The Continuing Problem of Highway Bridges Collapse

The Continuing Problem of Highway Bridges Collapse: 1900-Present

There has been a general inclination towards the use of tools that make life more efficient and convenient by human beings. It because on this thesis that individuals prefer the use of railways and highways; it makes traveling easier. Building of bridges makes life easier by shortening the distance between two areas, reducing pollution, linking cities, connecting two sides of a major river, and many other aspects. There are different kinds of bridges including; movable, arch, bowstring arch, box girder, cable-stayed, and cantilever. As a fact, the topographical characteristics of the ground is a significant consideration when deciding on the kind of bridge to build, which differs from one place to another. However, the problems with building well-constructed bridges are the main challenges facing infrastructure development. According to a journalist Jansen (2016), the American Road and Transportation Builders Association claims that “[n]early 10% of the country's bridges (58,495 out of 609,539) were considered structurally deficient last year and in need of repairs” (para. 2). There has been documented evidence of the breaking down of bridges since the 20th century; the San Francisco–Oakland Bay Bridge being evidence of these. The Bay Bridge was built between 1933-1936. The bridge then collapsed because of a natural disaster in 1989; three years after establishment as a usable bridge. The disaster resulted in 67 fatalities (History, 2009, para. 1). The Bay Bridge was not the first to collapse, and it was not the last. Another bridge that collapsed was the I-35W Mississippi River Bridge in 2007, but the causative factor was different. As Al Jazeera America (2013) explained, the I-35W Mississippi Bridge was missing some structural components before it collapsed (para. 4). The reason of the breakdown was the transverse deck that was relying on the main trusses. This happened due to lack of maintenance. This incident shows the importance of maintenance.

Many bridges have been constructed for economic reasons. A number of bridges cost twice the estimated cost of construction before they collapse. These kind of bridges were not qualified to stand for long term period. If people who were in charge were thinking that the cost of bridges collapsing will cost them more money than the original construction of the bridge, then they would try to reduce the risks by building stronger bridges. This would diminish the amount of spending and reduce costs therefore ensuring sustainability. Jaffe (2015) indicated that the Bay Bridge, which connects San Francisco and Oakland, fell down in 1989 following the Loma Prieta earthquake cost $250 million. However, in 2013, after the collapse of the bridge, the reconstruction cost increased dramatically to $6.5 billion (para 1). This is because of the 2500 percent rise in the sea level. The project therefore required more materials to reconstruct and hence became more expensive. In fact, professionals say the current $6.5 billion is a variable estimate that can change in the next few years.

The question here is how did these bridges collapse. The major cause of bridge collapses is climate change, earthquakes, and oversight. It does not matter the type of the bridge because these factors always play a significant role and go in the front page. Therefore, building dykes, using durable materials, locating previously struck zones, writing and sharing weekly engineers’ reports and implementing communication policies between bridge agencies to ensure accurate exchange of information are being introduced as solutions to prevent bridges collapse.

Causes of Bridge Collapses

Climate Change

Many different aspects of climate change play a role in bridge collapse; therefore, bridges must be built more carefully to account for varying climate conditions. Different climate conditions can be caused by natural activities, which are hard to predict. Indeed, the weather plays considerable portion during the planning phase of bridge construction. In fact, weather factors have already been accounted for in shaping bridges and how to build the transportation infrastructure. However, many bridges still break down as a result of climate change. According to the Heartland Institute (2008), the average temperature has increased globally in the mid-20th century (para.1). When engineers built these bridges, they forecasted the weather hazards at that time. Nevertheless, the temperature has increased, and pervious forecasting might seem wrong today because engineers at time of building did not expect climate change.

In addition, heat waves, cold weather, storms, sea levels, and rain are the greatest factors affected by climate change, which make bridges to fall. Firstly, heat is one of the main contributing factors of bridge collapses. When bridges face prolonged exposure to high heat, it could cause unfavorable outcomes. According to Committee on Climate Change and U.S. Transportation (2008), pavements could be less safe when it is exposed to high temperatures which leads to softening asphalt and increased cracks from traffic. (para. 12). To clarify, high heat waves affect the composite parts of bridges; making them likely to collapse. For example, the I-35W Mississippi River Bridge experienced extreme heat that was one of the aspects made the bridge to collapse. Although high heat played a role in eroding the bridge, several previous reports showed many components of the bridge needed repair because these materials were too old to resist future disasters. ThinkProgress (2007) quoted a Minneapolis resident who said, “Several eyewitnesses reported seeing what looked like ‘explosions’ coming up from the concrete roadway just prior to the collapse. I am reasonably certain that authorities and investigators will find that the extreme heat of the last several days in Minneapolis had caused the expansion joints in the bridge to close completely” (para. 6). As can be seen in the I-35W Mississippi River Bridge case, high heat led to expansion of the concrete used to construct the bridge. Consequently, bridge piers did not endure the pressure caused by the concrete expansion. This resulted in the collapse of the bridge. Conclusively, engineers should figure out how to deal with high degree of heat in emergency situations to build resistant bridges.

