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This course covers the stages of construction for roads, highways, and bridges. It focuses on the different types, functions, and design considerations of these structures.
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CONSTRUCTION TECHNOLOGY & maintenance CEM 417
WEEK 3 Building Retaining walls, Drainage Road, Highway, Bridges Airports, Offshore/Marine structure Stages for construction
WEEK 3 • At the end of week 3 lectures, student will be able to : • Identify the different types of roads, highways and bridges and their respective functions. (CO1; CO3)
flash.lakeheadu.ca/.../Highway%20Design%20-%20Class%20notes%202%20-%20Functional%20classification.pptflash.lakeheadu.ca/.../Highway%20Design%20-%20Class%20notes%202%20-%20Functional%20classification.ppt Highway Development Process and Functional Classification
Overview of the Highway Development Process http://www.fhwa.dot.gov/environment/flex/ch01.htm
Highway Development Process • Highway design is only one element of the overall development process • Five stages of highway development process: planning, project development, final design, right-of-way, and construction • Different activities with overlap in terms of coordination • Flexibility available for highway design during the detailed design phase is limited by decisions on early stages
Planning • Initial definition of the need for any highway or bridge improvement project takes place in this phase • Problems identified fall into these categories: • Existing physical structure needs major repair/replacement • Existing or projected future travel demands exceed available capacity, and access to transportation and mobility need to be increased (capacity). • The route is experiencing an inordinate number of safety and accident problems that can only be resolved through physical, geometric changes (safety). • Developmental pressures along the route make a reexamination of the number, location, and physical design of access points necessary (access).
Planning (contd.) • Once problem is identified, it is important that all parties agree that the problem exists and that it should be fixed • Consider potential impacts of project: • How will the proposed transportation improvement affect the general physical character of the area surrounding the project? • Does the area to be affected have unique historic or scenic characteristics? • What are the safety, capacity, and cost concerns of the community? • Answers on this phase
Factors in Planning http://www.fhwa.dot.gov/environment/flex/ch01.htm
Project Development • Environmental analysis intensifies • Includes a description of the location and major design features of the recommended project • Try to avoid, minimize and mitigate environmental impacts • Basic steps: • Refinement of purpose and need • Development of a range of alternatives (including the "no-build" and traffic management system) • Evaluation of alternatives and their impact on the natural and built environments • Development of appropriate mitigation
Project Development (contd.) • Assess area • Consider context and physical location • Data collection effort • Identify constraints • Consider factors and select preferred alternative http://www.fhwa.dot.gov/environment/flex/ch01.htm
Final Design • After a preferred alternative is selected and the project description agreed on upon as stated in the environmental document, the final design occurs • The product of this phase is a complete set of plans, specifications, and estimates (PS&Es) of required quantities of materials ready for the solicitation of construction bids and subsequent construction • Depending on the scale and complexity, this phase may take from a few months to several years
Final Design (contd.) • Need to employ imagination, ingenuity and flexibility • Be aware of commitment of previous phases • Ability of making minor changes to original concept • Design considerations • Developing a concept • Considering scale • Detailing the design
Right-of-Way, Construction and Maintenance • During the right-of-way acquisition and construction phases, minor adjustments in the design may be necessary • Construction may be simple or complex and may require a few months to several years • Maintenance is very important to keep the character of the road
Functional Classification • Is the process by which streets and highways are grouped into classes, or systems, according to the character of traffic service that they are intended to provide • Streets and highways classification • Orderly grouping roads based on service • Assist in geometric design features • In accordance with operational needs • Establishes hierarchy of roads • Efficient and safe if road serve their purpose
Functional Classification (contd.) • Assessment of operating conditions • Comparison between actual and intended purpose • Chance to sort data based on type of road • Collision data not yet available • Three functional classifications: • arterials • Collector • local roads
ROADWAY FUNCTIONAL CLASSES • Determined by characteristics: • function • access density • traffic demands • trip length • expected speed http://www.fhwa.dot.gov/environment/flex/ch01.htm
