The Age of Infrastructure in a Time of Security and Natural Hazards R. Zimmerman, C.E. Restrepo and J.S. Simonoff New York University For internal purposes only; not for distribution due to copyright restrictions. Abstract The age of U.S. infrastructure connects in subtle ways with many other threats such as terrorism, natural hazards, and climate change that these facilities and services face. Many new infrastructure initiatives being introduced to address these threats are also likely to address many of the condition and performance problems of aging infrastructure. This paper evaluates a number of infrastructure areas to identify how measures of condition are associated with age as well as other factors such as environmental stresses, usage, design, and operations and maintenance practices. This type of knowledge is an important prerequisite to understanding how infrastructure age relates to infrastructure resilience in the face of extreme events. Introduction Age is one of many factors that affect the performance of infrastructure for its users and its robustness against threats posed by common environmental conditions external to a given infrastructure, extreme natural hazards, and terrorism. Infrastructure age often acts together with and may reinforce the effect of other factors such as design, maintenance, and operation in increasing the vulnerability of infrastructure to these various threats. This paper evaluates a number of infrastructure areas and types of hazards in order to identify to common themes with respect to the extent age is associated with infrastructure condition and performance as well as other factors such as environmental stresses, usage, design, and operations and maintenance practices that may also contribute to condition and performance problems. New initiatives in the way that infrastructure is designed can address both new public concerns such as sustainability and security and the problems of condition and performance to which age contributes. Infrastructure will be increasingly faced with threats that potentially compromise its integrity. This is supported by the increasing number of major federally declared disasters, increasing by about 2.7% per year between 1990 and 2005 (Simonoff, Restrepo, Zimmerman and Naphtali 2008) and the fact that most of the major hurricanes have occurred since 2000 (Blake, Rappaport, and Landsea 2007). Terrorist attacks, likewise, have targeted infrastructure, particularly transportation (Mineta Institute; summarized in Zimmerman and Restrepo 2009) and electric power (Simonoff, Restrepo and Zimmerman 2007). 1
Whether age is used to prioritize infrastructure for rehabilitation or reconstruction will depend on how it has contributed to past condition and performance problems. There are various indications of infrastructure weaknesses and outages that are indicative of age, some of which are described below, but more research is needed to definitively associate these weaknesses. The ASCE (2009) report card for infrastructure cites the poor quality of infrastructure in the U.S., but it is difficult to separate out age as a factor. Factors Potentially Reinforcing Infrastructure Age Problems Environmental Factors Environmental factors can reinforce or perhaps override age as a contributor to infrastructure failure. Examples of environmental factors often cited as affecting underground infrastructure include soil movement and pressure created by seasonal freeze-thaw cycles and attack by biological or chemical agents in the underground environment. Other environmental factors related more to human actions include construction interference involving inadvertent breakages of utility lines (backhoe failure), failure to back fill supporting material for other infrastructure after construction, and breakages in water lines during winter months that can cause freezing of water around other utilities lines. Infrastructures that are in poorer condition due to age can be more vulnerable to such environmental intrusions. A wide range of other environmental factors affect above ground infrastructure facilities that are weather related and also involve destruction by animals and birds. The relevance of environmental factors as affecting underground infrastructure was underscored by an extensive investigation of water distribution pipes in New York City, which could also apply to energy and transportation networks as well. In the NYC study, the U.S. Army