Indian Road network comprises of National Highways (under Ministry of Roads, Transport & Highways; GOI), State highways, Major district roads (both under various state government PWD), Rural roads (under various Gram panchayats, State government) and Urban Roads (under various Municipal Corporations). National Highways constitute less than about 3 percent of the total road network.
MORTH initiated a program to develop and implement a digitized Indian Bridge Management System (IBMS) on National Highways in 2015. Prior to this three efforts were made. No other state government has yet initiated any parallel activity on this front. Hon Minister Nitin Gadkari has offered IBMS software free from the Central Government to any State Government who so ever is desirous to implement the same.
Parallel to this NHAI initiated the Road Asset Management System (RAMS) which included the Bridge Information System (BIS). Many State Government also initiated their own RAMS. There are presently 7 to 8 different agencies working on the development of RAMS using different software and a different set of information to achieve the varying level of same goals and objectives.
There is a myth that BIS in RAMS can perform the functions of IBMS. This article is an attempt to clarify this myth
Bridge Information System (BIS):
BIS is the collection of data related to various aspects of the bridge. This set of data information is collected physically by field engineers by visiting each bridge location. The information that is collected includes inventory and inspection details of the bridge. This information is then used in RAMS to evolve the MRSR strategies and cost estimates for MRSR interventions. Most of BIS in RAMS does not include the bridge testing data and evolution of prognosis and cause identification to define the MRSR intervention. Such interventions are decided based only on inspection data which at times could be misleading. Due to failures of various bridge rehabilitation projects much before the designed service life,
IBMS also relies on BIS for its information and data to apply various functions of management. Typically IBMS has three main bridge data collection modules. They are
- Bridge Inventory data
- Bridge Inspection data
- Bridge Testing results
Bridge Inventory consists of the following data parameters each having varying numbers of input fields
- National Identity Number
- Bridge Location Number
- Administrative Details
- Bridge Geometric Details
- Bridge Classification Number
- Bridge Structural Rating Number (BSRN)
- Bridge Functional Rating Number (BFRN)
- Bridge Socio-Economic Rating Number (BSERN)
Bridge Inspection data consists of information that a senior bridge inspection engineer collects by from hand touch distance. (This hand touch distance is critical aspect of bridge inspection)
- Bridge structural details
- General details
- Details of approaches
- Details of protection works
- Details of waterways
- Foundation details
- Substructure details
- Super structure details
- Bearing and pedestal details
- Expansion joints details
- Deck slab details
- Wearing coat details
- Drainage details
- Handrail, parapet, crash barrier details
- Footpath details
- Details of utilities etc
Based on the hand touch approach the senior bridge engineer is able to confirm or modify the Bridge Structural Rating Number, Bridge Functional Rating Number and Bridge Socio-Economic Rating Number. This confirmation forms the internal validation and quality control process of IBMS.
Based on the same a prognosis is evolved as to what is the cause of distress. Cause being primarily arising due to the aggression of either Mechanical elements, Chemical elements or physical elements. Once a prognosis is established, testing on the bridge is conducted to confirm or modify the prognosis. This test result form the third most important element of BIS in IBMS.
To supplement the bridge location data we have the database of climatic zones, seismic zones of India which along with the local hydraulic data form the last set of information in the BIS.
Indian Bridge Management System (IBMS)
A Bridge management system or IBMS in India; is a means for managing bridges throughout the design, construction, operation and maintenance of the bridges by performing rational and systematic approach to the functional activities related to the bridge. As funds available become tighter, road network authorities are facing challenges related to bridge management and the escalating maintenance requirements of large infrastructure assets. Bridge management systems help agencies to meet their objectives, such as assimilation of inventories and inspection databases, planning for Maintenance, Repair/ Rehab, Strengthening or Replacement (MR&R) interventions in a systematic way, optimizing the allocation of financial resources, and increasing the safety of bridge users. BMS provides the owners with system assisted decision making during the Life cycle.
Objective of IBMS
- Maintain bridge inventory and network in an efficient manner
- Guarantee safety of the users for specified risks.
- Determine inspection and maintenance needs
- Ensure the level of service
- Predict future needs of funds
- Optimize fund utilization
- Prioritize asset for maintenance needs
- Predict balance service life and optimize its life cycle costs
Provide accurate and real-time information of the asset to users and owners
How do we achieve these objectives?
Taking data information from the BIS, we move ahead to apply various other functionalities within IBMS. The first logical step post-BIS is to create a subset of bridges which show distress.
Within this subset a bridge specific cause identification and confirmation as to what is causing the bridge to show distress. This cause confirmation is based on the prognosis established within the inspection database and the results of testing done on the bridge. This results of the this Cause identification process provides data to two other functions of IBMS namely
- Deterioration modeling
- MRSR interventions
Deterioration modelling is bridge specific analysis to determine the time domain based on the various causes acting on the bridge which could lead to failure. Primary cause and secondary causes are identified in deterioration model and their impact on the bridge elements which could result in failure is determined using the BSRN and Cause Matrix developed from data of that bridge.
The results of deterioration modelling enable us to evaluate the risk to the bridge if no MRSR interventions are not provided under the Risk Analysis module of IBMS. Basically, the risk involved is estimated based on the Balance Service Life of the deteriorating bridge.
Once the risk analysis is done, we can evolve the Priority and Ranking of the bridge to undergo the MRSR interventions. Such ranking is dependent on allocation of funds to the network maintenance by the owners of the network. At times we need to evaluate the importance of network to assign the Ranking to the bridge. This network importance is assigned based on the total movements on a particular highway based on the data of ADT and also on an external database of HTOA which is published.
Having selected the bridge for MRSR interventions, the type of interventions are decided based on the Cause identification and the standards published under Euro codes (EN 1504) wherein the principle of MRSR interventions are defined for various causes identified. There could be multiple methods based on various brands, but the generic principle of MRSR interventions are critical. You cannot provide the same solution for all causes.
MRSR interventions provided over years to various bridges and estimates prepared for such bridges enable the compilation of the Cost Module of IBMS. This is a historical compilation module and hence will evolve over a period of time as data gets accumulated.
The main function of IBMS is to be able to predict the fund required in short and long-term to manage all the bridges on the network in an optimised manner, Budget in short term and long term is compiled based on inputs from deterioration modelling of each bridge that needs MRSR intervention based on Ranking and priority accorded.
Finally, the level of MRSR intervention, the funds available have to be matched. This is the main objective of IBMS. To achieve Fund Optimization we have to ensure that the funds are allocated to the most deserving of the bridges and to the most essential MRSR intervention.
BIS is the starting point for any bridge management system and not the final output. Data collected under RAMS unless it is aligned with the objectives of IBMS will not be able to fulfill the objectives of IBMS and hence will need to be upgraded in times to come by the implementation of complete IBMS for those networks. This would lead to duplication of cost and can be avoided if the BIS within RAMS are aligned with the BIS of IBMS. Such a step will save millions for every state government.
Indian Road Congress has reconstituted their B8 Committee to include Bridge Management along with Bridge Rehabilitation. Various Special publications are undergoing changes to include the importance of testing in the decision making of the MRSR interventions. A manual on Inventory, Inspection and Maintenance of road bridges is also under compilation which will then be able to provide a synchronized database for both RAMS and IBMS. Till such time that the manual is published IBMS centre can provide the details of the BIS requirements for IBMS so that RAMS developers and implementing agencies can save duplication of costs.