DDF vicente carrasco
topical advanced design studio 5501, Prof. Pongrantz, FA2013, digital design and fabrication, DDF, College of Architecture, Texas Tech University
contents a 00
fiber reingorced concrete research
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movable molds research
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hauer building skin
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2d pattern
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3d pattern
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b 03
optimization
team4
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29-30 31-32
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fiber-reinforced concrete
The use of fibers in construction is an old concept with straw and horse hair being used in mortar and mud bricks since the time of the Egyptians. The modern use of FRC was invented at the end of the 19th century by Ludwig Hatschek. He sought a new roofing material and created a material using portland cement and asbestos, which is known for its fire-proofing and resistance to breaking under tension. The process he developed, called the Hatschek process on Hatscheck machines, is still in use today even though the industry has moved from asbestos to other fibers. He named his product Eternit, which is what FRC is known synonymously as today.
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hatscheck process A water-based slurry of fibres with adhering fine cement particles is formed into a thin layer on the surface of a sieve cylinder. Three such sieve cylinders rotate with up to two-thirds of their diameter immersed in the slurry. The parts of the sieve cyliders projecting out of the slurry come into contact with an endless, continuously moving felt belt. This felt takes up the fibres and the adhering cement particles to form a thin layer of randomly oriented fibres. The still moist fibre layer is transported on the rotating transport belt, has a water reduced by a suction system and is then transferred to a forming roller. This process continues until the required thickness is achieved
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classification according to volume fraction low volume fraction (<1%)
The fibers are used to reduce shrinkage cracking. These fibers are used in slabs and pavements that have large exposed surface leading to high shrinkage crack. Disperse fibers offer various advantages of steel bars and wiremesh to reduce shrinkage cracks: â&#x20AC;&#x201C; (a) the fibers are uniformly distributed in three-dimensions making an efficient load distribution; â&#x20AC;&#x201C; (b) the fibers are less sensitive to corrosion than the reinforcing steel bars, â&#x20AC;&#x201C; (c) the fibers can reduce the labor cost of placing the bars and wiremesh.
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moderate volume fraction (between 1% and 2%) high volume fraction (greater than 2%)
The presence of fibers at this volume fraction increase the modulus of rupture, fracture toughness, and impact resistance. These composite are used in construction methods such as shotcrete and in structures that require energy absorption capability, improved capacity against delamination, spalling, and fatigue.
The fibers used at this level lead to strain hardening of the composites. Because of this improved behavior, these composites are often referred as high-performance fiber-reinforced composites (HPFRC). In the last decade, even better composites were developed and are referred as ultra-high-performance fiber reinforced concretes (UHPFRC).
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mechanism
The composite will carry increasing loads after the first cracking of the matrix if the pull-out resistance of the fibers at the first crack is greater than the load at first cracking; At the cracked section, the matrix does not resist any tension and the fibers carry the entire load taken by the composite. With an increasing load on the composite, the fibers will tend to transfer the additional stress to the matrix through bond stresses. This process of multiple cracking will continue until either fibers fail or the accumulated local debonding will lead to fiber pull-out .
According to the report by ACI Committee 554 the total energy absorbed in fiber debonding as measured by the area under the load-deflection curve before complete separation of a beam is at least 10 to 40 times higher for fiberreinforced concrete than for plain concrete.
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fibers
fiber size To bridge the large number of microcracks in the composite under load and to avoid large strain localization it is necessary to have a large number of short fibers. The uniform distribution of short fibers can increase the strength and ductility of the composite. Long fibers are needed to bridge discrete macrocracks at higher loads; however the volume fraction of long fibers can be much smaller than the volume fraction of short fibers. The presence of long fibers significantly reduces the workability of the mix.
microcrack macrocrack
steel fibers
When well compacted and cured, concretes containing steel fibers seem to possess excellent durability as long as fibers remain protected by the cement paste. In most environments, especially those containing chloride, surface rusting is inevitable but the fibers in the interior usually remain uncorroded. Long-term tests of steel-fiber concrete durability at the Battelle Laboratories in Columbus, Ohio, showed minimum corrosion of fibers and no adverse effect after 7 years of exposure to deicing salt
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glass fibers Ordinary glass fiber cannot be used in portland cement mortars or concretes because of chemical attack by the alkaline cement paste. Zirconia and other alkali-resistant glass fibers possess better durability to alkaline environments, but even these are reported to show a gradual deterioration with time. Similarly, most natural fibers, such as cotton and wool, and many synthetic polymers suffer from lack of durability to the alkaline environment of the portland cement paste.
