This is the inaugural issue of Urban Lifeline (UBLL), a new peer-reviewed interdisciplinary academic journal, initiated by Southeast University and published by Springer Nature. UBLL is the first international journal that focuses on urban lifeline systems, covering the full spectrum of scientific and engineering disciplines relevant to urban lifelines. Our vision is to cultivate a global community of scholars and practitioners to advance the collective understanding of urban lifelines. With this in mind, our intrinsic motivation stems from the pressing challenges presented by global urbanization that need to achieve multiple and compounded goals including safety, resilience, low-carbon emission and sustainability throughout the life cycle of urban lifelines. These challenges are further intensified by the confluence of environmental degradation, climate change, natural disasters and health crisis (e.g., epidemics and pandemics), as well as other socioeconomic calamities.

Urban lifelines include constructed utilities (e.g., electric power, natural gas, water and wastewater), transportation systems (e.g., roads and highways, passenger and freight rail systems, and ports and airports), telecommunication systems, and critical facilities (e.g., bridges, tunnels and hospitals), etc. Together, these infrastructure assets are crucial to the distribution and flow of services and supplies essential for human livelihoods and economic prosperity in urban centers. In the meantime, urban lifelines are interconnected when serving the public and communities, which often span extensively over large geographic areas.

Urban lifelines have been constructed along with the global urbanization process. Since 1950’s with one third of global population living in urban areas, the percentage has risen to more than one half, and is projected to be two thirds by 2050 [8].

To elucidate this global trend, first, we note that the majority of modern urban lifelines were built in the period from the 1950s to the 1970s in the developed nations. As representative as they are in the United States (US), lifeline facilities face aging issues. In 2021, the American Society of Civil Engineers (ASCE) issued its Infrastructure Report Card and reported that the overall grade for the condition of the US’s infrastructure systems was ‘C-’ (11 of the 17 categories of infrastructures assessed were given the ‘D’ grade). For the instance of water infrastructure in North America, recent studies show that water main break rates have increased by 27% during 2012–2018 from 11.0 to 14.0 breaks/(100 miles)/year [2]. With the accelerated pipe failures, more than US$1.7 trillion are needed for pipe replacement over the coming decades through 2050 [6]. In Japan, as of 2023, more than 730,000 bridges, 11,000 tunnels, 10,000 water gates, 470,000 m of sewage pipe and 5,000 harbor quays are 50 years or older [10]. Similarly, many European cities have been facing serious problems associated with aged urban lifelines [4]. Maintaining and managing these aged urban lifelines in services calls for not only scientifically innovative but also socially, economically and environmentally well-balanced solutions, amid attention and scrutiny from governments and the public.

China provides a different perspective in urban lifeline development. Contrary to the developed nations, the rapid urbanization process in China takes place since 1980s. Urban centers in China have been expanding apace, and their infrastructure systems accumulate at an unprecedent rate. As of 2021, the total length of municipal roads in China is 53,200,000 km with 83,673 urban bridges, the total length of urban rail systems exceeded 8,571 km, the gas pipelines added up to 94,120,000 km long, the total length of water pipelines in urban areas is close to 1.06 million km while that of sewage pipelines is 87,200,000 km [7]. The rapid constructions and the overloaded operations have accumulated considerable and complex risk scenarios specific to China’s urban lifelines.

Beyond the developed nations and China, urbanization in the ‘Global-South’ nations and regions possess both general and specific challenges due to their demographic, economic and infrastructural shifts in these regions. Representative developments include rapid expansion of urban centers in sub-Saharan Africa and many nations in Asia. These developments in turn demand for infrastructures, including transportation, sanitation, housing and energy. However, urban lifeline and infrastructure construction can unavoidably impact the environment if dominated by the so-called gray infrastructures, including increased pollution and loss of biodiversity [9].

Urban lifelines are inter-connected systems by nature, given the complicated interaction between its various infrastructure assets as well as the direct or indirect interdependency between different lifeline systems. Even a local failure of urban lifeline infrastructure can cause cascading socio-economic consequences. In January 2011, a water main break on the Capital Beltway in Maryland, U.S., damaged the surrounding offices and shops, and caused the closure of Interstate 95 Highway for several hours because of the ice formed on the road. More than 400,000 residents were affected in this event [11].

The operation of urban lifelines is subject to natural hazards, and specially, extreme weather events due to climate change seemly occur with increased frequency and intensity [5]. In the long term, climate change and climatic disasters may ultimately influence urbanization patterns, hence urban lifeline design, construction and maintenance. As sea levels rise and extreme cyclone and surging events strike the coastal cities, it may drive migration from the vulnerable areas, leading to rapid urban expansion or abrupt stress on urban lifelines elsewhere. In semi- to arid areas, drought, urban heat and wildfire effects may exacerbate, amplifying life risks for city-dwellers and creating unexpected demands for water, health, utility and other infrastructures.

