Challenges in Bridge Structures and the Way Forward
ROLE OF TRANSPORTATION
The road network is the most significant system in a country’s transportation infrastructure. It supports business in almost every sector of the national economy and is utilized by almost every person for both pleasure and need. Maintaining high levels of effectiveness in this system is essential for public safety, social well-being, and economic productivity and growth. Bridges are important and necessary discrete linkages in the road transportation system. Clearly, monitoring and maintaining the bridges is a big task. Roads, highways, and bridges are lifelines that must be maintained in good shape.
The bridge structure and its components are planned, designed, built, and maintained so that they can operate effectively and safely during construction and service life. Road bridge design and construction need extensive and thorough understanding of the science and technology involved, and must be entrusted exclusively to specially qualified engineers with significant practical expertise in bridge engineering and capable of assuring precise execution of tasks.
However, within a bridge’s planned service life, a natural or man-made extreme dangerous situation may emerge. However, in strong seismic zones and hilly places, landslides and earthquakes cause the majority of damage to roadway and bridge constructions. Earthquakes can cause damage to bridges, tunnels, pavements, and other roadway infrastructure components.
A major percentage of today’s technical understanding about bridge engineering is based on historical bridge disasters. Bridge engineers have learnt a lot over the past century by researching previous bridge collapses. Deficits in design, detailing, construction, and maintenance, as well as the use of weak materials and inadequate consideration of external events, were identified as the primary causes of bridge collapses.
CAUSES OF FAILURE
Deficiency in design refers to faults, blunders, oversight, omission, or conceptual law that may have occurred throughout the bridge’s design process. Moreover, various natural risks such as flood, scour, wind, earthquake, landslide, debris flow, storm surge, and sudden breaking are unavoidable and are among the root causes of many bridge failures.
Increased traffic in recent years has put greater strain on road infrastructure than it was designed for, but it is also true that bridges and other structures built in the past perform better than more recently constructed concrete structures in the same environment. Professionals today blame the lack of structural endurance on the more corrosive nature of the environment, and partly on poor workmanship in completing the structures.
Whatever the source, most reinforced and prestressed concrete bridges built in recent decades have suffered from early corrosion in the metal components, resulting in structural degradation and discomfort.
Bridge structure rehabilitation or strengthening may be required due to increased traffic loads, loss of prestress, ageing, weathering, or damage caused by environmental conditions or structural issues. External causes of foundation settlement, such as earthquakes and floods, must be handled. Bridge rehabilitation is a difficult task that necessitates a multidisciplinary approach for carrying out numerous operations such as research, interpretation, analytical studies, sensitivity analysis, design of repair/rehabilitation plans, and precise execution during actual execution.
Prior to the load test, an evaluation of residual prestress by endoscopy is required. A review of the original design, including details of the as-built structure and structure analysis for current design loads and codes. For this objective, field investigation is followed by a desk analysis of the original design and a preliminary visual assessment to determine the cause of the suffering.
Although thousands of bridges are built around the world each year, only a few of them collapse due to natural factors (flood, scour, earthquake, landslide, wind, etc.) and human factors (improper design and construction method, collision, overloading, fire, corrosion, overloading, lack of inspection and maintenance, etc.). Some of these unfortunate incidents result not only in financial loss, but also in human life loss. Bridge designers attempt to avoid failures by examining and learning from them.
The development of new materials, new and more efficient types of substructure and superstructure, as well as new construction techniques, resulting in longer spans, will clearly necessitate a more rigorous evaluation of some of the variables highlighted in this study. It is the responsibility of engineers and contractors to learn from each collapse and ensure that the next bridge is safer.
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