Two people wearing safety helmets, with a tablet and a plan, on a marked construction area in front of a drilling rig.

Explosive ordnance surveys for specialist foundation works

For piles, retaining structures and other specialist foundation elements, the complete intervention volume is established from location, working elevation, depth and inclination where applicable. FONTANA-EOD checks existing explosive ordnance reports against your execution plans and selects the survey according to local measurement conditions. As the client or specialist foundation planner, send the current plans with sections and elevation references to coordinate the survey.

Structural element

State the location, path and final depth.

Working platform

Relate depths to the intended working elevation.

Execution

Have changed structures checked before execution.

Environment, contaminated land and geotechnics

Enquire about an explosive ordnance assessment for your foundationsSelect suitable investigation services
Context

Describe the structure's path through the ground

A floor plan shows the location of a structure but does not always describe its full path through the ground. Supplementary sections, elevations or inclination details may therefore be needed to prepare explosive ordnance work. Identify which parts of the plan are already defined and which options are still being considered.

Project references

Selected project examples

Explosive ordnance survey – Hannover (Mecklenheide) – harbour railway station, new stabling tracks and lighting mast foundations Hannover (Mecklenheide) / Germany

The scope of services for “Hannover (Mecklenheide) – harbour railway station, new stabling tracks and lighting mast foundations Hannover (Mecklenheide) / Germany” comprised downhole magnetometry.

Service period: 2025-01

Service areas:Downhole magnetometry / deep-ground survey

View project details · Deep-ground and downhole surveys · Project location: Hannover

Investigation task

Align foundation geometry and the survey

Two people with a tablet beside a marked construction area; plans lie in the foreground.

Describe the structure's path in three dimensions

For the enquiry, the location, intended depth and path of structures in contact with the ground are brought together. Supplementary sections and elevation references help describe the intervention volume. Options still open remain identifiable. The specialist contractor relates its task to the works actually intended.

Select survey services for the structural geometry
Two people discussing plans at a table beside a vehicle on a construction site.

Compare existing results with the plan

Earlier surveys are compared with the current foundation plan. Area, depth and relevant conditions are considered together. A report is retained with its original scope. Matching the property designation alone does not establish findings applicable to the new structure.

Compare reports with the current plan
Two people with a tablet beside a marked construction area; plans lie in the foreground.

Include local survey conditions

Existing conditions, access and known installations are considered in specialist planning. The choice of method follows the task and conditions. Inaccessible areas are identified separately. If site conditions change, the survey scope now possible is agreed again.

Coordinate methods according to local conditions
Two people discussing plans at a table beside a vehicle on a construction site.

Assign planning changes before the ground intervention

Relocated starting points, different depths or changed inclinations are compared with the existing survey status. The responsible parties receive the updated plan. Additional survey requirements relate to the specific change. Earlier results are retained with their spatial assignment.

Assign changed foundation points to the documentation

Determine the survey volume from the foundation plan

Pile foundations, retaining structures and preparatory groundworks may concern different volumes. The explosive ordnance task is therefore defined by the actual structural geometry and intended working platform.

Person beside a survey instrument on a construction site; a wheeled excavator with drilling equipment stands behind them.

Foundation elements with defined geometry

Once location, path and final depth are defined, these details are compared with existing survey results. The number of elements alone does not describe the assignment. Each affected area must have a traceable relationship to the plan. For similar structures, documents can be brought together clearly without concealing different depths or outstanding edge areas. The specialist choice of method follows the intervention volume and actual conditions.

Survey foundation elements with reference to depth
Person beside a survey instrument on a construction site; a wheeled excavator with drilling equipment stands behind them.

Retaining structures and inclined elements

An inclined element may reach a volume in the ground that is not apparent from its above-ground starting point. Therefore provide the necessary sections and details of its path. The explosive ordnance task considers this volume insofar as the planned intervention affects it. The specialist planners describe the geometry. Neither inclination nor a universal survey width is inferred from a point on the site plan.

Clarify surveying for the planned structural path
Two people with a tablet beside a marked construction area; plans lie in the foreground.

