e-mosty December 2018 e-mosty December 2018 | Page 31

Following the previous question, was it difficult to convince or guide the Contractor to achieve the
final results, in terms of geometry variations, and overall quality?
It is my belief that most contractors shy away from precasting because of the preplanning and skill
involved in the work which by definition requires few skilled workmen. If this information is well
documented in advance and available for the contractor to follow, he feels confident to embrace it.
In my experience on almost all our projects the contractor has accepted our suggestion of
construction methods which had been well thought out and well documented at tender stage and
made a success of it. It is useful to note that almost all our projects have been built by advanced
precast design based on careful thought and experience. These projects have included structures on
significant curves.
Regarding the Bandra-Worli bridge; we understand that part of the work was already built when the
Authorities decided to substitute the Designer, and you came on board. Please give us some details on
how the original design was transitioned to your design.
Our involvement on the Worli Bandra Project has an interesting history which gives great credits to
our work as a firm involved in the design of bridges. Our involvement as far as the design is
concerned was related to the Design of the Bandra and the Worli cable stayed bridges and the
supervision of the whole project which included in addition the standard approach spans.
The basic design consisted of a single tower supporting two interconnected deck structures by four
lines of cables with anchorages in the tower. Our design, which had some constraints because the
contractor was already on site, consisted of two deck structures with two dedicated towers. The
advantages of this design are significant and the contractor and client accepted alternative with
grace.
Our alternative design was a single deck approx. 40m wide consisting of spine and cantilever
supported by a single tower with 250m spans on either side of the tower and a single plane of cable
in the middle. The savings in cost were significant.
How do you see the status of bridge design today? Do you see any interesting developments?
Bridge Design today is a process that has taken a very different course to what used to be an
organised established system with well defined responsibilities. A number of consultants are now
involved in the same project and it is not very clear how the responsibilities are shared. The design is
more by committee and the process certainly may not be able to bring out the single minded focus
that is so necessary for the success of a project.
The main drawback and a reason for some of the problems now on delivering a project is that very
few involved can visualise the project as a whole. Engineers are more committed to a digital process
reducing the need to think it through. This has virtually killed the Art of design. We do not produce
stalwarts in the profession like Nervi, Ove Arup, Christian Menn, Fritz Leonhardt to name a few,
anymore.
The scene is now set for more computerised intervention with robots that one might see more the
garbled type of structures requiring structural gymnastics and complex construction methods rather
than the varied simple brilliance of work that often distinguished engineers of the past. Perhaps less
need for engineers but more for technicians.
Thank you very much for your time and cooperation.
4/2018