[seismic]

Link http://www.antiseismic-systems.com/


HYDRAULIC TIE ROD FOR CONSTRUCTION PROJECTS

The present invention relates to a hydraulic tie rod for construction projects ensuring the protection of the construction structures against damage caused by earthquakes and hurricanes.



Anti-seismic system placed in a shaft of a load-bearing structure
The main object of the hydraulic tie rod for construction projects of our invention along with its application method in the construction field for structural projects is to minimise the problems associated with the safety of structural projects such as buildings in the case of natural phenomena such as earthquakes, tornados and very powerful winds in general. According to the present invention, this can be achieved by a continuous pre-stressing (pulling) of both the roof of a large, geometrical part of the building structure which independent of the load-bearing structure towards the ground and of the ground towards the structure, making these two parts one body like a sandwich.

This pre-stressing force is applied by the mechanism of the hydraulic tie rod for construction projects, said mechanism mainly consisting of a steel cable penetrating free in the centre the vertical support elements of the structure, as well as the drilling length, beneath them. Said steel cable's lower end is tied to an anchor-type mechanism http://postimage.org/image/2dmcy79yc/

that is embedded into the banks (walls) of the drilling to prevent it from being uplifted. This embedding is attained due to the drilling hole being somewhat smaller than the exterior diameter of the completely opened anchor mechanism.

Said steel cable's top end is also tied to a hydraulic pulling mechanism exerting a continuous uplifting force. http://postimage.org/image/2mlql3ag4/

This pulling mechanism comprises a piston, said piston reciprocating within a piston sleeve, connected to a pressure chamber beneath it. This pulling force, exerted on the top-end of the steel cable, by the hydraulic mechanism http://postimage.org/image/qwytuv44/

due to the hydraulic pressure originating from the rise of the chamber towards the piston, and the reaction in this pulling force originating from the embedded anchor at its other end generate the desirable compression in the construction project which in turn is tied to the ground and thus rendered resistant to the horizontal forces of an earthquake. http://postimage.org/image/14tj1webo/



THE BENEFICIAL EFECTS OF PRESTRESSING (TRACTION) BETWEEN THE BULDING STRUCTURE AND THE GROUND

a) If we have a solid concrete column anchored to the ground with the traction mechanism and fortified with steel
or
b) If we have a solid concrete column prestressed with the ground (like a sandwich)

and we apply a horizontal traction, these columns will have more resistance to the sideways traction compared to a single column which simply stands on the ground.

This, I believe, is understandable to all.

Now, if we have two solid concrete columns that are not anchored to the ground but connected to each other at the top by a beam and we then apply a sideways force, in my opinion the following will occur:

1) Firstly, the columns themselves will produce a small resistance to the sideways force
2) When this resistance in the columns bends they do not subside as before because another force acts.
3) This additional force which resists the sideways traction is in the nodes.

This strength in the nodes arises from the union of the two columns with the beam which creates structural integrity and entity.

This node strength resists the sideways force like a torque.

If we consider all the resistance forces acting against the sideways traction we see that:

Concrete columns which are anchored or prestressed with the ground will create greater resistance than those which are simply resting upon the ground.

The corners will not need to act in resistance if the anchored or prestressed columns manage on their own to bring about enough resistance to the side force which we are applying.

Here we see that the prestressed or anchored columns act in addition to the existing resistance of the structure with regards to the horizontal inertia tension when faced with the opposing acceleration of an earthquake.

If the cross-section plan of the solid concrete walls http://postimage.org/image/r1aadhj8/ is appropriately constructed and the anchoring or prestressing is also appropriate then the corners will not need to undergo any torque resistance to side forces.

In this way we eliminate torque of the corners.

The union of the walls with the ground is carried out by the traction mechanism.