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types of frc compact reinforced composites (cpc) Researchers in Denmark created Compact Reinforced Composites using metal fibers, 6 mm long and 0.15 mm in diameter, and volume fractions in the range of 5 to 10 %. High frequency vibration is needed to obtain adequate compaction. These short fibers increase the tensile strength and toughness of the material. The increase of strength is greater than the increase in ductility, therefore the structural design of large beams and slabs requires that a higher amount of reinforcing bars be used to take advantage of the composite. The short fibers are an efficient mechanism of crack control around the reinforcing bars. The final cost of the structure will be much higher than if the structure would be made by traditional methods, therefore the use of compact reinforced composites is mainly justified when the structure requires special behavior, such as high impact resistance or very high mechanical properties
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slurry-infiltrated-fibered concrete (SIFCON) The processing of this composite consists in placing the fibers in a formwork and then infiltrating a high w/c ratio mortar slurry to coat the fibers. Compressive and tensile strengths up to 120 MPa and 40 MPa, respectively have been obtained. Modulus of rupture up 90 MPa and shear strength up to 28 MPa have been also reported. In direct tension along the direction of the fibers, the material shows a very ductile response. This composite has been used in pavements slabs, and repair
reactive powder concrete (RPC) Investigators in France by adding metal fibers, 13 mm long and 0.15 mm in diameter, with a maximum volume fraction of 2.5%. This composite uses fibers that are twice as long as the compact reinforced composites therefore, because of workability limitations, cannot incorporate the same volume fraction of fibers. The smaller volume fraction results in a smaller increase in the tensile strength of the concrete. Commercial versions of this product have further improved the strength of the matrix, chemically treated the surface of the fiber, and added microfibers.
multiscale-scale fiber-reinforced (MSFRC) Researchers the Laboratoire Central des Ponts et Chaussees (France) proposed to combine short and long fibers to increase the tensile strength, the bearing capacity, and the ductility). With this blend, good workability was achieved with fiber volume fractions up to 7%. One typical combination of fibers is 5% straight drawn steel fibers, 5-mm long and 0.25 mm in diameter, and 2% hooked-end drawn steel fibers, 25-mm long and 0.3 mm in diameter.
engineered cementitious composite (EEC) The ultra high-ductility of this composite, 3-7%, was obtained by optimizing the interactions between fiber, matrix and its interface. Mathematical models were developed so that a small volume fraction of 2% was able to provide the large ductility. The material has a very high stain capacity and toughness and controlled crack propagation The manufacturing of ECC can be done by normal casting or by extrusion. By using an optimum amount of superplasticizer and non-ionic polymer with steric action, it was possible to obtain self-compacting casting. 12
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fibre C by rieder
The glassfibreconcrete panels fibreC are large-format thin concrete panels, reinforced throughout their thickness with glass and are designed for the cladding facades of buildings, and for interior decoration. The fibre-reinforced concrete panels fibreC successfully combine strength, formability, fire resistance, light weight and the authentic appearance of concrete. Fibrous concrete and its production technology have been well known for over 30 years. This material is used mainly for architectural decoration and special design solutions. The dispersion interaction of concrete and glass greatly increases the strength of the material throughout the reinforcement area. The glassfibreconcrete panels fibreC divided into: facade concrete panels; interior concrete panels; concrete siding; shaped concrete elements; small architectural forms; items Glassfibreconcrete panels fibreC are large canvases and calibrated with a flat geometry, which is achieved by over a 4-week production cycle. The technology of production of concrete panels fibreC implies, first of all, a batch of the correct colour, and then its placement in a special form with liquid concrete and six layers of fibreglass, of which the four middle layers are woven into a network, while the remaining two are placed in random order. After a 28-day production cycle of hardening the fibre-reinforced concrete by surface treatment and additional boards, including water-repellence treatment, the panels gain water-repellent properties. Each concrete panel fibreC always has an individual character due to a combination of different shades of colour and texture, such as thin strips, smooth shades, small dents, surface cracks and pores. Panels Fibre C are concrete, nothing more and nothing less. 13
Glassfibreconcrete panels have a fibre thickness of 8, 10, 13 mm and are available in formats of 1200x2500 and 1200x3600 mm when installing the panels using the technology of ventilated facades. The concrete panels fibreC are a non-combustible material. They have successfully passed fire tests in Russia and are guaranteed against fires at temperatures up to 350 째 C. Fiber-reinforced concrete panels fibreC are distinguished by: strength and durability lightweight, high fire-resistant properties, resistance to dynamic and climatic influences, frost resistance, a wide range of colours, a variety of options for the surface an individual look.
