LAMANNA Luigi FrancoApril, 2017

STRENGTHENING AND STABILIZATION THE CONCRETE STRUCTURE WITH POLIMERIC PRODUCT

Solutions for

BELLICINI AnnaLaura

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(a) (b)

The two photos illustrate the activation of the "soft floor" in buildings subject to different entities seismicmechanism:- Building (a) earthquake of magnitude 6.5 on the Richter scale;- Building (b) earthquake of magnitude 6.2 on the Richter scale.

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(a)

(b)

(a) and (b) illustrate the collapse in the upper part of the pillar.

Vertical descensons in heads of walls with possible disappointments thattranslate into horizontal displacements at higher levels, greater than oneper thousand, maximum consensus value.

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(a) (b)

(a) and (b) illustrate the collapse in the lower part of the pillar. Photo (a) the total absence of stirrups in columns

COLLAPSE OF THE STRUCTURE

Particular "A"

“A”

STRUCTURAL POLYMER CONCRETE - SPC

STUDY CONCERNINGNG PLANNING CRITERIA TO REINFORCE THE BEAM-COLUMN KNOTS IN SEISMIC AREAS WITH”STRUCUTURAL POLYMER CONCRETE - SPC”

Particular "A"

STRUCTURAL POLYMER CONCRETE

EXAMPLE OF CASTING DISTRIBUTION WITH STRUCTURAL POLYMER CONCRETE-SPC WITHOUT USING STRONGREINFORCEMENT AS PRESCRIBED BY “ACI 352” CAUSING SEVERAL DIFFICULTIES IS THE EXECUTION

EXAMPLE OF A CONSTRUCTIVE DETAIL

This study intends to stimulate the development of a new material. There are nanely several reasons to consider the “StructuralPolymer Concrete-SPC” a new material, even if same ins not causing a revolutonary follow-up.

This statement is due to the fact that the stress breaking point is 4 to 5 times higher than that of the ordinary concrete.

Furthermore it has a doubling of the elstic modulus and it is completely watertproof and unalterable by atmospheric agents.

FIG. 1EXAMPLE OF STRESS DISTRIBUTION IN THEREINFORCEMENTS AND IN THE CONCRETEIN THE BEAM-COLUMN CONNECTION AREA

Owing to this it is important to write a complete and reliable advice,suplemented with both experimental and theoretical probings.

A normal concrete usually reaches after hardening an average mechanicalcompressive strength of about 400 kg/cm2 , and seldom more than 600kg/cm2 . On the contrary a special “Structural Polymer Concrete-SPC” , mayhave a strength of about 1200 kg/cm2. Furthermore with special devices inthe aggregates, the figures of compressive strength may reach nearly 3000kg/cm2.

Also tensile strength increase from about 30/40 kg/cm2 of the normalconcretes to about 200/500 kg/cm2.

For what concerns other characteristics: in the “Structural Polymer Concrete -SPC” there is no water absorption, therefore it has a nearly total frostresistance.

Upon examining the properties of the “structural concrete” it is evident that itsutilization concerns, above all, those applications where traditional concretesdo not give satisfactory results to comply with the needs of the buildingtechniques and the purposes of the work to assure sufficient stiffness,resistance and ductility levels as well as capability of energy dissipation forwhat concerns seismic problems.

Regretfully, today “structural concretes” are not so frequently used, both forthe scarse knowledge of non-traditional products, and for a mistrust often dueto prejudice and mostly unjustified commonplaces.

FIG. 2EXAMPLE OF SHEAR STRESS ON A BEAM-COLUMN KNOT

After the above necessary forword, it is time to illustrate the peculiarities of the “Structural Polymer Concrete-SPC”, as wellas itsantiseismic reinforcement and adaptation features, for what concers both economy and safety problems.

The discussion more than dealing about calculations, will particularly revert on the application procedures and the building detailsinvolved. This is due to the fact that good behaviour under the action of an earthquake is not due to accurate calculations, but mainlyto the careful study of certain “details” and to the material responsible for the antiseismic safety.

Main characteristics of the “Structural Polymer Concrete- SPC” for its structural use are the following:

- Good workability;- Thixotrophic properties;- Hardening or polymerization process undependent on temperature or humidity;- Low shrinkage and viscosity phenomena and consequent lack of cracks;- Characteristics of mechanical influences not influenced by any ageing or alternating stress process;- Nearly total reduction of water permeability or absorption, therefore exceptional resistance to frost and aggressive agents of any

kind;- Adhesion iron/reinforced concrete increased of about 4 times the values of the ordinary reinforced concrete.

All these characteristics are to be included in a complete and articulated frame, like the standards to calculate the limit states of the normaland prestressed concrete.

The “Structural Polymer Concrete-SPC” is a non-traditional concrete where the binding function is not done by cement but by thermosettingsynthetic resins . This can produce some structural reinforcement “details”, in causing a seismic matching of the work completely modifyingthe stativ diagram and building, while working, some “dissipators” at the beam-column knots.

The dimensioning of this kind of interference has to be done according to the instructions of stress trasmission inside the knots (fig. 1 and 2):that is to say in a rather wide area to avoid stress concentration in correspondence of the linkage knots of beams and pillars.

Furthermore, wile making the project, it is necessary to verify the difference between the mechanical and deforming characteristics of the twomaterials in contact, that have been cast at different times. One has to keep in mind that this kind of interference cannot be codified, not onlyto standardize it as it concerns the use of materials with peculiar characteristics, which efficacy has to be absolutely guaranteed. And there isalso to consider the fact that this kind of interference has a high percentace of costs.

It is necessary to study and experiment materials and components and inform of any result all those involved in the project, keeping in mind atthe same time thath wrong or wrongly known results may be damage to the community.

