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[Audio] Hi Good day, My name is Andy Krisna. Today I would like to explain regarding design of shallow foundation in Civil Engineering.

[Audio] Scope I would like to explain of how to design the shallow foundation in Civil Engineering. There are 2 steps in designing the shallow foundation First is design the foundation stability Second is design the foundation strength. In this Slide, I will explain only for foundation stability check..

[Audio] Let me explain about how to design foundation stability. First we need to check the foundation stability against soil bearing capacity. The soil bearing capacity was obtained from soil investigation test that is conducted on the early phase of the project. Soil bearing capacity normally represented in Kilo Newton per meter square. We have to ensure if the load working on the foundation and foundation weight is less than soil bearing capacity or otherwise the soil will fail to support the foundation and foundation load..

[Audio] Let see the figures to see how to check foundation stability against Soil Bearing Capacity. W E is the vertical load. M O P is the Moment force load. V O P or V is the horizontal load. W F is the Weight of foundation. Q max is the maximum soil pressure occurred due to load from above and Q min is the minimum soil pressure occurred due to load from above. I also shown the formula to check maximum and minimum soil pressure for quick references. Q Max and Q Min shall be smaller than the soil bearing capacity obtained from soil investigation test..

[Audio] Second, We need to check for foundation stability against sliding. Sliding force is the load working on the foundation in horizontal direction. We have to make sure that the foundation will not slide or move when the sliding or horizontal force working on the foundation. From the figure you can see V O P or V is the horizontal or sliding load working on the foundation, W E is the vertical load working on the foundation, W F is the weight of foundation and the V R is the Resistant friction force from foundation. The Resistant Friction Force V R is the Friction coefficient of soil and concrete Miu multiply by sum of Vertical load of foundation and Foundation weight. The Ratio of Resistant Friction Force against Horizontal load must be bigger than allowable safety factor. Safety factor is normally 1.5 depends on specific project specification..

[Audio] Third, we need to check the foundation stability against overturning Moment. From figure above, the overturning moment M O T is M O P plus M plus V O P plus P multiply by H. And M R or resistant Moment is the W E Equipment Weight Plus W F weight of foundation minus buoyancy load multiply by 0.5 footing length. The ratio of resistant moment divided by total moment force must be bigger than safety factor. Safety factor is normally 1.5 depends on specific project specification..

[Audio] Next we would like to have some question or quiz from previous explanation. The Question is from above three criteria, which foundation stability check which have relation with soil investigation data. Soil Bearing capacity or Sliding or All of stability check item. We will give time for you to answer the question in ten seconds. 1 2 3 4 5 6 7 8 9 10.

[Audio] The Answer is C All of Stability check item To do Soil bearing capacity check, we need to obtained soil bearing capacity data from soil investigation. For sliding and overturning moment, the soil water level data is needed from soil investigation to be consider for buoyancy force for sliding and overturning moment check. Thank you everybody..