Roadway Functional Classes (contd.) • Arterial: highest level of service, high mobility, low access, long trips, fast speeds • Collector: less highly developed level of service, lower speed for shorter trips, collects traffic from local roads and connecting them with arterials • Local: all roads not defined as arterials or collectors, provides access to land with littler or not through traffic, low speed
Service FunctionSource: TAC Geometric Design Guide for Canadian Roads
Functional Classification in the Design Process • The first step in the design process is to define the function that the facility is to serve. • The level of service required to fulfill this function provides the basis for design speed and geometric criteria within the range of values available to the designer • Functional classification decisions are made before the design phase, but there is flexibility in the major controlling factor of design speed
Design Classification System • Source: TAC Geometric Design Guide for Canadian Roads • Classification system (differences in) • Traffic and land service • Design features • Operational needs (adjacent land use) • For all areas in Canada • Rural (R) Urban (U) Lane Local (L) Local (L) Collector (C) Collector (C) Arterial (A) Arterial (A) Expressway (E) Freeway (F) Freeway (F)
Design Classification (contd.) • Ten primary divisions • Design subdivisions • Divided (D) or undivided (U) • Design speed (value) • Example (See Table 1.3.2.1, next slide) • RAD (90) • UCU (80) Comments • Number of classes: 63 • Design speed increases from local to freeways • All locals street are undivided • All freeways are divided
Rural Design ClassificationSource: TAC Geometric Design Guide for Canadian Roads
Factors considered in Classification • Adjacent Land Use: • Urban vs. rural classification • Service Function: • Access to land. Ex: local • Service to traffic. Ex: freeways • both • Traffic Volume: • Freeways: high volume • Collectors and locals: low volume • Flow Characteristics: • Freeways: uninterrupted facility • Locals; interrupted facility
Factors considered in Classification (contd.) • Running Speed: • Generally increase from locals to collectors to arterials to freeways • Vehicle Type: • Proportion of passenger cars, buses, large trucks • Connections: • Normal for roads to connect to the same classification or one higher or one lower • See Table 1.3.3.1 For Characteristics of Rural Roads • See Table 1.3.4.1 For Characteristics of Urban Roads • See Table 1.3.4.2
Comments • Comments: • Rural and urban roads are the same in terms of service function, and land service • Volumes are higher on urban roads than on rural roads • Design speeds on urban roads are lower than in rural roads • Vehicles types are different, especially for local streets • Government agency responsible for each type of road: • Municipal government -urban: local, collectors • Provincial government –rural - freeways • Similar roads have similar designs, construction, maintenance and operation • Similar roads: similar costs
HTTP://WWW.BUZZLE.COM/ARTICLES/TYPES-OF-BRIDGES.HTML • Top 20 Most Popular Bridges in the WorldOther than the above given names, here are some more names of the most famous bridges of the world. • Kintai Bridge, Japan • Chain Bridge, Hungary • Ponte Vecchio, Italy • Pont des Arts, France • Bosphorus Bridge, Turkey • Charles Bridge, Czech Republic • Rialto Bridge, Italy • Jacques Cartier Bridge, Canada • Stari Most, Bosnia and Herzegovina • Great Belt Bridge, Denmark • Chengyang Bridge, China • Akashi-Kaikyo Bridge, Japan • Alcántara Bridge, Spain • Millau Bridge, France • Chapel Bridge, Switzerland • Galata Bridge, Turkey • Tsing Ma Bridge, Hong Kong • Banpo Bridge, South Korea • Magdeburg Water Bridge, Germany • Howrah Bridge, India
Bridge is not a construction but it is a concept, the concept of crossing over large spans of land or huge masses of water. The idea behind a bridge is to connect two far-off points eventually reducing the distance between them. Apart from this poetic aspect of ‘bridges’, there is a technical aspect to them that classifies bridges on the basis of the techniques of their construction
Beam Bridge: A beam bridge was derived from the log bridge. It is built from shallow steel beams, box girders and concrete. Highway overpasses, flyovers or walkways are often beam bridges. A horizontal beam supported at its ends comprises the structure of a beam bridge. The construction of a beam bridge is the simplest of all the types of bridges.
Truss Bridge: A truss bridge is built by connecting straight elements with the help of pin joints. Owing to the abundance of wood in the United States, truss bridges of the olden times used timbers for compression and iron rods for bearing tension. Truss bridges came to be commonly constructed from the 1870s to the 1930s. Deck truss railroad bridge that extends over the Erie Canal is one of the many famous truss bridges.
Arch Bridge: Going by its name, it is arch-shaped and has supports at both its ends. The weight of an arch-shaped bridge is forced into the supports at either end. The Mycenaean Arkadiko Bridge in Greece of 1300 BC is the oldest existing arch-shaped bridge. Etruscans and the ancient Greeks were aware of arches since long. But the Romans were foremost in discovering the use of arches in the construction of bridges. Arch bridges have now evolved into compression arch suspended-deck bridge enabling the use of light and strongly tensile materials in their construction.
