Current Research Status
Traffic hazard, coupled with aging and vulnerable infrastructure, pose the potential for damage and loss of resource. Precast prestressed concrete girder bridges appeared as a mean by which more efficient designs can be achieved. They offer many advantages such as the ease of construction and a relatively high durability. The prestressed girders are usually precast of site and transported for erection before pouring composite decks. As a result, full continuity between the girders has generally been sacrificed for the sake of ease of construction. Traditionally bridge deck joints have gabs of 1-3 inches under operating conditions (LADOTD, 2002). These gabs within the joints have the disadvantages of causing ride discomfort, debris accumulation, the need for maintenance as the gab can grow larger over time due to support settlement, shrinkage, and/or temperature change, concrete deterioration due to larger dynamic impact load from the tire hitting span adjacent to the gab, in addition to the leakage of rain water on the bridge substructure which can cause corrosion to the substructure (Saber et al. 2005, 2007). Even when strip seal joints installed, they are usually worn down by vehicles and often break.
Bridge expansion joints are used to accommodate thermal movements in the deck and other short- and long-term deck movements caused by creep, shrinkage, moisture changes, vehicular traffic, and other loads. However, deck joints are costly to construct, install, and maintain. Deck drainage water, contaminated with chemicals such as deicing salts, leaks through joints and can damage the bridge superstructure and the pier caps below. This can lead to the destruction of vital bridge parts, such as prestressing c...
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...oment equation as well as proposed FE models. This will permit the development of a simplified procedure that can be used in a design environment.
Figure 1 Corrosion damage caused by chloride-contamination leaks in bridge deck expansion joints (Lam, 2011).
Barrier 1: Evaluation of continuity performance of bridge decks through real-time data collection. This requires a plan for field monitoring and data collection under both live loads and environmental loads, including temperature change.
Barrier 2: The collected data contain outliers, and require special statistical analysis. To alleviate this problem a graphical user interface (GUI) executable software package will be developed for the analysis and processing of the collected data. An educational plan is thought to train the engineers involved in the bridge monitoring program to collect and analyze the data.
The area of where the bridge was to cross the Ohio River was said to be one of the hardest places to build but came with some advantages. The section of the river had a solid rock base for the supporting pier to be built on. Since the engineers knew they could build a pier that would not settle they decided on a continuous bridge design. This design type distributes the weight so the steel trusses could be smaller and riveted together. This alone saved an estimates twenty percent of steel that was originally thought to be need to make the bridge cutting down the cost. The two continuous trusses span a collective 1,550 feet across the water. With addition of the north and south approach viaducts, for trains to go under the bridge, the superstructure’s total length is 3,463 feet. The bridge was made to hold two sets of tracks making the width 38 feet and 9 inches. The design called for 27,000 cubic yards of concrete and 13,200 tons of steel with some members being four foot square beams that span a distance of seventy feet. The design was the first step in a long process that would take several years to
Following the collapse of the I-35 Bridge, other bridges in the country, with similar construction designs, were scrutinized. According to federal statistics, more than 70,000 of the 607,363 or roughly 12 percent of the bridges in the United States are classified as “structurally deficient.”
According to Suspension bridges: Concepts and various innovative techniques of structural evaluation, “During the past 200 years, suspension bridges have been at the forefront in all aspects of structural engineering” (“Suspension”). This statement shows that suspension bridges have been used for over 200 years, and that people are still using them today because they are structurally better bridges. This paper shows four arguments on the advantages of suspension bridges, and why you should use one when building a bridge. When deciding on building a suspension bridge, it has many advantages such as; its lightness, ability to span over a long distance, easy construction, cost effective, easy to maintain, less risk
Compare with other types of bridges, suspension bridge can span the longest distance without using lots of material. However, if the issue of stiffness was not fully cosidered, vibration would be occurred on the bridge deck under high wind. A few week after the Tacoma Narrow Bridge was operated, the bridge start oscillation and its oscillation kept increasing day by day. Therefore engineers tried to build more cable between the bridge, but it is still unsuccessful. After four months the Tacoma Narrows Bridge was build, the bridgre which normally vibrated in a vertiacal motion, began to oscillate with the opposite side out of phase (torsional model), under the wind of 68 km/h. Due to the extremely violent oscillation, the failure bagan at the mid-...
The engineering design process helped my two partners and I through this project. First, we identified the problem of needing to hold weight from the center of the bridge. Next, we established a very detailed design of our bridge and how much total wood was needed to build it. After spending much time on the design, we built the design. The building of the bridge took a long time to do and took much precision. Next we tested it and presented it all at one time. We realized what we could do to improve it if we ever do it again and what design flaws that we
Press, A. (2013, December 11). Seattle Deicer Error Made Bridge Roadway Slick. Retrieved January 26, 2014, from My NorthWest: www.mynorthwest.com
One of the great engineering feats when building this bridge was the use of steel. Despite its maximum height of 343m span of 2.46km, 280m above the valley floor, the bridge is actually quite light. 242,000 tonnes seems like a lot but without the use of steel on the structure, this bridge would have been more than twice as heavy. Steel is a much stronger material than concrete, so can support more weight with less mass. The actual road deck, which is comprised almost entirely of steel, only weighs 36,000 tonnes. The other 206,000 tonnes comes primarily from the massive pylons, which are m...