There are six methods of placement
HYDRAULIC TIE ROD FOR CONSTRUCTION PROJECTS

AN ALTERNATIVE APPROACH TO BUILDING STABILITY

FIRST PLACEMENT METHOD

The patented video shows the mode of operation and method of collaboration of the antiseismic system, with bearings, which offers effective seismic isolation of the vertical and horizontal axes of a structure so that buildings repairs are avoided to the greatest extent following an earthquake: http://www.youtube.com/watch?v=KPaNZ...layer_embedded
The above is achieved by placing right at the centre of the load-bearing structure, (Or both ends of the building) architecturally exploitable in an effort to lower the cost, pre-stressed with the ground but independent from the load-bearing structure, rigid shaft, or dimensionally large cross-shaped column, or even a big room. The essential condition for the above rigid geometrical forms is for them to have axial vertical continuity, along the whole height of the building, and to be constructed entirely from reinforced pre-stressed with the ground concrete.

This pre-stressing applied by the hydraulic tie rod on the shaft and on the ground, is mainly imposed in order for these two parts to become one body, such that at the horizontal acceleration of the earthquake, the ground, the base, and the loft of the shaft are found in the same acceleration phase (in the same time-space as one body in the three dimensions).

The larger the geometric dimensions of the base (cross-section area), relative to the height, the larger is the resistance in the foot block, as well as in the emerging shearing.

An increase in the pre-stressing placed on the shaft, means a corresponding increase in its resistance to shearing, an increase in the compaction of the drilling banks, and consequently a better embedding of the anchor mechanism.



In order to achieve the independence of the rigid shaft from the load-bearing structure, we leave a gap between them. This gap is useful for the following reasons:

· earthquake dynamics is not transferred from the shaft to the load-bearing structure,

· the load-bearing structure remains independent in the seismic insulation offered to it by the double “one-piece” base-plate away from the oscillating shaft,

· the load-bearing structure exhausts the mechanical resistance properties of the existing reinforcement, (so that it does not transfer large impact forces to the shaft), and just before it breaks, there occurs damping and retaining of the load-bearing structure on hydraulic systems placed in the lift gap, (rubber, or dampers),

· to prevent the load-bearing structure from leaning on the lift shaft and transferring the additional compressive forces of its weight, thereby making the application of further pre-stressing forces on the shaft possible, thus rendering it more rigid.

· to help the columns in transferring the earthquake forces, not only vertically, but also laterally in same time-space, by means of the pre-stressed rigid shaft and the dampers.



All this elasticity of the vertical axis of the load-bearing structure may be put under control in such a fashion as to achieve the smooth transfer of its vertical axis torques to the shaft.

When it is intended for the upper floors to oscillate more than the lower ones, the gap on the upper floors is made larger, setting a lower pressure on their hydraulics, in relation to the lower floors. Operating in such a manner, and in order to keep the bending action of the vertical axis under control to avoid the destructive transfer of torque towards the lower floors, the transfer of torque is computed statically during the plate impact from each and every floor onto the shaft and following that the proper gap between each floor plate and the rigid structure is computed and the proper hydraulic pressure is applied on the dampers.

In order to further strengthen the rigidity of the rigid structure (shaft), to decrease the oscillation amplitude, to prevent the overthrow, and to increase the shaft resistance to the shearing stress that is generated by the lateral impact of the plates due to their inertia, it is necessary to render the rigid structure “one-body” with the ground.

This can be achieved by means of the hydraulic tie rod for construction projects mechanism, applying pre-stressing between the loft (top floor) and the ground, making these two parts “one-body”.

CONCLUSION

It is wrong to let the columns transfer all alone the horizontal forces of an earthquake from the bottom to the top in the load-bearing structure, as is currently the case in the majority of the building construction methods.

The horizontal forces of an earthquake are not transferred effortlessly from the columns to the structure framework, this being due to the existence of other forces acting contrary to the direction of the earthquake horizontal forces, said forces originating from the inertia of the plates and resulting in the plates not responding readily to the direction of the earthquake horizontal forces. This opposition of forces on the horizontal axis of the building structure, creates shearing stresses, as well as non-uniform bending in the shape of an S (for the reasons reported above) deforming the vertical axis of the structure, with the known results.