Preparatory works and ancillary installations

Further groundworks may be intended before the specialist foundation work itself. They are identified with their own interventions and are not automatically treated as part of a survey of individual foundation elements. This also applies where all works serve the same construction project. Identify which preparatory activities are already defined and which are still being planned. Their prerequisites and sequence must be coordinated by specialists before work begins.

Select services for preparatory ground interventions

Compare existing findings with the specific structure

Location and depth are already recorded traceably

An existing report may be usable for the intended foundation if its documented scope and specialist findings apply. The plan, elevation reference and limitations are read together for this purpose. A report is not discarded merely because of its age. Nor is it treated as sufficient merely because it has the same property address. What matters is which conclusions it supports for the actual intervention volume. Show whether individual foundation points, a pile group or additional working volumes are to be considered. The specialist assessment needs the corresponding execution plans with identifiable point and axis designations. Results for a single point are not transferred to an entire foundation area without checking. Where stages of work differ, it is made clear which document applies to which part of the construction task. This assignment is retained when handing over to the executing contractors.

An element is relocated or changed

A new location, greater depth or different inclination may change the volume considered. Mark the deviation from the previous plan version. The specialist comparison focuses on this exact change. Existing usable findings are retained insofar as they still apply. Any necessary addition is described separately so that it is not confused with areas already worked on or a complete repetition of the assignment. For inclined elements, the planned path must be described traceably using suitable plan information. An unchanged starting point may be associated with a changed path deeper down. The responsible planner provides the relevant geometry data and identifies the difference from the version previously checked. The explosive ordnance assessment relates to this; unknown paths are not inferred from neighbouring foundation elements. The client coordinates the resulting additional work with the specialist contractor.

Information is missing for further planning

If the geometry is not yet defined, the existing state of knowledge can first be assessed. A definitive statement about an unknown path cannot be inferred from it. Identify open options and responsible contacts. This allows clarification of which information is already sufficient for the next steps and which will only become available through further execution planning. Missing planning data is not replaced by general assumptions. Assign each planning option a clear designation and revision status. It remains identifiable which geometry data is already binding and which is still being coordinated. Changes to the foundation plan are communicated to those involved using the same option designation. Later specialist feedback can then be assigned to the intervention actually selected. If an option is dropped, its outstanding tasks are distinguished from surveys still required.

Project-specific tasks

Provide the foundation plan, sections and elevations

01

State the path and inclination of the structures

Send the foundation or retaining structure plans relevant to the explosive ordnance task. For inclined elements, their three-dimensional path must be communicated; an above-ground point alone does not describe it. Include the corresponding sections and depths. Have the responsible specialist planners supply missing information rather than estimating the survey area yourself.

02

Relate the working platform to the final depth

Identify the intended working platform and the elevation reference of the planned structures. If ground is excavated or filled before the specialist foundation work, this change must be considered. A depth below the previous surface cannot be transferred unchecked to a different working platform. Have the specialist planners specify the elevation to which the intended depth relates.

03

Also identify ancillary works involving ground interventions

The project may include further groundworks, for example for intended utilities or other preparatory structures. Identify the affected areas and depths in the assignment insofar as they involve ground interventions. An assignment to assess individual foundation elements does not automatically include all ancillary works on the construction site.

Prepare foundation documents for the explosive ordnance task

Bring together the site plan and sections

Send the plans currently in use with traceable version designations. The site plan locates the structures; sections can supplement their paths and depth relationships. Where documents refer to each other, the relevant appendices should be available in full. An isolated cropped view may lose context. The review must be able to identify which details belong together and which version governs the intended execution.

State the working platform and reference elevation

State the level from which work is to take place and how the depth information relates to it. If ground is to be excavated or filled beforehand, include this step in the description. Available survey measurements can support the comparison. A depth below the earlier surface is not automatically the same as a depth below the later working platform. The responsible planners clarify the relevant reference.

Identify existing conditions and local restrictions

Existing foundations, utilities and other installations may affect preparation. Provide available existing-condition plans and identify known uncertainties. Access and usable working areas are also relevant to the survey. An area planned to be clear is not assumed to be actually available. Specialist coordination considers the conditions intended for the survey date and the prerequisites that still need to be created.