Secondly, winds, cold weather, and storms in different climates could also cause problems to the bridge because some materials had not been considered carefully and planed for, for future unpredicted weather. Some people are blame the cold weather. However, details on the factors that cause bridges to suffer such a major mechanical failure are yet to be confirmed. Recently, Nipigon River Bridge in Canada; considered a great example of a bridge facing weather problems with a huge number of winds and storms. Due to the high cold weather and winds, the bridge divided to two sides. Mortillaro (2016) mentioned that cold weather has been noticed as the main factor leading the bridge to separate from the eastern side; however, the bridge has experienced a strong unpredicted cold weather estimates from normal temperature -6.3 C to -15.7 on the next day, which led to great frost. One more factor in leading the bridge to break up is high wind storms (para 4,5). 

Figure 1. Nipigon River Bridge exposed to extremely low temperatures (CBC, 2016)

As it shown in the picture, when strong winds hit the bridge, the expansion joint, which is designed to absorb the heat and connect the western and eastern sides, had expanded. As a result, the western and eastern sides divided into two parts. The Nipigon River Bridge restored the Tacoma Bridge collapse event in 1940 because they both faced the great winds even though they had different weather. The Engineer (2006) explained how the bridge collapsed by saying higher blast speed struck the bridge resulting the bridge to collapse despite the fact that there was no relationship between the blast speed and vibration rates (para 13). Although these two bridges collapsed for the same reason, no considerations have been shown. The disparity between the Nipigon River Bridge and Tacoma Bridge confirm that engineers could not fix weather problems. This issue will be discussed more in the oversight section. Engineers must rectify their mistakes to identify the problems and fix it. 

Thirdly, highway bridges are facing major issues from increasing sea level and heavy rain that affect their infrastructure because of varying climate conditions. Global warming is considered one of the greater risks that comes from climate changes. It is also the main influence in increasing sea level. Committee on Climate Change and U.S. Transportation (2008) stated that 99% likelihood that increasing sea level is going to keep up in the 21st century due to temperature growth and loss of chunk from ice sheet (p. 21). To demonstrate, global warming is going to increase the risks of highway bridges by affecting the sea levels. When the sea level exceeds the highway bridge, it will collapse. As a matter of fact, global warming cause convertible high amount of humidity in some areas creates heavy rain, which means too much rain leads the bridge to collapse because engineers did not take heavy rain in account. These two elements harm the infrastructure. In their 2008 study, Committee on Climate Change and U.S. Transportation commented that most of the collapses toward bridges are environment that has a hand on influencing the effects in which the infrastructure is located by increasing rainfall in some zones. In addition, the bridge foundations might be harmed by stream flow. At the same time, sediment is a significant influence. Sea levels create some changes in bringing storms waves. (p. 84). On the other hand, sea water contains salt that makes great risk to bridge’s concrete. NACE (2012) indicated that the bridges locating near, or above sea water are in danger because the Chloride ions carry salt. Waves action should be studied before building a bridge (p. 17). Also, Crete Defender (n.d.) emphasized one of salt hazards to the concrete, “First, salt, a mild acid, lowers the pH in the concrete. The acidic reaction attacks the concrete paste and aggregate, increasing the pore size and allowing additional water and chemicals into the concrete which can exacerbate the freeze/thaw cycle damage” (para. 3). All in all, bridges close to the sea are in danger because of the raising sea water. Sea water consist of salt that harms bridge’s parts. In addition, many chemicals like Chloride ions, which comes from salt affects the infrastructure. Heavy rain one of the great aspects affects the surface’s infrastructure. All of these are related problems, and strongly harm the concrete even though each issue affects the concrete differently. As it can be seen, bridges are facing a major problem, and it is important to account the increase sea level and rain fall in the concentration before bad outcomes be showing up.

