Report.docx

1.1

METHODOLOGY Based on the objectives and scope of the consultancy services, an appropriate methodology has been developed in order to address the various requirements of the project. Since the scope of the services to be provided covers both independent and inter-dependent activities, it has been proposed to adopt a Task Approach to ensure that the entire scope of services is completed comprehensively and with reasonable accuracy.

1.1.1

Investigations for Bridges and Structures

1.1.1.1

Inventory and Condition Survey for Bridges and Culverts Inventory and condition survey of culverts, bridges and other structures shall be done to ascertain the need for reconstruction / widening and rehabilitation of these structures. The condition assessment of bridges will be carried out by Senior Bridge/Structural Engineer in accordance with guidelines given in IRC-SP:35-1990. The data shall include construction details, type of foundation, substructure and superstructure, details of span, waterway, design loading and functioning of the structure in the past, both from hydraulic and structural considerations.

1.1.1.2

Hydraulic and Hydrological Investigations These studies will be carried out in accordance with IRC Special Publication No.13 (Guidelines for the design of small bridges and culverts) and IRC:5-1998 (Standard Specifications & Code of Practice for road, bridge section 1 - General features of design). These investigations will be carried out for all existing drainage structures along the road sections under the study. Its quality will be ensured by: 

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Collection of data by an experienced engineer  Its correct interpretation based on experience, site inspection and behaviour of other structures across such streams in the near vicinity by such experienced engineers.  For HFL, reliance will be placed on past records, local enquiries and flood marks on structures in the vicinity.  For road sections getting overtopped during heavy rains will be placed on local enquiries. Geo-technical investigations will be carried out for determining engineering characteristics of subgrade soil, the sub-soil underlying the foundations of the proposed bridges and other structures, etc. as per IRC 78-2000 and underneath the road pavement. Appropriate field tests will be conducted and boreholes drilled at selected locations as indicated in the TOR. The minimum scope of geo-technical investigations for bridge structures is: Procedure Quality Assurance requires that activities at every stage of geo-technical and material investigations shall be carried out strictly in accordance with the procedures prescribed in the relevant codes, so that the results of these investigations reflect truly the sub-soil and material characteristics. Every geo-technical and material investigation will be carried out and completed principally in four sequential stages, namely: a) b) c) d)

Field Investigations Sampling Laboratory Testing Report Preparation

While the investigations will be carried out by competent technical staff comprising trained technicians and well qualified engineers, the Materials and Geo-technical Engineer will pay periodic visits to the boring sites. An experience geo-technical Engineer will be posted at site for the entire duration of the boring work to have constant check. The results of the investigations as furnished by the sub-consultants shall be examined by the Materials and Geo-technical Engineer for consistency and compatibility before acceptance. Standards to be followed for testing i)

In Situ Testing Standard Penetration Test (SPT)-IS:2131 Collection of Samples – IS:1892, IS:2132

ii)

Laboratory Testing Tests on Soil Samples              

Visual and Engineering Classification – IS 1498 Sieve Analysis and Hydrometer Analysis-IS:2720, Part IV Liquid and Plastic Limits-IS: 2720, Part V Specific Gravity-IS: 2720, Part III Proctor Compaction Test-IS:2720, Parts VII and VIII Field Density-IS: 2720, Parts VII, VIII and IX Field Moisture Content-IS: 2720 Part II Unconfined Compression Test-IS: 2720, Part X Direct Shear Test-IS: 2720, Part XIII Triaxial Shear Tests: Unconsolidated Undrained (UU) Test-IS: 2720, Part XI Consolidated Undrained (CU) Test-IS: 2720, Part XII Consolidation Test-IS: 2720, Part XV Cholride and Sulphate test