It is at this point that the invention provides for the columns to transfer the earthquake forces uniformly and smoothly, not only vertically towards the top, but also horizontally to the floor plates, by means of the hydraulic tie rod, the pre-stressed shaft, and the hydraulic dampers placed in the gap.

Deductively in this way, the framework vertical axis maintains its initial form, not deforming into an S shape, due to the uniform movement of the mass of the multiple plates in the same time-space imposed on them by the pre-stressed shaft, relieving and helping this way the columns to transfer the destructive earthquake forces to the plates. That is to say, the invention creates controlled flexibility on the load-bearing structure vertical axis, helps the columns transfer laterally the earthquake forces to the plates, at the same time achieving the seismic insulation of the load-bearing structure horizontal axis (with double “one-piece” base-plates carrying elastic inserts between them). Moreover it also stops the tendency of the building to rise unilaterally, said tendency originating from the increase of the oscillation co-ordination, which oscillation co-ordination depends on the height of the building, the time duration of the earthquake as well as the wavelength of the earthquake and the amplitude of its oscillation.

Ground fluidization (subsidence) as well as the cracks, caused by an earthquake, are a major problem, which, however, in part has been resolved by the invention.



Stopping the video at the point showing under the ground surface, http://www.youtube.com/watch?v=KPaNZ...layer_embedded

or http://postimage.org/image/2dmcy79yc/

a pipe can be observed starting from the anchor and reaching up to the bottom part of the base.



This is called resistance pipe, and is useful for the following reasons:

· it constitutes the passage of the steel cable applying the pre-stressing,

· should the ground recede under the base, then this resistance pipe undertakes the weight of the base and transfers it to the banks (side-walls) of the drilling (this is a very important reason),

· should the banks of the drilling recede (due to oscillations), the steel cable does not sag because the hydraulic pressure (under the piston in the upper part of the system) causes the tightening of the steel cable which in turn generates resistance on the bottom anchor piston the movement of which activates the anchor pins to move towards the solid ground around them restoring the desirable embedding in the banks (side-walls) of the drilling.

SECOND PLACEMENT METHOD

There is another method of placement of the hydraulic traction mechanism in building structures.
This method does not include horizontal seismic isolation, http://postimage.org/image/r1aadhj8/
Or bearings
Or gaps
We simply convert sections of the internal brick-built walls of the building to walls consisting of reinforced concrete which have the same continuation on all of the floors. We insert these at carefully placed low pre-stress points between the bore hole and the hydraulic mechanism on the roof.

What we achieve with this method:

a) If the skeletal framework of a building tilts by a few degrees due to oscillation created by an earthquake, do the corners of the framework nodes have the possibility to remain at 90 degree angles?
Of course not,
Why not?
Simply stated, because the skeletal framework has a static load. During oscillation the nodes are required to take the force, but they cannot withstand this so the corners change shape, and, from right angles, some become greater and some lesser than 90 degrees. This results in slanting or bowed cracks in the corner nodes.
If the corners do withstand the static load so that they remain as right angles, logic tells us that the front and back columns will alternatively raise each other off the ground during oscillation. This, though, is impossible because the bearing element is full of nodes and static loads.

b) If the oscillation creates the above problems on the nodes, wouldn’t it be best if we can prevent this? And if so, how can we achieve this?

c) Another option might be to bind the building all around with steel cables at 45 degrees and anchor them (something which is impossible in practice).
Alternatively, we could take a portion of the structure, for example the internal walls and replace them with reinforced concrete and anchor these with the ground at appropriate points. In this way oscillation is prevented by bringing about resistance with roof, the connecting columns and the foundations of the structure.

Why do I recommend that we convert the internal brick walls to reinforced concrete and to anchor these with the ground?