Assess two typical changes before execution

A structure is given a different path

If the inclination of an intended element changes, its underground path may shift relative to the volume previously considered. The specialist planners show the change traceably. It is then compared with the existing survey result. An unchanged starting point alone does not establish that the new path is also covered. The feedback describes which part can continue to rely on existing findings and where further clarification remains necessary. Updated sections, elevations and final depths are needed for the supplementary survey. Historical baseline information, measurement data and assessments of findings remain linked to the original plan version and the changed structural designation. Where explosive ordnance is recovered, the clearance record documents its location, depth and the recovery result; outstanding follow-up measures remain assigned to the affected area.

The working platform is lowered in advance

When the working platform changes, the old and new elevation references are considered together. First, the groundworks intended for lowering it must be clarified. Their prerequisites cannot be derived solely from the later foundation survey. A check is then made whether the existing findings apply to the structure now planned. A numerically unchanged depth below ground level is not sufficient evidence of this. The documentation must identify the actual volume intended traceably.

Next steps

From foundation planning to the survey and results handover

01

Identify the current plan version and open options

Send the current plan with its version and the responsible contact. Pass on existing explosive ordnance documents in full. If the location or geometry is not yet final, this should be explicitly identifiable. This distinguishes areas already defined from survey questions that depend on an option still open.

02

Compare changed structures with the documentation again

A relocated element, greater depth or different path may affect a ground volume not previously covered. Report such changes to the responsible specialists before the affected intervention. The earlier survey remains usable within the scope of its findings but does not automatically extend to the new execution.

03

Review historical evidence

Existing information about site use, historical documents and aerial photograph assessments are compared with the planned foundation area. They help assess suspected explosive ordnance and outstanding survey questions. Existing results are used with their actual location, elevation and depth references. If historical questions remain open, supplementary records of site use are researched and suitable wartime aerial photographs are assessed where available. The findings and limits of the assessment are assigned to the planned foundation area.

04

Select investigation methods

The structural path, intervention depth, ground composition, metallic interference and accessible areas determine the suitability of the methods. The measurement grid and borehole points where applicable are aligned with the survey volume required. Preparatory ground interventions, access, nearby utilities and protective requirements are clarified before execution.

05

Carry out the survey

The commissioned survey is carried out in the agreed foundation area. Measurement data, findings and limitations are recorded with location, elevation and depth references. Structural designations and the plan version used remain linked to the surveyed volumes.

06

Assess and document results

Measurement data and findings are evaluated by specialists. The report documents the surveyed ground volume, site conditions, methods used and remaining limitations. Further surveys or other specialist checks still required remain assigned to the affected structure or section and are coordinated before the respective subsequent works.

07

Hand over reports and outstanding areas to the specialist foundation contractor

Link the plan version used with its corresponding survey results. Outstanding subareas and documented limitations must also be known to the executing specialist foundation contractor. Refer to the complete reports and their limitations in a brief overview.

Technical assessment

Which areas the existing survey covers

Compare reports with location, depth and path

Survey reports may concern different areas, depths and methods. Compare these details with the planned structure and the ground conditions at the time. A survey from the surface does not automatically establish that every intended final pile or retaining structure depth was covered. The technically documented findings of the respective method are decisive.

Take foundations, metal and ground conditions into account

Existing foundations, metallic installations and ground conditions may affect geophysical surveys. The BFR KMR describe such conditions and the limits of the methods. For the assignment, a check is made which method is suitable under those conditions. No universal survey depth or measurement grid can be defined without this check.

Assign the explosive ordnance survey and foundation design to their respective tasks

The geotechnical or structural suitability of a foundation is a different specialist question from the explosive ordnance survey of its intervention volume. The appointed specialist planners design the foundation and assess its load-bearing capacity. FONTANA-EOD surveys the agreed area for explosive ordnance. We coordinate the structural geometry information needed for this with the responsible specialist planners.

Select the method according to the task and measurement conditions

Use existing survey results

The document review considers the method, scope and results of previous work. It clarifies which parts of the foundation plan are actually covered. It can identify usable findings and specific gaps. An additional survey assignment arises from these outstanding questions. The review itself does not replace new measurement data for a ground volume not previously covered. Historical information on site use and aerial photograph assessments help assess suspected explosive ordnance and the need for further surveys.

