Challenge

Establish the condition of an existing reinforced-concrete bridge and identify whether concrete quality or reinforcement arrangement required further structural attention.

LUMEN role

Commissioned by GEMT Ltd as the testing and laboratory specialist for on-site assessment, laboratory analysis and technical reporting.

Approach

Rebound-hammer NDT across five structural elements, extraction and compressive testing of concrete cores, electromagnetic reinforcement scanning, visual inspection and documented technical interpretation.

Outcome / decision supported

Testing indicated generally serviceable concrete conditions in the sampled areas while identifying a localised low-strength crossing-beam zone and reinforcement-spacing irregularities. The evidence supported targeted follow-up verification rather than treating the entire bridge as uniformly deficient.

Challenge

Understand foundation, slope and scour risks at a bridge site affected by seasonal flooding and moisture-sensitive soils.

LUMEN role

Geotechnical investigation partner responsible for field investigation, laboratory testing, engineering analysis and recommendations for foundation, drainage, settlement and scour design.

Approach

Five DCP investigations to 4 m, trial pits, controlled soil sampling, Atterberg limits, particle-size distribution, compaction, CBR, direct shear and consolidation testing, followed by slope, settlement and scour-risk interpretation.

Outcome / decision supported

The investigation identified a soft, moisture-sensitive fine-grained profile with no competent bearing stratum encountered within 4 m and critical flood/scour exposure. The findings supported deeper-foundation investigation, drainage and stabilisation measures, scour protection and further borehole/hydraulic studies before detailed design.

Challenge

Define foundation and slope-design parameters in a valley setting with weathered near-surface materials, shallow groundwater and variable depth to competent rock.

LUMEN role

Comprehensive geotechnical investigation for bridge foundations, abutments, embankments, drainage and retaining works.

Approach

Rotary drilling and coring, SPT, continuous geological logging, groundwater measurement, laboratory shear, physical and consolidation testing, equipment traceability and engineering interpretation.

Outcome / decision supported

The investigation identified competent granite at approximately 9.4–12 m and shallow groundwater at approximately 4–6 m. The findings supported a deep-foundation strategy, groundwater-adjusted bearing design, comprehensive drainage and conservative slope-stability measures.

Challenge

Establish a reliable foundation strategy where competent rock lies deeper and groundwater is shallow across the proposed bridge footprint.

LUMEN role

Field investigation, drilling and coring, laboratory testing, groundwater assessment and engineering interpretation for foundation, slope and drainage design.

Approach

Four boreholes, SPT and core recovery, continuous logging, groundwater monitoring, direct shear, density and moisture and consolidation testing, followed by bearing-capacity and geotechnical-risk assessment.

Outcome / decision supported

The investigation identified competent schist at approximately 15 m and groundwater at approximately 3–4 m. The results supported longer deep-foundation elements, groundwater-adjusted design bearing values, drainage and dewatering measures and conservative slope design.

Challenge

Major road works depend on a clear understanding of what lies below the surface. Across multiple corridors, ground conditions varied significantly, from weathered rock to mixed clayey, silty and granular soils. The investigation also identified shallow groundwater at several locations and highly fractured rock in parts of the alignment. LUMEN's task was to convert these variable site conditions into traceable, practical engineering information for drainage, slope, foundation and construction-risk decisions.

LUMEN role

Field drilling, in-situ testing, laboratory analysis and integrated geotechnical reporting, coordinated across the project corridors with specialist equipment, water supply and field personnel.

Approach

Four integrated workstreams. Borehole drilling and geological logging — a borehole programme using rotary wash boring, with systematic lithological logging, sample identification and core-box preservation. In-situ testing and groundwater monitoring — Standard Penetration Tests at specified intervals, standpipe piezometer installation and initial groundwater levels recorded after drilling. Laboratory testing — direct-shear, triaxial and physical-property testing to determine key soil and rock parameters. Integrated geotechnical reporting — borehole logs, field observations, test data, groundwater records and engineering interpretation consolidated in a final geotechnical report with documented recommendations and appendices.

What the investigation delivered

An organised, multi-corridor geotechnical evidence base: borehole logs, drilling records and core-recovery documentation; in-situ SPT results, lithological logs and initial groundwater measurements; standpipe piezometer installation records for ongoing monitoring; direct-shear, triaxial and physical-property laboratory results including reported shear-strength parameters; and a final integrated geotechnical report with engineering evaluation, design considerations and recommendations.

Design-relevant findings

Groundwater management — comprehensive surface and subsurface drainage, including sub-drains and lined surface ditches, was recommended to manage seepage and runoff. Slope stability — fractured rock conditions called for conservative slope design, with lower-bound strength parameters, flatter slopes where appropriate, and structural support or ground improvement where required. Foundation design — reported allowable bearing values were identified as subject to groundwater correction and location-specific detailed assessment. Monitoring — continued piezometer monitoring was recommended during design and construction, especially in rainy periods, to validate groundwater assumptions and manage associated risk.