QUESTIONS
1) It is known that anything that is overturned is screwed onto something solid to prevent it from tipping over.
Why civil engineers do not screw the sides of the walls on both sides, with the ground?
The overturning of the walls deforms beams and walls until it breaks them;
Do you like to break concrete?
2) Bending is a second deformation factor that breaks the cross sections of the bearing elements.
It is known that the bilateral pre-tensioning of the sides of the walls when they have suitable cross-sections eliminates the bending.
A combination of strong ground anchorage and at the same time pre-tensioning of the sides of the walls from their upper levels with tendons without relevance would stop overturning and bending which are the only causes of deformation and we know that deformation and failure are interrelated concepts.
Do you want distortion and failures?
3) Intersecting If in the cross section of the wall we impose compressive intensities of 70% of the breaking factor, we increase the strength of the cross section by 40%.
Why do you use the mechanism of relevance as the main reinforcement and not tense walls?
4) We all know that deformation creates inelastic failure.
We mentioned the overturning of the wall and the bending of its trunk as causes of deformation and failure of all load-bearing elements.
However, deformation and even very serious can occur due to inhomogeneous subsidence of the soil.
The ground is inhomogeneous, by nature, with different support strengths at each base.
Soil sampling is required at each base foot, and if necessary soil compaction is required to increase the soil's ability to support the base.
However, due to cost, it is rarely applied and if it is applied, it is done only in great projects.
5) The non-prestressed connection of the sides of the walls with the ground diverts the seismic intensities, leading them on the cross sections.
The prestressed connection of the sides of the walls to the ground from the top level with unrelated tendons diverts the seismic intensities, leading them into the ground.
Why not apply this design?
No more excuses.
The absolute seismic system and the method that follows ensures little deformation and no failure as it controls the overturning and bending of the wall, increases the resistance of its cross-section to cut, ensures sample ground control before the construction of the project, and creates a very strong support strength of construction after compacting the foundation soil.
These are all fundamental laws of engineering, and you continue to design wrong.
Very interesting question...worth following.
This is a geotechnical engineering issue related to particular failure modes...mostly related to base failures related to horizontal accelerations and transfer of horizontal acceleration to rigid nodes. Actual toppling is not something I see...and I have been through some huge earthquakes...the Good Friday EQ in Alaska. Horizontal pins on a vertical support would not help much. Failure would occur as shear closer to the "free end" up high where strain and load max out. For example, the attached image from Santiago's 2010 earthquake shows axial failure in a vertical support column manifesting as concrete shear failure. Was the reinforcing steel present? I have personally experienced accidents when the steel was actually left out of a prestressed concrete beam support pillar spanning an interstate highway. The arm of the pillar fell off. My boss rode the beam down! The Nevertheless, where earthquake standards have been applied some buildings actually have an exoskeleton. See the image of one from Santiago. I recently rode one through a small quake in Santiago. It swayed a fair amount on the 6th floor. To address your suggestions and concerns about failure to design adequately. Some structures, the Santiago airport for example, actually do have cable tension systems. The rigid walls are tensioned. Where horizontal motions are expected, many buildings are actually pinned to their footings. Footings don't usually go deep enough to hit bedrock but some do. I have had people call me about it. Residential retrofits were required in at least some parts of Seattle where gravity footings were no longer insurable. Earthquake standards are very hard to meet and even then the best efforts to establish them are easily questioned. One thing...tall buildings are actually pinned to "bedrock" at least in Chicago and they sway uncomfortably in the wind. There are probably lots of "gravity structures" and more are being built. One example is the 3 gorges dam in china. It's so stiff and heavy it acts like a "ship". Maps predicting earthquake motions are pretty subjective. I have followed some of them from the New Madrid event when I worked landfill impoundment systems. I looked for ancient sand blowouts in google earth to map seismic regions all over southern Illinois. The USGS does too. Yes...I have both geology and civil engineering training and experience. Remember...engineers are trained to say yes sir...how high sir. Geologists step in when engineers get in trouble with the money folks. My experiences with geotechnical engineers is that they love the belt and suspenders approach.
I am not sure I answered the question. Are you thinking of pre-stressing individual concrete slabs to replace load bearing members like steel girders or concrete support columns and then somehow attaching slabs to each other and rock bolting them to "bedrock"? I'm sure somebody has suggested it. Earthquake engineering is designers paradise...and a builder's hell.