Assess surface-based results on technical grounds

A survey from the surface is assessed according to its documented reach and local conditions. The method designation alone does not establish that every planned foundation depth is covered. Metallic installations and other conditions may affect interpretability. For further use, the report's actual findings are therefore compared with the geometry of the new ground intervention. Magnetometry records magnetic anomalies; TDEM records time-dependent electromagnetic responses from electrically conductive bodies. Under suitable ground conditions, ground-penetrating radar can provide additional information about structures and strata boundaries. Highly conductive soils may limit its usable range. Methods are combined according to their respective survey objectives and identifiable interference.

Prepare a deeper-reaching survey

Whether a deep-ground or downhole survey is suitable is checked for the specific intervention volume. Neither a general grid nor a fixed range can be inferred from the number of structures. Planning requires local conditions and relevant information on existing installations. Necessary preparatory ground interventions are also considered by specialists. Starting elevation, path and planned final depth are compared with the ground volume to be surveyed and the measurement coverage achievable. Required surveys and protective measures are determined before drilling. Drilling depth, casing where applicable and documentation follow the task and local conditions.

Surveying alongside construction during preparatory excavation

For preparatory excavation, a separate check is made whether explosive ordnance surveying alongside construction is technically suitable. Each working level is technically surveyed and assessed before controlled layer-by-layer excavation with supplementary visual inspection follows. The steps are repeated down to the agreed excavation base. Excavation layers, the stop signal, authority to issue instructions, reporting procedures and documentation are coordinated with construction management and specialist personnel before work begins.

Link planning changes and results clearly

The governing version must be identifiable for execution

FONTANA-EOD compares the agreed explosive ordnance task with the foundation or retaining structure plans provided. The survey and its documentation remain related to this defined scope. For later use, the plan version considered and the limitations that applied should remain traceable.

If a structure changes, old results are not discarded indiscriminately. The specialist comparison shows which findings remain usable and which new question arises. Conversely, earlier evidence is not extended merely because the change belongs to the same construction project. A clear description of the deviation supports targeted supplementary work.

Reports and current plans are linked for handover to the executing contractor. A brief overview can help assign findings to individual elements or retaining structure sections. However, it should refer to the complete documents and not conceal outstanding areas. An overall project status does not replace findings for the specific ground volume.

If several plan versions circulate at the same time, the version intended for execution should be explicitly identified. Outdated drawings remain traceable as the basis for earlier results but are not used unchecked as current working documents. Questions can then relate to the actual change rather than mixing different plan versions.

Task

The question and affected area are defined before work begins.

Basis

The reports and planning versions used remain traceable.

Result

The answer identifies its scope and the specialist questions still unresolved.

Assign planning information and specialist decisions

Foundation and retaining structure planning

It describes the location, path, depth and working platform of the intended structures. Open options and changes are communicated. Structural and geotechnical design remain its separate task.

Ordnance specialist contractor and responsible authorities

The appointed explosive ordnance specialist contractor assesses existing findings in relation to the ground intervention and agrees the survey scope needed. The method is selected according to actual conditions. The report identifies the areas covered, results and limits on further use.

In Germany, state ordnance disposal services and locally competent authorities carry out hazard response and find management. Their involvement and public-order or building-control tasks are established for the project location. Outside Germany, local responsibilities apply. Contacts, requirements and reporting are assigned to the specific works.

Construction management and executing contractor

They need the current plan version with the assigned survey results. Deviations are passed to the responsible specialists in good time. Access, survey status and necessary protective measures are coordinated with those responsible before each execution step.

Bring structural geometry and the surveyed ground volume together

The footprint, path and elevation reference are considered together during preparation. The survey relates to the actual ground intervention rather than a general property designation.

Person beside a survey instrument on a construction site; a wheeled excavator with drilling equipment stands behind them.

Prepare a deep intervention

A person beside a measuring instrument on a construction site, with a wheeled excavator and drilling rig behind. Starting elevation, path and final depth are agreed before the survey.