This subject is of great interest first of all to planners, chief engineers, testing surveyors and consignors involved in earthquake problems.

It is necessary, as indicated in our vorword, to succeed in obtaining coditied standars to apply easily, to use them to prepare specifications andtechnical cars of materials and components to guarantee tha the excution of works will be technically reilable.

To answer allthis, it is necessary to effect a deep survey to satisfy the chamge demand to all technical problems to obtain good quality inworks. On our part, we realize we are not well prepared also for what concerns the skillfullness of the workers who need to be wellexperienced in dealing with these materials: the thermosetting synthetic resins, a hard and always new field.

TAB. 1MECHNICAL STRENGTH CHARACTERISTICS OF THE

“STRUCTURAL POLYMER CONCRETE- SPC”

In my opinion this problem has to be dealt with the utmost care and seriousness, in promoting enterprises tending to qualifyboth technicians and building contractors.

COMPRENSIVE STRENGTH DIN 1164 120 N/mm2

FLEXURAL STRENGTH DIN 1164 30/80 “

TENSILE STRENGTH DIN 53445 15 “

ELASTIC MODULUS DIN 53457 7000 “

CRACKING ELONGATION DIN 53445 6,7 “

ADHESIVE PROPERTIES ORDINARY CONCRETE STRUCTURAL AND STRUCTURAL POLYMER CONCRETE-SPC

It is very important to point out the influence and employ possibilities due to the adhesive properties of polymer concretes on theordinary concrete.

Polymer concretes can WET surfaces of ordinart concrete, and another facot to remember is that polymer chemistry has given origin toa rich series of adhesive materials. They vary conspicuously according to the inert charges, without causing SALACKERING.

EXAMPLE OF BEHAVIOR OF THE ”NODES” BEAM-COLUMN

(a1) armed node according to legislation;(a2) node with reduced confinement;(b) a constructive detail of external nodewith additional inclined armor;(c) external node response with inclinedarmor;(d) Reinforced external node response inconventional manner.

(a) (b) (c)

(d) (e)

TYPE OF COLLAPSE INTO NODES "BEAM-COLUMN":

a) - the achievement of the bearing capacity of the beam;b) - attainment of the load-bearing capacity in the column;c) - expulsion of the concrete cover in the node;d) - the collapse for anchoring of the reinforcement beam;e) - to collapse the node cut.

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(a) (b) (c)

COLLAPSE OF A "CORNER NODE"

COLLAPSE OF AN "EXTERNAL NODE"

(a) (b) (c)

COLLAPSE OF AN ”INTERNAL NODE"

(a) (b) (c)

DETERMINATION OF THE SHARES IN "NODES"

a) – Forces acting on the column

b) – Bendingmoments

c) – Sheorforces

d) – Crackpatterns

e) – Variation of internaltension forces alongthe column

DETERMINING TRANSFER OF ACTIONS IN THE "NODES"

a) – Concrete strut b) – Diagonal compression

(a) (b) (c) (d)

MECHANISMS RESISTANT IN THE CHECKS – 1 of 2A

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COLLAPSE OF THE STRUCTURE

MECHANISMS RESISTANT IN THE CHECKS – 2 of 2a)

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DESTRUCTIVE TESTING PERFORMED ON SAMPLES OF “STRUCTURAL POLYMER CONCRETE-SPC”

Dimension sample of "StructuralPolymer Concrete -SPC" 4x4x4 cm

MECHANICAL RESISTANCE TEST

Sample of "Structural Polymer Concrete -SPC" subjected to compression test inthe laboratory after only 24 hours from its mixing.

Mix study of the aggregates for the “SPC” samples to besubjected in the laboratory to mechanical resistance tests

Samples of “SPC” (measuring 4x4x16 cm and 4x4x4 cm)to be subjected in the laboratory to mechanical resistancetests: compression, direct tensile and flexural.

Visual assessment on the "fluidity"and "flowability" of the “SPC”.

AnnaLaura BelliciniArchitect

Graduated in architecture at the University "La Sapienza" of ROME (ITALY), regularly registered in the professional, carries outindependent professional activities.

From the outset has developed career path focused on the study and design of interventions that employ advanced technologies andinnovative materials.

Has experienced collaborators of professionals, technicians, consultants, production companies and executing, it provides specificsolutions for the consolidation and rehabilitation of buildings and civil structures.

e-mail: belliciniannalaura @ gmail.com

INDEPENDENT CONSULTANT TUNNELING , MINING AND OIL SPECIALIZED IN MECHANIZED TUNNELING WITH HARD ROCK

TBM AND SOFT SOIL EPB SHIELDSEXPERT AND CONSULTANT IN STRUCTURAL REINFORCEMENT

LAMANNA Luigi Franco, performs for 45 years professional consulting and technical direction in the various sectorsof civil, industrial, military, hydraulics, railway, highway and recent years in the sector of “tunneling” and “mining” onthe correct use of special “resin” and related technologies for consolidation, repair and maintenance of masonry,concrete, iron and wood.

Is the author of numerous scientific publications and is always engaged in the study and development of “innovativematerials” and related techniques and technologies used.

e-mail: lamannaluigifranco1 @ gmail.com

- MAINTENANCE OF AIRPORT PAVEMENTS, ROAD TRANSPORT AND CONDUCTIVE/DISSIPATIVEPAVEMENTS- INJECTION RESINS SYSTEM IN TUNNELLING, MINING AND CIVIL ENGINEERING

- DAMS and BRIDGS - REPAIR, PROTECTION AND REINFORCEMENT OF STRUCTURALCONCRETE

- SOLUTIONS FOR PRE-EXCAVATION GROUTING IN ROCK TUNNELING AND MINING

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