Feasibility Study : Assemblying of a Prefabricated Flyover Bridge (at a Busy Intersection), Withing a 10 - 11 Hour Time Window.
Rational & Sypnosis:
This R&D project intends to look into the feasibility of Onsite Assemblying of a Prefabricated Flyover Bridge (at an intersection), withing a 10 - 11 hour time window. Thus if one starts the Assembly Process around 10 pm on a Saturday night, the Process should be Completed by 9 am, Sunday.
The rational is to Assemble the Flyover so that no significant blockage occurs to the traffic going through the intersection. The current approach, where the ground works (ex. Laying of the Foundations etc), requires a significant amount of disruptions to the already jammed/ crowded traffic flow (thus inducing added strains / delays onto the commuters / during the times of constructions).
Project Description - Part I -
In this modified approach, all such foundation laying ground works / diggings etc. will be carried out, during night shifts (away from the traffic congestion hours). And by the time, of next day traffic rush, all the partially completed ground works/ foundation layings etc would be covered with Temporary Steel/ Concrete "Cross-Overs", so that the traffic can move over the ground works / foundation digs, without much disturbance (Refer Fig 1 under section: Follow on project - Part II -).
(The partially completed ground works, could be constructed inside of recycled plastic sheeting, so that ground water as well as rain water will not seep into the Foundations, Concretions etc. )
While the Ground Works /Foundations are being put in place, at a suitable closeby location, the Concrete Columns, Beams / Box Girders etc (aka the above ground works of the Flyover), would be constructed in suitable moulds.
And once the Concretes of the Foundations and the remainder of the Flyover have sufficiently / properly Set, then a following weekend time window (low traffic window), would be selected to Move and Assemble the Flyover at its Destination.
(For moving the concrete structures, available heavy prime movers would be contracted.)
And while, the Flyover is Assembled, the completed sections can be asphalted in parallel.
Note that if an unexpected thunderstorm brings in heavy showers, it would not have much effect on the Assembly Work, as all the Concrete Structures would have had properly Set (by this stage). Thus if proper lightning protection is provided to the site (aka lightning conductor towers placed at closeby locations, thus diverting all lightning away from the construction site, as lightning would always prefer the least resistance path), the construction crew can continue the work with proper rain gear.
(A flash flooding incident or excessive winds could however probably cause a disturbance / delay? But usually Met Departments can provide advance notice of such severe weather events... Thus...)
To lay the asphalt on a rainy day, (and keep the concrete sections that needs to be asphalted dry), weighted plastic or canvas sheeting could probably be utilized, to cover such sections that needs to be kept dry.
And in parallel, seperate teams could fix the side railings / lighting fixtures, sign post modifications, signal light modifications and new lane markings.
Alternatively this Moving and Final Assembly could also be carried out in two stages. Here the Properly Set Concrete Structures would be moved first to The Sidewalks, (or to a close proximity) of the intersection. And once all the sections have been so moved (from the "moulding" location), then at a suitable time frame / window, the Final Assembly can be carried out.
Informing the motorists of the new Lane Layouts
Suitable PR campaigns will have to be utilized, to inform the motorists (whom commutes via this intersection) of the modification, that would be carried out, so that "come next Monday morning", they do not find themselves on the incorrect lane, which could cause a lot of unnecessary headackes...
One possible technique would be to inform / update the motorists, (while they are waiting in traffic at the intersection), that such a modification will be carried out soon, and to pay close attention to the lane markings and overhead gantry sign boards... These PR campaigns could be carried out for 1 or 2 weeks prior to the modification (final Assembly of the Flyover), each day highlighting how many days left before this modification is expected to take effect (if all goes as planned).
And begining Sunday morning, to highlight the new Lane patterns, suitable highlighters could be placed in the gantry sign boards (To Clearly Indicate That Lanes Have Changed). GPS maps and GPS based navigation systems as well, will have to be modified accordingly (as in the case of any road/ lane modification).
If Assembly of the Flyover can be completed by Sunday morning, first trial runs and monitorings can be carried out beginning Sunday itself.
Traffic Congestion of Major City Motorways
For example, if a Major Motorway (Traffic Artery) of a City, goes through 5 major intersections, and if Traffic Flow Simulation Softwares indicates / confirms that placing 5 Flyovers / Underpasses at these intersections would significantly reduce the traffic congestion in this route, then by Assemblying 5 Flyovers (in 5 weekends), could most likely bring significant reduction of stress and time wastage in traffic congestion for the commuters of this route.
Follow on project - Part II -
If above R&D project does yield, successful results (aka if found feasible), as a follow on project would like to investigate techniques of building an underpass, in this same manner (aka engaging in construction of an underpass, whilst causing minimal disturbance to overhead traffic). However intuition indicates, that this might be a more trickier / more complicated / more involved than building a flyover.
For example; first, the underground side Walls of the Underpass will have to be constructed. Then at locations that would require a Concrete Roof above the Underpass, (which will eventually become the surface road at the center of the intersection), such will have to constructed. Again as this would entail surface work, utilisation of Temporary Steel/ Concrete "Cross-Over", would be required to allow the existing traffic to move as smoothly as possible, with least disturbance.
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| Fig 1. |
Then once this Concrete Roof section of the Underpass (which will eventually also become the pavement/ tarmac at the center of the intersection) has Set sufficiently, the earth underneath it, can be dug out / removed upto the depth of the underpass bedding / floor and work on the Underpass floor / pavement, can be carried out.
In sections not covered by the Roof Concrete, the Underground Construction Works will have to be carried out, via/ underneath the Temporary Steel/ Concrete "Cross-Over".
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| Fig 2. |
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| Fig 3. |
And in parallel, the new street markings, gantry sign board modifications and signal light modifications etc could also be carried out...
Field Trials / Test Runs
A few Field Trial Runs would most likely be very helpful, to fully understand grasp all the issues / complications (that can usually slip, design stages). As with any new approaches / techniques, with a few "Trial Runs" (Field Tests/ Ground Tests / Trial & Error Runs), most such unforseen issues can be identified and remedial measures adopted and / or better approaches formulated/ implemented.
Follow on project - Part III -
If Part I & Part II of this R&D project yields positive results (aka if found to be feasible and ground issues can be resolved to sufficient degrees / levels), then as Part III, could also look into constructing a combined Overpass and Underpass at the same intersection (whilst causing minimum disturbance to existing traffic).
© ly de sandaru
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