Author Ioannis Lymperis
Independent researcher of antiseismic construction technology.
The anti-seismic construction technology has modern and good anti-seismic regulations! However, the structures do not withstand any major earthquake. There are too many unpredictable factors that can bring destruction to what modern earthquake structures. The factors that determine the seismic behavior of structures are numerous, and in part probable. Unknown direction of the earthquake, unknown exact content of seismic excitation frequencies, unknown its duration. The maximum possible accelerations given by the seismologists, and determining the coefficient of earthquake resistance design, have a probability of exceedance of more than 10%. The correlation of quantities such as "Inertial tensions - damping forces - elastic forces - dynamic construction features - soil construction interaction - imposed ground movement " is non-linear, directional. According to the modern regulations, the seismic design of the buildings is based on the requirements of efficient node design and ductility. The inevitable inelastic behavior under strong seismic stimulation is directed to selected elements and failure mechanisms. The incompetence of the nodes, and the limited ductility of the elements, will produce blatant forms of failure. The purpose of the modern anti-seismic regulation is to construct structures that: a) In frequent small earthquakes, with a high probability to happen, construction will suffer nothing, b) In medium-sized earthquakes, medium probability of becoming, construction will suffer minor repairable damage and c) In very strong earthquakes, little chance of happening will have no losses of human lives. So we should not use the term "The Ultimate Anti-Seismic Design." We should use the term "Quality constructions" This means applying the requirements of all modern regulations. The quality of construction and its safety is also a function of the economic situation of the countries. It is understandable that poor countries can not be compared with countries where they have very expensive modern anti-seismic regulations. Conclusion ... there is no Ultimate Anti-Seismic Design today, and we should not refer to Ultimate Anti-Seismic Design. So, there is a great need today to invent the Ultimate Anti-Seismic Design with lower construction costs.
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The design mechanisms and methods of the invention are intended to minimize the problems associated with building safety in the event of natural phenomena such as earthquake, hurricanes, and lateral gusts of strong winds. This is achieved by controlling the deformations of the structure. Damage and deformations are closely related concepts, since by controlling the deformations, controlled and damage. The invention controls deformations, irrespective of the duration and intensity of the earthquake. It regulates shaking to the limits of the elastic displacement, preventing, inelastic displacement.
According to the present invention, this can be achieved by a continuous pre-stressing ( applied by the upper edges of the walls of the building) of both the building structure towards the ground and of the ground towards the structure, making these two parts one body Said pre-stressing is applied by means of the mechanism. Said mechanisms comprises steel cables crossing freely (through pipes) the edges of the structure vertical support walls and also the length of drillings beneath them. Said steel cable's lower end is tied to an anchor-type mechanism that is embedded into the walls of the drilling to prevent it from being uplifted. Said steel cable's top end is tied to a hydraulic pulling mechanism, exerting a continuous uplifting force. The pulling force applied to the steel cable by means of the hydraulic mechanism and the reaction to such pulling from the fixed anchor at the other end of it generate the desired compression in the construction project. Basically we have build one clamped structure with the ground from the nodes of the highest level. But if we want, we have the mechanism to impose compressive tensions from the nodes of the highest level at the edges of the wall sections. Before we build the foundation of the building, we apply tension to the tendons (twice the design stresses that the mechanism must take) between the height of the foundation soil surface and the anchoring mechanism at the depths of the drilling. When pulling the tendon, the anchor mechanism expands, exerting peripheral radial pressures on the loose slopes of the drill, ensuring (a) condensation of loose slopes, and (b) great friction at the interface of the jaws of the mechanism and the soil, creating conditions of relevance for the locking of the mechanism in the ground. While maintaining the mechanical stresses, we place an injection of reinforced concrete into the hole for further adhesion. By completing the locking of the mechanism in the ground, we have an in-depth foundation mechanism that successfully receives the upward and downward tensions of the construction walls. It follows the gradual construction of the project and the free passage of the tendons through the edges of the walls through diode tubes. The extension of the tendons is applied with bolt connections. There is the possibility, to have a simple clamped structure with the ground, or alternatively, we can apply compressive tensions to the cross-section with the mechanisms.
One method of the design methods, includes the construction of a sufficient number and size of reinforced concrete walls, with cross sections of different geometric shapes and directions, placed in the appropriate positions, in which the mechanisms impose on their upper edges compressive loads on all sides of their cross-section, in order to apply stability moments, against torsional moments. The compressive loads in the cross sections are derived from an external force, that of the foundation soil.