Earthquakes

Another major problem facing bridges is earthquakes. The phenomenon of bridge collapses as a result of earthquakes was first identified in 1971 when five bridges were hit by an earthquake in California. Earthquake was considered a big issue when an engineer planned to build a structurally perfect bridge that can withstand any natural disaster. In 1989, the Loma Prieta Earthquake struck the northern part of California resulting in the collapse of the Bay Bridge linking San Francisco and Oakland a phenomenon that shocked California’s population. Although the earthquake was short, it resulted in devastating damages. As reported by USGS (2016); 63 deaths, 3757 injuries, and an estimated number of $6 billion asset damages in California were due to the Loma Prieta Earthquake (para. 2). The devastating earthquake which measured 7.1 on the Richter scale could not be stopped. Unstable bridges with poor structural design could not withstand the effects of the Loma Prieta Earthquake. In another example, the Cypress Bridge collapsed as a result of an earthquake. Both incidents happened for the same reason. Engineers did not take earthquake into account when they build the Cypress Bridge. A year after the Bay Bridge collapse, The U.S. Government Accountability Office (1990) reported that engineers noticed impairment in the Cypress' piers when it was aligned with the effects from the earthquake. Moreover, the smooth dust affects the structure that was built 20 years ago making the bridge to collapse (p. 2). To put it another way, engineers believe that the structure of the bridge was too old, and its materials were affected by the earthquake. More importantly, the columns and the soft soils of the Cypress Bridge were weak. These elements caused the bridge to fall. Therefore, earthquakes are considered one of the most devastating causes of bridge collapses.

Oversight

Furthermore , oversight is another problem causing bridge failures. In other words, lack of coordination between engineers and highway bridge departments. With little inspection from engineers of the building process, unwarranted outcomes could arise. Baum Hedlund (2016) commented the utility of many bridges have been changed without taking into consideration the structural changes that would have to be incorporated. This is as a result of the lack of coordination between the engineers and the transport safety authorities. This might result more bridge collapses (para. 13). To explain more, there is a complete lack of concern between departments who are responsible to for the maintenance of the bridges. This means there is no communication because if there was, they could predict and prepare for major bridge failures. Hyde (2006) said the federal bridge and FHWA (Federal Highway Administration) work together with more than 50 engineers on carrying oversight programs towards bridges (p. 13). In spite of the cooperation between the two departments to protect and follow future actions on the bridge, it seems that there is less attention from the departments. If there was truly cooperation between them, they could have prevented the collapse before it started. As discussed before in the climate change influencing the two bridges the Nipigon River Bridge and Tacoma Bridge, were as a result of lack of attention from engineers. More than fifty years of lack of administrative and risk management efficacy from engineers between the two incidents emphasizes oversight problem. In fact, Denver has experienced some form of a bridge breakdown resulting in the death of a family. Sprengelmeyer (2006) explained that the Colorado Department of Transportation is the first to blame for the oversight for the 2004 girder collapse that killed a family because of poorly installed 40-ton girder slump over Interstate 70, Lakewood (para. 1). Human lives matter and could have been saved if administrations had been more careful and monitored bridges to prevent any risk events before it would happen.

Solutions

These three main problems causing bridge collapses need to be addressed, for the sake of safety of citizens; a policy incorporated in the national security updates. More structural work is needed, and good planning for future changes would create a well-designed bridge that could withstand any hazards. For that reason, professionals found three solutions, one for each problem.

Building Dykes and Using Durable Materials

Dykes and durable materials are solutions for climate change problems. Both of them can handle the effects of climate change risks. The two major dynamics are increasing sea levels and high temperature. Moreover, high level of sea water is a great factor affecting the structural capacity of the bridge.   If the water gets into the bridge structure, it will affect the steel or the concrete resulting in associated risks. As a solution for increasing sea water that consists of salt, dykes can control water levels. Climate Change Adaptation (n.d.) claimed that in varying climate conditions, like increasing water levels, dykes take control in protecting the bridge by releasing and keeping water from going over the expected levels (para. 25). In support, dykes keep or release sea water as the situation requires. In other words, bridges that are near to or above the sea will benefit from building dykes because dykes are going to keep salt from affecting the structural integrity of the bridges, which would prevent future collapses.

On the other hand, high temperature is another great risk contributing to bridge failures, but the technological advancement in construction, HPC mix has provided solution to the issue. HPC is a type of material used in all bridge construction parts. It can withstand the high heat helping the concrete to maintain adequate internal temperatures. Gajda (2008) explained that the maximum concrete temperature is 158°F (70°C), while HPC can endure more than 190°F (88°C) thus solving the issue of high temperature that bridges have been facing (para. 1-4). In reflection of the I-35W Mississippi River Bridge, HPC would suffice as a plausible solution if it had been used in the construction of the bridge. HPC is a great solution to preventing any bridge collapse in the future because it will reduce the expansion of the concrete. Both dykes and HPC will help prohibiting future collapses, and improving bridge component longevity. Finally, more research need from professionals to find solutions for cold weather, storms, and rainfall. These three issues are considered great risk toward bridges. 

