Truss bridge report
Bridge design report
In this case also, box sections are preferable for ease of maintenance but open sections may well prove cheaper. Improvement We extended the span to 41cm,allowing 3cm of offset on each side of clearance on the table but due the weight restriction of 80g, we had no choice but to decrease the height and width of the bridge where we can have more materials to be used and focused on strengthening each member. In cases, where only one lateral system exists then the single bracing system must carry the entire wind load. They were attached to the top of the bottom chords, allowing load to be transferred from the beams onto the bottom chords. With lesser needs to be reinforced, we chose to reduce the layers for the diagonal bracing members to prevent the weight of the bridge from exceeding the quota. The vertical load bearing truss with 3 triple layers of fettucine is constructed to carry the Shook for the pail to rest on. The chords are created through many joints of mm fettuccines. Underslung trusses are rarely used in modern construction. The design was not a complete failure. In the bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension, shear, and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension. Theres a huge variation between each truss bridge; the truss structure itself can vary as can the plane this is applied to. The main reason behind this is because the top chord undergoes strong compressive force when load is applied on the bridge. Where the spans of railway bridges are long the economic depth is usually great enough to allow bracing to be provided above the loading gauge level. Another change we applied was the center beams which are the points that the load will be latched on to. Especially for shorter spans the warren truss is more economical s it requires less material than either the Pratt or Howe trusses.
It should be noted here that the design loading has a considerable effect on the truss configuration. To cater for the heavy loading on railway bridges, the cross girders should be fairly close together.
These vertical members serve as vertical poles for the fettuccine bridge to resist the compression force exerted. Load Figure 7 n : Identification of compressive and tensile members using online software.
For shorter spans the choice is between the Warren and the Pratt configuration.
Truss bridge analysis
We have experimented numerous times just to get the best design of the bridge, which is to carry as many load as it can and also the numbers of fettuccine used should be lessen. Finally, when the bridge is able to stand upright, we cross-braced the open ends to ensure the bridge retain its shape. The spacing between main truss depends upon the railway or road way clearances required. The relatively rare Howe truss, patented in by Massachusetts millwright William Howe, includes vertical members and diagonals that slope up towards the center, the opposite of the Pratt truss. However, this is not always possible, for example when cross girders are deeper than the bottom chord then bracing members can be attached to only one flange of the chords. Design of Compression chord members Generally, the effective length for the buckling of compression chord member in the plane of truss is not same as that for buckling out-of-plane of the truss i. Not only that the load supporting member was emphasis on the next trial to ensure that the load supporting member would be able to resist snapping till the bridge itself could not hold the weight. We too manage to hone our time management skills through work delegation and careful planning ahead of time in order to maximize work done over time so that no time is wasted. Theres a huge variation between each truss bridge; the truss structure itself can vary as can the plane this is applied to. However, for longer spans, a greater depth is required at the centre and variable depth trusses are adopted for economy.
Figure 7 s : Collapsing of bridge. The 4 main chords and the 2 connecting beams in the center were properly reinforced. Structural elements will be found above and below Half Through Truss similar to the through truss structural elements can be found above and below the roadbed, however here the exposed truss above the roadbed isnt attached to the deck.
Modern labour costs dictate a minimum of members and connections. Proper way of adhesive and consistency of jointing the members are important to ensure the connections are strong.
based on 72 review