LIGHT GFRC FAÇADES CLADDING FOR THE CARREFOUR MALL OF BOGOTÁ.

The Project Management of the spanish firm Architectonic Concrete, S.L., for this project can be summarized as:

1.- Previous definition of cladding panels adapted to the architectural project.

2.- Supervision of the manufacturing and assembly budget study for definite budget making with local parameters.

3.- Definition and making of the first panel as a prototype, which was initially intended as 1,20 m. width, and nerved totally with GFRC, therefore saving the iron stud-frame.

With technical assistance of Francisco X. Regas in the Bogotá precast plant.

4.- Texturing of the prototypes by sand-blasting.

5.-With Architectonic Concrete S.L. advice, it is finally decided to manufacture the series panels in 2,40m. width, doubled than originally, variable heights and stud-frame reinforcement sollution.

Thus, halve the total panels ammount and speeding the rate of assembly.

Prices are then re-calculated by our precast client and he agrees on a rigourous assembly calendar.

6.- A strenght test is advised and done over a prototype panel skin, overloading it with water, up to 200 kg/m2, thus forcing large deformation but not appearing any fissuration on the panel skin, in spite of that load.

7.- Precast manufacturing of the panels run at 100 sq. m. /day, and façade assembly at the same rate.

With assembly tecnical assistance of “Architectonic Concrete, S.L.” at the woksite.

8.- The assembly advances in a synchroniced process, due to high speed required cycles: sooner free cranes by holding panels provisionally, then anchor panels permanent while crane comes loaded again.

9.- Cladding of the façades progress, untill full termination of its 5.000 sq. m. project.

GFRC-Studframe cladding for a Cartagena de Indias cement plant.

The new plant of the colombian cement manufacturer ARGOS is located next to the shore, in the Cartagena de Indias bay, that is surrounded by nice landscapes.

The tallest element of the plant, the preheater, has been cladded with precast GFRC pannels, understood GFRC is glassfiber reinforced concrete.

Architectonic Concrete, S.L. has provided technical assesment to all the main stakeholders and steps for this particular cladding sollution to be done: the plant owner, architects, precaster, and the assembling teams; about cost and schedule, detail definition of the elements, anchorage systems, precast manufacturing quality, and assembly proceeds.

The architects entitled for design wished this ventilated façade to resemble the shape of a modern sail, to evocate the discoverer Columbus, after who the plant itself is named.

These precast pannels are conformed as GFRC shells, half an inch thick, which are connected flexibly, to an extend, through embeds to an iron studframe, sized to each shell.

The whole element (shell + studframe) weights around 45 Kg./m2.

Diedral main face.

Diedral side face.

The total cladding is a by-faced diedral, forming a sharp edge to give a perception of volume and hide the panels back-face as well.

The average pannel size is about 6 m2 and for the total closure it is 3.000 m2.

Elevation means for all the elements was through a winch placed on ground. The heaviest pannels to lift were of 400 kg.

In order to reduce the façades exposure to pollution of the surrounding atmosphere, the pannels where coated with silicate pigments.

Also wind loads at 40 m/s. speed where integrated, while in design fase, as a potential stress to the elements.

GFRC-Studframe cladding for the Argos plant. Constructive details.

This image shows the back face of a pannel, while stocked, (it is 90º counter-clock when mounted).

Detail is an anchor plate serving the union with the "L" bracket support to the façade structure.

The iron studframe is calculated to sustain the stress due the wind loads, it is joined to the back of the GFRC shells (15 mm. thick), through L iron rods, embeded in the GFRC shell during the precast process.

This method for GFRC cladding pannel manufacturing was first introduced in USA, some 30 years ago, being a wordlwide standard now.

Bending and tensile resistance of this GFRC is higher than 10 Mpa (about 1.500 psi) at 24 h, thus allowing the whole precast pannel to demould next day without damage.

Pannels are fixed to the auxiliary structure of the building, through bolted unions, each comprising bottom to sustain self load and top to avoid tilt. That also makes pannel pre-positioning easier.

The back face of the whole cladding remain allways accessible to the maintenance services of the building.

Modular precast housing.

It is a single floor housing contruction system, 100% precasted and terminated before place.

Each module have a 30 m2 living surface, and is made of two elements, each comprising a base concrete slab and GFRC for the cladding and roof.

A whole element, even including a kitchen and bathroom is about 8 tones weight, that is possible due to the lattice of the base slab, and GFRC to be a foam cored sandwich.

GFRC sandwich makes also a great thermal and acoustic insulation.

This image shows the handling of a whole element, through four fixings in the base slab.

Elements where sized to fit regular truck platforms, so a single trip may carry two elements in most cases.

Being GFRC an easily mouldable material, façades and roof may be shaped as will, with innings and extrusions,if proper moulds.

As an example of that, the façade protruding seen in the images is an embeded cabinet.

Module roofing drains through a tube inside the GFRC cladding.

