Civil Engineering. Civil Engineering Civil engineering is considered to be the oldest field in engineering. still the same: Civil engineering is the.

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1 Civil Engineering NAME: CLASS: Civil Engineering Civil engineering is considered to be the oldest field in engineering. Engineered structures have been found dating back thousands of years like the pyramids in Egypt or the Roman aqueducts. Even though the materials, techniques, and knowledge have changed and evolved, the objective is still the same: -. Civil engineering is the. Public works projects are that are for use by the public. are all examples of public work projects. Many projects that civil engineers design are used to control natural resources, such as dams and water drainage systems, or to protect shorelines. Civil engineers work in fields that include, and geomatics engineering. Principles of Civil Engineering Civil engineering is a broad field of engineering and because of this, there is a large knowledge base that civil engineers must understand. As civil engineers begin to focus on their specialization areas, their knowledge base also becomes more specialized. But, there are concepts that are fundamental to all areas of civil engineering. 1

2 The most fundamental of all engineering knowledge is the. Structures A structure is an built to remain stable while. Structures are built to for a. A bicycle, for example, is built to withstand the weight of the rider and the forces that occur as it is ridden. A shed is built to hold its own weight and the weight of the objects it stores while withstanding wind, rain, and snow. Structural Load The forces a structure must withstand are known as. Structures are designed to from the into the beneath it. There are two main types of loads:. Static Load Static load is the and the to the structure. The static load of a building includes. The static load of a building can be a tremendous amount of weight. Imagine how much just the building materials of a skyscraper weigh. Dynamic Load Dynamic load is a on the structure. 2

3 A are examples of dynamic loads on a building. Structural Forces Engineers must build structures so the of the structure that are placed on them. When structures are not able to withstand external loads, such as hurricane winds, excessive snow on the roof, or too much weight within the structure, they fail. All structures must be built to withstand that are applied through several different. The first two of these forces often act in opposite directions. Compression Compression is a, resulting in shortening the material. Standing a paper towel tube on one end and placing books on the open end can demonstrate compression. At some point, the tube will no longer be able to withstand the stress of compression. Opposite compression is. Tension Tension is. In a tug-of-war, the rope must withstand the stress of tension. Other forces that are applied to structures and structural members include the forces of. Shear, Torsion & Bending Shear forces are. Imagine, placing a book at the edge of a table and dropping a brick straight down on the book. 3

4 The shear force is the interaction between the downward force of the brick and the upward force of table. Torsion. An example of torsion is the action of a. As you turn the screwdriver, you are applying a torsion force to the shaft of the screwdriver. A skyscraper experiences. The building will twist in the wind and the higher the building the higher the torsion can be. The last force is. Sitting in the middle of a picnic bench and it will sag in the middle. This is a bending force. When a is applied to a material, the material is under. Structural Components Engineers take into account a number of forces as they determine the best components to use in the structure. Many structures contain three main components:. Beams Beams are the structural members. They are used to. A floor joist is a beam that is designed to resist bending as people walk across a floor. Beams can made out of a number of materials and shapes. In construction, are commonly used. The load of a beam is often transferred to either. Columns Columns are. 4

5 Columns transmit the load. In the case of buildings, columns transmit the load to the building's foundation. are common materials for columns. Columns and beams have been used in construction for centuries. While beams and columns handle vertical and horizontal forces, there is often a need for the third structural element -. Braces Braces are that are used to. They are often used to. Braces from one of two forces -. Braces that resist compression are known as. are braces that. An example of struts and ties can be found in a wall bookshelf. The final structural component is the structural joint. Structural Joint The is the device that connects structural members together. Joints may be. Examples of fasteners used in joints include. The type of joint has a large impact on how well the structure functions. 5

6 If the joint is strong enough to withstand the forces that are applied to the structure, the structure will fail. Structural Materials The materials that are selected by civil and structural engineers are an important component of the design. Some of the materials that are used today, such as, have been used for -. Wood and concrete have also been used for hundreds of years. More recently, the use of as a structural material led to the. Advantages & Disadvantages All structural materials have advantages and disadvantages based on their properties. when in compression but it has a., but it weighs more. Cost also impacts the selection of a material. Technological Developments Technological and scientific advancements have led to new developments in structural and building materials, which allow engineers to take advantage of new material properties. is one example. Reinforced concrete is a structural material that has. This creates concrete with a, as it takes advantage of the. Other structures, not just buildings, have been designed to take advantage of new advances in materials. 6

