METHODS BASED ON THE EXPERIMENTAL INVESTIGATIONS ON MODEL OR FULL SIZE STRUCTURE MAY BE TAKEN FOR ANALYSIS CONNECTED FIRST,AS APPROVED BY THE ENGINEER -IN -CHARGE (DESIGN FAILURE AND COLLAPSE OF THE BRIDGES IN HIMACHAL PRADESH) .

Bridge collapse in the lower range of Himachal Pradesh constructed by the Department of Public Works in state is a serious concern for which the department must think deeply on the captioned subject matter deliberation required to be designed on the basis of loads and forces that occur during the course of construction and use and must fulfil all requirements of the code for consideration.The design shall be made in accordance with the principles of mechanics , recognised methods of the design and the sound engineering practice In particular,adequate consideration shall be given to the effects of continuity on the distribution of bending moments and shears due to monolithic construction.While designing the such bridges on the various rivers the Engineering eye que related to the methods based on experimental investigations on models or full size structure or element should be connected therewith being approved by the engineer -in - charge and the structure shall satisfy the requirements for deflection and cracking when subjected to a load for 24 hours and the structure shall have adequate strength to sustain for the 24 hours and the structure must show recovery of at least 75 percent of the maximum deflection shown during the 24 hours under the load ,the test loading should be repeated after a lapse of at least 72 hours and the recovery after the second test should be at least 75 percent of the maximum deflection shown during the second test .The design Engineers are responsible to follow all parameters related to the methods of design and the structural elements may be designed as per the analysis of the appropriate method of the Design ,and when the dead load counteracts the effects due to other loads and forces in a structural member of the joint,special care shall be exercised by the design Engineer to ensure adequate safety for possible stress reversals.In addition to the above guidelines account shall be taken of the following forces and effects if they are liable,to effect the safety and serviceability of the structure, Foundation movement,elastic axial shortening,Soil and the fluid pressures,Vibration , Fatigue, Impact ,Erection loads and the stress concentration effect due to point loads and the like .The practice to check the design work prepared by the various agencies working for the General Design Requirements must have proper look and study by the department responsible for the construction and durability .The recommendations made by the code and references to the specialist for knowledge and experience on aspects of the design must be taken into consideration and brought to the notice of the Engineer in charge as required for adequate safety and strength as well as satisfactory serviceability of the structure for construction.