Permanent formwork is a highly efficient construction method but can lead to hidden honeycombing and voids. OBJECTIVES The client was constructing a multi-storey building using a concrete permanent formwork system. This consisted of two precast leaves, infilled with concrete. However, if the concrete was not correctly vibrated it can lead to hidden voids or honeycombing within the wall. SOLUTIONS Trace-SI advised on a fully non-intrusive survey method that allowed for complete coverage of the walls. The works were completed by a consultant covering two floors of the building in less than a week, all while other works continued on site. The data was analysed offsite and detailed CAD drawings were created showing the size and locations of areas of honeycombing and voiding present within the walls. This allowed the client to drill and grout the defects. Once grouted, Trace-SI returned to site to check the effectiveness of the grouting and map remaining voids. With this, the client was able to confirm the compliance of the walls to the asset owners BENEFITS Site works were fast, non-destructive and comprehensive, preventing disruption to the project. Accurate and detailed CAD drawings showed the areas of concern allowing for efficient remediation. TRACE-SI undertook a return visit to quality check the repair works and ensure all voids were sufficiently grouted.

TRACE-SI accurately identified mezzanine construction details through holistic nonintrusive investigation. OBJECTIVES TRACE-SI was approached to analyse the structural details of two mezzanine levels. These platforms, around 13 x 6m each, supported by concrete columns and upstand beams. Details of the structures was limited. The client required a comprehensive analysis of the mezzanine construction details without a heavy reliance on intrusive methods. SOLUTIONS The second part of the investigation involved targeted intrusive breakouts to confirm reinforcement bar details. All data collected were meticulously processed and analysed by experienced TRACE-SI personnel leading to the creation of a detail report that provided the required, comprehensive information to the client. BENEFITS TRACE-SI's expert analysis ensured confirmation of the element and joint details, providing much-needed clarity for the client. The integration of non-intrusive investigation with targeted intrusive breakouts allowed for comprehensive and efficient assessment while minimizing disruption to the site. TRACE-SI designed and implemented a twopronged investigation approach. First, a nonintrusive investigation was executed using a high-frequency ground-penetrating radar system to delineate the overall and typical construction details. The holistic approach undertaken by TRACE-SI not only provided accurate and detailed results but also promoted informed decisionmaking by the client for future structural considerations.

To allow for targeted repairs mapping of key affected areas was essential. OBJECTIVES A main A-Road in the east of England was constructed with un-reinforced concrete slabs joined with dowel bars. Visual deterioration to the surface caused concern about the condition of the dowel bars. SOLUTIONS The client brought in Trace-SI to investigate the key areas of concern using non-intrusive investigation methods. Trace-SI undertook extensive scanning to map the areas of increased corrosion potential. A system, connected to an RTK GPS that embeds coordinate data directly into the GPR data as it is being collected, greatly increasing the positional accuracy of detected features. The data was collected on site and TRACE-SI analysed and interpreted the data off site. TRACE-SI have developed bespoke workflows to increase the accuracy of corrosion potential mapping by combining automatic analysis with manual interpretation by experienced consultants. This ensured that the areas suspected of corrosion were accurate and not anomalies in the data All results were geospatially accurate and plotted onto CAD or Google Earth, as required. BENEFITS Site works were fast, non-destructive and could be undertaken through existing pavement layers - with no drilling required. Data was collected at high-way speeds, without traffic management. Through repeat scanning, any changes of the bars could be mapped and future repairs predicted

A section of the slab was presenting with significant heave, the cause of which was unknown OBJECTIVES The client had a section of slab that had raised up within their asset. The construction details of the slab were unknown, as was the extent of the damage; was the whole slab lifting or was it only surface finishes. The likely cause of the lifting was also unknown. SOLUTIONS The client brought in TRACE-SI to investigate the affected area using non-intrusive investigation methods. Trace-SI scanned the defective area extensively, as well as the surrounding areas, to determine the typical construction details. TRACE-SI analysed the data off site and were able to determine the typical construction details of the slab and where they varied around the defect. It was found that, while voiding was detected below the slab, only the surface finishes were rising up. Furthermore, the gap between the slab and the surface finishes was filled with water. Water had penetrated through the surface finishes and likely caused corrosion to the steel within the concrete slab, resulting in expansion of material BENEFITS Site works were non-destructive, completed quickly and comprehensive allowing for no disruption to the project Accurate and detailed interpretation of the collected data allowed for detailed analysis of potential causes for the problem. Follow up intrusive works and repairs could be better planned with the knowledge of what would be found upon exposure.

TRACE-SI's tailored non-intrusive survey and analysis approach allowed the client to gain valuable insights into the structural integrity and construction details of a quay in the south of England. OBJECTIVES To address concerns regarding a large crack, subsidence, and potential voids at their quay in the south of England. The client required a comprehensive understanding of the structural details and needed an effective solution to map the voids without causing further damage to the site. SOLUTIONS TRACE-SI designed and executed a nonintrusive survey using ground penetrating radar (GPR) to identify voids and determine construction details of the quay. The survey successfully mapped the voids beneath the slab, providing the client with the necessary information to plan remediation works. The geospatially accurate data allowed the client to precisely identify the location and depth of the voids, as well as gather valuable construction details about the slab. Furthermore, TRACE-SI's expertise in data processing and analysis enabled the client to understand the structural integrity of the quay wall and its connection to the slab, despite the presence of a steel surface plate obstructing visibility. BENEFITS TRACE-SI's non-intrusive survey method preserved the site's integrity and minimised disruption to the client's operations. The geospatially accurate data enabled the client to make informed decisions for remediation works. TRACE-SI's comprehensive report provided the client with insights into the structural details, supporting better long-term planning and management of the quay.