Lesson 3: Specialized Fields of Civil Engineering PDF

SPECIALIZED FIELDS OF CIVIL ENGINEERING STRUCTURAL ENGINEERING Structural engineering is the technical specialty that deals with the analysis and design of constructed structures. From spacecraft to deep sea submarines, from tiny micro-electro-mechanical system (MEMS) devic...

SPECIALIZED FIELDS OF CIVIL ENGINEERING STRUCTURAL ENGINEERING Structural engineering is the technical specialty that deals with the analysis and design of constructed structures. From spacecraft to deep sea submarines, from tiny micro-electro-mechanical system (MEMS) devices to long bridges and tall buildings, these are all human-made structures that serve specific functions. A structure is always subjected to the many “loads” the environment forces upon it. These loads include the omnipresent gravitational load of its own weight (called the dead load), the weight of things moving about in or upon the structure (the live load), and event-driven loads originated from Structural design aims at providing a structure with sufficient level of resistance against these loads with minimum cost. Within structural engineering, there are several technical sub-areas. Some are named according to the type of structure. Some are named according to the type of load. Earthquake Engineering The suddenness of earthquakes and the damage they could cause in a matter of seconds inspired the study of the nature of earthquakes and the effects they inflict on structures. The effects of earthquake ground motion create vertical and horizontal forces that change violently within a short duration. The time-varying nature and the multi-directional nature of the earthquake-induced load require special design and analysis considerations. The fundamental approach in earthquake engineering is not to design a structure to withstand any earthquake at all costs but to design a structure that will not inflict injury to human lives at a reasonable cost. Wind Engineering Strong wind caused by a hurricane, a tornado, or a storm creates effects on structures that are also time-varying and multi-directional. Strong wind around a structure may push against a surface while creating a partial vacuum behind another structural surface. Unlike earthquakes, which occur infrequently, especially the damaging ones, strong wind in some areas occurs frequently and so is the damage it incurs. Design against such wind-related effects is the realm of wind engineering. Here again, the design approach is to protect human lives with a reasonable cost. Structural Reliability The many loads a structure must withstand during its life span are mostly of a “random” nature, meaning it cannot be defined precisely with respect to its magnitude and time of occurrence.  So are the resistance provided by the size and material of structural components. Design in the face of uncertainty requires the application of probability and statistics. Structural reliability is the methodology applying these mathematical tools to the load- resistance analysis in structural design. It is used in the development of design codes and specifications that are followed by designers to provide acceptable levels of safety against all loads. Fire Engineering In the event of a fire in a building, the high temperature created by the fire may cause the building material to lose its strength and eventually fail under the weight of the building. Fire engineering in the context of structural engineering deals with the effective application of protective materials to the structural components such as steel beams and columns such that sufficient time is provided for the occupants to escape and the firefighters to arrive. The research in fire engineering provides data to be incorporated into design and construction codes and specifications. Bridge Engineering Some structural engineers specialize in bridge design and construction. Bridge design can be categorized according to material and bridge type. One unique feature of bridge design is it is closely integrated with construction. From the bridge foundation to the superstructure, the process of construction and erection often requires detailed analysis by the design engineers and likely dictates the designers’ choice of bridge type. Dam Engineering The design of dams requires detailed study of the geological characteristics of the site and the mechanical properties of the foundation before the dam type is selected. For some types of dams, it is necessary to ensure the dam material is placed in such a manner that seepage of water through and under the dam body is within acceptable limits. Dam engineers also design all details on how to divert water during construction and specify maintenance and operations procedures post construction. Building Engineering Structural engineers often become building design specialists because building design is more frequently in demand than bridge or dam designs, especially in urban centers. Building engineers also design special buildings such as stadiums and large dome structures.  