Locating Previously Struck Zones and FRP

Natural catastrophes like earthquakes cannot be fully stopped because they are created by the nature. However, engineers can tremendously reduce the perceived and real risk associated with natural disasters. One thing that can be done is locating previously struck areas to study them. This will help engineers to find bases and evidences for future solutions. Furthermore, regulation needs to be developed to emphasize the risk of earthquakes, and identify areas that have been hit by earthquakes in the past. Knowing where earthquakes occurred helps engineers and city planners to make decisions about where to place future bridges. Although predicting and locating an earthquake was hard in the past, professionals have invented FRP technology to study earthquake processes. FRP are composites of seismic column retrofit. In fact, this technology emerged after the Bay Bridge collapse in 1989. Tang (2004) said, "Since the Loma Prieta earthquake in Oakland in 1989, the California Department of Transportation (Caltrans) has retrofitted thousands of concrete pier columns using FRP composite materials" (para.6). If authorities had used the FRP technology, the Bay Bridge would have been safeguarded against the Loma Prieta earthquake. Also, many people would have been saved, and less damage would have been incurred. A lot of future incidents can be prevented if FRP used in bridges. In over all, identifying zones previously stuck by earthquakes to study their hazards is a solution to drop high risk levels to more controlled and less dangerous outcomes.

Writing and sharing Weekly Engineers’ Reports and Implementing Communication Policies

If engineers had monitored strictly and scheduled weekly reports for maintenance, then bridge failures would not have occurred. Higher levels of professionalism in the engineering profession, especially with reference to maintenance of bridges could have ensured the prevention of many of the previous bridge collapses. Therefore, engineers can prevent incoming disaster, so it can be fixed soon before bridge collapse. Moreover, clear Highway Department policies will determine the future of bridges significantly. Higher levels of cooperation between Highway Bridge Departments maintaining a high level of knowledge of bridge construction and maintenance process would increase collaboration between the different professional stakeholders. 

The Union of Concerned Scientists (2007) reported, 

"…Decision makers and resource managers must keep informed about the specific consequences of global warming for their region and areas of oversight. In particular, improved monitoring of both the climate and the condition of natural systems can give decision makers clearer signals about the need for action and more time to formulate appropriate adaptation strategies…" (p. 124). 

To explain further, directors who have the final word must receive weekly reports about the bridge, so that they can provide future solutions that the situation needs. Besides that, it gives them more time to think of actionable instances at the time the issue is identified and before the situation gets worse. For instance, Nipigon River Bridge and Tacoma Bridge collapsed as a result of less attention from engineers and highway bridge departments. If engineers and responsible departments were tracking the two bridges’ activities, the two collapses could have been prevented. At the end, more monitor, reports, and communication between bridge administrations are solutions to prevent bridge collapse.

Conclusion

In the final analysis, varying climate conditions, earthquakes, and oversight are the three main causes of bridge failures. Of these, the most immediate is climate change because each year the effects of climate change as well as its rapidness increase. It is hard to predict because it is controlled by natural factors. Until today, professionals have not found solutions for cold weather, storms, and rainfall, which are three factors caused by the climate change. However, strict rules from departments in managing engineers is the optimum way to prevent a bridge from collapsing because it monitors bridge components and activities that would be reported weekly by engineers. This gives administrations a management strategy for any incidences concerning the bridge at risk before it collapses. Building dykes, locating previously struck zones are the other solutions that prevent bridge collapses. All in all, more work is needed in bridges. Lives were lost, properties were damaged, and a lot of resources were spent on repairing the bridges due to mechanical failures.

Many engineers have faced challenges to find solutions for weather uncertainty in order to design sustainable bridge. Future oversight technology might venture into real-time prediction of different climate conditions. Committee on Climate Change and U.S. Transportation (2008) found, “…Greater use of technology would enable infrastructure providers to monitor climate changes and receive advance warning of potential failures due to water levels and currents, wave action, winds, and temperatures exceeding what the infrastructure was designed to withstand…” (p. 32). Another challenge bridges are facing is infrastructure because it does not have any real protection against extreme natural events. In the next few years, more smart technologies will be established for infrastructure purposes. In fact, bridges reduce pollution by shortening the distance resulting in reduced gas usage.

References

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