For the following reasons:

a) So that the external walls are fully available for placement of doors, windows and glass panelling.

b) Because the internal walls due to their architectural nature have a cruciform shape and this dimensional form creates greater resistance to an earthquake from whichever direction it comes.

c) Because the formwork can be placed and removed easily.

d) Because dimensionally they are capable of withstanding the tendency to bend.

e) Because they have a superior dimensional plan and are capable of creating greater resistance in the chambers and columns.


In the diagrams below we illustrate the conversion of brick walls to reinforced concrete as well as the anchor points necessary to prevent oscillation of the building which strains the nodes of the structure creating slanting cracks: http://postimage.org/image/r1aadhj8/





Placement in underwater roads:
http://www.postimage.org/image.php?v=aVsUYe0

Placement in continuous brick- based structures:
http://www.postimage.org/image.php?v=aVsUGM0

Placement in subordinate and wooden houses for protection from both earthquake and hurricane damage:
http://www.postimage.org/image.php?v=aVsUEgS

Placement in a dam:
http://www.postimage.org/image.php?v=aVsUQKA

This system can also be placed in bridge pylons under the bearings.




THIRD PLACEMENT METHOD

By applying prestressing with the hydraulic traction mechanism between the drill hole and the top of the structure via the vertical supports. This prestressing not only improves endurance against shearing, but there is an additional advantage.

During inertia tension of the bearing element, oscillation is brought about. At the prestressed vertical support, two opposing forces are created. One in the pressure chamber and the other in the vertical column and it’s foundation as a reaction to the oscillation. Within the body of the vertical support these two opposing forces created act in resistance against the earthquake.

This resistance is in addition to the resistance already present in the nodes of the structure and acts against the catastrophic power of the earthquake.

We can exert prestress on the vertical elements in two ways:
a) normal prestress or
b) controlled lesser prestress.
If the preferred elements are able to withstand the stressing we apply the normal pre-stress. If they cannot, then we apply the controlled lesser prestress.

Greater prestress is applied initially, the moment we have sunk the traction mechanism in the drill hole, prior to construction of the support structure.

And afterwards, when we have anchored the steel cable with a wedge at ground level at the foundations, we fill the drill hole with concrete prior to constructing a pile. Then we continue the construction and when it is completed we undertake a simple pre-stressing of the upper chamber and foundations.

That is, the same steel cable will receive two pre-stresses. One initially between the ground surface and the anchor, and a second one between the foundations and upper chamber, with differing tensions.

With this method we have other benefits such as:

Compression of the ground (prior to the construction of the pile), protection of the mechanism from rust and avoidance of water extraction which may be present in coastal areas.

We can control the anchorage of the structure, with as much prestress or anchoring as is needed, since the prestress underneath the foundations will have a greater intensity than the subsequent prestressing of the foundations of the structure.



FOURTH PLACEMENT METHOD: BETWEEN THE RADIERE (FOUNDATIONS WHICH COVER THE COMPLETE AREA OF THE CONSTRUCTION) AND THE GROUND.

As can be seen in the photograph http://postimage.org/image/15or8eeuc/ , at the upper part there are two bricks which support a bolt.
Above and below the bolt there are two thick metal plates.
The lower plate is soldered to a resistance pipe.
The upper plate has a hole for the bolt to pass through.
The upper plate bears a nut on the top side and another nut on the underside.

The more this bolt is pulled upwards, the greater the anchor diameter anchor becomes below. This in turn presses increasingly against the walls of the borehole thereby providing anchorage.

If we drill a borehole with a diameter of 20cm and depth of 1.4m and we sink the anchor in it,http://postimage.org/image/2fyw5jh38/ the sinking will halt at the lower plate as it is larger than the hole.

If the bricks in the photograph are in fact hydraulic jacks.http://postimage.org/image/15or8eeuc/ By elevating these we can create a great amount prestress in the system and very strong anchorage against the sides of the borehole.

When the jacks are elevated they exert pressure both upwards and downwards.http://postimage.org/image/15or8eeuc/

The lower plate cannot move downwards because there is resistance from the ground.