Forensic Engineering Forensic engineering refers to the study of causes of an engineering event, usually a disaster or failure of some kind. In the context of structural engineering, it refers to the investigation of a structural failure. There are no courses or programs for structural forensic engineering training, but experienced structural engineers who have investigated past failures are often called upon to investigate a new event. In case of major disasters, often a team of experts are assembled to study the cause of the disaster and to make recommendations to prevent future disasters. In structural design in the context of civil engineering, there are three construction materials that are dominant: steel, reinforced concrete, and timber. Each has its own design specifications. Thus, steel structure design, reinforced-concrete structure design, and timber structure design are three main design disciplines. GEOTECHNICAL ENGINEERING Most civil engineering structures are earthbound. They sit on soil and rock ground directly or on constructed foundations that transfer the load to the soil or rock below. Geotechnical engineering is the technical specialty that deals with soil and rock as supporting materials for structures. It deals with the various foundation types that work between the structure and the ground. In addition it deals with the stability of soil or rock slopes whose failure may cause loss of human lives or damage to property. There are several technical areas of study that are pertinent to geotechnical engineering. Engineering Geology While geology is a basic science that is concerned with macroscopic earth structures or movements, engineering geology provides geological data pertinent to constructed structures. One obvious example of the application of engineering geology is the mapping of active seismic faults that are to be avoided when making plans for human habitat development, roadway construction, or power plant construction. At a more fundamental level, understanding various geological formation and rock types provides geotechnical engineers the knowledge necessary in assessing the suitability of a site for human activities. Soil Mechanics Most people would not consider soil as an engineering material, but it is, because most constructed structures are situated on it by necessity. Without due consideration of soil’s bearing capacity under various circumstances, a structure built over it may sink, tilt, or outright turn over. Soil mechanics is a branch of mechanics that studies the mechanical properties of various types of soil and its strength at different moisture-content levels. It provides the scientific  base upon which design formulas and codes are developed for everyday engineering design practice. Rock Mechanics The properties of rock become relevant when it is used as the foundation of a high-rise building or a large dam. It is also relevant when one examines the stability of the slope of a mountain or a tunnel. It is also the subject of study for the occurrence of earthquakes. Foundation Engineering A foundation is the interface between a superstructure and its supporting soil. A common type of foundation for single-family homes consists of strip footings placed under load- bearing basement walls. Another common practice is to use a concrete slab to spread the weight of the building over the soil underneath. Foundation engineering is the study of different types of foundation and their proper applications. Depending on the properties of soil at a site, shallow or deep piles may be deployed. The construction of a bridge over water may require the use of deep caissons on which piers are constructed. To stabilize an excavated slope, various types of methods may be used including retaining walls and slope-protection vegetation growth. Soil Improvement When a structure must be placed at a site with very weak soil, various techniques can be used to improve the soil properties. These typically involve the use of replacement material through excavation or the injection of special material (grouts) into the original soil to change its properties. Another special technique is to place geo-synthetic fabrics or textiles in horizontal layers to strengthen the soil or to limit soil’s permeability, which is essential in the design for landfill and hazardous material deposit sites. Tunnel Engineering Tunneling through soil or rock is sometimes necessary in the construction of roadways or special storage spaces. Tunnel engineering deals with the route determination, selection of tunneling machines, and the analysis and design of the tunnel structure. Most of the things designed by geotechnical engineers are not as visible as those by structural engineers because they are underground or under the superstructure above. But, it is safe to state that no civil engineering work can be constructed without the contribution of geotechnical engineers. ENVIRONMENTAL ENGINEERING Environmental engineering is the application of engineering means to protect human health and to preserve the natural environment by managing and developing water, air, and land resources. The application of environmental engineering relies on the fundamental sciences of chemistry, biology, ecology, and health sciences. Most modern environmental engineering projects are planned and implemented under the auspices of the Clean Water Act, Safe Drinking Water Act, Clean Air Act, and other federal and state environmental legislation. Several technical areas in environmental engineering are described below. Water Treatment And Supply Before water is consumed, it has to be collected first from either underground or above- ground sources. Therefore, source control is one of the most important tasks of water supply. Except for a few municipalities where the source water derived from deep aquifers, source water has to be treated to remove contaminants such as pathogenic bacteria, heavy metals, and pesticide residues. The process of treatment involves the removal of suspended solids and the use of chemicals or ultraviolet (UV) radiation to disinfect unwanted organisms so that the effluent water satisfies quality requirements dictated by the Federal Safe Drinking Water Act. For water used by industrial plants such as paper mills or nuclear power plants, special treatment is needed and its discharge is regulated. Wastewater Treatment And Disposal In a modern municipality, household wastewater is collected through underground pipelines to a treatment plant. The wastewater treatment process is very different from drinking water treatment and is classified into primary treatment, secondary treatment, and tertiary advanced treatment. Primary treatment removes suspended solids from wastewater