NEC3 contracts/options used: PSC/Option E – During ECI EEC & PSC/Option C - During Construction
Start-finish dates: ECI - Apr 13 to Oct13
Construction - Oct 13 to Sept 15
Main project team members:
Main Contractor: Costain
Designer: Ramboll - Parsons Brinkerhoff (RPB)
Key Sub-Contractors: Freyssinet & Structural Systems UK Ltd
Scope and significance of project:
The phase 2 strengthening of the 622m long Hammersmith Flyover was a phenomenally complex and demanding project required to address serious deterioration of a structure which forms a critical part of the main arterial route through west London carrying up to 70,000 vehicles a day. The works included the installation of new post-tensioning (PT) along the length of the bridge and also replacement of the bearings at each of the 16 piers and upgrade of drainage, central reserve barrier and road surfacing. The post tensioning tendons had been found to be deteriorating at a significant rate and the phase 2 strengthening followed the emergency, phase 1, works completed in 2012 to keep the Flyover open for the Olympics.
There was considerable urgency to complete the phase 2 works because the deterioration model predicted that traffic restrictions would be required only one year after start on site with serious consequences on the road network. At the same time it was imperative that the works were carried out with minimal traffic disruption.
The brief required installation of new post tensioning to remove any reliance on the original post-tensioning, whilst leaving the original system intact. It is believed this is first time this has ever been done and it was not clear at the outset that a solution existed which would satisfy all the objectives and constraints!
The project thus presented enormous challenges and an exemplary level of cooperation between the client, designer, contractor and key sub-contractors proved fundamental to the successful and timely delivery of the project.
Please detail how you demonstrated collaboration on your project:
In recognition of the technical complexity and the benefits of Early Contractor Involvement (ECI), TfL established an Integrated Design Team (IDT) comprising TfL’s technical team and project management staff, Costain as Contractor, RPB as Designer, Flint & Neill as CAT 3 checker and Freyssinet a specialist PT sub-contractor. The IDT was co-located in a central office in London to facilitate communication and collaborative working. During this ECI phase the IDT worked well together and developed the innovative concept and design.
Openness and honesty facilitated a dynamic decision making process. A number of non-standard design approaches were adopted to address the unique technical challenges. Co-location of the team, and trust and respect amongst the parties, was fundamental to formulating and agreeing these approaches within the tight time frame.
BIM was key to co-ordinating this innovation. An accurate 3D model was created from the original as-built construction drawings and verified against internal and external laser scans. This was used as a planning, design and construction tool to identify hazards, constraints and risks for both design and construction.
The integrated team moved to site at the start of construction where they were again co-located in open plan offices facilitating ease of communication and a “one team” ethos. This included members of the RPB’s design team and TfL’s project management and technical teams, all of whom maintained a permanent presence on site through the whole construction period. Continuity of staff from the ECI phase ensured the common understandings and relationships established at the outset were retained.
A “lessons learned” workshop was convened at the end of the ECI phase. Frank and open exchange was encouraged to address any issues and enable a clearer understanding of the respective party’s drivers and perceptions as the project moved into the construction phase. Whole team building social and charitable events were encouraged and supported by senior management and organised on a regular basis.
The team focussed on progressing the significantly changing Services and Works, without always relying on fully implemented change. This was only possible because the respective parties absolutely trusted one another knowing that retrospective change assessments would be fair.
Approved Design or methodology was sometimes unavailable at the necessary time and the Project team worked around these issues using EW’s and Risk reduction meetings to keep on track with objectives and not get hampered by contractual barriers. On occasions TfL agreed to the works progressing in the absence of full approvals demonstrating the high level of trust that existed that the Designer and Contractor would retrospectively provide the necessary assurance.
Cooperation was also enhanced through the use of;
Option X14 – Advance Payments to the Contractor and Subcontractors
Option X20 – KPIs to the Designer, Contractor and Subcontractors
Open and successful cooperation allowed the team to continually challenge drivers and constraints to manage both technical and commercial risk. Without this, the effective use of new technologies, and the ‘one team’ approach, it is unlikely that a solution to such a complex problem could have been defined and delivered.