Coordinate the deep ground intervention and survey
Four people in orange high-visibility vests in front of two excavators on a construction site.
Person with a yellow survey cart on a footpath in front of a hedge.
Documentation

Assign the plan version and report to each structure

For later questions, it should remain traceable which foundation or retaining structure section the explosive ordnance findings relate to. The documentation includes the volume worked on and relevant conditions of the method. Where there are several execution stages, the respective plan versions and corresponding survey results are assigned clearly and separately.

The explosive ordnance report describes the agreed survey and its result. The responsible planners and contractors clarify the construction and organisational prerequisites for the intended execution. For a quotation, we therefore need the location and geometry of the structures, existing reports and responsible contacts. The number of structures alone does not describe the survey assignment.

Technical sources: BFR KMR: clearance planning with a clearance concept – introduction · BFR KMR: geophysics · BFR KMR: documentation · BFR KMR: planning content of the clearance concept

The Baufachliche Richtlinien Kampfmittelräumung contain requirements for historical and technical investigation, clearance concepts, procurement and documentation within their defined federal remit. Their application to the particular specialist foundation project, together with locally applicable requirements and responsibilities, is clarified separately.

Construction phases

Keep foundation points traceable through to execution

Use the current design for the enquiry

Send the foundation plan with location, elevation reference and intended execution. Add existing explosive ordnance reports and known existing conditions. FONTANA-EOD can align the specialist task accordingly. Options not yet defined remain identified as such.

Coordinate this work step

Compare the execution version with the documents

Before each ground intervention, the current plan and existing survey status are compared. Deviations are coordinated with the responsible specialists. The plan versions used remain traceable. An earlier point designation is not silently transferred to changed geometry.

Coordinate this work step

Hand over documentation for further construction works

The specialist documents show the ground volume actually surveyed and its corresponding conditions. Construction management assigns this information to the forthcoming works. Further ground interventions and outstanding questions remain distinguishable. Construction decisions are provided by the parties responsible for them.

Coordinate this work step
Project site

Identify the location and foundation area specifically

Illustrated map of Germany with location markers on a construction site.

Provide the project location and contacts

State the location and affected construction phase. Add the contacts for foundation planning, construction management and access. The regional overview helps with initial orientation. Current plans and existing findings remain decisive for the specialist work.

Identify the project region
Two people discussing plans at a table beside a vehicle on a construction site.

Provide existing information with plan references

Reports and project-specific requirements are provided together with their spatial appendices. The responsible parties clarify outstanding points. Information about earlier designs remains distinguishable from the current execution version. This allows the task to relate to the foundation actually intended.

Assign site information and plan versions traceably
Understand the results

Read the foundation plan and survey documentation together

Understand the project-specific scope

The BFR KMR relate the clearance concept to the planned project and its relevant baseline information. For the foundation, a check is therefore made whether the report covers the ground intervention actually intended. Existing documentation does not become sufficient merely because its site plan shows the same property area.

The project documents describe the relationship between the planned foundation and the agreed explosive ordnance task. Spatial appendices and conditions remain part of the findings. For execution, this status is compared with the current design. Further works are assessed according to their actual intervention volume.

Explore results and terminology

Retain inclination and depth in plan comparisons

A change in the structural path may affect different ground volumes. Sections and depth information are therefore considered together with the site plan. The references used remain documented. An earlier survey is used within its actual scope and supplemented specifically where necessary.

Document inclination and depth references

Connect the tasks of the specialists involved

The explosive ordnance specialist contractor documents its agreed contribution. Geotechnical planners, structural engineers and construction management each provide the information needed for their tasks. The project organisation brings it together for the next work step. Different specialist findings remain identifiably assigned.

Explore results and terminology

Technical information

Environment, contaminated land and geotechnics: brochure

Ordnance checks, contaminated-land investigations and ground investigations serve different purposes. The brochure describes their interfaces and shows how drilling and other ground interventions are coordinated.

Download the brochure as a PDF
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Environment, contaminated land and geotechnics: brochure – page 1

German · 8 pages

Questions from planning

Questions about foundations and specialist foundation works

Is the starting point on the site plan sufficient for inclined structures?

