Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: Structure Demolition
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## Selective or partial demolition of a structure that is being retained is excluded. {note}
−## Removal of specific walls, ceilings, or MEP systems within a building that remains in service is governed by [[sync/selective-demolition]]. Where a single project contains both a retained portion and a demolished portion, the demolition boundary shall be fixed by a limit-of-demolition line on the drawings, and this section governs only the work on the demolition side of that line. {note}
+## Removal of specific walls, ceilings, or MEP systems within a building that remains in service is governed by [[sync/selective-demolition]]. Where a single project contains both a retained portion and a demolished portion, the demolition boundary shall be fixed by a limit-of-demolition line on the drawings, and this section governs only the work on the demolition side of that line.
## Clearing of vegetation, trees, and surface obstructions where no structure stands is excluded and is governed by [[sync/site-clearing]]. {note}
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## The engineering survey shall be performed by a licensed structural engineer for any structure over two stories or with unbraced spans exceeding 30 ft.
−## The competent-person survey is the federal floor, but multistory and long-span structures fail in ways that require a structural engineer's analysis of progressive collapse and lateral stability during partial demolition. Defaulting to an engineer-sealed survey for these cases closes the most common gap between a code-minimum survey and the analysis the work actually demands. {note}
−
```datasheet
label: Engineering survey performed by
…5 unchanged lines
```
+## The competent-person survey is the federal floor, but multistory and long-span structures fail in ways that require a structural engineer's analysis of progressive collapse and lateral stability during partial demolition. Defaulting to an engineer-sealed survey for these cases closes the most common gap between a code-minimum survey and the analysis the work actually demands. {note}
+
## The Contractor shall hold a pre-demolition conference with the Owner, Engineer, and affected utility companies before mobilizing.
## A pre-demolition condition survey of all adjacent structures within the zone of influence shall be completed and signed off by the Owner before any demolition begins.
−## Vibration and settlement claims from neighboring owners are routine on demolition projects, and a claim made without a baseline record is impossible to defend or refute. A photographic and descriptive record of existing cracks, settlement, and finishes, accepted by the Owner before work starts, protects both the Owner and the Contractor from unsubstantiated claims. {note}
−
```datasheet
label: Zone-of-influence radius for adjacent-structure condition survey
…6 unchanged lines
```
+## Vibration and settlement claims from neighboring owners are routine on demolition projects, and a claim made without a baseline record is impossible to defend or refute. A photographic and descriptive record of existing cracks, settlement, and finishes, accepted by the Owner before work starts, protects both the Owner and the Contractor from unsubstantiated claims. {note}
+
# Engineering Survey {toc}
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# Demolition Method {toc}
−## The demolition method shall be selected on the basis of structure height, construction type, site constraints, and proximity to occupied or sensitive adjacent structures. {note}
+## The demolition method shall be selected on the basis of structure height, construction type, site constraints, and proximity to occupied or sensitive adjacent structures.
−## No single method suits every structure. Method selection drives the protection scheme, the submittal requirements, and the cost, so it is the controlling decision of the project. The configurations below describe the methods this standard recognizes; the selected method shall be stated in the demolition work plan and reflected in the protection and monitoring plan. {note}
+## No single method suits every structure. Method selection drives the protection scheme, the submittal requirements, and the cost, so it is the controlling decision of the project. The configurations below describe the methods this standard recognizes; the selected method shall be stated in the demolition work plan and reflected in the protection and monitoring plan.
## Mechanical demolition with a high-reach excavator is the default method for structures within the reach of available demolition attachments. {note}
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## Implosion suits large urban high-rises, chimneys, and cooling towers that cannot be reached mechanically, but it is highly regulated and requires permits, a licensed blaster, a sealed blast plan, pre-weakening of structural members, blast-mat protection, and public notification. Specs that treat implosion as just another contractor option without these requirements generate extensive RFIs and may require permit modifications. {note}
−## Top-down systematic dismantlement shall be used where crane swing radius and debris throw cannot be tolerated on dense urban sites. {note}
+## Top-down systematic dismantlement shall be used where crane swing radius and debris throw cannot be tolerated on dense urban sites.
−## Standard excavators working on removable structural decking platforms remove the structure floor by floor from the top down. This is the method of choice on dense urban sites where debris throw and crane swing into adjacent properties are unacceptable. It transfers progressive floor-loading risk to the lower structure and demands floor-by-floor load analysis. {note}
−
```datasheet
label: Primary demolition method
…7 unchanged lines
```
+## Standard excavators working on removable structural decking platforms remove the structure floor by floor from the top down. This is the method of choice on dense urban sites where debris throw and crane swing into adjacent properties are unacceptable. It transfers progressive floor-loading risk to the lower structure and demands floor-by-floor load analysis. {note}
+
+## The high-reach excavator attachments required for top-down demolition shall be specified for the structural elements being removed at each floor level.