The walls may be on the perimeter of the building, (excluding shop facades) to surround the stairway and the elevator, (strong wells - cores) and possibly be internal walls separation of apartments, extending throughout the height of the building. The placement of many strong walls brings great stiffness, and a substantial reduction in the fundamental natural period of construction. This, combined with the view q = 1, leads to a correspondingly large increase in the seismic loads of the structure. However, it should not be overlooked that precisely because of the many strong walls the strength increases or, otherwise, the cross sectional loads are reduced, despite the large increase of seismic loads. The walls under seismic excitation receive torques (M), right forces (N) (compressive and tensile), and shear forces (Q). The wall under the compressive stresses of the mechanism, increases its strength, to the shear forces (Q) up to 36%. Enforcement of compressive forces in the cross-sections of the walls, is applied, to zero the tensile stresses, to create the torque of stability, against the wall torque overturning, and increasing the cross-sectional strength to the shear force. The application of compressive forces to cross sections has very positive results as it improves the orbits of the oblique tensile strength, ensures reduced cracking because there are compressive forces, while increasing the active cross section of the wall.
The compressive forces (N) are taken up by the cross-section of the wall and transferred to the grounding mechanism, which sends them into the slopes of the drilling. The mechanism increases the strength of the loose foundation soil creating strong territorial zones to receive static loads. Upward tensions and vertical load components of the wall create tensile strength (N). Upward tensions, which overturn the wall, are received by the tendon from the nodes of the highest level and deflecting these directs them into the ground, removing one of the two forces that creates the tension on the wall side. This method stops the rotation of the base shoe, and the bend of the wall, causes, which generate the torque of the nodes (M) responsible for the bending of the trunk, of the beam and of the wall. The tensile stresses (N) on the wall side no longer exist.
With the design method, of the clamped structure from the nodes of the highest level with the ground, hope I will deflect the inertia tensions of the construction and direct them straight into the ground, removing those from the areas currently driven, preventing and avoiding deforming shapes, which are so many, as well as the various directions of earthquake displacements, so that the tension in the structure,
to appear limited, while at the same time ensuring a stronger bearing capacity of the foundation soil. If we design the correct dimensioning and shape of the walls, and place them in appropriate locations, we prevent the torsional buckling which appears in asymmetrical and metallic high-rise constructions. The opening of the drilling shows us the quality of the foundation soil, which hides many surprises because of its natural inhomogeneity. The clamped structure does not allow vertical bounces, eliminating impact stresses that increase construction and ground loads. It maintains the construction, within the limits of the elastic phase of displacement, irrespective of the intensity and duration of the earthquake, preventing coordination.
The Mechanism of relevance. Problems and solutions.
The collaboration between concrete and steel is achieved with the relevance. By the term relevance defined the combined action of the mechanisms which prevent relative slippage between the reinforcement bars and the concrete surrounding them. The mechanisms of relevance are adhesion, friction and, in the case of steel bars with ribs, the resistance of the concrete that is trapped between the ribs. The combined action of these mechanisms considered to be equivalent with development shear stresses in the concrete and steel interface. When the stresses reach limit resistance, relevance of concrete is destroyed along the length of the steel rods and the steel rods are detached from the concrete.
A) The first problem of relevance is created by the high strength of steel, which turns the failure in shear failure and is extremely brittle. To solve the problem of shear failure, we need to ensure that it will not be created. As a partial solution of the problem , we know the following. The reduction of stresses is achieved by increasing the concrete coating and reducing the diameter of the reinforcement bars. The increase in the limit value of strength, is achieved by increasing the strength of the concrete. Placing horizontal reinforcement works favorably, limiting the opening of growing cracks. 1) Requested.
A method where the concrete receives only compressive forces and the steel receives only tensile stresses.
B) Second problem, uncounterbalancing, forces
When the wall is bent, are being developed, compressive forces on one side and tensile stresses on the other side. When the tensions reach to a marginal
point a failure occurs in a specific area of the cross section at the bottom of the ground floor which it is called critical failure area which you notice the maximum concentration of compressive and tensile stresses. It's the area where it exists the bend of the wall and which separate their direction the tensile forces in left and right directions, and the region of the other side,
where they collide the compressive forces. The contrast of the tensile forces
in this area, separates the trunk of the wall in two parts with uncounterbalancing, forces. The lower region receives higher stresses,
(those of the great moments where the lever arm of the wall lowers down to the base) with a shorter length of relevance. The result is early inexpediency
and failure of relevance. 2) Requested
A cooperation method of concrete and steel, in which will presented counterbalancing, forces.
