MS4 accessible gantry standardisation

Recognise

The SMP over the coming years has identified that hundreds of gantries will be required for the programme. The majority of these will be accessible cantilever MS4 gantries, which should in theory be identical across the SMP. Currently, all gantries are designed as bespoke to each scheme and previous standard designs (MCX) have become obsolete and have not been updated. Currently, ITS equipment is installed on gantries on site after erection of the steel superstructure, adding cost and health and safety issues which could be eliminated.

Define

Problem statement

How to introduce efficiencies into the design of gantries through standardisation and the removal of waste.

Purpose

Standardised gantry designs to enable standardised fabrication of steel superstructures and subsequent fitting of ITS equipment at source. Design once, use often. One solution for all occasions.

Benefits

The benefits to us and the supply chain are:

  • reduced design costs
  • reduced fabrication costs
  • standardised erection methods
  • programme and safety benefits

Deliverables

Standard details, drawings, models etc for each standardised gantry type which could be adopted on all other schemes across the SMP.

Associated guidance documents to explain use on schemes.

Contract works information for standardised fabrication and technical assurance compliance.

Success criteria

Success will be defined as:

  • use of standard designs for multiple schemes.
  • demonstration of cost saving from standardised fabrication and erection procedures.
  • demonstration of programme and safety benefits of fitting ITS equipment at source.
  • project programme met or improved.

Measure

Baseline: Current costs of each MS4 gantry location - £50,000 (provided by SMP team).

These costs are based on bespoke design and fabrication information for each scheme.

Analyse

We've developed technical optimisation of the accessible MS4 gantry design, ie minimising materials and cost while achieving a safe design.

Liaised with fabricators and asset maintainers to understand optimum layout arrangements and detailing.

Gained an understanding and agreement of technical assurance processes required for standardised use across multiple schemes. Lessons learned for other standard 'products'

Agreement on procurement strategy for inclusion of these gantries in multiple schemes.

Future design variants are being developed for fitting CCTV cameras etc.

Improve

Implementing SMP Programme Instruction and reflecting improvements over the 3 no tranches in RIS2 will:

  • Reduce the number of bespoke designs for gantries on future SMP schemes.
  • Facilitate standardised fabrication and erection procedures.
  • Influence the design of other disciplines to enable standardised gantry components, e.g. VRS, drainage and comms in verges

Control

Production of a set of standard design drawings, models, details to cover applications across all SMP schemes (similar to old MCX HCD drawings).

Production of model Works Information documents and technical assurance documents

Production of an accompanying set of rules and design parameters within which these designs can
be re-used and the structural design remains valid.

Production of implementation procedures and addition to the SMP Design Guide.

Transfer

Major Projects have issued a Programme Instruction No. 040

SMP Design Guide – includes reference to standard MS4 gantry superstructure design within Annex E2.03 for New Gantries version 4

SMP Structures Peer to Peer Group – sharing information and getting feedback

Operations Directorate (SW Region) team using this standard design for their M5 scheme

Uploaded on the National Highways Lean Tracker and shared more widely with National Highways and supply chain partners

Benefit summary

Expected benefits:

  • Design once, use many times
  • Reduced design costs
  • Reduced fabrication costs
  • Standardised erection methods
  • Programme & safety benefits
  • Better knowledge of the asset in the future for maintenance – standardised asset

Expected cost benefits per location (provided by SMP team):

  • £3000 for design process, £5000 of fabrication costs, £5000 for “production line” approach
  • Total approx. £13,000
  • Assuming approx. 200 sites across RIS 2 schemes and £100k development costs, this gives a net cost
    benefit to SMP of £2.5M

Potential future benefit opportunities include:

  • Combining CCTV camera mountings to remove need for separate support structures (design variant
    in progress)
  • Use of bulk purchase methods for procurement of the gantry superstructures
  • Ease of reuse in different locations due to standard design parameters applicable nationally
MS4 accessible gantry
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