+
```datasheet
label: High-reach excavator attachments
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# Foundation Removal {toc}
−## The extent of foundation removal shall be defined in the contract documents and shall not be inferred from the instruction to demolish the structure. {note}
+## The extent of foundation removal shall be defined in the contract documents and shall not be inferred from the instruction to demolish the structure.
−## "Demolish the building" is routinely bid as above-grade only, leaving grade beams, slabs, footings, and piles in place. Because the foundation removal scope is driven entirely by the future use of the site, it must be stated explicitly — the depth of removal, whether grade beams and piles are included, and how resulting cavities are to be filled. {note}
−
−## The foundation system shall be removed to the depth or condition specified for the site's intended future use.
−
−## Where the site will receive new construction, the default is removal to 24 in (600 mm) below finish subgrade or to undisturbed subgrade, whichever is deeper. Where the site will remain open or unbuilt, a shallower break-down or leave-in-place with cavity fill may be acceptable. The selected condition governs the backfill and grading that follow under [[sync/earthwork]]. {note}
−
```datasheet
label: Foundation removal extent
…6 unchanged lines
```
+## "Demolish the building" is routinely bid as above-grade only, leaving grade beams, slabs, footings, and piles in place. Because the foundation removal scope is driven entirely by the future use of the site, it must be stated explicitly — the depth of removal, whether grade beams and piles are included, and how resulting cavities are to be filled. {note}
+
+## The foundation system shall be removed to the depth or condition specified for the site's intended future use.
+
```datasheet
label: Foundation removal depth below finish subgrade
…6 unchanged lines
```
+## Where the site will receive new construction, the default is removal to 24 in (600 mm) below finish subgrade or to undisturbed subgrade, whichever is deeper. Where the site will remain open or unbuilt, a shallower break-down or leave-in-place with cavity fill may be acceptable. The selected condition governs the backfill and grading that follow under [[sync/earthwork]]. {note}
+
## Deep foundation elements — piles, caissons, and grade beams — shall be removed only where specified; otherwise they shall be cut off below the specified subgrade and left in place.
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## The Contractor shall protect adjacent structures, utilities, pedestrians, and the public throughout demolition by the means appropriate to the selected method and site.
−## The protection scheme is a direct function of method and proximity. A high-reach takedown on an open site needs only perimeter hoarding, whereas a top-down dismantlement adjacent to an occupied building may require underpinning, shoring, catch platforms, and continuous instrumentation. The protection and monitoring plan shall match the protection measures to the assessed risk from the engineering survey. {note}
+## The protection scheme is a direct function of method and proximity. A high-reach takedown on an open site needs only perimeter hoarding, whereas a top-down dismantlement adjacent to an occupied building may require underpinning, shoring, catch platforms, and continuous instrumentation. The protection and monitoring plan shall match the protection measures to the assessed risk from the engineering survey.
## Perimeter hoarding or fencing shall enclose the demolition site and exclude unauthorized persons for the duration of the work.
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## Ground vibration at the nearest occupied or sensitive adjacent structure shall not exceed the project peak particle velocity (PPV) limit.
−## Vibration damage and the claims it generates are a leading demolition liability. A defined PPV limit, monitored continuously at the nearest sensitive receptor, gives both an objective compliance threshold and a defensible record. The default limit of 0.5 in/s (12.7 mm/s) PPV reflects USBM RI 8507 guidance for occupied and sensitive structures; tighter limits apply to fragile or historic neighbors. {note}
−
```datasheet
label: Peak particle velocity (PPV) limit at adjacent structures
…6 unchanged lines
```
+## Vibration damage and the claims it generates are a leading demolition liability. A defined PPV limit, monitored continuously at the nearest sensitive receptor, gives both an objective compliance threshold and a defensible record. The default limit of 0.5 in/s (12.7 mm/s) PPV reflects USBM RI 8507 guidance for occupied and sensitive structures; tighter limits apply to fragile or historic neighbors. {note}
+
## Vibration shall be monitored continuously at the locations and reporting frequency stated in the monitoring plan, with exceedances reported to the Engineer.
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## Dust shall be controlled at the source by water spray, misting, or attachment shrouds appropriate to the climate and the proximity of occupied buildings.
−## Leaving dust control to contractor discretion fails predictably in arid climates and near occupied buildings. The suppression method and equipment shall be specified in the dust control plan, not assumed; water application rates shall be sufficient to suppress visible airborne dust at the property line. {note}
+## Leaving dust control to contractor discretion fails predictably in arid climates and near occupied buildings. The suppression method and equipment shall be specified in the dust control plan, not assumed; water application rates shall be sufficient to suppress visible airborne dust at the property line.