Corps of Engineers found that various environmental factors were associated with pipeline failures, not only age, concluding that there is no consistent pattern of increasing breaks as pipes get older (Betz Converse Murdoch Inc. 1980, pp. xiv-xv). Age, the study indicated, however, is indicative of the fact that older pipes were not designed to withstand newer stresses associated with increased usage and activities going on around the infrastructure. These stresses, often brought about by nearby energy and transportation infrastructure, include electrical currents, vibration from roadway traffic, and construction. The USACE study particularly cited beam failure as contributing to water pipeline breakage, where the supporting subsurface material is worn away or not replaced after construction. Environmental factors other than age were also acknowledged in a nationwide study of water infrastructure needs (U.S. EPA 2002; Cooper 2009). It should be noted that breakage is not the only indication of deteriorating water infrastructure. Leakage rates or lost water is indicative of a wide range of problems. A U.S. EPA (2007) report cited U.S.G.S. figures of 1.7 trillion gallons of lost water. The relationship of age to leakage rates is an important area of investigation. Infrastructures are highly interdependent and thus affect one another. Of particular relevance to condition of assets is spatial proximity of infrastructure, which has increased as utilities have found it more economical to locate utility lines in the same corridors. Zimmerman (2004) for 2
example found that breakages in different kinds of distribution systems affected one another with water breakages affecting other infrastructure distribution lines the most: Ratio Indicating the Number of Times One Infrastructure Caused a Disruption Disruption in Another Infrastructure vs. Another Infrastructure Disrupting Water mains 3.4 Roads 1.4 Sewers/ sewage treatment 1.3 Electric Lines 0.9 Gas lines 0.5 Fiber Optic/Telephone 0.5 Design Age might not necessarily be directly indicative of vulnerability, but may suggest design practices that contribute to vulnerability. As discussed in more detail in the section on bridges below, during the 1950s and 1960s, a shift toward non-redundancy in bridge design led to inflexibilities that restricted alternatives when materials were weakened due to maintenance problems. Age has not affected flexibility in some infrastructures. For example, the NYC transit system which is decades old, showed considerable flexibility in being able to recover from the subway damages and shutdowns following the September 11, 2001 attacks on the World Trade Center (Zimmerman and Simonoff 2009). Causes of Infrastructure Failures The first step in understanding the role of age in infrastructure resiliency and vulnerability is an analysis of the causes of failure and the extent to which these causes can be related to age. Below is a synopsis of the authors research findings in the energy area for oil and gas transport and electricity and in transportation with respect to bridges. Hazardous Liquid Distribution Pipelines Two-thirds of the petroleum supply (Rabinow 2004) as well as other materials collectively called hazardous liquids) move through approximately 170,000 miles of U.S. pipelines (Office of Pipeline Safety 2008) (Restrepo, Simonoff and Zimmerman 2009, p. 39). Restrepo, Simonoff and Zimmerman (2009, p. 40) found that of the causes of hazardous liquid accidents for those accidents reported, about 12% were attributed to internal and external corrosion which of the various causes cited are the ones that are potentially age-related. When the missing data items are eliminated, this percentage doubles. Thus, if age is related to corrosion (an important research question) then in fact age is indirectly a factor in such accidents. 3