That's what I'm thinking
https://www.youtube.com/watch?v=IO6MxxH0lMU&t=2s
https://www.youtube.com/watch?v=RoM5pEy7n9Q&t=133s
Walls in excavations are secured by anchor bolts and geogrid embedments. Exposed subgrade walls adjacent to tall structures are stabilized and braced. Freestanding walls rely on depth of embedment. The toppling danger to a freestanding “fin” wall is soil shear strength. strength is lost with soil saturation. Cover the soil with a “watertable”. The architectural kind.
I am not referring to retaining walls. I am referring to an anti-seismic system. 1) If we join the walls with the base concrete with anchors we will have torque at the node and failure of the concrete.
2) If we join the base of the wall with the foundation ground with an anchoring mechanism then we will have stopped the retraction of the foundation base, but the bending of the wall trunk will remain.
3) If we apply traction between the upper ends of the sides of the wall and the foundation ground, using unrelated tendons and ground anchoring mechanisms, then we have stopped the moments at the junction of the joints, we have stopped the retraction of the base, we have stopped the bending of the load-bearing elements, and in general we have stopped all the deformation of the building which causes failures.
ISorry, but I have no professional experience on that matter.
I can’t follow the train of thought in the anti seismic vibration article. Too many loose ends. It can’t find the main idea. It seems like there is something but i just can’t find it. Is it a system of counterbalanced levers?
The Patent Idea
We have placed on a table two columns, one column screwed on the table, and the other simply put on the table. If one shifts on the table, the unbolted column will be overthrown. The bolted column withstands the lateral loading. We do exactly the same in every column of a building to withstand more lateral earthquake loading. That is done, by simply screwing it to the ground. This pretension between the roof of the structure and the soil has been globally disclosed for the first time.
The horizontal earthquake load generates oscillation, and the result is that the upper plates shift more than the lower ones, the columns lose their eccentricity exerting a lifting force on the bases, as well as creating a twisting action in all of the nodes of the structure.
The ideal situation would be if one could construct a building framework where, during an earthquake, all the plates would shift by the same amplitude, at the ground without differing phases.
The research I have carried out resulted in just this. The method of the invention eliminates all these problems of deformation in the building construction applying pretension, through the mechanism, between the roof of the structure and the soil. Article The Ultimate Anti-Seismic System
Pre tension requires that the column-anchor act as one member and be under elastic strain after joining but before a live load. Bolts work that way. Rock and concrete are not sufficiently elastic and are designed using brittle failure shear strength Criteria. The type of connection may be gravity or not. Some structures have give some do mot.
The three methods of design and placement of the invention.
A core carrier attached to the ground, inside an elastic carrier with horizontal seismic insulation, which separates them seismic joint at the height of the seals
1) https://www.youtube.com/watch?v=IO6MxxH0lMU
https://www.youtube.com/watch?v=zhkUlxC6IK4
2) https://www.youtube.com/watch?v=RoM5pEy7n9Q
3) https://www.youtube.com/watch?v=Q6og4VWFcGA
I think i get it. Tall structures under sway are lever arms. The taller the structure the greater the moment at the pinned end. So...What happens to the seismic-induced structural moment at a pinned node like a concrete footing. A thick or reinforced footing/foundation might handle the combined loads. If not rock bolt it.
A vertical rock bolt can counterbalance the induced moment but as you say...it needs to be tight...all the time...as a prestressed attachment/member. Instantaneous Seismic loads are high and quick. Strain at an unprestressed earth attachment will not likely develop adequate counterbalancing resistance.
And for thin unreinforced foundational structures, a pin to such a node like a footing designed only to support a “dead weight” gravity load could induce failure even in reinforced slabs if the rebar steel is not well distributed to accomodate reversing moments. Spread the rebar steel. Pretension wherever it is would have to anticipate a lot.
Your question was hard but fun. I think i got the overall gist of your concern...required retrofitting existing structures with rigid attachments to meet code a tall structure was not designed for. I think a very stiff tensioned vertical rockbolt even on a short lever arm would dissipate some of the moment.
In Santiago they built exoskeletons on some tall builldings. I don’t know if it was before or after construction.
Sir Steve Johnson What the patent mechanism does is pick up seismic loads from the structure and drive them into the ground. Today seismic loads drive them over the cross sections of the beams and break them. More here ... Preprint DYNAMICS OF CONSTRUCTIONS RESEARCH
and hereArticle The Ultimate Anti-Seismic System
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