```datasheet
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# Debris Management and Material Diversion {toc}
−## Demolition debris shall be managed in accordance with the approved debris management plan, with diversion and recycling targets met by weight. {note}
+## Demolition debris shall be managed in accordance with the approved debris management plan, with diversion and recycling targets met by weight.
## Construction and demolition debris is the largest material stream a demolition project produces, and diversion targets are increasingly tied to LEED credits and state mandates. The plan governs on-site processing, the recycling target, and the off-site venues; concrete and metal routinely divert above 90%, so an aggregate target in the 50–75% range is readily achievable. {note}
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## Salvage items designated for the Owner shall be removed carefully and turned over undamaged; the salvage plan shall list each item, the responsible party, and the Owner's removal deadline.
−## Salvage conflicts arise when an owner lists items to retain without a firm cutoff date and the contractor proceeds and damages or removes them. Stating each salvage item, the responsible party, and a removal deadline with a defined consequence for missed deadlines prevents the dispute before it starts. {note}
−
```datasheet
label: Salvage designation
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```
+## Salvage conflicts arise when an owner lists items to retain without a firm cutoff date and the contractor proceeds and damages or removes them. Stating each salvage item, the responsible party, and a removal deadline with a defined consequence for missed deadlines prevents the dispute before it starts. {note}
+
## Where concrete is processed on site into recycled concrete aggregate (RCA) for reuse, it shall be crushed and screened to the specified gradation and tested for abrasion resistance.
−## On-site crushing of concrete rubble into RCA for sub-base fill avoids both disposal cost and import cost, but reuse requires that the product meet a defined gradation and abrasion limit. Gradation per ASTM C33 No. 57 or No. 67 and abrasion testing per ASTM C131 or C535 confirm the RCA is suitable before it is placed; the final fill use is governed by [[sync/earthwork]] and the geotechnical recommendations. {note}
−
```datasheet
label: On-site recycled concrete aggregate (RCA) production
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```
+## On-site crushing of concrete rubble into RCA for sub-base fill avoids both disposal cost and import cost, but reuse requires that the product meet a defined gradation and abrasion limit. Gradation per ASTM C33 No. 57 or No. 67 and abrasion testing per ASTM C131 or C535 confirm the RCA is suitable before it is placed; the final fill use is governed by [[sync/earthwork]] and the geotechnical recommendations. {note}
+
## Off-site disposal shall be to permitted facilities, with weight tickets and manifests retained for the diversion report.
# Controlled Explosive Demolition {toc}
−## Controlled explosive demolition shall be performed only by a licensed blaster under the sealed blast plan and required permits. {note}
+## Controlled explosive demolition shall be performed only by a licensed blaster under the sealed blast plan and required permits.
## Implosion is the most heavily regulated demolition method and concentrates risk into a single irreversible event. The blast plan, the pre-weakening of structural members, the charge layout, and the initiation sequence shall all be the work of a licensed blaster, and no explosive material shall be brought to the site before the permits and submittals of this section are approved. {note}
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# Bridge and Special-Structure Demolition {toc}
−## Bridge demolition shall be sequenced and load-managed in accordance with NCHRP Report 460 and the project structural analysis. {note}
+## Bridge demolition shall be sequenced and load-managed in accordance with NCHRP Report 460 and the project structural analysis.
−## Bridges, towers, silos, and similar discrete structures fail differently from buildings because their stability depends on a load path that the demolition sequence progressively dismantles. NCHRP Report 460 provides the sequencing and load-management framework for bridge removal; an equivalent structural analysis shall govern other special structures. {note}
+## Bridges, towers, silos, and similar discrete structures fail differently from buildings because their stability depends on a load path that the demolition sequence progressively dismantles. NCHRP Report 460 provides the sequencing and load-management framework for bridge removal; an equivalent structural analysis shall govern other special structures.
## Removal of a span or structural member shall not proceed until the analysis confirms the stability of the remaining structure.
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# Site Restoration {toc}
−## On completion of demolition and foundation removal, the site shall be left in a demolition-complete condition ready to receive subsequent earthwork. {note}
+## On completion of demolition and foundation removal, the site shall be left in a demolition-complete condition ready to receive subsequent earthwork.
## This section ends at a clean, rough-graded pad. Final structural fill, compaction to design density, and finish grading are governed by [[sync/earthwork]], and erosion and sediment control measures are maintained under [[sync/erosion-and-sediment-control]] until the site is stabilized. {note}
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default: 12
```