Natural Gas Transmission and Distribution Natural gas provides about a fifth of the energy usage in the U.S. The transmission and distribution system is vast, and has evolved over many years. The extent of the natural gas system is reflected in the following statistics: U.S. gas infrastructure consists of... more than 210 natural gas pipeline systems; 302,000 miles of interstate and intrastate transmission pipelines; more than 1,400 compressor stations that maintain pressure on the natural gas pipeline network and assure continuous forward movement of supplies; and more than 11,000 delivery points, 5,000 receipt points, and 1,400 interconnection points that provide for the transfer of natural gas throughout the United States (Energy Information Administration 2007). The National Research Council report, Making the Nation Safer (2002) indicated that oil and gas infrastructure was a key source of vulnerability, and this infrastructure area has been included in the critical infrastructure categories that DHS targets for protection. The analysis of Office of Pipeline Safety data from 2002-2005 by Simonoff, Restrepo and Zimmerman (2009) found that as in the case of hazardous liquid pipelines, internal and external corrosion, potentially a sign of age, accounted for about a quarter of natural gas transmission incidents. Electric Power Weather and equipment failure were found to be leading causes of electricity outages in the U.S. from 1990-2005 with 28% of outages in the U.S. and 40% in Canada accounted for by equipment failure (Simonoff, Restrepo and Zimmerman 2007). Equipment failure is the factor most closely potentially related to age, but could be related to other factors as well. More information about this particular relationship is needed before age can be considered a contributing factor to such outages. Bridges It is well known that some of the more devastating bridge collapses were not due to age but rather to combinations of design, maintenance, operation, and the environmental stresses. The over two dozen bridges that collapsed tracked by the National Transportation Safety Board (NTSB) were not among the oldest, many of which were built in the mid-20 th century. The NTSB, for example, concluded that maintenance problems contributed to the collapse of a section of the Mianus Bridge over I-95 in Connecticut in 1983. That bridge was constructed in 1958. The Schoharie Creek Bridge, which opened in 1954 in New York State, collapsed in 1987. The collapse was attributed to structural elements that contributed to susceptibility to bridge scour that ultimately undermined the bridge supports. 4
Nevertheless, the National Inventory of Bridges database points to the fact that structural deficiencies and functional obsolescence may be related to age. Bridges in New York State are used as an example to illustrate this point. Figure 1 below gives the distribution of bridges in New York State by the period in which they were built, calculated from the FHWA National Bridge Inventory. Figure 2 portrays the declining proportion of bridges that are structural deteriorated and functionally obsolete with decreasing age for New York State bridges. Figure 3 gives the declining percentage of bridge superstructures in poor condition with decreasing age. Figure 1. Distribution of Bridges by Year Built, New York State, 1800-2005 5000 4500 4550 Number of bridges 4000 3500 3000 2500 2000 1500 1000 500 0 1800-09 3354 2682 2557 2526 2120 1229 1158 953 506 543 1 0 1 0 3 11 7 23 77 122 1820-29 1840-49 1860-69 1880-89 1900-09 1920-29 1940-49 1960-69 1980-89 2000-05 Source: Tabulated from the FHWA, National Bridge Inventory. 5
Figure 2. Number of Structurally Deficient and Obsolete Bridges in Each Time Period as a Percentage of the Number of Bridges Built in Each Time Period, New York State, 1800-2005 60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% 1904 and earlier 1905-1910 1911-1915 1916-1920 1921-1925 1926-1930 1931-1935 1936-1940 1941-1945 1946-1950 1951-1955 1956-1960 1961-1965 1966-1970 1971-1975 1976-1980 1981-1985 1986-1990 1991-1995 1996-1999 2001-2005 Structurally deficient bridges as a % of total bridges Functionally obsolete bridges as a % of total bridges Source: Graphed from the FHWA, National Bridge Inventory. Figure 3. Bridges with a Superstructure Condition Rating of Poor or Worse as a Percentage of Total Bridges Built in that Time Period, New York State 25 20 15 % 10 5 0 1890-99 1900-09 1910-19 1920-29 1930-39 1940-49 1950-59 1960-69 1970-79 1980-89 1990-99 2000-05 Source: Graphed from the FHWA, National Bridge Inventory. 6