by a sedimentation process. Secondary treatment is to remove dissolved organic wastes from wastewater by biochemical decom- position followed by further sedimentation. The Federal Clean Water Act establishes nationwide minimum treatment requirements for all wastewater. For municipal wastewater discharge, the minimum treatment is the secondary treatment, which removes 85% of biochemical oxygen demand (BOD) and total suspended solids (TSS). BOD is a measurement of oxygen-demanding organic wastes. In situations in which these minimum treatment levels are not sufficient, the Clean Water Act requires additional treatment, which is accomplished by membrane filtration and other physical-chemical processes. The outcomes of the wastewater treatment are solid sludge and effluent water. The solid sludge sometimes can be used for landfill or even as fertilizers. The effluent water can be used for irrigation or groundwater recharge or may be directly discharged into river, stream,  or lake or sea. For a municipality, the amount of rainfall determines the ways of collecting and treating wastewater. Obviously if a large amount of rainfall is expected, especially when storm water comes in a very short period of time, rainwater runoff should be separated or diverted either temporarily or permanently from household wastewater in order to avoid overwhelming the treatment plant. Thus, a wastewater collecting system can either be combined (for more arid areas) or separated. Some industrial plants produce special wastewater that requires the removal of heavy metal or hazardous chemicals before being discharged. Air Pollution Environmental engineers monitor, analyze, and assess the air quality around municipalities. Air pollution comes from natural and human-activity sources. Volcanic eruption is a major natural source of air pollution. The gaseous and particulate contents of a volcanic eruption are often studied by scientists rather than engineers. Around a large municipality, however, air pollutants come from automobile emissions, nearby industrial plant emission, and even from faraway sources. Health science advances have discovered that tiny solid particles in the air such as soot are hazardous to human health. The monitoring of these particles is as important as that for gases. Tracing plant emission in the atmosphere, called plume analysis, is important in the assessment of the environmental impact of a plant. Another form of air pollution is sand storm. Monitoring of sand storms may lead to the sources of the storm and policy for conservation or planting of new vegetation. Solid Waste Disposal Solid wastes, commonly known as trash and garbage, from domestic, commercial, and industrial sources are to be collected, separated, and partially recycled, and disposed of in landfills and special disposal sites. Environmental engineers, working with other civil engineers, select, design, and construct sanitary landfill sites. Water percolating through a sanitary landfill is intercepted, collected, and treated in order to prevent the seepage of hazardous materials into ground water strata. Some solid waste maybe burned by specially designed incinerating plants. Nuclear Waste Disposal Nuclear waste comes from used fuel rods in nuclear power plants. Though the degree of radiation from these spent fuel rods is low, long-term exposure to low-level radiation is hazardous to human health. Disposal of these wastes has few options. The basic approach is to store them in places far from human habitat. Furthermore, it must be assured that the storage containers will not leak to the environment in any way. Leakage to underground water would be disastrous because the contaminants can travel far and reach sources for human water consumption.  Noise Pollution In modern municipalities, human activities often generate sustained high levels of sound that are hazardous to the physical and mental wellbeing of habitants. Sound barriers are often needed to shield neighborhoods from highway traffic noises. Power plants or air-conditioning plants on large campuses produce high levels of noises that also require containment and shielding. Environmental engineers monitor the noise levels and design and implement mitigation strategies. Environmental Impact Assessment Environmental engineers are often called upon to assess the impacts on human health and the natural environment by a new development, a new industrial plant, or even a new commercial establishment such as a large shopping mall. Such assessment may entail the study of noise, traffic, water consumption and discharge, power requirements, air pollution potential, and other factors. Environmental engineering as a part of civil engineering is unique in its extensive applications of knowledge from health sciences and biology and chemistry. Its practice is also very much impacted by environmental laws enacted at the state and national levels. WATER RESOURCES ENGINEERING Water resources engineering is a specialty dealing with the use of water in support of modern living, including the agricultural, industrial, domestic, recreational, and environmental needs. Its scope includes the finding and preservation of above- and underground water sources, understanding the movement of water in nature, engineering the transport of water, and managing erosive effects of water wave and current on shorelines. Some core and related specialties are described below. Water Resources System Engineering The understanding of the circulation of water on earth and managing the sources of water in a region requires a system approach. Decision on the water supply for a city or a region requires the knowledge of water sources and the quality and quantity of each source. The application of system analysis in water resources management and the design and operations of multipurpose reservoir and river systems is at the core of water resources