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S U M M A R Y A variety of maintenance actions are performed by DOTs to preserve highway bridges. DOTs employ similar maintenance actions but can have different practices for reporting maintenance accomplishments, costs, and performances. There is no single system in the United States for uniform recording and reporting of data on bridge maintenance. NCHRP Project 14-15 was conducted to provide a framework for a database system for uniform reporting of bridge main- tenance actions and demonstrate the new systemâs capability with existing practices of U.S. DOTs. The database system, called the National Bridge Maintenance Database (NBMD), pro- motes sharing of data on bridge maintenance. The database allows DOTs to evaluate costs and performance of maintenance actions and execute cost-benefit analyses. The database system is intended to help DOTs manage bridge maintenance resources effectively. NBMD provides a uniform, readable format for bridge maintenance, condition, and inven- tory data. NBMD presents maintenance actions, contexts of actions, and outcomes of actions. For bridge condition data and inventory data, NBMD conforms to the U.S. National Bridge Inventory (35), and the Pontis bridge management system. U.S. state DOTs have various systems for recording bridge maintenance work, and often use separate systems for maintenance work by DOT crews and maintenance work by contract. NBMD offers a uniform, compatible format for reporting all bridge maintenance work. NBMD is a system for the collection and archiving of bridge maintenance data. DOTs that contribute to NBMD will continue their current practices for recording crew work and contract work. NBMD is a recipient of data. NBMD collects outputs from existing DOT data systems and casts these outputs into standard format. This report summarizes current practice in the United States in bridge maintenance work and bridge maintenance data systems, presents NBMD data tables and NBMD software utilities, reviews tasks in collection and use of bridge inventory, condition and maintenance data from US DOTs, applies NBMD data to the computation of element-level costs of maintenance, and proposes a plan for implementation of NBMD. Project Deliverables The deliverables of this project include the NBMD systemâs framework of data tables and stan- dard formats, software utilities for standard tables, datasets formed with data collected from DOTs, computation of element-level maintenance costs, background information on bridge maintenance programs among US DOTs, a glossary of terms in bridge maintenance, and an implementation plan for NBMD. Each deliverable is briefly described in the following sections. Framework for a National Database System for Maintenance Actions on Highway Bridges 1
2Background Information on DOT Bridge Maintenance Programs Design of the NBMD system is guided by information on current practices in work execution and reporting of bridge maintenance programs among U.S. DOTs. Background information on bridge maintenance programs is presented in Chapter 1. NBMD Data Tables and Standard Formats NBMD is a data system for collection, storage, and reporting of information on the contexts, actions and outcomes of bridge maintenance. NBMD is a set of 13 tables presenting bridge maintenance actions together with bridge inventory and condition data. The database is pre- sented in two formats that have identical structure and content. The first and primary format presents NBMD as a set of tab-delimited text files (called tab-text files in this report). The sec- ond format presents NBMD tables as a set of XML documents each conforming to a standard XSD schema. NBMD presents histories of bridge maintenance work. NBMD tables are collected as datasets. Each dataset is a complete, self-contained body of bridge work, condition, and inventory data for a single DOT and a specific reporting period. Within each dataset, the outcomes of mainte- nance actions can be evaluated and studied as changes in bridge conditions. NBMD datasets are stackable. Data from multiples years, residing in multiple, separate datasets can be merged into large datasets so that maintenance work and trends in conditions can be examined over time. Datasets can be combined from multiple DOTs so that large datasets can be assembled for nationwide studies, for regional studies, or to assemble larger populations of specific bridge types, bridge elements or maintenance actions. NBMDâs internal identifiers for maintenance events and for bridges accommodate the merging of datasets without loss of unique identification of events, bridges, and elements. NBMD data are readable. NBMD uses plain-language keywords to identify maintenance work, maintenance resources, bridge elements, and bridges. NBMD data headings are readable, also using plain language to identify the data that are reported. NBMD indexing fields are concatenations of identifiers. All identifiers begin with a global ID for a dataset that indicates the DOT and the reporting year. To these, NBI structure numbers are appended to create bridge IDs, abbreviations for maintenance actions are appended to create event IDs, element numbers are appended to create element IDs, inspection dates are appended to create bridge inspection IDs, etc. NBMD identifiers include strings to denote inspections, bridge elements, or maintenance resources, as needed. NBMD data tables include redundant entries. NBMD has tables that define maintenance actions, bridge elements and maintenance resources. Definition tables relate DOT data codes to NBMD plain language keywords. NBMD has tables that use NBMD keywords in presentation of bridge data. Data tables include both DOT identifiers and NBMD keywords, duplicating some information in definition tables. This is useful for stand-alone reading and use of NBMD tables. Format and structure of NBMD data tables are presented in Chapter 2. NBMD Software Utilities The NBMD system includes four software utilities to access, create, and check NBMD datasets. These are the following: ⢠A viewer for datasets that presents simple summaries of data content; it also can merge datasets and compute element-level unit costs of maintenance. ⢠An application for generation of XML documents from tab-text NBMD tables.