Suspension Bridge: A bridge falling under this category is suspended from cables. The suspension cables are anchored at each end of the bridge. The load that the bridge bears converts into the tension in the cables. These cables stretch beyond the pillars up to the dock-level supports further to the anchors in the ground. The Golden Gate Bridge of USA, Tsing Ma Bridge of China and the Humber Bridge of England are some of the famous suspension bridges.
Cable-stayed Bridge: Structured similar to the suspension bridges, the difference lies in the amount of cable used. Less cable is required and consequently, the towers holding the cables are shorter. Two variants of cable-stayed bridges exist. In the harp design, cables are attached to multiple points of the tower thus making them parallel. In the fan variant of design, all the cables connect to the tower or pass over it. Cable Bridge boasts of being the first cable-stayed bridge of USA. Centennial Bridge is another well-known cable-stayed bridge.
Cantilever bridge: Cantilevers are the structures that project along the X-axis in space. They are supported only on one end. Bridges intended to carry lesser traffic may use simple beams while those aimed at handling larger traffic make use of trusses or box girders. The 1800 feet Quebec Bridge of Canada and the San Francisco-Oakland Bay Bridge that is 1400 feet long are some examples of the cantilever bridges.
Truss Bridge TypesTruss is a structure composed of triangular units which consists of straight beams connected at the joints called nodes. The application of this principle and their improvisation further led to the invention and design of various types of truss bridges around the world. These are some truss bridge types with examples:
Howe Truss BridgeThis is named after its inventor William Howe, and was designed for the use of timber as diagonal compressions and iron as vertical tensions. Howe truss was later improvised to use steel for its construction and became a forerunner of iron bridges. These truss bridge types are popular as railroad bridges, and a well preserved example is the Comstock Bridge over the Salmon river, Colchester. Allan Truss BridgeThis was designed by Percy Allan, hence it was named as Allan Truss. Hampden Bridge in Wagga Wagga, New South Wales, Australia, is one of the most famous bridges and an example of Allan Truss Bridge. It is the first of this type and constructed with wood and ironbark for strength. This is the simplest among the other truss bridges, economical due to the use of less material and easier to repair. Truss Arch BridgeThis type of truss bridge combines the design of truss and arch bridges, in which the trusses are fitted within the arch. A famous example of this type is the Iron Bridge across the river Severn, Shropshire, England.
Bollman Truss BridgeNamed after its inventor Wendell Bollman, this type of truss bridge is built only using metals, mostly wrought iron and cast iron. Most of the railroad bridges around the world are built by adopting this design due to the ease of assembly and its durability. Though common after its invention, only one bridge of this type is available today. The oldest and most historic, the Bollman Truss Rail Road Bridge in Savage, Maryland, is an example of revolutionary truss bridge design in engineering history. Pratt Truss BridgeIt is exactly the opposite of Howe truss bridge in structure. Here, the diagonals are in tension and the vertical elements are under compression, both sloping towards the center in a V-shape. Earlier Pratt truss bridges were made of timber and iron truss, but later it was made of iron only. It has many variations, due to the modifications made on this design, to make it lighter, but was originally designed by Thomas and Celeb Pratt. An example of these truss bridge types is the Schell Bridge in Northfield, Massachusetts. Bowstring Arch Truce BridgeThe father of tied arch bridge is considered to be Squire Whipple. This involves complicated engineering among the various truss bridge types, where the tension of the top chord is supported by the bottom chord, rather than being supported by the ground foundation. Due to this quality, tied arch bridges are usually built in areas of unstable soil. An example of this type is the Torikai Big Bridge over the Yado river, Osaka, Japan.
Cantilever BridgeCantilever bridges are named after its use of cantilevers and involve one of the most complex designs among different truss bridges. For supporting heavy load, cantilever bridges either use steel trusses or concrete box girders. For long bridges, steel truss cantilevers are used, which gives it strength and can be easily constructed. The Quebec Bridge in Quebec, Canada, is not only listed as one of the famous bridges of the world, but is also the longest cantilever bridge around. Bailey BridgeThis type of truss bridge was originally designed by Donald Bailey for use by military engineering units. These are portable bridges and are small enough for easy transportation, handling, installation and reuse. They are modular bridges, and unlike previous portable bridges used by the military, these do not require complicated equipments while assembling, and are very cost-effective.
Comstock Bridge • Over Salmon River north of Route 16 • Colchester-East Hampton • Covered timber truss • Length: 2 spans, 110' overall, 80‘ Maximum span length • Built in 1873 The Howe Truss Bridge (designed byWilliamHowe) was patented in 1840. The advantages of the Howe Truss Bridge to the railroad companies of the era were that it was easy to prefabricate offsite and to ship by rail.