Dams Dams located in New York State are used here to illustrate some of the patterns with respect to age and hazard level as defined in the National Bridge Inventory program. With over 1,970 dams, New York State ranks 14th among states in the country in terms of total number of dams and 15th in total maximum storage capacity of dams. Dams are assigned a hazard level, and hazard level is one aspect of a dam s overall condition. Three hazard levels are assigned to dams high, significant, and low. High hazard dams are those that can cause loss of human life and serious damage to homes, properties and infrastructure in the event of a failure. Significant hazard dams are those that may cause important damage to properties and infrastructure in the event of a failure. Low hazard dams are those that may cause damage to agricultural land and roads in the event of a failure. The designated hazard level and the presence of an emergency action plan for dams are important in addressing vulnerabilities that may adversely affect the values for measures of consequences, such as fatalities and injuries and economic losses in case of a terrorist attack or a natural hazard. Age may also be a factor to consider in prioritizing security and emergency action preparedness in the event of a terrorist attack or a natural hazard. However, the importance of age as a factor in vulnerability depends on maintenance and design, both of which are difficult to capture given data collected and available in data sets such as the National Performance of Dams Program (NPDP) database. Descriptive statistics relating age of dams to hazard level in NYS reveal a pattern that suggests that hazard level increases with age, however, the role of other factors mentioned earlier needs to be kept in mind in interpreting these findings. Descriptive Statistics for Age of Dams by Hazard Level, New York State Age Hazard Level Mean Median Mode Standard Deviation N Maximum Minimum High 81.0 84 97 35.8 375 209 8 Hazard Significant 75.9 79 99 34.3 694 221 9 Hazard Low Hazard 66.3 57 45 34.2 715 226 8 Source: Computed using data from the National Performance of Dams Program (NPDP) database. Figures 4-7 show histograms of the number of dams in New York State by the year they were completed. Figure 4 shows the distribution of dams in the state by year built. Figure 5 shows the age distribution for high hazard dams, showing that a high number of them were built in the early 1900s. Figure 6 shows the age distribution for significant hazard dams and Figure 7 for low hazard dams. The age distributions are bimodal, with peaks for number of dams completed in the early 1900s and in the middle part of the second half of the 20 th Century. 7
Figure 4. Histogram of number of dams by year built, New York State Source: Graphed using data from the National Performance of Dams Program (NPDP) database. Figure 5. Histogram of number of dams (N=375) by year built for high hazard dams,, New York State Source: Graphed using data from the National Performance of Dams Program (NPDP) database. 8
Figure 6. Histogram of number of dams (N=694) by year built for significant hazard dams Source: Graphed using data from the National Performance of Dams Program (NPDP) database. Figure 7. Histogram of number of dams (N=715) by year built for low hazard dams Source: Graphed using data from the National Performance of Dams Program (NPDP) database. Conclusions It is instructive to evaluate common patterns and trends across many different infrastructures to identify common themes with respect to the extent to which infrastructure age contributes to other problems and reduces the ability of the infrastructure to withstand stresses from extreme events. This paper covered energy infrastructure for oil and natural gas transport and electricity production, transportation infrastructure primarily with respect to bridges, and water-related 9
infrastructure that also provides electric power that of dams. First, it is apparent that although age may be available in very detailed inventories, consistent ways are needed of incorporating dates that rehabilitation and reconstruction occurred and ways of differentiating the age of different components of a given type of infrastructure. Second, what is apparent from the information presented above and from the literature is that the significance of age as a factor influencing infrastructure condition is different for different types of infrastructures, agencies, and objectives. Third, relationships identified between age and other infrastructure characteristics related to condition or performance are complicated by the many environmental stresses that infrastructure faces, especially in urban areas, and design practices that limit flexibility. Much of the new funding that is being targeted to infrastructure under the American Recovery and Reinvestment Act of 2009 (New York State 2009) is likely to address the age issue as well as