International Journal of Scientific & Engineering Research, Volume 5, Issue 5, May-2014 471 ISSN 2229-5518 IJSER © 2014 http://www.ijser.org Damage Evaluation and Partial Retrofitting of Old Steel Bridge Suresh Kumar Walia 1 , Hemant Kumar Vinayak 2 and Raman Parti 3 1 Research Scholar, Department of Civil Engineering, NIT Hamirpur 2 Assistant Professor, Department of Civil Engineering, NIT Hamirpur, 3 Professor, Department of Civil Engineering, NIT Hamirpur, Author mail ID sureshkumarwalia@gmail.com ABSTRACT This study presents the method of evaluating the damage level of opposite trusses of a bridge through deflection test. The work is carried out on a damaged old deck type steel bridge using total Station and Dial Gauges under similar environmental conditions with the midpoint loading. Further the strength of the bridge is increased as per existing codal provision with partial retrofitting. Serviceability, or deflection, is very important in monitoring the health of not only a structural system, but also in analyzing the affects of a new technology applied in the field. The study presents the use of general survey equipment such as total station because of limited access for specific monitoring equipments with the owner agencies. Keywords: steel truss bridge, deflection, total station, retrofitting ——————————  —————————— 1. INTRODUCTION Among the various issues being faced by the infrastructure maintenance authorities retrofitting deficiency in the bridges is one of the biggest challenges. Further the lack of fund availability forces the state authorities to use the bridges beyond their service life. Among various countries which are facing this type of problem of bridge, India is among such countries. The structural members of the any bridges are subjected to dynamic loading leading to degradation of their constituent material. These bridges are subjected to heavier and faster moving loads, compared to their original design loads. Such overloading of bridges along with their deterioration with age can lead to either catastrophic failure or improper functionality of the bridge((10). The poor quality of construction, defects in the material in the form of cracks, inefficient working of bearings and expansion joints and excessive deflection may require the replacement and retrofit of same. To strengthen the bridges, they should be firstly categorized so that bridges damaged more can be retrofitted sooner by appropriate retrofitting method (2). The relatively good condition of the bridge is primarily attributed to the systematic and periodic inspection and maintenance(5). The detected defects may be then be strengthened and further retrofitted as per the respective codal provisions of load and stresses (11). The work presented in this paper is on steel bridges in one of the states of northern part of India i.e Himachal Pradesh. Many of the bridges in the state of Himachal Pradesh in India has been designed and built several decades ago. 2.STATUS OF BRIDGES The northern part of India at the foothills of Himalaya is mainly a mountainous region with large of bridges constructed on naturally developed perennial and non-perennial rivers. In order to have present status of bridges in this state, the data was collected from the different parts of state for about 650 bridges above 25m span. It has been observed that about 45% bridges have been constructed before the year 1990. Due to different revisions of IRC code 6 from 1964 onwards and continuous increase in volume of traffic and axle loading, it is necessary to develop a strengthening mechanism to make the bridge fit for present loading condition(2). As per the data collected about 3% bridges have been declared as structurally and/or geometrically deficient. Some of the deficient bridges are in service with speed and/or load restrictions and some are out of service. Deficiencies that may be found in bridges are numerous, including uncertainty in load carrying capacity, damage to bridge members due to accidents, excessive loss of the member cross-sectional. Most of the bridges are having a span of 25 to 40m. About14% bridges have been designed based upon IRC Class 18R,Class 24R and Class B loading which is for temporary bridges(11)and due to IJSER