Holdfast Training Services Trial Blog

Phase 3A must construct three large temporary bridges that provide access through our site – both for adjacent phase’s construction traffic and future residents. The 3D CAD model below provides an illustration.  I have responsibility for bridge 1.  The bridge section spans over 54m and it has two decks of 24m length at either end.  It will be suspended 18m above formation level (when we eventually dig down to basement 3 level).

Temporary Bridge Structure – 3D CAD Model

The Problem

Bridge 1 must be in place to allow residential occupation of Phase 1 (Carillion’s site) in Q4 2016. As a result, the client’s driver is time.  Unfortunately, the temporary bridges have been designed in isolation to the permanent structure and only considered on plan.  As one can imagine this situation has created many clashes.

The Solution

The Devil is in the detail and the solution requires all the stakeholders input. De-confliction is the name of the game and the majority of my time has been spent in meetings trying to work through solutions.  The greatest difficulty lies in the area of the temporary bridge deck supports.  These ‘dolphins’ (the nomenclature on the drawings) consist of piled foundations with high level pile caps that support the bridge deck.  The drawing below illustrates the initial design with uniform spacing (coinciding with the deck spans).

Bridge Supports – Initial Design (relatively uniform supports)

My task has been to knock heads together to come up with a mutually beneficial solution for all.  I have convened meetings with the temporary bridge designers (McGee), the permanent structure designers (BuroHappold Engineering), the piling contractors (BBGE), the M&E designers (Chapman BDSP) and the construction sequencing team (Bouygues UK).  The outcome of these painful liaison meetings can be seen below.  One reason these meetings are so painful is because still no-one has signed a contract.  Whilst not the most exciting Blog post the two photos represent a couple of weeks work and provide an idea of the small victories won.  The next stage is to attempt to reduce the size of these temporary bridge supports…

Bridge Supports – Post De-confliction  (variable shaped supports)

In my last blog I mentioned that there had been a bit of a question 4 moment with regards to steam at LSHTM. This was based around the client asking me to explore other opportunities with regards to steam distribution.

In mid-March I took isometric drawings produced on Revit to the client for approval on the distribution strategy. Prior to conducting the work in Revit to produce these drawings I had discussed the proposed route with the Project Manager (PM) within the LSHTM estate’s team. The route I was proposing was based on taking steam from one side of the building where it was being generated at high level to where it was required on the other side of the building via an external route. This was because I had been briefed to minimise the amount of disruption to the building which would be fully operational during the works. I discussed this route with LSHTM’s PM and even took him to look at it with a possible contractor for comment on the buildability of my proposal. Having gained buy in of the client I proceeded to continue with the work and produce the required drawings in Revit, which took me approximately 1 week. What I failed to do was quickly mark-up a drawing by hand and send it to the client for them to approve formally. It was then at the meeting in March that a more senior member of the client team expressed disapproval with my proposal and asked me to look at another option. This is frustrating on a personal point of view as it is duplicating my work on the same experience and there is little competency experience to be gained from producing drawings in Revit (although being able to use Revit can go towards my A competency). It was also a missed opportunity from a BWL point of view. Because BWL are attempting to develop a relationship with LSHTM there was no resistance to LSHTM’s suggestion from my director.  Probably in part because with me doing the work there is limited cost to BWL. If I had sent a mark-up which had been signed off by the client there is more chance that my time wouldn’t have been wasted in that the desire to explore other options could have been looked at prior to me doing the work in Revit, or if it had been approved I would have had an audit trail to fall back on. I could have more rigorously demonstrated that I had developed the design in good faith and that the proposal being made to consider another route was effectively a variation and required an additional fee. Whether my director would have wanted to do this is questionable, but it would have at least given BWL the option and has certainly taught me valuable lesson.