The Tacoma Narrows Bridge is perhaps the most notorious failure in the world of engineering. It collapsed on November 7, 1940 just months after its opening on July 1, 1940. It was designed by Leon Moisseiff and at its time it was the third largest suspension bridge in the world with a center span of over half a mile long. The bridge was very narrow and sleek giving it a look of grace, but this design made it very flexible in the wind. Nicknamed the "Galloping Gertie," because of its undulating behavior, the Tacoma Narrows Bridge drew the attention of motorists seeking a cheap thrill. Drivers felt that they were driving on a roller coaster, as they would disappear from sight in the trough of the wave. On the last day of the bridge's existence it gave fair warning that its destruction was eminent. Not only did it oscillate up and down, but twisted side to side in a cork screw motion. After hours of this violent motion with wind speeds reaching forty and fifty miles per hour, the bridge collapsed. With such a catastrophic failure, many people ask why such an apparently well thought out plan could have failed so badly?(This rhetorical question clearly sets up a position of inquiry-which iniates all research.) The reason for the collapse of the Tacoma Narrows Bridge is still controversial, but three theories reveal the basis of an engineering explanation. (Jason then directly asserts what he found to be a possible answer to his question.)
There are two main things that can be used to secure joints: balsa cement or cyanoacrylate glue. Before gluing two pieces together, lay them out on a work board or wax paper and use pins to prevent the members from moving apart; the pins should not be placed near the joints so that it is easier while gluing (Anderson 2006). Then, apply the glue to the members and make sure that they touch to create the strongest joint possible. Despite it seeming as if more glue would make a structure stronger, using bulks of glue can cause the bridge to fail as cyanoacrylate bulk will cause the joint to become more brittle (Anderson 2006). To prevent excess gluing with cyanoacrylate, a special glue applicator should be used to minimize the amount of glue added to the wood, and to increase strength with balsa cement, thin the glue out first by making the solution 30% water. This process will be utilized when constructing the bridge to ensure that the joints are sturdy enough to withstand weight and won’t be the cause of failure.
A calm crisp breeze circled my body as I sat emerged in my thoughts, hopes, and memories. The rough bark on which I sat reminded me of the rough road many people have traveled, only to end with something no one in human form can contemplate.
The 1.78 mile western span of the bridge between San Francisco and Yerba Buena Island presented the first obstacle. The bay was up to 100 feet deep in some places and required a new foundation-laying technique. Engineers developed a type of foundation called a pneumatic caisson to support the western section. A series of concrete cylinders were grouped together and then capped-off, having the air pressure of each cylinder identical to balance the beginning of the structure. From there, the workers added sets of new cylinders until the caisson reached the bottom of the bay. Then, in order to reach the bedrock, they inserted long drills down the cylinders, digging until they reached bedrock. After the caisson was balanced at the bottom of the bay, workers filled it with 1 million cubic yards of concrete, more concrete than was used for the construction of the Empire State Building! This caisson connected the two suspension bridges that make up the western part of the bridge.
Narrative Essay It all started my sophomore year of high school. People always tell you that when someone knocks you down, you should always get back up and keep trying. I had this mindset at the beginning of my sophomore year, but I ended up letting a teacher knock me down to the point where I did not get back up for a couple of years. I never expected my second year of high school to go so awry.
One first issue is introduced in the article Civil Engineering Grand Challenges: Opportunities for Data Sensing, Information Analysis, and Knowledge Discovery written by several engineers. Ten current challenges were selected to be investigated further five have been included here. First to analyze was high building energy consumption, which includes: lightning, heating, cooling, and running of appliances. With the resource scarcity ...
Conventional breakwaters are massive in size and generally associated with large scales in construction materials, effort and cost. The development of large breakwater schemes with poor design and management may trigger a number of adverse effects on neighbouring coastal environment, e.g. large amount of wave reflection, alteration of beach morphology, water quality deterioration and change of marine ecosystem. To alleviate the above problems, various ingenious designs of light-weight breakwaters have been proposed, tested and constructed in the past as alternatives to the conventional breakwaters, one of which is the free surface breakwaters.
Engineers set up all building codes based on accurate calculations that are based on theories and actual observations known as seismic assessment. . There are two different types of seismic performance assessments, experimental assessment and numerical assessment. Experimental assessments are very expensive since engineers need to build a scaled m...