The bolt on the upper side of the top plate prevents it from rising due to the upward pressure which the hydraulic jacks create.

We then screw the nut which is situated between the two plates downwards until it reaches the lower plate and in this way we complete the prestressing.

Then we remove the jacks.

Now consider the bolt which protrudes from the ground. We stated that it is secured to the top plate at its upper surface by a nut.

The upper part of the bolt which bears the plate is anchored inside the fortified concrete of the foundations (the radiere). Also, the foundations are connected to the concrete walls via the joining mechanism.http://postimage.org/image/xci31flw/

In this way we will have the beneficial results that I have stated above. That is, we will prevent torque of the corners.

FIFTH PLACEMENT METHOD FOR EXISTING PILOTIS

Here, on each column of the pilotis which is situated around the perimeter of the foundations, we place metal beams which are connected to each other and prestressed at their four corners with the ground using the patented mechanism. After doing this, we place another four metal beams parallel and tangent to the sides of the column. These are anchored into the grooves of the other metal beams. Afterwards we make grooves in the parallel metal beams so that they can be tightened with nuts and bolt. We pass the bolt inside a pipe so that it is independent from the concrete. Around the perimeter of the column we place clamps or insert screws which protrude from the column. We construct a concrete mantle around the perimeter of the column. When this is set, the upper end of the bolt is tightened using the nuts, so creating prestressed concrete.
The same process is repeated on each column of the pilotis.

SIXTH PLACEMENT METHOD FOR EXISTING PREFABRICATED HOUSES

Here, in order to apply prestressing to the structure there are two problems:

1) How will we drill a bore hole?
2) How will we pass the metal cable through the reinforced concrete walls?

SOLUTION
1) Instead of drilling a bore hole under the base, we drill it 40 cm beyond the external fortified concrete walls of the existing prefabricated house.
2) We apply surface prestress between the ground surface and the drill hole so that we anchor the traction mechanism well with the ground.

Prior to applying prestress on the traction mechanism though we have carried out the following:
Underneath the tightening nut we place a hollow steel beam of which one end extends outwards and penetrates into the fortified concrete walls of the structure (which we have previously dug out).

The other end extends back from the bore hole so that we have lever resistance.

The outer end of the hollow beam has a U-shaped groove which is used to anchor one end of the metal cable.

The other end of the cable is anchored to the top of the concrete wall once we have ensured its passage through it by opening a deep gully which is plastered over after the prestressing operation.

In this way we anchor the building externally.

By the same method we can prestress with the ground other prefabricated structures such as dams, pylons, bridges etc.

The traction mechanism is appropriate for all works where piles and cement injection are required. In fact it is far superior to these because it has the added benefit of greater resistance as well as improvement in the relaxation of the ground due to prestressing and ground compression.

It can even be used for containment of loose ground on mountain slopes during the excavation and construction of roads.

Other beneficial properties offered by prestressing of a structure with the ground include:

1) Prestressing (in general, compression) has a very positive result as it improves the trajectories of oblique tension.
2) Compression means that there is reduced cracking. This increases the active cross section and increases rigidity of the structure.

We have two types of construction traction mechanisms and two patent licences pending internationally:

1) The simple traction mechanism for construction. This has exactly the same utility with the hydraulic one on solid ground.
2) The hydraulic traction mechanism for construction. This is suited to loose ground because is protects the structure more from subsidence.

How it achieves this


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FOUNDATIONS

I propose using large area foundations (radiere) and not individual bases

ECONOMICAL/TECHNICAL STUDY

There are three methods of construction:

a) Frame structure, where the weight of the furniture, the slabs, the walls and the beams is transferred to the columns and then from the columns it is transferred to the foundations.

In a skeletal structure, the walls even though they are counted as static load play an important role in the strength of the structure.

Here, building alterations which are carried out by an individual owner within an apartment building are wrong, not only for his own apartment, but for the whole apartment building.

