The Planning, Designs and Investigation Wing comprises one Chief Engineer, one Joint Chief Engineer, four Designs Divisions at Headquarters and eight Investigation Divisions with their Headquarters at various places in Tamil Nadu.

This wing undertakes field investigation works at bridge sites, preparation of detailed design, preparation of detailed drawings and quantity estimates and giving technical guidance for the bridge projects proposed and implemented by various wings of the Highways Department.

Design divisions functioning at Headquarters carry out the design works. The field works are being carried out by the Investigation Divisions.


  • Carrying out investigation for new road and bridge works.
  • Preparation of structural designs, drawings and estimates for bridge works costing Rs.2 Crore and above

Activities of the wing:

Investigation Divisions and their Activities:

The eight investigation divisions with their Headquarters at Chennai, Villupuram, Tiruchirappalli, Madurai, Tirunelveli, Salem, Coimbatore and Tiruppur undertake the following field works.


Detailed investigations at bridge sites and collection of field data.

Obtaining required particulars from the Public Works Department for River Bridges and from the Railways for Railway Over Bridges and Railway Under Bridges.

Sub-Soil Investigation for Foundation Design

Sub-soil investigation through exploratory bores to arrive at the bearing capacity of the sub-soil to design the foundation of the bridges

Preparation of Reports and Drawings

Recommending suitable proposals based on field and sub-soil investigations.

Preparation of cross sectional and longitudinal sectional drawings along the stream & alignment and arriving at hydraulic particulars.

Preparation of alignment drawings and specification report for the proposals and obtaining approval for the feasible proposals.

Preparation of site plans and details for the works of formation of new bypasses and link roads

Designs Divisions and their Activities

The activities of designs divisions are as follows:

As a result of effectively carrying-out all the above activities, during 2012-2013, the Quality Assurance and Research wing has earned a Revenue to the tune of Rs.4.17 Crore to the State’s exchequer by way of Lab and field tests.

  • Preparation of designs, drawings, quantity estimates and technical guidance for River Bridges, Railway Over Bridges, Railway Under Bridges and Grade Separators and other Highway structures, costing more than two crore.
  • Scrutinizing the alternative designs furnished by the contractors and according approval.
  • Checking the Detailed Project Reports prepared by the consultants who are   engaged by the various wings of the Department.
  • Re-designing the bridges if there is any change in alignment and in Railway   proposals.
  • Re-designing the foundations of bridges and other bridge components, if warranted, in accordance with the sub-soil conditions during execution.
  • Scrutinizing and giving recommendations to facilitate issue of permits for non-standard heavy motor vehicles to ply on roads based on the rules   prescribed.
  • Scrutinizing and according approvals for the structural design of bridges to be constructed by other Departments

Works completed in 2012-2013

In 2012-2013, Preparation and Proof Checking of design and drawings for          8 Railway Over Bridges, 15 River Bridges,  one Railway Under Bridges, one Grade Separator, 7 Foot Over Bridges and          11 design modifications totalling 43 Bridge works have been completed by the Design Divisions.

Works to be taken up in 2013-2014

In 2013-2014, it is proposed to collect field particulars and prepare designs for 38 ROBs, 6 RUBs, 14 River Bridges, 5 Grade Separators, 3 design modifications and 4 Flyovers totalling 70 works.  The detailed project reports to be prepared by the consultants will also be taken up for proof checking.