Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
What is bridge? |
It is a structure which covers a gap and serves the purpose of carrying road or railway across a natural or artificial obstacle such as river, canal or another road or railway. |
|
|
Components of bridge |
*Superstructure - A structural system which carries a transportation facility such as a roadway or a railway over an obstacle.- This consists of a flooring supported by beams, slabs, archestrusses and cable * Substructure: Supporting system for the superstructure, comprising, abutments, piers and wing walls |
|
|
General Components of bridge(4)- main answer |
*Upper structure: main load bearing structure *Bearing: A force transmission device, and to ensure that the upper structure according to the design requirements can produce a certain change. *Lower structure:- Bridge piers: supporting the superstructure, and transferthe load to the foundation -Abutment: supporting the upper structure, the loadtransfer to the base, and with the convergence of theembankment, the embankment of earth pressure against. -Foundation: the foundation part, bear the load from all piers and abutments. *Accessory: bridge decking, expansion joint, transition slab at bridge head and conical slope, etc. |
|
|
Functions of bridge components |
*Bearing (metal rockets, rollers, rub.) - They are supports on bridge pier which carry the weight of the bridge and control movement at the bridge support (includes temperature expansion and contraction) *Dampers & Isolators - Devices that absorb energy generated by earthquake waves and lateral load
- A wide column or reinforce concrete for carrying load as a support for a bridge *Gap - The highest part of a bridge pier on which the bridge bearing or rolllers are seated.
* Deck - The load bearing floor of a bridge which carries and spread load to the main beam. *Piers - A wide column or reinforce concrete for carrying load as a support for a bridge *Gap - The highest part of a bridge pier on which the bridge bearing or rolllers are seated. * Deck - The load bearing floor of a bridge which carries and spread load to the main beam. *Abutment - A support of an arch or bridge which may carry a horizontal force as well as weight. *Expansion joint - Provided to accommodate the translation due to possible shrinkage and expansion due to temperature changes. *Abutment - A support of an arch or bridge which may carry a horizontal force as well as weight. *Expansion joint - Provided to accommodate the translation due to possible shrinkage and expansion due to temperature changes. |
|
|
Components of suspension bridge |
*Anchor Block: Just looking at the figure we can compare it as a dead man having no function of its own other than its weight. *Suspension girder: lt is a girder built into a suspension bridge to distribte the loads uniformly among the suspenders and thus to reduce the local deflections under concentrated loads *Suspenders: a vertical hanger in a suspension bridge by which the road is carried on the cables *Tower: Towers transfers compression forces to the foundation through piers. *Saddles: A steel block over the towers of a suspension bridge which acts as a bearing surface for the cable passing over it. *Cables: Members that take tensile forces and transmit it through saddles to towers and rest of the forces to anchorage block |
|
|
Common terms |
*Span length or clear span or design span Horizontal distance between center of two bearing at support * Total length - The distance between the wing wall end at either abutment or deck lane length for bridge without using abutment * Deck width - The sum of the carriageway width, sidewalk width, shoulder widtg and individual elements required to make up the desired bridge cross section. * Span clearance measured from the water surface or ground to the under surface of the bridge. *Deck clearance The space limit for carriageway and sidewalk which is generally specified in the bridge design specification to ensure the traffic safety above the bridge. |
|
|
Classification of bridge |
1. According to Construction materials * Steel * Concrete * Hybrid * Wood * Stone * Brick
2. According to usage * Pedestrian bridge * Road bridge * Railway bridge * Aqueduct bridge
3. According to span length * Short span ( <15) * Medium span(15<L<50) *Long span (50-150) *Extra large (>150)
4. According to structural form * Beam/Truss/Girder- 300m span * Arch bridge- 2(300)m= 600m * Cable-stayed- 1200m * Suspension bridge - >1200m 5. According to structural arrangements *Main Structure Below the Deck LineArch Bridge/Truss-Arch Bridge*Main Structure Above the Deck LineSuspension Bridges/Cable Stayed Bridges/Through-Truss Bridge *Main Structure coincides with the Deck LineGirder Bridge |
|
|
Distinctive features of girder bridge |
*Widely constructed*Usually used for Short and Medium spans *Carry load in Shear and Flexural bending *Efficient distribution of material is not possible *Stability concerns limits the stresses and associated economy *Economical and long lasting solution for vast majority of bridges *Decks and girder usually act together to support the entire load in highway bridges
a bridge that utilizes girders as the means of supporting the deck the most commonly built and utilized bridge the most simplified form No moments are transferred throughout the support |
|
|
Types of beam bridges |
* Simple supported beam bridge* Continuous beam bridge* Cantilever bridge* Steel bridge and steel - concrete * composite beam bridge |
|
|
Rigid frame beam |
1. Form Beam (or plate) and column (or vertical wall) combined with the whole frame structure, the link has a lot of rigidity, in order to assume the role of negative bending moment 2. Stress characteristicsUnder the vertical load, the heel with horizontal reaction force, the beam is mainly affected by the bending, but for the moment the level value is of the same span simply supported beam small, beams, and axial pressure h, and its stress state between beam and arch bridges 3. Materialsreinforced concrete, prestressed concrete, steel etc 4. Types * Portal rigid frame* T rigid frame bridge* Continuous rigid frame* Rigid frame continuouscombination system* Rigid frame bridge with inclined legs f |
|
|
Distinctive features of cable-stayed bridge |
|
|
|
Distinctive features of suspension bridge |
|
|
|
Classification according to span |
1. Small span bridge (up to 15m) * Culvert bridge * Slab bridge * T-beam bridge * Wood beam bridge * Pre-cast concrete box and I beam bridge ....
2. Medium span bridge(up to 50m * Pre-cast concrete box beam bridge * Composite rolled steel beam * Composite steel plate girder * Cast-in place RCC box girder ...
3. Large span bridge * Composite steel plate girder *Cast-in place post tensioned concrete box girder * Post tensioned concrete *Concrete arch and steel arch 4. Extra large * Cable stayed bridge * Suspension bridge |
|
|
Table-span length |
|
|
|
Factors considered in deciding bridge type |
* Geometric Conditions of the Site *Subsurface Conditions of the Site *Functional Requirements*Aesthetics*Economics and Ease of Maintenance *Construction and Erection Consideration *Legal Considerations details in ppt |
|
|
Geometric conditions of site |
*The type of bridge selected will always depend on the horizontal and vertical alignmentof the highway route and on the clearances above and below the roadway*For Example: if the roadways is on a cuve.continuous box girder and slabs ae food choce because they have a pleasing apearance.can readily be built on curve and have retvey high torsion resistance *Relatively high bridges with larger spans with medium spans crossing a flood plain*The site geometry will also dictate how traffic can be handled construction, which is an important safety issue and must be considered early in the planning stage |