system engineering. Hydraulic Engineering Hydraulic engineers design artificial waterways such as canals, channels, and aqueducts as well as manage water movement by designing and constructing dams, levees, canal locks, and other water-regulating devices. For many regions a major task of hydraulic engineers is flood prevention and control, which entails the assessment of potential rainfall quantity, prediction of water levels along  natural rivers, streams, or channels, and strategies to mitigate flooding hazards by improving the natural topography. Hydraulic engineering is also fundamental to hydraulic-power generation. In hydraulic- power generation a prerequisite is a high water-level differential (water head). When water moves from a high level to a lower level, the difference in the water levels provides the energy potential for power generation. Some dams are constructed mainly for power generation although usually a dam also has the potential to be used for flood control. The stored water in a dam’s reservoir can be used for agricultural, industrial, and domestic consumption as well as recreational sports. Coastal Engineering The movement of water in oceans and lakes has erosive effects on their shorelines. The preservation of wetland for flood mitigation or marine ecology requires the knowledge of such effects. Use of artificial barriers such as breakwaters or dikes at a shore or a harbor can result in reducing the water wave level within protected areas, eliminate or reduce the effects of shoreline erosion, and redirect natural sediment so that new land can be created over time. Ocean Engineering Ocean engineering deals with the effects of ocean currents and waves on ocean- bound structures and the analysis and design of such structures to withstand the wave forces. The most prominent ocean-bound structures are offshore platforms for oil exploration and production. Ocean engineers provide estimates of forces generated from waves and currents and the interaction of wave and structure so that structural engineers can design a platform to withstand such forces. Other ocean-bound structures include offshore wind farms and pipelines to transport materials from offshore to shore. While ships are obvious ocean-bound structures, their design usually falls in the realm of naval architecture, which integrates several engineering disciplines: structural, ocean, mechanical, and electrical for the design of ships. Naval architecture is not considered as a part of civil engineering. TRANSPORTATION ENGINEERING Transportation engineering deals with the efficient transport of people and goods. The content of transportation engineering changes whenever a new mode of transportation becomes viable. For example the advent of airplanes and air travel led to new technical fields such as airport design and air traffic control. Several sometimes overlapping technical specialties are part of transportation engineering: Transportation Planning Transportation infrastructure is mostly government funded or at least government approved.  Before any physical facilities are designed and built for moving people and goods, decisions must be made from policy and political considerations. Transportation planning considers policy formation processes, cost, financing, and projected performance of potential transportation systems, including inter-modal transportation that involves more than one mode of travel such as sea-land-air travels. Transportation System Engineering Transportation System Engineering entails the efficient management and operation practices, design, and assessment of the cost-effectiveness of transportation systems. The assessment of transportation systems requires performance modeling techniques, traffic simulation, and environmental impact (noise and air pollution) analyses. Highway Engineering Highway engineering focuses on the planning, design, construction, and operation and maintenance of highways. Unique to highway engineering is the design and construction of highway pavements and foundations, and the design of highway interchanges. The operation of highways includes the use of high-occupancy lanes and networked signals and displays that can alter lane direction during rush traffic and warn travelers of road conditions ahead. Design and construction of toll booths and ways of collecting tolls are part of highway engineering as well. Railway Engineering With the advent of high speed railway, light-rail systems, and magnetic levitation systems, railway engineering gained renewed interest in civil engineering. Railway transportation remains a cost-effective way of transporting large quantities of goods on land. Railway engineering focuses on the planning, design, construction, operation, and maintenance of railways. Advances in electronic signal design and communication technology provide new tools in the control of railway traffic for efficiency and safety. Port And Harbor Engineering Even under the most favorable natural conditions, a port requires additional engineering to make sure ships can safely navigate through and dock, and cargoes can be efficiently unloaded and uploaded for shipping elsewhere. Some harbors require routine dredging to maintain the navigation channel. Some harbors need breakwaters to tame the ocean waves. These are the scope of port and harbor engineering. Airport Engineering The construction of a new airport requires extensive planning, including the study on demand, environmental impact, cost analysis, and investment returns. Since an airport is part of an air transport system, the impact of a new airport must consider the regional air traffic demand. Airport site selection requires extensive study of regional topography, including local constructed structures, prevailing winds, and, for airplane safety, movements of birds. The impact on nearby neighborhoods includes the new land traffic generated