In our current practice, the continued operability of urban lifelines during and after a natural disaster is key to the efficacy of emergency response, to the continued occupancy of buildings, and to the timely recovery of cities and communities. On 20 July 2021, a pluvial flood in Zhengzhou Municipality, China, caused a low-lying, kilometer-long section of the city’s Metro Line 5 tunnel to fill with water, trapping more than 500 riders in a subway train. Rescuers, hampered by extensive street-level flooding, arrived 4 h later, but 14 people did not make it out alive. The 22 February 2011 Christchurch earthquake, New Zealand, created very strong ground motions and widespread soil liquefaction, leading to significant damage and disruption of lifeline systems throughout the Christchurch urban area and surroundings. It caused an estimate of 629 million customer-minutes loss of power. Christchurch water and waste networks suffered extensive damage. Road networks were extensively damaged, and traffic congestion remained problematic for months following the earthquake. The widespread disruption to services caused significant social impacts, leading to major economic disruption, political involvement and social trauma—which contributed in part to the migration of thousands of Christchurch residents out of the affected areas.

To sum, global urban lifelines are facing many grand challenges even only from a technical perspective. To name a few, they include accelerated deterioration, dominant grey-infrastructure construction, lack of efficient assessment and management technologies, inadequate consideration of climate change and multiple hazards, and finally uncertain system resilience.

We assert that novel STEM (science, technology, engineering and mathematics) theories and methods play crucial roles and are critically essential to resolve these challenges described above. Nonetheless, historical lessons have taught that these challenges cannot be fully addressed without considering societal, economic and policy-making variables.

World Bank [3] identified five obstacles to resilient infrastructures: (1) Poor design, operation and maintenance of infrastructure systems; (2) Political economy challenges and coordination failures; (3) Lack of incentives to increase resilience; (4) Inadequate data, models, skills or tools; and (5) Affordability and financing constraints. The report further offered concrete recommendations that can be taken by governments, stakeholders and the international community to improve the quality and resilience of essential services supported by urban lifelines. Beginning in the late summer of 2020, the World Economic Forum Infrastructure 4.0 project community was formed to encourage a more holistic, outcome-focused framing for infrastructures and to share the best strategies for improving the adoption of technology into infrastructure development. Japan’s Ministry of Land, Infrastructure and Transportation began promoting Digital Transformation for infrastructures in 2021, and is urging municipalities to authorize and utilize new technologies for inspection. In the same year, the U.S. Congress passed the Bipartisan Infrastructure Law, aiming to rebuild roads, bridges, ports and airports, to upgrade public transit and rail systems, to replace lead pipes to provide clean water, and to expand the telecommunication systems. In May 2023, the Chinese Ministry of Housing and Urban–Rural Development launched the nation-wide project for the safety of urban lifeline infrastructures, including the tasks of building up inventory database, risk surveying and assessment, real-time monitoring and early warning, and improving emergency management.

Lifeline engineering, originated from the investigation on the lifeline systems damaged by the 1971 San Fernando Earthquake in Los Angeles, U.S. [1], has evolved into an actively growing subdiscipline of Civil Engineering, which has been applied worldwide and extended to address additional hazards beyond earthquakes.

Over the last 50 years, the knowledge on lifeline engineering has been formulated to address many technical areas pertinent to urban lifelines, ranging from design, construction and rehabilitation to hazard characterization, disaster assessment and socioeconomic impacts of loss of functionality. Such development and progress under the umbrella of the conventional Civil Engineering discipline form a solid global base for us launching UBLL.

Nonetheless, the scope of UBLL goes beyond creating yet another ‘Civil Engineering’ journal. Rather, it encompasses a broader set of multi-disciplinary themes spanning the dimensions of urban lifeline systems, including not only physical and conventional engineering realms, but also those in social, economic and organizational spaces. For example, UBLL welcomes synergetic integration of advanced digital technologies and information technologies in enhancing the safety, resilience and sustainability of urban lifelines. Moreover, the Journal invites research endeavors that enlighten the complexity of human and organizational factors for adopting digital technologies.

To this end, we have created and formed 10 themes centering around Urban Lifeline, subject to our continuous reflection, revision and scrutiny from the global community. The topics of interest include, but are not limited to:

  • ▪ Urban structural and geotechnical engineering

  • ▪ Urban utilities, critical infrastructure, spaces and their connectivity

  • ▪ Urban transportation, automation and mobility intelligence

  • ▪ Advanced information and communication technology (ICT), artificial intelligence (AI) and applications in urban lifelines

  • ▪ Intelligent and sustainable construction of urban lifeline infrastructures

  • ▪ Social- and human-centered engineering solutions for urban lifeline systems

  • ▪ Risk, resilience and economics of urban socio-technical systems

UBLL has gathered a renowned, interdisciplinary and international editorial board to warrant its high publication standard and international dissemination. Our professional editorial team will provide highly efficient and responsive services to the authors. We warmly invite you to submit your original research work, reviews or case studies to our Journal. For more detailed information, please refer to the Journal website:

Upon publication of the inaugural issue of UBLL, we would like to extend our sincere gratitude to the advisory board members, editorial board members, authors, reviewers and Journal secretariat for their supports and contributions. Together, we will strive to create a holistic arena that transcends the current interdisciplinary boundaries for global Urban Lifeline research communities.