greenness Rieder has been certified according to ISO 9001 and ISO 14001. The large number of our patents, tests and certificates underscore the enormous innovative force and technical progress of our company and guarantee the safety and reliability of our products. All our products undergo multi-stage testing in accordance with international standards (e.g. EN 12467) to ensure the highest product quality. Apart from standardised testing procedures we underscore our high demands on quality through a close co-operation with architects and suppliers, who are integrated into our quality management system. Definition of variation in quality according to the DIN 18202 standard. 14
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[c] space pavilion by alan dempsey and alvin huang
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The pavilion was is the winning submission for competition hosted by AAâ&#x20AC;&#x2122;s Design Research Labratory. It called for the use of Fibre C. The basis of the competition was constructability within a tight schedule and budget, simplicity and elegant form, effective use of material, pavilion as a continuous extension of furniture to roof structure.
joint detail
winning submission
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fibre C-special fibreC is a high-strength, thin, flexible and mouldable material and can be used for flat, curved and all kinds of special shapes. Owing to the unparalleled mouldability of glassfibreConcrete panels, its unrivalled slenderness and the entire production system as such, fibreC can be used for the most extraordinary applications. The formation of closed corners and curves in one continuous piece and with uniform robustness opens up new perspectives for wall construction and interior design. Formed parts and 2D elements are custom-made to achieve flowing transitions from interior to exterior surfaces and a smoothcovering for edges.
references http://www.ce.berkeley.edu/~paulmont/241/fibers.pdf http://www.profasad.com/fibre-c/ http://cspacepavilion.blogspot.com/
Standard 2500/1200 mm and 3600/1200 mm Size on request Special sizes EN 12467 Dimensional variation length (3.6 m) ± 3 mm ± 2 mm EN 12467 Dimensional variation width (1.2 m) DIN 18202 Diagonal difference up to | over 1.5 m ± 3,5 mm| ± 4 mm DIN 18202 Diagonal difference over 2.5 m | 3.6 m± 5 mm| ± 6 mm Thickness Thickness tolerance Edge straightness (Level 1) Perpendicularity (Level 1)
13 mm ± 1,3 mm ± 0,05 % ± 2 mm/m
EN 12467 EN 12467 EN 12467
Physical characteristics ± 2 mm | ± 4 mm Tolerances facing up to 0.6 | 1.2 m ± 8 mm Tolerances facing up to 3.6 m 0,384 mm/m Swelling 0,737 mm/m Shrinkage 3 2,0 - 2,42 kg/dm Bulk density > 18,5 N/mm² (MOR) Bending tensile strength approx.10.000 N/mm² Elastic modulus Dead load / Mass per unit area (13 mm)26 - 31,5 kg/m² 10*10^(-6) 1/˚ k A1 - incombustible Building material class according to humidity up to 350˚ Temperature stability approx. 1.000 Joule / (kg * K) Conductivity lambda: ca. 2,0 W / (m * K) Weather-resistance Water impermeability Heat-rain-alternate test Frost resistance Frost-defrost-alternate test UV-light resistance Hot water resistance Wet storage resistance
given given given given light-, UV-colour pigments given given
Fastening visible Fastening not visible Substructure Joint width
rivets adhesive,undercut anchor aluminium, steel min. 8 mm
DIN 18202 DIN 18202
EN 12467, Category 4
DIN 51045 DIN 4102| EN 13501
EN 12467 EN 12467 EN 12467 EN 12467 DIN 12878 EN 12467 EN 12467
Reinforcement Edge formation ** MOR: Modus of Rupture; Design values deviate from MOR in accordance with national rules an regulations. National approvals, rules and regulations apply to the calculation of the rated resistance
Colours Polar White Ivory Silvergrey Anthracite Liquide Black
Surfaces Sahara Sandstone Terra Terracotta Venice Green
MA brushed / smooth surface, natural blushing effect FE sandblasted: blasted at higher pressure, surface is rougher FL sandblast Assembling and Weather Protection Hydrophobicity
Colour, Design & Surface ness for purpose of the panels, are permitted. EN 12467 / Data sheet Exposed concrete 02/2004 [Publisher.:BDZ/DB
