What is Bridge: Definition and 481 Discussions

A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as: the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it and the funds available to build it.
The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge (dating from the 13th century BC, in the Peloponnese) is one of the oldest arch bridges still in existence and use.

View More On Wikipedia.org
Recent contents Top users
  1. S

    Wheatstone bridge, prove converse.

    Homework Statement You are given a standard Wheatstone bridge, prove that the bridge is balanced if and only if R_x = R_3 \frac{R_2}{R_1} . Subindexes depend on the names assigned to each resistance. Proving that if the bridge is balanced THEN the resistors satisfy said relationship is easy...
  2. A

    Distributed load - model bridge project

    Homework Statement check out: so this is for a bridge project right and that picture is simply a basic design just enough to get the jist to answer my question. what I am wondering is, if 20kg's was applied to the very centre of that loading plate - is it fair to say that each of the long...
  3. C

    Joints/fixtures for a beam bridge

    I have a group project where we must build a small scale, cable-stayed bridge, with only one pylon (it's really an observation deck). The actual bridge is going to be a beam one. I'm just wondering if anyone knows of some decent joints/fixtures that can be used to hold the wood pieces...
  4. W

    Engineering Design: Truss Bridge Questions

    Hey. I am currently in an engineering class designing a truss bridge and had a couple questions. (Note all truss members are considered to be two-force members) 1) Suppose the truss is symmetric and a force is applied through the middle of it. Is it normal in industry for any individual...
  5. M

    NEED HELP Wheatstone bridge and DC series/parallel Please look

    NEED HELP ASAP! Wheatstone bridge and DC series/parallel ! Please look! I have three problems I need help solving. Problem #1: Fine the value R1 in the figure if R2 = 30ohm, I = 0.5A and V = 10V My try was: Rp = R1 + R2 , 20 = R1 + 30 , R1 = -10? ** please look for...
  6. P

    Calculating Forces and Acceleration in a Castle Bridge Mishap

    Homework Statement Sir Lost-a-Lot dons his armor and sets out from the castle on his trusty steed in his quest to improve communication between damsels and dragons. Unfortunately his squire lowered the draw bridge too far and finally stopped it 20.0° below the horizontal. Lost-a-Lot and his...
  7. F

    Will multi-core processors reach their limit with Intel's new Ivy Bridge?

    I think it's a little early for a die shot of the 8-16 core Intel "Ivy Bridge" processor, but this is an alleged photo. Is it real?
  8. L

    Bridge to mathematical physics book?

    Background Next year I am going to be a final year student - Msci Physics. I am fairly mathematically competent even though I don't "take" any theoretical/math options (my confidence in this area is another question). In first year we had a standard introduction to all the topics we were...
  9. K

    Balsa Bridge Design Optimisation

    Hi, I need to design a balsa bridge that will cover a distance of 200mm. It will be loaded centrally for testing. The objective of this however is not to test until failure, but to have it fail at a certain weight. Points are also given for high strength to weight ratios and simplicity of the...
  10. F

    How does Changing Salt Bridge Solution affect observed voltages?

    Homework Statement In a lab in which many half-cells are constructed, one of which contains Zn2+, the original salt bridge solution is Potassium nitrate. Suppose we needed to change this solution to Zinc nitrate. What would be the effect on the observed cell potentials? Homework Equations...
  11. P

    Bridge truss Static Equilibrium

    Homework Statement A bridge truss extends x = 214 m across a river (Fig. P12.68) where θ = 35°. The structure is free to slide horizontally to permit thermal expansion. The structural components are connected by pin joints, and the masses of the bars are small compared with the mass of a 1270...
  12. E

    Weird Oscillation in wheatstone bridge circuit

    I have this weird oscillation coming from my circuit. its a wheatstone bridge with a single strain gage. I am using The PST 4130 from Omega Engineering to supply +10vdc. When I first turn it on the signal is pretty clean, but after a while, it turns into this...
  13. C

    Help Free fall, looking for time of motion off of a bridge.

