GIVEN BY SOIL CONSULTANT TO ALLOWABLE SETTLEMENTS. IN A LAYRED SOIL SETTLEMENT IMEDIATE, LONG TERM AND DIFFETENTIAL COMESįROM SOIL COINSULTANTS NON-LINEAR ANALYSIS. THIS COMPUTER DEFLECTIONS AND SPRING FORCESĪRE USED ONLY TO CALCULATE ACTUAL BEARING PRESSURES, SHEAR AND FLEXURE DESIGN OF CONCRETE RAFT. If you need to adjust this Ks at the edges you can modify Ks = 414.72 K/ft to any number you want.ī) I NEVER USE MY COPUTER RAFT ANALYSIS OUT-PUT DEFLECTIONS AS SETTLEMENT CALCULATIONS. And that is a fairly acccurate representation of soil support of Raft. So Ks in computer model is aready calculatedīased on Tributary area. unit (Deflections in FT.) your Spring Constant under each node Let us say your soil consultant gives you K = 30 pci or Lb/inch***3. Your Plate Element model grid is 4ftX4ft in plan with 4ft thickness. Let us say you are using STADD/PRO PLATE AND SHELL ELEMENT for a 100ft.X100ftx4ft thick Raft Foundation.

SINGLE SPRING CONSTANT IN STAAD/PRO OR RISA-3D PLATE ELEMENT MODEL FOR RAFT FOUNDATIONS:Ī)This not a problem.

Posted: Fri 10:18 am Post subject: SINGLE SPRING CONSTANT IN STAAD/PRO OR RISA-3D PLATE EL.

Can seniors please share their experience? Is the assignment of a unique 'ks' value justified? But, in actual scenario the settlements are larger under the center point and lesser towards the ends. Here the 'ks' is based on tributary area. Using a uniform 'ks' value under a rectangularly loaded footing will produce constant settlement at each point. Now, I have noticed that, consultants tend to use the same 'ks' value ( where ks is the modulus of subgrade reaction) under all points in combined footings or rafts. To simulate elastic foundation we use springs. We know that the base contact pressure contributes to the settlement in footings and that there is no dependence of modulus of subgrade reaction on base contact pressure. Posted: Fri 8:27 am Post subject: Modulus of Subgrade Reaction. Use online scanners here and here to upload downloaded attachment to check for safety. Warning: Make sure you scan the downloaded attachment with updated antivirus tools before opening them.

Copy nodes in risa 3d