Not always. The intended path through the ground must be traceable to define the task. Supplementary sections, inclinations and elevation and depth information may be necessary for this.

Does a surface survey cover every pile depth?

The documented reach of the surface survey is compared with the intended intervention volume. The method and local conditions determine whether the planned depth is covered or a supplementary survey is needed.

Must a changed foundation be compared again?

Yes, insofar as its location, depth or path differs from the ground intervention previously considered. Before the affected construction activity, specialists must clarify whether the existing survey still applies or needs supplementation.

What should we do if a suspicious object is found in the foundation area?

If an unexpected suspicious object is found, stop work in the affected area immediately. Do not touch, move or uncover it further. Leave the immediate area, keep your distance and keep others away without putting yourself at risk. In Germany, call the police immediately on 110; outside Germany, use the local emergency procedure. The competent authorities determine the next steps. Inform site management and the client; internal notification must not delay the emergency call.

Which documents are needed for a quotation and cost assessment?

The current foundation or retaining structure plan with relevant sections, elevation and depth information, the intended working platform and existing explosive ordnance reports are helpful. Options still open and known local restrictions should be identified. Cost assessment also takes account of the number and spatial survey scope of the elements, measurement conditions, accessibility, suitable methods, evaluation and documentation.

How are older and current plan versions distinguished?

The plan version intended for execution is explicitly identified. Older drawings remain traceable as the basis of earlier survey results but are not used unchecked as current working documents. Questions can then relate to the actual change between the plan versions.

What needs checking when the working platform changes?

The elevation references of the previous survey and new plan are compared. Preparatory groundworks for creating the platform must also be considered with their own survey requirements.

How are survey documents handed over to the executing contractor?

Reports and current plans are linked and assigned to individual foundation elements or retaining structure sections. A brief overview refers to the complete documents and identifies outstanding areas. For each intended ground intervention, its ground volume is compared with the documented scope.

Project enquiry

Send the foundation plan for specialist coordination

Execution status of the structures

Send the current foundation or retaining structure plan. Include the relevant sections and inclination details. For options still open, state their current planning status. Provide the address or region and affected cadastral parcels insofar as known.

Elevations and planned preparatory works

State the intended working platform and the reference for the depth information. Planned excavation, fill or other preparatory groundworks are described with their own scope.

Existing results and conditions

Send explosive ordnance reports in full with their corresponding appendices. Available information about foundations, utilities and installations helps assess the methods. Known uncertainties and areas with restricted access remain identifiable in the enquiry. Include available historical findings and aerial photograph assessments.

Changes and contacts

State what has changed since an earlier survey. A marked-up revision helps with comparison but should be provided together with the complete current plan. Identify the responsible specialist planners for questions about geometry and elevations.

Schedule and results handover

Agree which section is to be executed first and who needs the report. The survey and its evaluation must be technically compatible with this sequence. Initial feedback on documents must be distinguished from a completed survey. Baseline information still outstanding is identified so that those involved can plan the next step using the actual state of knowledge. State the planned construction windows and known authority conditions for the section.

Scope of services for the quotation

Describe the survey required so that it can be assigned to the planned structures. Identify known quantities and options still open. When reviewing the quotation, clarify which preparation, survey, evaluation and documentation are included. A price for an earlier plan version is not transferred unchecked to a changed foundation. Additional structures or new local conditions may change the scope required. The technical comparison therefore precedes the final definition of services. The quotation should identify the information and prerequisites on which it is based so that later questions can refer precisely to them.

Project enquiry

Have your project assessed

Whether historical aerial photograph analysis, explosive ordnance surveying, surface surveying using GPR, magnetometry or TDEM, deep-ground surveys, downhole surveys, excavation supervision, area clearance or ordnance recovery is needed depends on the location, ground disturbance, depth, ground and existing documents. An early ordnance assessment provides clarity for tendering, programming, occupational safety and construction.

FONTANA-EOD combines its Section 7 SprengG licence, specialists holding Section 20 SprengG certificates of competence, suitable survey and clearance methods, and traceable documentation. Send the site plan, depth of ground disturbance, construction phase and existing documents for an initial technical assessment.

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