    Help! Free fall, looking for time of motion off of a bridge. Homework Statement A person standing on a bridge throws a ball upward with an initial velocity of 23 m/s straight upwards so if it comes back down it will just pass the edge of the bridge and keep going down. a) where will the ball...
  14. C

    Wheatstone Bridge - Max power delivered

    Homework Statement The Attempt at a Solution I was able to find the net resistance as its a balanced wheat stone bridge ... But how to find R for max power delivered?
  15. U

    Wheatstone Bridge Experiment

    Homework Statement 1. Why is the Wheatstone bridge measurement capable of so much greater accuracy than the measurement or resistance with voltmeters and ammeters, using R = V/I? and 2. R in this experiment is a resistance box and so is accurate to the nearest ohm. Is this uncertainty in R...
  16. N

    Wheatstone bridge offset-nulling circuit

    Hi all, I’m making a simple cantilever beam measurement system using 2 strain gages (120Ω). The two gages make up one leg of my Wheatstone bridge; the other leg will be made up using 120Ω resistors. Because of tolerances etc I will need to null the system before I add any weight to the end...
  17. J

    Please help with this bridge circuit question

    Homework Statement for the bridge circuit shown in the figure (see the attached file...question number 8), find the current in each resistor and also the equivalent resistance of the netowrk of five resistors. R1=150ohms, R2=50 ohms, R3=100ohms, R4=300 ohms, R5= 250 ohms, and E1=24V...
  18. P

    Build a Pasta Bridge: Physics Challenge & Tutorials

    hello there Physics friends. I am building a Pasta Bridge. The Bridge can be made of Any solid, round, commercial pasta (e.g. spaghetti, spaghettini or vermicelli) may be used as long as its initial diameter is not greater than 3 mm and not less than 1 mm. The Bridges must span a gorge...
  19. J

    What is the role of a salt bridge in a Daniell cell?

    What is the function of salt bridge in a daniell cell?Why KNO3 is used in salt bridge ?
  20. E

    Bridge Full Wave Rectifier Peak Voltages and Capacitcane Value

    Note: This is not a homework or coursework, simply revision for an exam. Thanks Homework Statement [PLAIN]http://img194.imageshack.us/img194/223/question2z.jpg Homework Equations Peak voltage = RMS voltage x root2 r = T/(2RlC) T = 1/f The Attempt at a Solution part d)...
  21. A

    Wein Bridge Oscillators, how do they work?

    Homework Statement Hi, I am revising for an exam, so this isn't really a homework question, but not sure which sub-forum it really fits on so its here. Anyway, I am trying to understand how a simple wein brige oscillator circuit works, as shown in the diagram...
  22. R

    Understanding Wheatstone Bridge: Benefits and Simplified Explanation

    Why would one use a bridge measurement circuit instead of a wheatsone bridge (I know for increase accuracy) This website I found explains it (I think) but its far to complex: http://www.sensorland.com/HowPage002.html Can someone please explain it simply
  23. N

    Truss Bridge Tension and Compressions

    Homework Statement Given the weight of a CL-625 design truck (625 kN) on a truss bridge of span 50m, divided into 8 sections (each 6.25 m) with a height of 6.25m making 45deg angles and a width of 6m, what are the tension and compression forces of the members? Homework Equations Mb =...
  24. B

    Solving the Truss Bridge Problem

    First time poster, long time reader... Consider the truss bridge as shown in the attached diagram (Each member is the same length) A force of 1000N is applied 3/4 of the way across the bridge. We get: R1 = 250 N R2 = 750 N Resolving from the left we get: T1 = 250 / sin 60 T1 sin 60...
  25. D

    An impractical bridge, but would it work?