by travelers and the inevitable noise generated along air traffic routes. The engineering of airport infrastructure such as runways, terminals, and signals falls in the domain of other civil engineering specialties. Traffic Engineering Traffic engineering sometimes is considered as synonymous to transportation engineering but it is usually defined as the narrower field of management of traffic flow. From huge metropolises to small towns, surface traffic must be controlled and modulated for safety and speed. Traffic engineers use projected and monitored traffic patterns and volume to design automated or centrally controlled street signals to modulate traffic. Tools used for traffic control include weight sensors for triggering of left-turn signals and ramp-entry signals for freeway entry during rush hours. Traffic engineering sometimes is considered as synonymous to transportation engineering but it is usually defined as the narrower field of management of traffic flow. From huge metropolises to small towns, surface traffic must be controlled and modulated for safety and speed. Traffic engineers use projected and monitored traffic patterns and volume to design automated or centrally controlled street signals to modulate traffic. Tools used for traffic control include weight sensors for triggering of left-turn signals and ramp-entry signals for freeway entry during rush hours. Intelligent Transportation Systems New and emerging electronic and computer technologies make it possible to efficiently monitor, evaluate, and improve the performance of transportation systems. An example of the applications to new vehicle engineering is the possibility of high-speed automated highway travel by automobiles in groups. Another example is the centrally controlled traffic monitoring and management systems used in large cities. Fully automated automobiles without drivers are in development and testing. Transportation engineering is a specialty whose content is changing with emerging technologies. The operational aspect of transportation engineering is heavily influenced by the advances in new technologies. CONSTRUCTION ENGINEERING Transforming design details on paper or a computer file into physical reality is the task for construction engineers and managers. The successful completion of a construction project requires the integration of several areas: human resources management; financial resources and cost management; construction processes; schedule design and control; construction machinery; electric and mechanical facilities; legal, health, and safety issues; and risk management. Construction firms may specialize in one or more types of structures: buildings, bridges, dams, highways, airports, and ports and harbors. In the following some of the engineering and management aspects of construction engineering are described. Construction Processes Depending on the types of structures to be constructed and the materials to be used, each project has a unique process to follow to erect the structure step by step. The execution of a physical construction process often requires the knowledge of geotechnical engineering, structural engineering, construction materials, and site surveying. For example the construction of a multi-story building starts with the placement of foundations, which may consist of multiple steel or concrete piles. The story-by-story erection process depends on whether the building is of concrete or steel construction. These processes follow well-developed practices deeply rooted in accumulated experience of construction engineers. Intertwined with the construction process is construction scheduling, which lays out in detail the daily activities to be performed. Creating a construction schedule must consider the critical phases that determine the time length of the project. Electric And Mechanical Facilities In most construction projects electric and mechanical facilities are to be installed. Basic knowledge of common electrical and mechanical facilities is required for the installation of these facilities and their integration into the main structure. Construction Machinery From conveyer belts and bulldozers to scrapers, excavators, loaders, graders, compactors, cranes, and pipe-layers, many different machines are used in construction. Knowledge of these machines’ capabilities is required in planning the types and quantity needed for a construction project. Financial And Cost Management From the bidding for a project to the actual execution, financial management is at the center of concern of construction management. Bidding is the critical process by which potential contractors compete to earn the contract from the owner of the project.  Cost estimating is done at the beginning of a potential project and updated throughout the project. During the project period, cash flow management is needed to keep the project going. Successful contractors often have sufficient cash reserve or credit to ride through tough periods of low income cash flow and high outward cash payments. Contracts And Specifications A contract is a legal document that specifies the responsibilities of both the contractor who delivers the service and the owner who receives the service. Specifications are also legal documents that the contractor must follow throughout the project. Specifications are often based on well-developed construction practices but sometimes may include special requirements added by the owner. These legal documents are developed, negotiated, and decided upon between the contractor and the owner. Health And Safety Issues The health and safety of not only construction workers but also neighboring residents or passersby is regulated by the government. The Occupational Safety and Health Administration (OSHA) of the Department of Labor enforces regulations and laws pertaining to construction. Knowledge of these regulations and the strict