All of the modules GFRC can be painted with silicates, at factory, before delivery. Thus extending even more long-term durability.

The element inside shown in the image contains door and windows allready.


This constructive industrialized system gives room to plenty of architects creativity, since it allows infinite combinations of volumes, shapes and modularity, while to urbanize large compounds too.

Our engineering assist precasters, constructors, promoters, but specially architects, to obtain the highest quality at the lowest cost for these kind of industriallized sollutions, anywhere.

Big sized vertical flaps for façade. Tordera, Barcelona.

These precast "flaps" are 7 m. long, 50 cm. wide, and 5 cm. thick, weighting 440 kg. each.

They've been manufactured with suitable iron anchors and plates embeded on, to connect to the building's structure.

The element's concrete can be considered as a Ultra High Performance Concrete(UHPC), constituted by cement in much higher dose, silica agreggates, nano-silica, glassfiber, and corrugated iron reinforcement (galvanized).

All the exposed surfaces of the flaps were silica-coated, color as per architect's choice.

In precast sollutions with UHPC concretes, we mind more to increase bending and tensile resistance rather than compressive. For these "flaps", bending-tensile resistance was higher than 5 MPa. at 48 h. and >11 Mpa at 28 days.

As the building is really close to the sea, another very important feature to control for the long term durability of these new concrete flaps is the absortion ratios. That we achieved lower that 0.1 grams / cm2 of exposed surface after submerged 24h. in water.

Self load for each flap hangs mainly from the structural top eave, but additional bottom and half-height fixings ensure the best connection of the flaps to the building structure.

All the fixing solutions of the projetc were bolted, Hilti-like.

First of all, a prototype flap mock-up was mounted in the façade to confirm the fixings solution fitted the service, and learn the optimal mounting sequence. Then the whole precast series entered production.

After the mock-up conclusions, a team of three workers and a technical supervisor sufficed to mount some 20 of these flaps / day, with reliable elevation means (which were rented by daily basis).

Architectural project solutions with precast façade flaps, are getting common nowadays, wordlwide. Their main purpose is to regulate light and shadows income, and aesthetic as well.

Precast flap type elements suffer typically of more fisuration problems, even cracking, than other kinds of elements. Therefore, experience with high resistance concrete is the key issue to ensure a good result, considering long-term durability too.

Precast façade elements for housing projects. Karnataka, India.

Image is for some residential in construction, whose façade cladding is traditional brick laying coated with plaster mortar and painted...

...but the exposed structure, on the left, is a stone-like precast whole corner element, same as that of the ground, yet to be mounted.

The façade project for a series of buildings like this one was to compose traditional masonry together with precast corners and window pannels. That precast was intended granite-like, as cast stone or architectural concrete.

The most practical cladding sequence required to mount the precast elements onto the structure first, so masonry can fill around, way easier.

This way makes structural dimensions tolerance to be higher than that of a 100% precast cladding project, giving room to architects for more freedom to conceive.

However, in many cases, when it comes to the details design for precast, best for them is to rely on engineers advise.

The concrete for this precast was white cement based, slightly mass colored, together with white to beige agreggates.

Exposed surfaces were textured by manual bush-hammering, same treatment common to most natural stones.

Moulds were negatives of GFR polyester, after a wood model for each type of element.

Architectonic Concrete, S.L. assisted the whole precast process untill the first elements where fixed to the structures: from the architect's design fase to the precaster manufacturing of moulds and finished elements, plus qualify the key-worker assembly teams, on the site.

Slabs precast on site, for street channeling closure. Karnataka, India.

Architectonic Concrete, S.L. performed tecnical assessment to all the teams involved in these works, untill these first precast slabs were placed:
to the architects while in design fase, moulds-making process, precast workers and engineers on the site... all local, in northern Karnataka state for a cement manufacturing group, who was the whole task promoter.

First image shows weighting for a precise dossage of pigments and fluidifier.

Mastering self-compacting concrete allows for good precast in the very same erection site, thus eliminating factory and cost of carriage for the terminated elements.

Architect wished a terracotta color for the slabs, which we decided to integrate on the fresh mix, to obtain total color durability under the strong solar exposure in the long run.

Then color was set by mixing white cement dry with 3% w.c. iron oxides, which are fully compatible with the fluidifiers.

Though our concrete mixer was elementary, it sufficed perfectly, since most important is the dossage precision of the fresh mix, speciallly the fillers, and over all: the water ammount.

Slabs demould after 24 hours, only. That concrete is able for 4 Mpa. bending resistance, at that time.

Besides, elevation fixings are embeded in the material, and conected to its inner iron bar reinforcement.

Slabs surface is that of the moulds negative, with slotted diagonals to avoid slipery, when wet.

Right after demould slabs turn up side and place directly in their intended location, for street sidewalk while as a registrable closure of the services gallery to the whole residential urbanization.

This project was inspired by our experience with a similar project of Barcelona (Spain), some 20 years ago, though with a different aesthetics, more granite-like, but similar conception and processes.