    What I'm asking is this: I'm researching bridge designs for a balsa wood bridge, but I'm wondering why that the ellipse of a curve of a bridge support system is never completed? I understand that bridge that had an ellipse bisected by a roadway would be impractical in reality, but would it be...
  26. T

    Maple Graphite vs maple bridge on a cello

    Hi! I have a cello with a hard maple bridge, as well as a spare graphite bridge. The bridge pushes the strings away from the body, as you can see in this picture: http://upload.wikimedia.org/wikipedia/commons/d/da/Cello_bridge.jpg" The problem is the following: The spare graphite bridge is...
  27. Z

    Calculating Time for Truck-Trailer Combination to Pass Bridge

    Homework Statement A truck tractor pulls two trailers, one behind the other, at a constant speed of 100 km/h. It takes 0.610 s for the big rig to completely pass onto a bridge 390 m long. For what duration of time is all or part of the truck-trailer combination on the bridge? d = 390 m v...
  28. P

    Tension on Suspension Bridge

    So I'm working on assignment dealing with creating a simulation of a bridge made with springs and masses. **THIS IS NOT A HOMEWORK PROBLEM (I just want some explanation)** When I calculate the tension on each of the springs, I find that the springs towards the middle have the least tension on...
  29. S

    Calculating the Volume Ratio of Concrete & Styrofoam for a Floating Bridge Pontoon

    Homework Statement In many locations, such as Lake Washington in Seattle, floating bridges are preferable to conventional bridges. Such a bridge can be constructed out of concrete pontoons, which are essentially concrete boxes filled with air, Styrofoam, or another extremely low-density...
  30. S

    Calculating max. speed of car over humpback bridge before it leaves the ground?

    Homework Statement A car travels over a humpback bridge of radius of curvature 45m, what is the max speed it can reach before the wheel lose contact with the road? Homework Equations mg - R = (mv^2) / r The Attempt at a Solution When the car is about to lose contact with...
  31. H

    Bridge Support Without Lengths

    Homework Statement A hiker, who weighs 986 N, is strolling through the woods and crosses a small horizontal bridge. The bridge is uniform, weighs 3550 N, and rests on two concrete supports, one at each end. He stops one-fifth of the way along the bridge. What is the magnitude of the force...
  32. K

    How to Determine AC and DC Pins for a Full-Wave Bridge Rectifier?

    1. Quick question about Full-Wave BRs. If you have a FWBR with unmarked pins, how do you figure out the AC pins and the output DC pins?
  33. M

    Forces on a Bridge - Torque

    Homework Statement A bridge, constructed of 11 beams of equal length and negligible mass, supports an object of mass as shown. Real bridges of this sort have steel rockers at the ends, these assure that the support forces on the bridge are vertical even when it expands or contracts...
  34. C

    Impact and Damage from falling from a bridge into water

    If an average adult male fell from a bridge (ex. golden gate) what would be the impact on his body when he hit still water versus water with waves. What is his acceleration, momentum, and his change of momentum when he hits the water With these in mind how does the fall affect his organs...
  35. James889

    Get Expert Help with Wheatstone Bridge Circuit Analysis - 15mV Voltage Given

    Hi, I have this circuit: [PLAIN]http://img813.imageshack.us/img813/1189/wheatstone.png All resistors are 1K except Rx which is unknown. The voltage across the terminals are given to be 15mV. Im assuming i have to write a KCL equation but I am not sure how. Any hints?
  36. H

    Question regarding bridge rectifier.

    In the picture 1, the capacitor is grounded In the picture 2, the capacitor is not grounded. what are the purpose of this different models. Advance thanks
  37. Q

    Solving for x: A Narrow Bridge Challenge

    Homework Statement You are crossing a narrow bridge 1km long when you notice a truck approaching at 90km/h. If you can run at 5m/s, how far from the far end must you be if you could reach either end just before being hit by the truck? My attempt Displacement between the two...
  38. E

    Why 2 diodes in series for full bridge rectifier

    A friend of mine builds tube audio amplifiers for a hobby. Being an electrical engineer, who works exclusively with micro-electronics, I thought I might mess around in spice a bit to better understand some of the standard circuit topologies they use. My friend is not an engineer so he doesn't...
  39. A

    Centripetal force on a curved bridge

    Homework Statement When a car is speeding over a curved surface e.g a bridge, it sometimes loses contact with the ground. We have seen this many times in high speed chases and rally driving. In this scenario, the textbook wrote this equation: S-mg =Mv^2/r The RHS side is obviously the...
  40. S

