Explosive ordnance investigation for railway bridges and culverts

Assessment should begin as soon as design options, the structure location, the extent of demolition and likely ground disturbance can be identified. Early design stages allow review of the historical evidence of ordnance, existing reports and gaps in spatial data. Before tendering, abutments, piers, piles, excavation supports, excavations, slopes, culvert alignments, temporary diversions and utility diversions must be defined, including depths and construction methods.

Abutments, piers, wingwalls, approach slabs, foundation points, sheet-pile and anchor alignments, slopes, working areas, culvert inlets and outlets, and temporary access routes have different area and depth geometries. Records for an accessible surface therefore do not automatically apply to deep piles, built-over zones or temporary working areas outside that footprint.

Key documents include the current site and structural drawings, alignments and chainage, as-built and demolition drawings, the foundation and excavation-support concept, borehole and pile lists, utility and drainage drawings, ground investigation data, construction stages, possession windows, and existing aerial photograph assessments, official documents and previous survey or clearance reports. Temporary diversions, crane positions and assembly areas should also be included.

Official information and requirements are submitted with their dates, complete appendices and spatial references. In Germany, the involvement of the relevant KBD, KMBD or KRD and the local public order authority is clarified for the project location; outside Germany, the local allocation of responsibilities applies. Building control and the operator may have additional requirements of their own for the construction sequence and access.

This depends on the required investigation depth and survey conditions. A surface survey covers only the volume of ground that can be reliably assessed under those conditions. If this is insufficient for piles, boreholes, sheet piles, anchors or deep foundations, additional depth investigation is planned. It is matched to the coordinates, design depth, component geometry and installation method.

Existing foundations, reinforcement, sheet piles, utilities and rails can obscure geophysical data and restrict access. These areas are not automatically classified as being without anomalies. Depending on the construction stage, options include investigation after partial demolition, alternative survey methods, borehole or depth investigation, controlled exposure or a measure carried out during construction.

If an unexpected suspicious object is found, stop work. Do not touch, move or uncover it further. Leave the immediate area and warn others without putting yourself at risk. In Germany, notify the police on 110; outside Germany, use the local emergency reporting procedure. The competent authorities determine what happens next; a project enquiry does not replace reporting the find.

Inlet and outlet areas, slopes, channel beds and banks, working platforms, dewatering, excavation support and utility connections are planned separately. The key questions are which areas are actually accessible and which volumes of ground are affected by piles, sheet piles, excavation or demolition. Working areas on land and in the water may require different methods and involve different responsibilities.

The records link the structure and drawing revision, investigated subareas, borehole and pile positions, investigation depths, survey conditions, interference zones, results and follow-up measures. For each component area, they must show the working volume covered and which areas can only be investigated after demolition, at a later construction stage or using another method.

Key factors are the number and depth of foundation and excavation-support points, the size and accessibility of excavations, the existing structure and reinforcement, watercourse and slope conditions, possessions and construction stages, existing utilities, required methods, surveying, data and documentation requirements, and possible repeat mobilisations after partial demolition. A reliable estimate therefore requires the current structural and construction design.