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.

Universitat de València building. Spain.

Most architectural concrete solutions use to be conceived by the same architect who authors the whole project. However, even the most familiar with industrialization need to be assisted by other specialists to define precast elements with proper detail and sound production costs.

Architectonic Concrete, S.L, assisted the architect for this particular precast project and helped the most suitable precaster for the achievement.

The natural trend for precasters is to solve the explode and modulation of façades, with elements the most extensive the better, that usually reducing cost of the fixing systems and time of assembly, generally that involving lesser manpower required, in the erection site too.
Very volumetric precast of big size, as this case is, require to master moulds technology to a great extend. Moulds quality is a must for elements like these, with non co-planar exposed surfaces, bevels, etc...

This architectural sollution is mainly for sunlight breaking, as a kind of curtain-wall, detached in front of the glass cladding, to drive lower sunlight of winter, according to building's lattitude 40º North.

The assembly ratio was an average of 8 to 9 elements /day fully anchored, by a team of three assemblers plus the crane operator.

All anchors are bolted, Hilti and Halfen-like. Concrete for the elements is white cement based, white aggregates, reinforced according to the highest loads for the elements to sustain: while in demoulding phase.