7 The space program has created a number of that have specific properties that allow for safe and efficient spaceflight. Structural Analysis One of the roles of a civil engineer who designs structures is the analysis of structures. The goal of structural analysis is to and is as efficient as possible. An engineer ensures it will function as needed while making the best use of materials. It is widely accepted by engineers that to overbuild a structure is a waste of resources. Bridges The design and construction of bridges is a common application of civil engineering principles. A bridge can be as simple as a piece of lumber placed on the banks of a creek or as complex as a suspension bridge built to connect two cities over a mile apart. Because bridges are designed to serve a, they are almost as as the location in which they are placed. Bridge Design Every bridge design takes into account the. Once these are considered, the engineer will determine the type of bridge that is best suited for the location. The three common types of bridges are, and there are also combination and specialty bridges. Bridge Components All bridges share several that include. are the main that transfer the 7

8 . Piers are placed throughout the span of the bridge. are the structural components that. is the horizontal structure that across the bridge. Beam Bridges Beam bridges are the of bridge and are used to span the. are typically beam bridges in which several steel or concrete beams are placed on abutments. A reinforced concrete slab is placed on top of the steel beams as a driving surface. In this type of beam bridge, the beams, abutments, and piers must be strong enough to withstand the forces of vehicles. Beam bridges can if piers can be placed along the. For example, the Lake Ponchartrain Causeway in New Orleans, is a 24-mile beam bridge consisting of over 2000 short spans on one lane and 1500 on the other Truss Bridges Prior to use of in bridge construction, were used to. Truss bridges were popular from the 1800s to the early 1900s. The use of a in the bridge design allows for the out through all of the structural members in the truss. Truss bridges were able to span greater distances than traditional beam bridges of the time. 8

9 Cantilever Bridge A cantilever bridge is a type of beam bridge that can span greater distances than a simple beam bridge and often includes trusses in the framework. Cantilever bridges use a cantilever, so it can project outward without support from one end. Cantilever bridges are generally made up of. Arch Bridges Arch bridges have been used for thousands of years for both the movement of vehicles and water. Some of the most recognizable ancient arch bridges are Roman aqueducts. Arch bridges rely on the of the arch. The strength of an arch is that the structural members are always in and that it can throughout the arch to the. Because all of the force is distributed to the abutments, they are to withstand the great. This makes arch bridges impractical in areas that have naturally loose soil or have little rock on which to place the abutments. For centuries arch bridges were built from stone. Today, they are often built of steel and reinforced concrete. Modern arch bridges are able to span distances of over a. For arch bridges that span great distances, piers can also be used throughout the bridge. This places the arches in succession, decreases the length of arches, and extends the length of the bridge. 9

10 Suspension Bridges The world's longest type of bridge is the suspension bridge. The main section of a suspension bridge is similar to an. However, instead of relying on compression,. The main components of a suspension bridge are. The towers support the and transmit the load of the bridge into the ground. The cables stretch from and are attached to the that keep the cable in. Steel ropes, or cables, are hung from the main cable and attach to the roadway. The weight of the roadway is supported by the tension strength of the main cables. A is usually used the roadway to provide. Tacoma Narrows Bridge Construction started on September 27, 1938 and opened on July 1, Construction costs were $6.8 million. When it opened it was the third longest suspension bridge in the world. From the first day it opened, the bridge started oscillating up and down because of the narrow width of the roadway and the closed trusses underneath. The bridge quickly became known as Galloping Gertie. On November 7, 1940 high winds caused the bridge to not only oscillate up and down, but to also twist. 10

11 The forces were too great and the bridge collapsed. Skyscrapers Skyscrapers are an that has lead to a global. The first skyscrapers were built in around the turn of the twentieth century. Those two cities have by far the greatest number of high-rise buildings, but no longer have the tallest. Only three of the tallest 15 buildings in the world are currently in the United States. As buildings grow in height, their. In the past, builders made the walls of the to withstand the load caused by. In dense urban settings, it was unpractical for the base of the buildings to be as large as would be required to build a skyscraper. To solve this problem, civil engineers began to use to construct buildings with. This created an internal structural frame, called a -. The skeleton is attached to footings and piers that extended deep into the earth. The of the building then did not have to of the structure. The outer surface, known as a, can be made of. However, it alone could not always withstand the increased forces produced by wind. The tallest skyscraper today is Burj Khalifa in Dubai, United Arab Emirates. 11

12 It has 163 floors and reaches 2,717 feet, which is over I,200 feet taller than the roof of the Willis Tower in Chicago. The building of skyscrapers was made possible by engineering and material advancements that were better able to. Under construction now in Jeddah, Saudi Arabia is Jeddah Tower. When completed this building will have 200 stories and stand 3,307 feet, or 1-kilometer. It was originally planned to be 1-mile high but it was discovered that the ground couldn t support a building that height and weight. Civil Engineering in Action The work that civil engineers do is rarely completed individually. Civil engineers work in teams, offices, and firms that may comprise civil, structural, and architectural engineers as well as land surveyors. The largest employer of these is the. 12