    Paper Bridge Project: Design for Holding 20+ lbs with 1 Sheet of Paper

    Paper bridge project ! hi i have a paper bridge project coming up and need some help making a design that will hold the most. the rules are the bridge has to made with one sheet of lined paper and no adhesives are aloud including tape and glue. the bridge needs to span 12 cms and hold as much...
  41. D

    Dimensional Rifts, Windows, Einstein-Rosen Bridge & other Mindbenders

    Well, you guys were so great/polite/Knowledgable last time so I'm back again with another Screenplay related question. This time I've moved on from amateur screenwriter to Semi-Professional. It's been a good year :) So this is where I'm beginning my research. I've been pitched a new Sci-Fi...
  42. D

    Help on thevenizing a Scheering Bridge

    Help on "thevenizing" a Scheering Bridge Homework Statement Under the following conditions: C1=C, C2=0, Cx=2C, R2=R3=R, Rx=0, find the magnitude and phase of the sinusoidal current flowing through the galvanometer D (ID) whose internal resistance is neglibly small. The Attempt at a...
  43. D

    Unbalanced Scheering Bridge and Thevenin

    Homework Statement Find the magnitude and phase of the current flowing through the galvanometer whose internal resistance is negligible.C1=C, C2=0, Cx=2C, R2=R3=R, Rx=0 http://www.freeimagehosting.net/uploads/4ce4800510.png The Attempt at a Solution Magnitude of the current: Using the...
  44. A

    Radial motion into an Einstein-Rosen bridge (Poplawski)

    "Radial motion into an Einstein-Rosen bridge" (Poplawski) Hi everyone, this is my first post on Physicsforums. I've enjoyed lurking and learning from the knowledgeable folks here. I have a question about a paper titled: "Radial motion into an Einstein-Rosen bridge," Physics Letters B, by...
  45. M

    Leaping Off the 400-Year-Old Bridge in Bosnia

    Homework Statement In Bosnia, the ultimate test of a young man's courage used to be to jump off a 400 year old bridge (now destroyed) into the River Neretva, 23 m below the bridge. (a) How long did the jump last? (b) How fast was the jumper traveling upon impact with the river? (c) If the...
  46. P

    Salt Bridge Reactions: Fe2+ & Mg - Which is Correct?

    Does it matter which way I have the solutions? i.e. is this correct (in a reaction between iron and magnesium): Fe2+ | Fe || Mg | Mg 2+ Or is this correct: Fe | Fe2+ || Mg 2+ | Mg Or are they all correct, as long as I have them on the correct sides of the salt bridge?
  47. T

    Bridge Probabilities exactly 1 person with 1 suit?

    Homework Statement In the game of bridge, four players are dealt 13 cards each from a well-shuffled deck of 52 playing cards. What is the probability that one of the players holds a hand that is made up of only one suit? Homework Equations nCr = n!/(r!(n-r)!) The Attempt at a...
  48. G

    Design of individual members in a steel truss bridge?

    Hi, I have to design a steel structured truss footbridge. Im using beam anology to determine the correct member sizes. Having trouble determining the maximum design moment (M*) Here's what I have calculated thus far: Q=6kN/m G=1kN/m 50m long, 3m depth, 3.125m spacing Self Weight...
  49. A

    Salt Bridge Questions: Will Zinc Affect Cell Potential?

    I've just about had it with these salt bridges. It's such an easy concept but there are too many questions about it. I understand that the salt bridge enables the flow of ions for the cathodes and anodes by neutralizing charges, but if you use a different salt bridge (Say zinc nitrate instead...
  50. M

    Does a 10% Change in Power Supply Voltage Affect a Balanced Wheatstone Bridge?

    Homework Statement Suppose that in the course of a measurement the bridge is balanced and then the power supply voltage changes by 10%, what will happen to the balance of the bridge? Explain. Homework Equations No equations. The Attempt at a Solution When I think it out...
Back
Top