Earthquake resistant design Research Papers (original) (raw)

► SUMMARY: ♦ The Resilient Composite Systems (R.C.S.) could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure. They are the compound materials, with... more

► SUMMARY:

♦ The Resilient Composite Systems (R.C.S.) could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure. They are the compound materials, with some particular structural properties, in which, contrary to the basic geometrical assumption of the flexure theory in Solid Mechanics, the strain changes in the beam height during bending is typically "Nonlinear". The Resilient Composite Systems are made by expediently creating the disseminated suitable hollow pores and/or by distributing the appropriate lightweight aggregates throughout the methodically reinforced, fibered conjoined matrix so that; "the strain changes in the beam height during bending" is typically "nonlinear". Thereby, by applying the mentioned method to make the said composite systems, "considerably increasing the modulus of resilience and the bearing capacity in bending" together with "the significant decrease of the weight" and "the removal of the beam fracture possibility of primary compressive type" have been feasible. Through making these particular consistently functioning systems, the above-stated paradoxical virtues have been concomitantly fulfilled in "one functioning unit" altogether.

♦ The RCS (with the mentioned general structural properties and specific functional criteria) whose cement materials include the "C-S-H (Calcium Silicate hydrate) crystals" have been termed "Elastic Composite, Reinforced Lightweight Concrete (E.C.R.L.C.)".

♦ The RCS and ECRLC as a kind of RCS could be used in many cases. For instance, "Constructing Lightweightly and Consistently", also with practically utilizing the RCS and ECRLC in particular, can be counted as the pivotal and practical tactic to effectively increase the resistance & safety of the constructions against "earthquake" and lateral forces, in the large extent. For example, using some lightweight and insulating, "non-brittle", reinforced sandwich panels or 3D-panels, "with the high modulus of resilience and appropriate behavior against the bending loads and impacts", for construction could be taken into consideration according to the case... [It is worth remarking that; contrary to the ECRLC, the usual reinforced lightweight concretes, especially in the very low densities, are dramatically brittle; they do not have the appropriate behavior and resistance against the high bending loads and impacts.]
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● "Resilient Composite Systems (RCS)":

♦ "Resilient Composite Systems" (RCS) are the compound materials, having some particular structural properties, in which, contrary to the basic geometrical assumption of the flexure theory in Solid Mechanics, the strain changes in the beam height during bending is typically "Nonlinear". The RCS could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure. (Elastic Composite, Reinforced Lightweight Concrete; ECRLC is a type of RCS with the mentioned specifics.)

♦ Generally, the Resilient Composite Systems comprise these components as the main, necessary elements:
• 1) Mesh (Lattice);
• 2) Fibers or strands;
• 3) Conjoined matrix, having the disseminated suitable pores and/or the disseminated appropriate lightweight aggregates beads or particles. [Here, the general term of "lightweight aggregate" has a broad meaning, also including the polymeric and non-polymeric beads or particles.]

♦ The Resilient Composite Systems are made by creating the disseminated suitable hollow pores and/or by distributing the appropriate lightweight aggregates throughout the reinforced, fibered conjoined matrix so that; "the strain changes in the beam height during bending" is typically "nonlinear". Thereby, by applying the mentioned method to make the said particular composite systems, "considerably increasing the modulus of resilience and the bearing capacity in bending" together with "the significant decrease of the weight" and "the removal of the beam fracture possibility of primary compressive type" have been feasible. Through making these particular consistently (unitedly, integratedly) functioning systems, the stated paradoxical virtues have been concomitantly fulfilled in one functioning unit altogether.

♦ Generally, in these consistently functioning units, the amount and the use manner of the mentioned components in the organized system are so that; the reciprocal interactions among the components finally lead to the "typically nonlinear strain changes in the beam height during bending" (as the "basic functional character" of these systems with the specific testable criteria and indices) and the functional specifications fulfillment of the system.

♦ In the RCS in general, the main strategy to raise the modulus of resilience in bending is "increasing the strain capability of the system in bending" within the elastic limit.

♦ Here, the main tactic to realize the stated strategy is: "creating the suitable hollow pores and/or using the appropriate lightweight aggregates, all disseminated throughout the methodically reinforced conjoined matrix", to provide the possibility for occurring of the expedient internal deformities in the matrix during the bending course, which could lead to the more appropriate distribution of the stresses and the strains throughout the system and the more strain capability of the beam in flexure. On the other hand, only creating the hollow pores and/or using the lightweight aggregates in the matrix, by itself, not only cannot lead to the mentioned goals but also brings about weakening of the matrix and its fragility. Hence, concomitantly, the matrix should be well supported and strengthened. Here, this essentially ameliorating and strengthening the matrix are performed by giving attention to "the internal consistency of the matrix" and also via "employing the expedient reinforcements in two complementary levels": 1) Using the fibers to the better distribution of the tensile stresses and strains in the matrix, and to increase the matrix endurance and the modulus of resilience in tension and bending; 2) Using the mesh or lattice to better distribution of the tensile stresses and strains in the system, and to increase the system endurance and the modulus of resilience in tension and bending.

♦ In these systems, the presence of the mentioned hollow pores and/or lightweight aggregates disseminated throughout the conjoined matrix (which has been ameliorated through making "an integrated, reticular structure") provides the possibility for occurring of the expedient internal deformities in the matrix during the bending course. By the way, this can lead to the less accumulation of the internal stresses in the certain points of the matrix during bending, the better absorption and control of the stresses, and providing the more strain capability of the beam, especially within the elastic limit.

♦ The occurrence of the remarked internal deformities in the said methodically reinforced matrix during the bending course also means; the occurrence of the deformities in the said hollow pores and/or lightweight aggregates well disseminated throughout the conjoined matrix, in two different forms. Indeed, we have the internal deformities in the fibered lightweight matrix of the system throughout the bending course, in two main different forms, leading to: A) The comparative increase of the thickness (height) of the in-compressing layers (particularly in the upper parts of the beam) and the conversion of some internal compressive stresses to the internal tensile stresses (on the axis perpendicular to the mentioned internal compressive tensions) in the in-compressing layers; B) The comparative decrease of the thickness (height) of the in-tension layers (particularly in the lower parts of the beam) and the conversion of some internal tensile stresses to the internal compressive stresses (on the axis perpendicular to the mentioned internal tensile tensions) in the in-tension layers.

♦ In the under-bending sections of the "Resilient Composite Systems", the deformities occurring in the "conjoined layers perpendicular to the applied load direction" during the bending course are so that; "the initially plane sections perpendicular to the beam axis" typically shift from "the plane status" to "the curve status" during the bending course. Thereby, the basic geometrical assumption of the flexure theory in Solid Mechanics ("linearly" being of the strain changes in the beam height during bending) and the respective trigonometric equations & equalities are mainly overshadowed in these systems.

♦ This way, through occurring of the remarked internal deformities in the strengthened matrix during the flexure course, the stresses are more distributed and absorbed, and the rise rate of the internal stresses in the matrix ... reduces. ...
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