Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Deep Foundations (Piles and Drilled Piers)
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## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## Where the locally adopted building code differs from a referenced industry standard, the building code as adopted by the Authority Having Jurisdiction shall govern. {note}
+## Where the locally adopted building code differs from a referenced industry standard, the building code as adopted by the Authority Having Jurisdiction shall govern.
| Standard | Title |
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- Helical piles suit lighter loads, fast installation, and immediate loading, with installation torque used as a real-time capacity indicator.
+## The deep foundation system type shall be specified as shown on the Contract Documents, selected based on the load transfer mechanism given in the geotechnical report.
+
```datasheet
label: Deep foundation system type
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```
+## The load transfer mechanism (end bearing, skin friction, or combined) shall be as determined by the geotechnical report and shall govern the required tip elevation and embedment depth.
+
```datasheet
label: Primary load transfer mechanism
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```
−## The load transfer mechanism (end bearing, skin friction, or combined) shall be as determined by the geotechnical report and shall govern the required tip elevation and embedment depth.
−
# Design Loads and Capacity {toc}
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## The required minimum penetration into the bearing stratum for each element shall be shown on the Contract Documents.
−## Tip elevation fixes where the element must reach; minimum penetration fixes how far it must embed into competent material. An element that reaches the nominal tip elevation but has not penetrated the bearing stratum (for example, stopping on a boulder or a lens of dense fill) has not achieved capacity and shall not be accepted. {note}
+## Tip elevation fixes where the element must reach; minimum penetration fixes how far it must embed into competent material. An element that reaches the nominal tip elevation but has not penetrated the bearing stratum (for example, stopping on a boulder or a lens of dense fill) has not achieved capacity and shall not be accepted.
## An element that achieves design resistance above the specified tip elevation shall not be accepted as final without the written approval of the Engineer of Record, because premature refusal may indicate an obstruction rather than the bearing stratum.
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## Drilled shafts shall be constructed to the diameter, tip elevation, and rock socket (where shown) on the Contract Documents [[drawing: shaft schedule]].
−## Belled (underreamed) shafts shall be constructed only in cohesive soils capable of standing during belling, with the bell diameter and geometry shown on the Contract Documents.
−
−## A belled shaft enlarges the base to increase end bearing in stiff clay; bells are not used in sands, in caving soils, or in rock. The bell diameter is commonly limited to about three times the shaft diameter. {note}
−
```datasheet
label: Drilled shaft diameter
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```
+## Belled (underreamed) shafts shall be constructed only in cohesive soils capable of standing during belling, with the bell diameter and geometry shown on the Contract Documents.
+
```datasheet
label: Shaft base type
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```
+## A belled shaft enlarges the base to increase end bearing in stiff clay; bells are not used in sands, in caving soils, or in rock. The bell diameter is commonly limited to about three times the shaft diameter. {note}
+
## Hole Stabilization {toc}
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### Temporary or permanent steel casing shall be provided wherever the bore passes through caving soils, soft near-surface zones, or where groundwater is above the bearing stratum.
−### Failure to specify casing in caving sands or high groundwater leads contractors to assume open-hole drilling, which can cause the shaft to collapse and contaminate the concrete; casing requirements shall be explicit in the Contract Documents. {note}
+### Failure to specify casing in caving sands or high groundwater leads contractors to assume open-hole drilling, which can cause the shaft to collapse and contaminate the concrete; casing requirements shall be explicit in the Contract Documents.
### Where slurry is used to stabilize the bore, the slurry type (mineral/bentonite, polymer, or water) and its control properties shall be submitted and maintained throughout drilling and concrete placement.
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### Concrete placed by tremie or pump shall be a self-consolidating or high-slump-flow mix proportioned to flow through and around the reinforcing cage without vibration and without segregation.
−### Specifying only a slump for drilled shaft concrete, rather than a slump flow and a placement-specific mix design, produces stiff mixes that bridge across the cage and leave honeycombing and voids; the mix shall be specified for the actual placement method. {note}
+### Specifying only a slump for drilled shaft concrete, rather than a slump flow and a placement-specific mix design, produces stiff mixes that bridge across the cage and leave honeycombing and voids; the mix shall be specified for the actual placement method.
### Concrete shall be placed continuously and shall be raised at a rate that keeps the tremie or pump line embedded in fresh concrete at all times, so that no soil, water, or slurry is trapped within the shaft.
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## Each CFA pile shall be monitored with an automated recording system logging depth, grout pressure, grout volume, and auger rotation and withdrawal rate versus depth.
−## A grout-volume ratio (placed volume divided by theoretical volume) below the specified minimum at any depth indicates necking or soil inflow and shall be reported to the Engineer of Record. {note}
+## A grout-volume ratio (placed volume divided by theoretical volume) below the specified minimum at any depth indicates necking or soil inflow and shall be reported to the Engineer of Record.
```datasheet
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## Grout shall be a neat cement grout proportioned to the water-cement ratio and minimum compressive strength shown, and shall be placed to fill the drilled hole from the bottom up.
−## The bond zone is the portion of the micropile that transfers load to the ground; its length and the grouting method (gravity, pressure, or post-grouting) are the primary capacity controls and shall be as shown on the Contract Documents. {note}
+## The bond zone is the portion of the micropile that transfers load to the ground; its length and the grouting method (gravity, pressure, or post-grouting) are the primary capacity controls and shall be as shown on the Contract Documents.
```datasheet
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## The torque-to-capacity correlation factor (Kt) shall be project-verified against a load test, and shall not be taken solely from the manufacturer's generic published value.
−## Using a generic torque-to-capacity factor without a site-specific load-test correlation leads to systematic over- or under-installation; the Kt factor shall be confirmed by the project load test before it is applied to production acceptance. {note}
+## Using a generic torque-to-capacity factor without a site-specific load-test correlation leads to systematic over- or under-installation; the Kt factor shall be confirmed by the project load test before it is applied to production acceptance.
