PROJECT REPORTThis estimate amounting to Rs. 3,84,86,000.00 Rupees (Rupees Three crore eighty four lakh eighty six thousand) only has been framed by the Executive Engineer, PWD, Guwahati NH Division to show the probable cost for Special repair to NH - 37 for the year 2014-15 ; Repair of Bridge Approaches of RCC Bridge No: 34/1 (Krishnai Bridge) & 84/1 (Singra Bridge) by providing pitched protection in front Slope and approach road with apron etc. under Guwahati NH Division in the State of Assam.Bridge No.34/1 (Krishnai Bridge) and Bridge No 84/1 (Singra Bridge) are two important major bridges located in Dudhnoi Agia & Boko- Dudhnoi Sections of NH-37 in the District of Goalpara & Kamrup (Rural) respectively. The details of the two bridge structures are as followsBridge No.Carriage way width(in mtr.)No. of span & length of each spanDetail of Bridge Structures

FoundationSub StructureSuper Structure

34/17.503 X 32.23 WellRCC Solid P.S.C. girder bridge

84/17.5(1 X 40.60) + (1X39.10) WellRCC Solid P.S.C. girder bridge

The details of existing protection works are as follows:Bridge NoBank Protection & Present condition

34/1Stone boulder pitching with apron in front slope and approach washed away

84/1Stone boulder pitching with apron in front slope and approach washed away

The bridge approaches were eroded by heavy rush of flood water on 22nd September 2014 forcing the authorities to close the movement of all heavy vehicles through the Bridges. The Goalpara end of Br No. 34/1 was badly affected and the extent of scouring was such that only light vehicles carrying relief materials to flood affected people, were allowed to move over the Bridge.The Guwahati end of Br. No. 84/1 was also affected and light traffic was only allowed through one half of the bridge Section.Temporary restoration works were started immediately from 23rd September and the bridge approaches were temporarily restored by 28/09/2014. Photographs of the bridges along with the damaged approaches are attached at annexure X. The Highway closer report to the Ministry was sent immediately after occurrence of the heavy flood and enclosed at annexure Y for ready reference.The Regional Officer, MoRT&H, Guwahati, visited the affected bridge sites on 27th September 2014 and advised to take up the permanent restoration work of the two bridges under Special repair head for the year 2014-15. Accordingly this estimate has been framed with detailed repair proposals for immediate approval and sanction.Necessity: - The flash flood that devastated many parts of Garo Hills and districts of Kamrup Rural and Goalpara in western Assam during September 22/23 this year was triggered by cloud burst in Garo Hills. The Cloud bursts are meteorological events which generate copious rainfall usually more than 100mm per hour over a short spell of time with the downpour concentrated on a small geographical area. The continuous down pour in upper reach of the rivers and adjoining Garo Hills carried heavy Storm water and floating debris with high velocity. The water way of the Bridge was not sufficient to discharge such huge volume of water as the flow of water was not axial, resulting in the scouring and frontal attack of the approaches.The Hydraulic data observed during the recent flood have therefore been used to design the protection works capable of withstanding such scouring and frontal attacks of similar magnitude in future.Scope of Work: - This estimate comprises of protection works at embankment and front along with repair of damaged road sections.The detailed scope of work for Br no. 34/1 is as follows: (A) Road works :-(1) Construction of embankment Sub grade & Shoulder.(2) Construction of Granular Sub - Base of 250mm thick (Bottom-150mm will be executed for full formation width).(3) Construction of 250mm thick WMM in two layers.(4) Construction of 50mm thick BM layer.(5) Construction of 75mm thick DBM layer.(6) Construction of 30mm thick BC layer.(7) Construction of Mastic Asphalt of 69mm thick is provided for full bridge length.(8) Safety works, traffic signs and road appurtenances such as R.P.M., Solar Stud, tubular Delineators & Metal Crash barrier etc. (9) Construction of Approach slab, Back Filling behind abutment etc.

(B) Protection Works:-(1) Protection works at the embankment and front slopes by laying of boulder apron in wire crates, filter media underneath the pitching.The detailed scope of work for Br no. 84/1 is as follows: (A) Road works :-(1) Construction of embankment Sub grade & Shoulder.(2) Construction of Granular Sub - Base of 225mm thick (Bottom-150mm will be executed for full formation width).(3) Construction of 225mm thick WMM in two layers.(4) Construction of 50mm thick BM. (5) Construction of 60mm thick DBM layer.(6) Construction of 40mm thick BC layer.(7) Construction of Mastic Asphalt wearing coat of 69mm thick is provided for full bridge length.(8) Safety works, traffic signs and road appurtenances such as R.P.M., Solar Stud, tubular Delineators & Metal Crash barrier.(9) Construction of Approach slab, Back Filling behind abutment etc.

The Pavement thickness has been considered as per the existing crust thickness at the bridge approaches which are 655mm for Br.No: 34/1 and 600mm for Br.No: 84/1

(B) Protection Works:-(1) Protection works at the embankment and front slopes by laying of boulder apron in wire crates, filter media underneath the pitching.

Specification: The works are proposed to be carried out as per MoRT&H specification (5th revision) for Road and Bridge Works.Construction Programme:-Schedule of completion of work: 120 days after allotment of the work.Phasing:YearPhysicalFinancial (Rs in Lakhs)

2014-15100%384.86

Rates: The rates provided in this estimate are taken from SOR for Roads, bridges and culverts for all National Highways Assam P.W. (Building & N.H.) Department for the year 2014-15. The Lead considered in case of analysis of rates for Earthwork, Sub-base and base-courses are as per Quarry & Borrow Area Chart enclosed.

(Afzal Karim)Executive Engineer, PWDGuwahati NH Division, Guwahati