Examining Smart Fully Prefabricated Bridge Systems Construction Essay

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Since bridges are representing the most important and vital sector of nation's infrastructures, the following demonstration focus on how to create an innovative and smart prefabricated bridge systems with an ambition of having most of nation's bridges secure, smart, and durable with low maintenance in the next few decades.

Incorporation of smart sensors and materials into the prefabricated bridge components creates a smart structure that can perform smart actions very beneficial in many aspects. For example a structure can be smart enough to inform its owner about its day-to-day condition and give alarm to possible critical problems that may result in total collapse or may cause severe deterioration that requires substantial cost to repair. The smart structures can sense the condition and take protective actions individually or with the help of their occupants before the problems become very critical so that efficient and proactive measures can be taken. Examples of danger source are high chloride levels that may initiate corrosion and high stress or strain levels that may cause local or global damage. Early detection of damage or structural degradation prior to local failure can prevent catastrophic failure of the system save significant amounts of money and time. However, early signs of deterioration are often not seen because some of the bridge components mask them; thus high quality, accurate, compact, durable, and reliable smart sensors and materials are required to fulfill this smart functionality in real time. Structural health monitoring (SHM) is one of the most common techniques that lead to creating smart structures. Active and passive control or semi-active control technologies are other common methods.

In many cases, the major obstacle that is faced when trying to incorporate smart sensors and materials into a structure is the requirement for highly skilled individuals, special equipment, safe and silence working environment, time of installation and testing of their workability, and sophisticated wiring and drilling. Such problems can be substantially eliminated for the case of prefabricated bridges since most of the installation requirements are performed at the fabrication site. However, some sensors require in site installation especially at the major joints and connections between the prefabricated elements. The following items outline the possible sources of danger in each bridge component:

Past experimentation with monitoring structures involved expensive, elaborate systems requiring installation of strain gauges and data collection systems for evaluation. These systems were not always reliable and were easily damaged by the elements. To overcome these problems, an intelligent technology suitable for inspection and monitoring of existing as well as newly constructed bridges and components are needed. The proper sensors must operate reliably with a lifespan similar to, or preferably exceeding, that of the structure. Typically, the current philosophy of bridge design is to design the bridge with a service life of about 75 years prior to receive major rehabilitation. To achieve this target ambition, there is a crucial need for developing long-term reliable, robustness, and durable smart sensors and materials in conjunction with developing robust algorithms that can provide a reliable damage detection capability even under malfunction of some sensors.

An innovative full-scale totally prefabricated bridge system will be constructed. Smart sensors and materials as well as appropriate network algorithms will be incorporated in the system components, thus creating a demonstration bridge that is innovative and smart simultaneously. This intent is to provide essential information about the constructability, advantages, and structural behavior of the system and to validate the performance and reliability of the smart sensors and materials under the exposure to real loading and environmental exposures. Such demonstration bridge and other demonstration essential structures are essential to achieve sufficient level of confidence about the technology and to promote their application on a nationwide level. Finite element analysis will be used as a supporting tool to optimize the system components and model the response of the system in order to determine the critical locations and to validate the actual obtained data from the smart sensors and materials. The bride system components, especially the bridge deck and supporting beams, can be built using high strength/high performance lightweight concrete or high strength/high performance normal weight concrete. In some cases, the use of lightweight concrete offers the ability to use longer span bridges and reduce the size of columns and footing.