* Subject to the particular quotation documentation. The information contained in this document and the technical description of product characteristics and the technical instructions for their use should not be interpreted as a contr commitment on the part of the manufacturers. Despite careful inspection, no liability can be accepted for the correctness, completeness and topicality of the document. This is par
04/2012
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a_00bc In the past in order to create curved concrete surfaces, individual molds would have had to been made. This was time consuming and costly. With the advent of 3-D cad design, a better method would have to arise
Flexible form work, specifically pin molds are advantageous for their reusability. Its cost effective when compared to creating individual molds for complex facades or systems.
The idea of flexible form work goes back to Renzo Piano in the 60â&#x20AC;&#x2122;s. He made the concept drawing to the right which has adjustable pins and a flexible material on top to hold the form.
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movable molds research
single curved mold local displacement
mold is too flexible
mold is too stiff
One issue that quickly arises from pin mold is that one has to use previously poured and slightly cured concrete sheets. However timing is key since if it is too stiff, cracks can from and it may not settle completely into the desired shape. If the slab is too fresh it runs the risk of the concrete slumping and getting displaced and also not remaining smooth with the pins. A a is
simple experiment to figuer out proper mixture and precure time to do a single curved panel.
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double curved mold
There are two possible options for a double curved surface, a plate model and strip model.
The best option though is the strip model since in allows for greater flexiblity without buckling from the plate.
A frame held the supports at a horizontal level, to pour the concrete at. This frame could be lowered with a crane to deform the mould.Foam, polyether, was used as a border for the formwork. It fulfilled the function of withstanding the horizontal concrete pressure, but it was also flexible enough to follow the deformations of the mould.
1. t = 0 min. The mould is ready for the concrete. The mould is horizontal and rests on a plate which is temporary supported. At t = 0 adding water to the mixture, start hardening of the concrete. 2. t = 8 min. Pouring the concrete into the mould. 3. t = 15 min. Smoothening of the fresh concrete. 4. t = 49 min. Lifting the formwork to be able to remove the temporary struts. 5. t = 47 min. Deforming of the mould. 6. t = 48 min. The end of deformation process. The element has the final shape. 7. t = 1 day After one day of hardening the element is removed from the mould. 8. t = 1 day The element above its mould. 9. t = 1 day The final element on the supporting points.
22 for more information and in depth testing of mixures and the processes visit: http://homepage.tudelft.nl/6w3a0/FlexibleMouldProject.htm
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erwin hauer design #5
Compared to Design 4, the molding of Design 5 involves a few extra steps and additional reinforcement for installations that require high load-bearing capabilities. Due to the comibination of structural simplicity and strength and a highly effective interaction with light.
development process
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plan side elevation
front elevation
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b_01 _rotated views
_section
rotated + mirrored
_assembly
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b_01 I was interested in creating a component that would allow for flexibility. I apporached the human spine and designed an interlocking linear componet with tolleraces allowed for subtle pivoting.
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b_02 base design
scale 1’:1”
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b_03 I cut out an inverted pyramid from the center of each faceted component. each pyramid a different height as to allow for variation in aperture.
connection
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team 4
section
assembly_side
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assembly_front
assembly_perspective
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fall 2013