The two main problems that civil engineers try to solve with computer programs to calculate the response of a structure to a large earthquake are
1) the displacement range of the columns at their top and
2) the maximum shear forces at their base .
To calculate them they need data on soil movements, design details of the structure, full dimensions of the structure and the properties and strengths of steel and concrete.
The only remaining uncertainty relates to the modeling and analysis of the structural response.
If you put 40 teachers to solve the construction response on a computer, you will get 40 different answers with a large deviation.
Things with my patent are simple. Prestressing + anchoring to the ground at all ends of the wall is able to reduce up to 90% the displacement width of the walls at their upper part and to increase up to 50% the strength of the wall cross-section to receive the maximum shear forces.
It has long been established that the lateral seismic loads that the construction must be able to receive are 10% of its weight.
With the method I suggest, the ground under the base and the cross section of the wall receive increased compressive loads due to the rigidity of the wall.
The method I propose, takes care to increase the capacity of the soil to accept loads, because it creates compaction in the ground horizontally and vertically, before the construction is erected. It basically creates an extra deep foundation beneath the existing foundation.
Dear Ioannis Lymperis
1- You mentioned, “If you put 40 teachers to solve the construction response on a computer, you will get 40 different answers with a large deviation.”
This is a wrong statement. If all loads (lateral, weight and..), mechanical properties of materials, load combinations, and the Code you are using were specified, all civil engineers would obtain the exact same responses for the structure.
2- Then you state, “With the method I suggest, the ground under the base and the cross section of the wall receive increased compressive loads due to the rigidity of the wall.”
Can you please explain how the “rigidity” of the wall can increase compressive loads of the wall? I think by rigidity, you meant prestress or..!
Dear Mehran Shahpari
The answer to the first question is here.
Article Analysis in seismic provisions for buildings: past, present ...
For the second question. The wall receives lateral forces which are converted into overturning torque. The wall rotates around the joint of the base, the one in which the compressive forces develop. If the wall stood upright on its own, without the connection of its upper end to the ground, it would be easy to overturn. When the ground anchoring mechanism + pre-tension (patent) prevents it from tipping over, then I believe that the ground under the base and the cross-section of the wall receives more compressive loads at the edge of the joint. I may be wrong ...
We know that bending creates cracks and pre-tensioning prevents cracks.
We know that the bending and retraction of the base are the causes that create the displacement range of the columns at their top If we stop the rotation of the base of the wall, and the bending of the wall, then we stop the displacement of the upper edge of the wall.
The bending and rotation of the base of the wall stops when we apply at the ends of the wall 1) pre-tension 2) anchoring to the ground, using the same tendon for both the anchor and the pre-tension.
For shear strength.
If we try to move a stack of books in a horizontal position they will disintegrate. If we apply force with both hands at both ends in the stack of books we will move them even in a horizontal position without disintegrating.
Conclusion The imposition of compressive stresses on the cross section increases its shear strength
Things are simple in practice.
1) If you place a pillar base on the ground and it is pushed by a loader at its top, it will overturn immediately.
2) If you screw the base of the column with my mechanism to the ground and a loader pushes it to its top, it will not overturn but there will be a bend in its trunk. 3) If you apply pre-tension - compression to the cross section of the column, + anchoring to the ground, and the loader pushes it from its upper level, the column will not overturn and will not bend.
4) If you apply pre-tension - compression in the cross section of a rigid wall + anchoring to the ground but not with a tendon as in the column, but with two tendons placed at its two distal ends, then things become difficult for the bulldozer.
This is due firstly because the wall is rigid in itself, and its pre-tensioning increases the stiffness more and secondly because the wall has a double lever arm.
Let's solve a pillar and a wall to see the difference.
a) We have a pillar with 3 meters height and cross section 40x40 cm. If the loader applies a force of 1 ton to its upper level then its tipping moment will be. Height X Lateral bulldozer force = 3mX1ton = 3ton
b) We have a wall with 3 meters height and cross section 3mX0.20cm If the loader applies a force of 1 ton to its upper level then its tipping moment will be. Height X Lateral force of the bulldozer / width of the base = 3Χ1 / 3 = 0
The higher the compressive strength at the cross section, the less bending we will have.
When we use a wall with compression at the edges of its cross sections, the bending is almost completely eliminated.
The tipping moment stops with the anchoring to the ground.
Applying compression to the cross section also increases its ability to withstand shear forces.
Since any change in the vertical axis of the wall or column resulting from bending and overturning is transferred through the joints and beams and breaks them, if we stop the displacement of the wall and the column we stop the deformation and without deformation do not occur.
https://cdn.ymaws.com/www.nibs.org/resource/resmgr/BSSC/P-749_Chapter5.pdf
- Badges
- Science topic
- Similar topics
- Analytical Chemistry
- Column