The range of application of this strengning technique is ideally suited for following situations: restoration of structures by rectifying constructional deficiencies that impair safety of structure as a result of faulty dimensioning, corrosion of reinforcement, insufficient reinforcement, overloading etc.

Crack propagation in concrete girders can be arrested by using principles of post tensioning and in this tensile cracking in girder are arrested by including compression using tension ties forced to sides of girder at locations of tensile cracks.

Most of long span bridges are built using prestressed concrete and those built by cantilever method developed by Finister walder, demonstrate latest refinements of construction techniques and this method eliminates use of expensive formwork and scaffolding especially for bridges in deep valleys and rivers with large depth of water.

The suspended span comprises of two prestressed concrete girders with reinforced concrete deck slab of span 40.6m and cast steel rocker and roller bearings have been provided at articulations for supporting suspended span and soon after bridge was constructed and opened to traffic in1975, it developed distress due to improper placing of roller bearings.

The staging method is adopted when low clearances required below deck and supporting formwork does not interfere with traffic and this method facilitates rapid construction by maintaining correct geometry of structure with relatively low cost.

The detailed examination of damage and review of calculations will help in selecting a cost effective and appropriate restoration technique for damaged structure and loss of prestress is excessive resulting in tensile cracks, preloading method should be seriously considered in making concrete repairs in order to restore equivalent full or partial prestresss effect, as per original designs and repair procedure may also include epoxy resin pressure injection, Shortcrete and additional welded fabric with drilled anchors and guniting.

Maintaining prestressed concrete structures of various types in a fit and serviceable condition is primary function of Maintenance engineer investment towards effective periodical maintenance forms only a fraction of cost to be incurred due to major repairs to rehabilitate structures and hence it is always advisable to establish a programmed preventive maintenance system to detect any signs of distress in initial stages itself through inspection procedures and appropriate repairs.

The main advantage of using precast segmental units is that y can be cast on ground near work site well in advance and quality of units will be better than those which are cast in situ and anor advantage is units can be curved to achieve ir full strength before bringing m to assemble at worksite.

Generally any grade of structural steel is suitable for bonded reinforcing plates and plate gauges below 3mm are not suitable because sand blasting can deform m and steel plates between 6-16mm thick were used in some strengning works.

In case of bridges greater than 10.7m in height and in those bridges which cannot be inspected from beneath due to rugged terrain or watery situations, a mechanical contraction widely known as Barins snooper vehicle is ideally suited for inspection work and snooper is mounted on a heavy duty truck with a swiveling platform and underside of bridge deck can be inspected by using hydraulically operated platform.