Structural steel beam fabrication welded hot dipped galvanized steel plate girder for steel structure bridge

Specification

Plate girders

The use of plate girders gives scope to vary the girder sections to suit the loads carried at different positions along the bridge. The designer is free to choose the thickness of web and size of flange to suit the internal forces at different positions along the length of the span, though it must be remembered that too many changes may not lead to economy, because of the additional fabrication work. Splices are expensive, whether bolted or welded.

Most often, the girders have parallel flanges, that is, they have a constant depth. However, with plate girders, the designer can also choose to vary the depth of the girder along its length. For longer spans it is quite common to increase the girder depth over intermediate supports. For spans below about 50m, the choice (constant or varying depth) is often governed by aesthetics. Above 50m, varied depth may offer economy because of the weight savings possible in midspan regions. The variation in depth can be achieved either by straight haunching (tapered girders) or by curving the bottom flange. The shaped web, either for a variable depth or constant depth girder with a vertical camber, is easily achieved by profile cutting during fabrication. Generally, webs have a high depth/thickness ratio and this leads to the need for intermediate transverse web stiffeners in regions of high shear (near supports).

Very occasionally, for reasons of appearance, the outermost girders are designed as a J-section; the bottom flange projects only on the inner side of the web. Requests for this detail arise from a dislike of the flange outstand, although there is little visible difference and the distinction is not noticed by most people. Use of such a section introduces torsional effects (because the shear centre is outside the line of the web) that require very careful consideration during design and construction, with significant penalty on costs an increased hazards during construction.

Also, on occasion, relatively small box girders are used in multi-girder construction. Box girders require special design consideration, because of their high torsional stiffness and high cost of fabrication. Advice on construction costs may be obtained from steelwork contractors.

Systems Plus Knowhow

FAMOUS Solutions for Bridges

FAMOUS provides full support to bridge owners, architects, engineers, and contractors with necessary technical advice and assistance to ensure a successful project. In particular for refurbishment projects, this includes assistance throughout the process, from the initial survey and assessment, root cause diagnosis, specification writing, detailing, method statements, on-site quality control, and practical application assistance. For new construction, FAMOUS can offer support to design structures for long service life. FAMOUS ’s expertise can make a significant contribution to minimizing the total project cost over the full defined service life-cycle.

FAMOUS today provides a complete range of innovative products and systems specially designed to solve all challenging requirements in differing bridge projects anywhere in the world.

Concrete Technology

Concrete structures such as bridges can be exposed to a broad range of forces and strains, starting internally with mechanical stresses resulting from the construction type and extending to various external attacks. Enormous stressors on the concrete include such factors as extreme hot or cold temperature conditions and fluctuations, aggressive water or chemicals, continually rolling, abrading or pulsating strains on surfaces, or even in extreme cases the impact of fire. Therefore, a highly durable concrete is necessary for the construction or repair of a bridge.

If you need to know more price information, please contact us as soon as possible, we will provide more details. whatever the US America standard, or EU Europe standard, UK Britian standard, AU Australia New Zealand standards are all no problem for us to do the fabrication based.