needs for sustainability and security. Acknowledgements and Disclaimer This research was supported by the United States Department of Homeland Security through the Center for Catastrophe Preparedness and Response at New York University, Grant number 2004- GTTX-0001, for the project Public Infrastructure Support for Protective Emergency Services, by the United States Department of Homeland Security through the Center for Risk and Economic Analysis of Terrorism Events (CREATE), Grant number 2007-ST-061-000001, and by the Institute for Information Infrastructure Protection (The I3P) under Award 2003-TK-TX- 0003. However, any opinions, findings, and conclusions or recommendations in this document are those of the authors and do not necessarily reflect views of the United States Department of Homeland Security. References American Society of Civil Engineers (ASCE) (2009) Report Card for America s Infrastructure. Washington, DC: ASCE. Available at http://www.infrastructurereportcard.org/ Betz Converse Murdoch Inc. (1980) New York City Water Supply Infrastructure Study Volume 1 Manhattan. New York, NY: Department of the Army NY District Corps of Engineers. Blake, E. S., Rappaport, E. N. and Landsea, C. W. (2007) The Deadliest, Costliest, and Most Intense United States Tropical Cyclones from 1851 to 2006 (and other frequently requested hurricane facts). Miami, FL: National Weather Service, National Hurricane Center, April. Cooper, M. (2009) Old Water Pipes Becoming Hard to Ignore, New York Times, April 18 http://www.nytimes.com/2009/04/18/us/18water.html Energy Information Administration (EIA). (2007) U.S. natural gas pipelines. Available at http://www.eia.doe.gov/pub/oil_gas/natural_gas/analysis_publications/ ngpipeline/index.html. 10
New York State (2009) Federal Stimulus Spending Provisions That Impact New York. Available at http://www.recovery.ny.gov/directaid/aidnewyork.htm Accessed April 18, 2009. Office of Pipeline Safety (2008) Pipeline basics. Available online: http://primis.phmsa.dot.gov/comm/pipelinebasics.htm Rabinow, R. A. (2004) The liquid pipeline industry in the United States: Where it s been where it s going. Available online: http://www.aopl.org/posted/888/final_rabinowpint_40804.57626.pdf. Restrepo, C. E., Simonoff, J. S. and Zimmerman, R. (2009) Causes, Cost Consequences, and Risk Implications of Accidents in U.S. Hazardous Liquid Pipeline Infrastructure, International Journal of Critical Infrastructure Protection, 2, pp. 38-50. Simonoff, J.S., Restrepo, C.E., and Zimmerman, R. (2009) Risk Management of Cost Consequences in Natural Gas Transmission and Distribution Infrastructures,, Journal of Loss Prevention in the Process Industries, accepted for publication, October 2009. Simonoff, J.S., Restrepo, C.E., and Zimmerman, R. (2007) Risk Management and Risk Analysis-Based Decision Tools for Attacks on Electric Power, Risk Analysis, Vol. 27, No. 3, pp. 547-570. Simonoff, J.S., Restrepo, C.E., Zimmerman, R., and Naphtali, Z.S. (2008) Analysis of Electrical Power and Oil and Gas Pipeline Failures, Chapter 27 in Critical Infrastructure Protection, edited by E.D. Goetz and S. Shenoi, New York, NY: Springer, pp. 381-394. U.S. EPA (2007) Aging Water Infrastructure Program. Addressing the Challenge Through Innovation, September. Washington, DC: U.S. EPA http://www.epa.gov/nrmrl/pubs/600f07015/600f07015.pdf U.S. EPA, Office of Water (2002) The Clean Water and Drinking Water Infrastructure Gap Analysis, Washington, DC: U.S. EPA, September. http://www.epa.gov/safewater/gapreport.pdf. Zimmerman, R. (2008) Managing Infrastructure Resiliency, Safety and Security, Encyclopedia of Quantitative Risk Assessment and Analysis, edited by E. Melnick and B. Everitt. Chichester, UK: John Wiley & Sons, Ltd, pp. 1033-1040. Zimmerman, R., Restrepo, C.E., and Simonoff, J.S. (2008) Infrastructure Disruptions and Recovery Rates in Disasters, ASCE Metropolitan Section Infrastructure Group Technical Seminar New York City Infrastructure Critical Needs, Brooklyn, NY: Polytechnic University of New York, March 24-25, pp. 28-35. 11
Zimmerman, R. and Restrepo, C.E. (2009) Analyzing Cascading Effects within Infrastructure Sectors for Consequence Reduction. IEEE International Conference on Technologies for Homeland Security, HST 2009, Waltham, MA. Zimmerman, R. and Simonoff, J.S. (2009) Transportation Density and Opportunities for Expediting Recovery to Promote Security, Journal of Applied Security Research, Vol. 4, pp. 48-59. 12