⢠An application for viewing and editing of keyword fields in NBMD tables. ⢠An application to determine line counts for NBMD tables, to assist the NBMD viewer. NBMD applications run under Windows operating systems. Applications are presented in Chapter 3. Tutorials in the use of software are provided. Bridge Maintenance Data In the course of this project, 12 U.S. state DOTs provided data on bridges and maintenance (Alabama, California, Colorado, Michigan, Minnesota, Ohio, Oregon, Pennsylvania, Tennessee, Texas, Virginia, and Wisconsin.). Data from eight DOTs were used to create 15 complete NBMD datasets. Data from two DOTs spanned several years. From these data, multiple single-year datasets were created. DOT data, its collection and preparation, are presented in Chapter 4. Element-Level Costs of Maintenance Actions NBMD data are used to compute unit costs for maintenance actions that improve conditions of bridge elements. Costs are computed when types of maintenance actions are compatible with observed improvements to conditions of elements. Element conditions are collected from element- level inspection reports. Improvements to conditions are computed as differences in element quantities in condition states before and after maintenance. Costs of actions are collected from DOT maintenance records, or summed from DOT resource records. Unit costs of element-level actions are computed as total costs divided by the quantities of elements improved. The compu- tation yields unit costs together with initial and final condition states for elements. Element-level costs of maintenance actions are presented in Chapter 5. Glossary of Terms in Bridge Maintenance A glossary of terms related to bridges and maintenance is provided in Chapter 6. Implementation Plan NBMD becomes more useful and more valuable as its store of bridge maintenance data grows. The implementation plan is twofold: to provide for ongoing data collection and associated man- agement of NBMD datasets, and; to develop applications for NBMD data that can be adopted by DOTs. Early tasks in NBMD implementation focus on expanding the number of datasets to include more state DOTs and, among DOTs already participating, more years of data. Later tasks address development and dissemination of evaluations of maintenance programs based on NBMD data. It is proposed that NBMD be implemented through identification of a sponsoring agency, for- mation of a technical working group of DOTs, and selection of a contractor for NBMD system maintenance and development. The contractor will manage an internet web site for public access to NBMD datasets, software utilities, documentation, and bridge maintenance studies. The con- tractor will provide training materials for DOT users. The contractor will develop applications for data transfer between NBMD and other applications including Pontis and enterprise data systems at individual DOTs. Specific tasks in implementation are: 1. Identify a supporting agency. Support for NBMD is needed to fund continuing collection of data, formation of NBMD datasets, and maintenance of NBMD internet services. NBMD might be supported by a research funding agency, a federal agency or a pool of state agencies. 3
42. Establish a technical working group (TWG) of DOTs that commit to participate in NBMD for a period of five years (or other fixed term). The working group will: a. Contribute to the NBMD data collection by making annual uploads of bridge mainte- nance, inventory and condition data for their bridge networks. b. Evaluate outputs from data analysis based on NBMD tables, such as the element-level unit costs. c. Assess, through active use among TWG members, the effectiveness of NBMD in evalua- tion and deployment of best practices for bridge maintenance. d. Recommend new applications for NBMD data; that is, pose questions of interest to their own DOT and other DOTs that can be answered or studied with NBMD data. e. Participate in focused development of data transfer procedures from DOTsâ data systems to NBMD data tables. 3. Engage a contractor for NBMD to perform system maintenance and development. The con- tractor will do the following: a. Host the website for NBMD data. b. Prepare and deploy datasets collected from DOTs. Make regular updates to the catalog of datasets as DOTs on the TWG provide data. c. Develop and maintain training materials for DOT staff. Printed guides and web-based tutorials are likely to be sufficient for self-directed training of staff at US state DOTs. d. Develop applications for data collection and formatting at individual DOTs. e. Develop applications for use of NBMD data, focusing on stand-alone applications for specific computations and evaluations. f. Provide technical support to NBMD users. g. Respond to TWG membersâ requests for data reports and application development. h. Maintain the structures, formats and standard keywords for NBMD data tables. i. Make periodic (annual) reports of the status of the NBMD system, its data content, its applications, its file creation capabilities, and its products in element-level costs and other evaluations. j. Coordinate regular meetings of the technical working group. 4. Integrate NBMD with Pontis BMS in two key areas: a. NBMD records for maintenance work should offer automated reporting of completed maintenance work to Pontis. b. NBMD computation of element-level costs of maintenance should be generated as Pontis- compatible values, delivered from NBMD as a Pontis Data Interchange File, and sent to Pontis to update cost tables in the Pontis preservation model. 5. Integrate NBMD outputs with Pontis training by Providing demonstrations and training for use of NBMD data in the computation of unit costs for element-level actions required in Pontis. 6. Integrate NBMD with DOT enterprise software. a. Develop methods to collect bid tabulations from Trns*port to form NBMD data for main- tenance events. b. Develop methods to collect crew work accomplishments and costs from SAP Plant Main- tenance module. Deployment at DOTs NBMD establishes a framework for collaboration and sharing of data on bridge maintenance among interested DOTs. DOTs individually create NBMD-compatible data records and assem- ble NBMD data tables. The NBMD use of plain language keywords and plain-text files allows DOTs to create in-house procedures to transfer their bridge maintenance data to NBMD.
NBMD is a framework for data content rather than a set of procedures for evaluation. Meth- ods of evaluation and parameters used in evaluations such as discount rate, cost basis, and infla- tion index are supplied by users of NBMD data. Costs may be direct costs, or a combination of direct costs and user costs, agency costs or other explicit or implicit costs. Inflation indexes may be obtained from the US Army Corps of Engineers, from RS Means, from the US Department of Commerce or other sources. Appendices Appendices A through E provide detailed information on the different aspects of the research. These appendices are not published herein but they are available on the NCHRP Report 668 sum- mary webpage at http://www.trb.org/Publications/Blurbs/164203.aspx. 5
