or the Pile Driving Contractors
Association (PDCA) to operate this
equipment. Supply the Engineer a copy of the certificate showing that
personnel operating dynamic testing equipment are currently certified. Supply
all personnel and equipment needed to strike the test piles with the pile
hammer.
523.04 Test Report. Perform the dynamic
test and signal matching analysis and immediately provide the Engineer driving
criteria for any piles to be driven within the next 48 hours. Within 48 hours
after performing the dynamic pile test or restrike tests, supply the Engineer
with a written report confirming driving requirements for piles represented by
the test. Include in the report, the required blow count for:
A. The different strokes of the ram at
6-inch (150 mm) intervals within the expected range of operation as determined
by a wave equation analysis, when open ended diesel hammers and drop hammers
are used.
B. The selected bounce pressures when
closed end diesel hammers are used.
C. The operating air pressure and stroke
when an air operated hammer is used.
D. The selected output energy or stroke
when a hydraulic hammer is used.
Also
include in the report a minimum depth of penetration if applicable.
Submit
an electronic version of the report and data files from the testing and
analysis to the Office
of Structural Engineering.
523.05 Basis of Payment. The
Department will pay for dynamic load testing after being provided the written
test at the contract price as follows:
Item
Unit
Description
523
Each
Dynamic Load Testing
523
Each
Restrike