How the width of a foundation beam is determined?

Science JfreemanMD August 8, 2016 0 0
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A building gives many taxes, which focused on a beam grid come down. The beams ensure that the tax is introduced in the posts, and the posts transferred to the load-bearing sands. In this way, structural safety is achieved, so that the building remains standing. So there should always be plenty of attention given to the combination of beam structure, spans, taxes and pile load capacity. How is determined within this spectrum, the width of the foundation beam?

Determine width groundbeam

  • Width of the bearing walls
  • Combination of span and taxes
  • Load capacity ground versus pole diameter
  • Taxes determine size

Width of the bearing walls

Taxes come out of the building as weight down where made bearing walls. Floors tensioning shaft to shaft and supported on limestone walls. This can also apply to the weight of the roof. In addition, the walls need a certain width to pay all those taxes. Within standard homes may mean that the wall is 120 or 150 mm thick. The ground floor can thereby be carried out as ribcassettevloer, which often stops for the load-bearing wall. In other words, then there must be extra bearing space on either side of the supporting wall are realized by additionally applying a 100 mm sand-lime brick. This implies that, from the wall at least 100 + 120 + 100 = 320 mm or 100 + 150 + 100 = 350 mm is required. Note that in apartment buildings, there is sufficient sound damping effect of the walls must be present, so that the wall is carried out 300 mm thick. The floors often consist of a wide slab floor, which lay no additional space is needed.

Combination of span and taxes

The beam grid is extremely important for transferring loads to the foundation piles. The poles have to transfer the forces from deep soil layers. Before the load is in the piles, the concrete beam, the load transfer from the field through reinforcement. Naturally, any reinforcement that must fit into the bar and that everything can be transferred. Normally, it will be maintained a height of the bar of 1/10 of the maximum span. That is, by 5 m span then the beam is 500 mm high. Standard bottom bar must be minimum 800 mm below ground level with top beam approximately 300 mm is below ground level. Often the width, hereby depend on pole pole diameter or prefabricated format.

Load capacity ground versus pole diameter

The load should be taken up by the bottom of the beam grid. Depending on soil conditions and the completed surveys a strength calculation can be performed. On the basis of the depth, hardness of the bottom layer in combination with the pole tip area there can be a load-bearing capacity to be known. A long pole can mean a smaller pile diameter, but sometimes no such possibility exists. In this case can be a larger size. If the pile is drilled you can think of a pile diameter of at least around 300 to around 350 mm. This loads can be recorded. However, it should be held on both sides additional 50 mm clearance, whereby the beam with a pole diameter of 300 mm must be at least 400 mm wide.

Taxes determine size

Above may be true for standard homes, but if the heavily loaded structures concerned could turn it wider. For relatively large spans, it may mean that the beam is 600 mm high and 500 mm wide. Also because there are poles to be around 400 mm used in a span of 6 m. As the loads or stresses are greater the pile load increases, which makes a greater diameter must be used. This translates to an extra wide beam. It's here inside a cost consideration what is better to do. Longer narrower poles in a narrow beam or something thicker shorter posts with a wider beam. Let you always advise on the dimensions of the beam grid and carrying capacity of a pile foundation by a specialized engineering firm.
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