Peckham Arch, Peckham High Street Condition Survey & Life Extension Consulting Services

Figure 1: Peckham Arch at night - McAslan Design - Beta Provided a Condition Survey of Structure & Services

Background

Beta Design Consultants secured a public tender with Southwark Council, to prepare a Condition Survey and Life Extension Options Appraisal for Peckham Arch and Peckham Square future. Peckham Arch is a 35m-span, 11.9m high, steel arch installed in the 1994 and designed by Troughton McAslan to be the centrepiece in the public realm area of Peckham Square. Our role was to advise the council on its structural condition and actions required to extend its life span by at least 20 years. The scope allowed for the following extra support activities:

market engagement to establish costs associated with recommended actions.
MEWP access for visual inspection of steel members and connections as well as cladding
MEWP access for structural testing (ultrasonic) to confirm steel sections sizes
MEWP access for coating assessment using adhesion cross-hatch testing
trial pits to confirm foundations type and depth
electrical testing for lighting
GPR scans to confirm utilities layout and depth in the public square
CCTV survey for the drains

The Arch in Peckham Square sits within the Peckham Rye Lane Conservation Area that is defined by three principal roads: Peckham High Street, Rye Lane and Peckham Hill Street. The Arch is located at the northern end of Peckham High Street and Rye Lane.

Figure 2: Peckham Arch site location within Peckham Square – scope included surveying all utiltites

Figure 4: Site plan prepared by Beta Engineers

Figure 5: The Utility Survey showed the complicated services under the arch and square

Figure 6: Columns supporting steel arch were assessed with their foundations

Figure 7: Arch roof coverings were assessed using MEWP for close inspection

Beta Solution

We prepared the utilities layout including all services (UKPN, Fiber, Drainage) to feed into the overall scheme for the square and incorporated the findings of the topographical survey and the trial pits findings in the drawings.

We carried out a MEWP inspection after submitting a temporary traffic management proposal to ensure the continuous and safe use of the square by pedestrians and cyclists and to create an exclusion zone for safety that did not cause significant disruption for users. Sufficient signage and notice was provided to stakeholders.

Figure 8: Temporary Traffic Management during the MEWP Inspeciton at high level

During the MEWP mobilization we coordinated the access for operatives from the grit blasting subcontractor, the cladding subcontractor, the electrical lighting inspection and our own inspection engineers who carried out the required NDT testing at height.

Figure 9: Ultrasonic Testing of Steel Sections by Beta Engineers to check hollow sections thickness and corrosion section loss

Figure 10: The adhesion cross-hatch test for the steel coating

We prepared the condition survey following the visual inspection and the structural testing. The condition survey identified all defects with a criticality and costing advice based on early contractor involvement to allow the client to plan costs associated with a life extension of 20 years.

One of the challenges was to establish the type and capacity of the foundation of the columns supporting the steel arch. Trial pits allowed us to establish the foundation depth which was used in assessing foundations.

Another challenge was planning for the coating re-application. Our proposal was to organize scaffolding in two stages to allow phased grit-blasting on site followed by site application of coating following the assessment of the coating as being life-expired.

Our condition survey provided advise on the state of corrosion in structural elements, the connections elements (bolts and plates) and the condition of the bracing/tie elements. As these tie rods were special supply, we coordinated with the specialist supplier to ensure they are provided at the same gauge and end details.