We must agree that with regards to frame structure, he who carries out alterations must be aware of this.

b) Continuous construction, where the loads are assumed by the walls and transmitted to the ground.

Here alterations are prohibited without an expert.

c) Composite construction, which either utilises different materials (metal beams plus concrete) or continuous construction together with a frame.

I consider that the construction suitable for the traction mechanism is continuous construction internally and frame structure externally.

How I propose to deal with the problem of building alterations:

If, for example, we are constructing an apartment building where every floor contains four apartments, I would carry out the following so that individual owners can carry out the alterations they wish.

Firstly, I would place columns around the perimeter of the building.

After, internally I would construct the internal design in a cross pattern so that the cross creates the partition walls of the four apartments.

I would convert the cross to walls of reinforced concrete and I would anchor their ends with the hydraulic traction mechanism.

At the centre of the cross the elevator shaft would be built and the hallway around this would provide entrance to the apartments (these also made out of reinforced concrete).

If this is done, from whichever direction the earthquake comes there is resistance in the roof and the foundations. Not only this, but because of the large profile area of the cross section of the concrete walls, we eliminate the problem of shearing and bending.

Another possibility which we could carry out so that there is the option to carry out building alterations is the following:

If the apartment building has adjacent walls (which have no windows) we convert the adjacent walls to fortified concrete ones with anchoring. In addition, we convert another central internal wall of the apartment building to fortified concrete so that a double T cross section is formed.

Another possible form which we can give so that we can carry out alterations is to place two elevator shafts together with the corridor shafts at two opposing ends of the structure and insert the traction mechanism in their corners.

These square shafts may serve either as elevators, storerooms or other communal spaces.

If you search, there are always solutions.

I am a builder by trade and when I give an estimate for concrete construction work, the first thing I examine is the degree of difficulty of the formwork.

If you were to ask me to take on the whole construction including the excavation, I would make certain comparisons as to what is in my best interests. Radiere (continuous foundations which cover the whole area of the construction) or foundations with connecting beams ?

Initially I would calculate how many cubic metres of concrete are required for the radiere and how many for the foundations with connecting beams.

From my experience, I believe that the radiere uses 20% more fortified concrete compared to foundations with their connecting beams. The latter though requires much more work than the former in the following areas:

a) formwork
b) excavation

Comparing the figures, we see that the two options if not exactly the same, the radiere is slightly cheaper than the foundations and connecting beams.

It is a fact that more cubic metres of concrete with less formwork create more profit for the contractor. The estimate then per cubic metre of fortified concrete for the radiere will be markedly lower.

Comparing these figures, we see that the radiere is somewhat cheaper even if it does have 20% more fortified concrete.

As for the walls, it is cheaper to build one solid fortified concrete wall than it is to constructing in its place two columns with beam and double masonry.

If the whole house is constructed from fortified concrete there will still be sideways deflections (cracks) because the static loads increase on the bearing element, the inertia of which during an earthquake, will cause the building to lift up on one side and transfer its weight to moment of the nodes.

The cost is approximately 4,000 euro for an anchored radiere of 100 metres square. This includes the mechanisms (the cost of the anchor is 200 euro), construction works and boreholes.

http://postimage.org/image/w37m65ms/
http://postimage.org/image/2mkga1kmc/
http://postimage.org/image/14s73bc04/
http://postimage.org/image/15qym72jo/
http://postimage.org/image/2r7apjukk/


With rock we have a difficult but shallow borehole. On soft ground we have an easy but deeper one. I estimate that these will have the same cost.

link.... anti seismic systems http://www.antiseismic-systems.com/

http://www.michanikos.gr/showthread.php?t=12040

http://www.youtube.com/watch?v=JJIsx1sKkLk

Ideal for prefabricated houses made ​​of reinforced concrete
Makes Homebuilding cheaper 30 - 50%
Because prefabricated houses made ​​of reinforced concrete are cheap 30 - 50% less than conventional housing