C) C) Third problem. Lever arm.
The walls are powerful lever arms, where their height extends from the roof to the base. They have an invisible fulcrum at the point of bending and a articulation located at the side of the base. The method of reinforcing the concrete, with the mechanism of relevance, helps the lever arm to multiply
and to lower very high torques at the base, imposing large torque loads in the cross section of the wall and the body of the foot girders. In the large longitudinal columns
( walls ), due to the large moments which occur during an earthquake, it is practically impossible to prevent rotation with the classical way of construction of the foot girders.
Requested.
A method of reinforcing the concrete where it does not exist the mechanism of lever arm that multiplies the tensions of torques which drops to the base.
SOLUTION OF RELEVANCE PROBLEMS WITH THE NEW DESIGN METHODS
A) In the new design method for the cooperation of cement and steel, the concrete receives only compressive forces at their two opposite ends, up and down, and steel receives only tensile strengths. We know the concrete it can withstand 12 times more in compressive forces than it does in tensile forces, and that the steel has high tensile strengths.
Conclusion,
The absence of shear stress in the concrete and steel interface, which is achieved by the free passage of the tendon through the concrete cross sections of the wall with the help of the passage pipes, combined, with the high strength of concrete in the compressive forces, as well as the high strength of steel in tensile stresses, are three great factors offered by the new method which contribute to higher strength of construction, with less steel.
Because with this method do not exist the premature material failure of the concrete and the concrete, giving steel the time to exhaust its specifications for its high tensile strength.
Result
Economics in steel with greater durability. All that needs to be calculated is the cross sections of the concrete, to has the required strengths to compressive forces and the steel the corresponding strengths in tensile stresses.
B) The new design method does not present non counterbalancing, forces as presented in the relevance Tensions are applied at both ends of the tendon.
At the upper end it receives compressive forces resulting from its application
torque stability of the mechanism, against upward tensions of the wall overturning torque. At the lower end of the tendon we have frictional tension between the bars of the clamping mechanism and the drilling slopes. The tensile stresses in the cross section of the tendon separate in the middle of its length.
Result. balance of tension equilibrium, counterbalancing forces, up, down
C) The new design method eliminates the lever arm mechanism and the large torques that are lowered near the base. Because there is no torque at the nodes, there is no bend in the wall responsible for the lever arm mechanism, which increases the torque intensities, if there is no tensile on one side of the wall, as well as if there is no turning of the wall.
Result. a) Removes stresses from the construction b) Removes tension from the tendon of the mechanism c) Does not lower any torque on the base.
Question.
And where are directed these tensions are removed;
Answer
Inside the ground. Today we drive them cyclically over the sections of the bearing elements
Experiment Higher Acceleration Measurement.
https://www.youtube.com/watch?v=RoM5pEy7n9Q
I did a lot of experiments
microscale
with a scale of 1 to 7,
mass 900kg
with steel reinforcement
with double squares
5Χ5 cm Φ / 1,5mm,
with concrete material
on a microscale.
I used sand with cement
proportion
1 part of cement 6
parts
sand.
Width of oscillation 0.15m
Shift 0.30m
Full oscillation 0.60m
Frequency 2 Hz
Acceleration in (g) a = (- (2 * π * 2) ^ 2 * 0.15) / 9.81
a = 3,14x2 = 6,28x2 = 12,56x12,56 = 157,754X0,15 = 23,6631 / 9,81 = 2,41g of natural earthquake.
Inertia power (F) ground floor F = m.a 450 X 23,663 = 10648 Newton or 10,65 kN.
first floor 450 x 23,663 = 10648 Newton or 10,65 kN.
Total force F (Inertia) 10,65 + 10,65 = 21,3 kN
Moment of inertia
Strength X Height ^ 2
Ground floor 10,65x0,67x0,67 = 4,8 kN
First floor 10,65x1,35x1,35 = 19,4 kN
Total Inertia Torque 4.8 + 19.4 = 24.2 Kn
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