Can we check an allowable bearing pressure against serviceability loads in Tekla Structural Designer?

Question

We often receive Soil Investigation Reports with allowable bearing pressures for use with pad / strip footing design which can be used in accordance with BS EN 1997 CL 2.5 "Design by prescriptive measures".

This capability is available in Tekla Tedds, where the allowable bearing pressure is checked against the SLS Loads applied.

Image

Is a similar option available within Tekla Structural Designer as it would appear it will only check bearing capacity based upon the ULS design bearing pressure against the net ultimate bearing capacity?

Image

Image

Answer

Tekla Structural Designer can undertake foundation bearing capacity checks on pad bases and strip footings using two alternative methods allowed in BS EN 1997-1

1. Ultimate Bearing Pressure (default)
2. Presumed Bearing Resistance

The choice of method is controlled via the user setting Foundation ribbon tab > Settings > Concrete > Cast-in-place > Foundations > General > “Use presumed bearing capacity method for pad bases and mats (EN1997-1 cl.6.5.2.4)" setting.

Image

By default this is unchecked so method 1 “Ultimate Bearing Pressure” is adopted as shown in the calculation results above.

If this option is checked, method 2 “ Presumed Bearing Resistance” is adopted.

Note that the Pad base or Strip footing properties will need reviewing as this settings change requires a Presumed bearing resistance to be specified.

Image

Following a design you will see a Service loads - Applied Loads Summary. The bearing capacity check is then based upon this sls pad base pressure checked against the Presumed bearing resistance.

Image

Image