```datasheet
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# Corrosion Protection {toc}
−## Steel deep foundation elements in aggressive soils lose section over the service life; the protection method shall match the soil aggressiveness established by the geotechnical report (resistivity, pH, chlorides, sulfates) and the required service life. {note}
+## Steel deep foundation elements in aggressive soils lose section over the service life; the protection method shall match the soil aggressiveness established by the geotechnical report (resistivity, pH, chlorides, sulfates) and the required service life.
## The corrosion protection method for steel elements shall be as shown on the Contract Documents, based on the soil resistivity, pH, and chloride content reported in the geotechnical report.
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# Splices {toc}
−## Deep foundation elements are spliced where the required length exceeds the mill, plant, or handling length; the splice must transfer the full design force and survive driving where the element is driven. {note}
+## Deep foundation elements are spliced where the required length exceeds the mill, plant, or handling length; the splice must transfer the full design force and survive driving where the element is driven.
## Pile and shaft splices shall be of the type shown on the Contract Documents and shall develop the full design axial, tension, and bending capacity of the spliced section.
## Steel pile field splices shall be full-penetration welded splices or approved mechanical couplers, made by qualified welders to a qualified procedure.
−## Precast concrete pile splices shall be the approved dowel or mechanical splice detailed for the pile section, and shall be cured or set before driving resumes.
−
−## Splice locations shall be staggered between adjacent elements where shown, and shall not be located within the bond or bearing zone, to avoid concentrating splices at a single plane in the group. {note}
−
```datasheet
label: Field splice type (steel elements)
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```
+## Precast concrete pile splices shall be the approved dowel or mechanical splice detailed for the pile section, and shall be cured or set before driving resumes.
+
+## Splice locations shall be staggered between adjacent elements where shown, and shall not be located within the bond or bearing zone, to avoid concentrating splices at a single plane in the group. {note}
+
# Submittals {toc}
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### A wave equation analysis (WEAP) shall be performed for each pile type and hammer combination before production driving, to establish the relationship between blow count, driving stress, and capacity.
−### Driving criteria established without a wave equation analysis or dynamic testing are arbitrary and lead contractors to drive to refusal on obstructions or to under-drive in variable fill; the WEAP analysis shall set the driving criteria. {note}
+### Driving criteria established without a wave equation analysis or dynamic testing are arbitrary and lead contractors to drive to refusal on obstructions or to under-drive in variable fill; the WEAP analysis shall set the driving criteria.
### The Contractor shall record, for each driven pile, the hammer energy, blow count per foot, final set, and any interruptions or splices.
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### The Inspector shall log, for each drilled shaft, the drilled depth, soil/rock conditions, base cleanliness, casing or slurry use, and concrete placement volume versus theoretical volume.
−### A plot of placed concrete volume versus depth shall be maintained for each shaft; an over-volume or under-volume relative to theoretical indicates overbreak or necking and shall be reported to the Engineer of Record. {note}
+### A plot of placed concrete volume versus depth shall be maintained for each shaft; an over-volume or under-volume relative to theoretical indicates overbreak or necking and shall be reported to the Engineer of Record.
### For CFA piles, the automated grout pressure and volume record shall be reviewed against the acceptance criteria immediately after each pile, and any deficient pile shall be flagged before the rig leaves the location.
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### Where driven piles or vibratory installation occur near existing structures, utilities, or sensitive equipment, the Contractor shall monitor ground vibration and shall not exceed the peak particle velocity (PPV) limit shown on the Contract Documents.
−### Driven-pile vibration in built-up areas can damage adjacent buildings and buried utilities; a PPV limit and monitoring requirement protect those assets and are a frequent omission in urban specifications. {note}
−
```datasheet
label: Peak particle velocity (PPV) limit at nearest sensitive receptor
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```
+### Driven-pile vibration in built-up areas can damage adjacent buildings and buried utilities; a PPV limit and monitoring requirement protect those assets and are a frequent omission in urban specifications. {note}
+
# Testing {toc}
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### Crosshole sonic logging (CSL) to ASTM D6760 shall be performed on drilled shafts where shown, to verify concrete integrity between pre-installed access tubes.
−### Where crosshole sonic logging is required, access tubes shall be tied to the reinforcing cage and shown on the structural drawings; if the tubes are omitted, integrity verification reverts to coring, which is far more expensive and disruptive. {note}
+### Where crosshole sonic logging is required, access tubes shall be tied to the reinforcing cage and shown on the structural drawings; if the tubes are omitted, integrity verification reverts to coring, which is far more expensive and disruptive.
### The number of CSL access tubes per shaft shall be as shown on the Contract Documents, based on the shaft diameter.
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## Pile cap and grade beam concrete and reinforcement shall conform to [[sync/cast-in-place-concrete]] and [[sync/concrete-reinforcement]].
−## The connection detail shall account for installation position tolerance, so that an element installed within the specified location tolerance still develops the required load path into the cap. {note}
+## The connection detail shall account for installation position tolerance, so that an element installed within the specified location tolerance still develops the required load path into the cap.
## Installation Tolerances {toc}
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## The Contractor shall warrant that all deep foundation elements are installed in conformance with the Contract Documents and the approved installation work plan, free of defects in materials and workmanship, for the warranty period shown on the Contract Documents.
−## Warranty coverage shall not relieve the Contractor of responsibility for elements that fail acceptance testing or that are shown by the installation record to have been installed outside the approved criteria. {note}
+## Warranty coverage shall not relieve the Contractor of responsibility for elements that fail acceptance testing or that are shown by the installation record to have been installed outside the approved criteria.