adherence to the regulations are the responsibilities of the construction engineers or managers. Legal Issues And Risk Management Examples of potential liabilities of a construction project include negative cash flow, missing construction time milestones, mistakes in the constructed configurations or the strength of materials used, and accidents resulting in human injury or death. The prevention of any of the above and the timely management of the damage once any of them has occurred are the realm of risk management. Legal and ethical guidelines are to be followed at all times. GEOMATICS (SURVEYING ENGINEERING) Geomatics is the new name for an expanded technical area of what used to be called surveying or surveying engineering. Surveying engineering is the technical specialty that applies the science of measurement to the assembling of spatial data on land and sea and any natural or constructed objects thereof. Its applications often involve legally required documentation related to the transaction of property, the location of routes or points needed in construction, and the collecting of global data for resources analysis and utilization. Some of the technical areas in surveying engineering are described herein. Plane Surveying The earth is a near circular sphere with a curved surface. When the area of interest on the earth’s surface is small enough such that the curvature throughout the area can be neglected in measuring and locating any point in the area without causing any significant amount of error, the earth surface is treated as if it is a plane. With this simplification, the measuring and locating of points or routes are mathematically much simpler. Plane surveying deals with the techniques and skills in carrying out such tasks within the limit of the simplification. In plane surveying, optical instruments are used in conjunction with basic mathematics to accurately locate points and lines, to calculate areas and volumes, and to map existing surface features. Since no scientific measurements can be made without error because of limited resolution of instruments or even human mistakes, techniques are developed to minimize measurement errors. Route Location For highway or railway construction, the roadway configuration contains straight lines and curves in the horizontal and vertical planes necessitated by the change of natural topography and the need to minimize the cost of changing the natural topography. These lines and curves are designed and documented on paper or in computer files. Route location is the technique to transform points on these lines and curves on file to points on location with reference to some existing points on the earth’s surface. Land Surveying Land surveying pertains to the measuring and documentation of property lines, streets and alleys, subdivisions and lots within a city or a village. The map of the area is called a plat, which forms the legal document in ownership transactions. Geodetic Surveying In contrast to plane surveying, geodetic surveying includes the earth’s surface curvature in its calculations and mapping. More advanced mathematical tools such as spherical geometry and curvilinear coordinate systems are utilized for the computation of measure data and locating of points and lines. Surveying instruments may include the use of aerial photography, satellite imaging, and the global positioning system (GPS). Geodetic survey is necessary in the construction of long-span bridges and other structures covering a large stretch of area (a long tunnel, for example).  Aerial Photography And Satellite Imaging With the advances in optical and electronics technologies resulting in improved measurement resolution and accuracy, images produced from airplane- or satellite- based instruments can be used in the mapping of ground features for various applications. Advances in digital photography and computer automation make the mapping efficient and much less time consuming. Applications of such images and maps range from real estate information generation and agricultural resources evaluation to military and intelligence information evaluations. Geographical Information System Surveying engineering provides the basis for the geographical information system (GIS) of a state, city, town, or smaller unit. Useful information such as basic population data, infrastructure, average income of population, demographic distribution, educational and recreational resources, crime rate, etc., is compiled in a single database for easy retrieving and application. GIS is also an example of the increasing application of information technology to surveying engineering. It should be mentioned that surveying nowadays is often considered a technical area outside of civil engineering or engineering in general. After all, the organization in charge of testing for professional licensing in engineering and surveying, National Council of Examiners for Engineering and Surveying (NCEES), has separate exams for engineers and surveyors. Some civil engineering programs do not require any surveying courses. URBAN PLANNING Urban planning integrates land use planning, infrastructure planning, and public policy for new developments or renewal of urbanized communities. Successful urban planning requires the application of the knowledge developed in social, economic, architectural, and engineering studies. Educational programs for future urban planners can be found in Bachelor of Arts degree programs in arts, architecture, and public policy colleges. Bachelor of Science degree programs are also available in some universities. The application of civil engineering to urban planning emphasizes the physical aspects of urban planning: street patterns, park and recreational areas, industrial and residential areas, transportation systems such as freeway access, airport access, public works and utilities, infrastructure management, etc.