Bridges are intricate structures that take time and effortin order to build one. If you make a mistake in design and do not realize it thenwhen you make a model bridge, that error you made in design will cause a hugeissue when testing whether or not the model will hold up an efficient weight.For instance if a designer of a bridge designs pillars for a bridge that aremeant to stay on land and can’t endure water, but his bridge is over water thenhe has most certainly made a crucial mistake.
When he makes his model of thebridge it may hold up the weight it’s supposed to and work fine, but whenbecause he overlooked the fact that his pillars won’t stand up well in water. Thenwhen it comes time for construction to take place the bridge, it will fail andthousands of dollars would have been wasted all because of that one key mistakein the planning and design of the bridge. When it comes to designing a bridgethere many factors to take in mind first being the bridge type. It would makesense logically to make a truss bridge in an area where there are usuallyearthquakes and large winds rather than in an area where it is generally calmbecause a truss bridge has advantages that others do not (Lewis, n.
d.). A trussbridge’s advantages include the ability to support/resist lateral loads andprevent twisting and swaying during earthquakes and high winds, in addition, italso resists forces of compression and tension (Lewis, n.d.
). After verifying,that the bridge type selected will work the best out of the others and has themost benefits noticeably compared to the other bridge types. The designer ofthe bridge also must make thorough tests to discover the physics of the bridgeand how much weight/force it can sustain.
The formula used is W = 500 LN/N-1 +12N + 36, W meaning the gross weight of two+ axles; L meaning distance in feetbetween outer axles; and N meaning the number of axles in the group (“BridgeFormula,” n.d.). After finding, the weights that will be on the bridge thedesigner must calculate different loads included with his bridge, this includesDead load, Live load, and Dynamic Load (Dickinson, 2017).
The dead load is the entirebridge and what it weighs, that being said it mainly includes the weight of thematerials put into the bridge as a whole (Dickinson, 2017). Live load is themoving weight of the bridge (traffic) (Dickinson, 2017). The dynamic loadincludes all outside force such as weather: wind, hurricanes, tornadoes, hail,snow, etc. and the environment around the bridge (Dickinson, 2017). All ofthose loads need to be calculated so the designer can adjust his bridge to fitits environment and be ready for anything, there is no point in designing abridge if it cannot do its job.
If the loads are not calculated, that can leadto severe consequences such as bridge failure/malfunction in its job and how itworks. If you build a bridge that can withstand 60mph wind speeds and then ahurricane occurs and has 120 mph wind speeds, then the bridge will eventuallycollapse. If that bridge collapse that means many lives will be cost and themoney; time, effort put into the bridge will be wasted. Overall, there is no pointin designing a bridge if it is being set up for failure. In conclusion, thereare steps needed in order to formulate a good efficient bridge that will lastmany generations. A designer must calculate loads of the bridge, use theplanning process of a bridge, conduct experiments with models, refer to bridgeand vehicle restrictions, and take in account the materials that are best andare used in making the bridge itself (“New Vehicle,” n.d.).