Locrete Building System: the Technology Handbook 1
3... Introduction 4... Characteristics 6... Locrete Production 8... Locrete Testing 12... Building with Locrete 16... Shuttering System 13... External Walls 19... Internal Partitions 20... Slabs 23... Adaptability for Expansion 24... Service Installation 25... Photo Gallery 2 CONTENTS
Locrete is an innovative patent protected building system for constructing walls and structural slabs. It consists of precast, prestressed concrete elements that have a unified cross section and variable lengths and can span up to six metres. Locrete is intended for various applications in the construction industry ranging from small developments to social housing projects. The system provides a substantial improvement in quality of structure as well as major savings in construction cost, time, equipment and labour. Particular characteristics make Locrete a preferred solution, especially for projects with repetitive nature and modular form. The prestressed Locrete element is the basic building block of this system. It is used in constructing ground beams, insulated external walls, internal partitions and slabs. The system has proven advantages in the construction of boundary walls, retaining walls, hard landscape, highway noise barriers and road barriers. Its applications are various and limited only by the client's imagination. Locrete is currently expanding its global reach through the construction of production facilities where the system advantages can be optimised and where its simple method of application can be best used and developed. 3 Introduction
Locrete elements are machine cast, compacted concrete reinforced with prestressed steel wires or strands. The element is designed with a fixed cross sectional dimension and form to allow construction of walls and slabs efficiently and economically, maintaining international and national building codes with superior quality, less cost, time and complexity. The maximum useful length of the element is six metres. The weight of the element is 10kg per metre length. This allows human handling during construction. Concrete strength in the fully cured element is around 50 MPa. The industrialized production of Locrete allows: Virtually limitless configuration of plans and spaces Volumes & Areas Area of cross section is 42.5 cm 2 Volume of a square metre of Locrete in slab is 0.0563 m 3 Elements weigh 10.5 kg per metre Accurate calculation of prices Easy and repetitive structural analysis for the ground beams, walls, suspended beams and slabs Preparation of construction drawings with ease through minimising architectural, structural and services details. 4 General Characteristics
Locrete is easy to handle, transport and construct without the use of heavy equipment and with a minimal use of formwork material. It introduces technical benefits in terms of durability, structural sturdiness and the ability to perform better in terms of fire resistance, heat, water and noise insulation. Locrete homes are energy efficient and practially soundproof. They are environmentally responsible, will not rot or rust and require low maintenance and fewer repairs. It provides the best shelter against the elements. The practical and technical advantages of Locrete are provided with a substantial reduction in cost compared to other systems used in the market. Advantages of Locrete Sustainability: minimal maintenance and use of long life material. Affordability: reduction of labour and equipment cost and optimized use of material and reduced waste. Availability: made of commonly available material. Constructability: simplification of construction methods and standardization of technology. 5 General Characteristics
Production process is characterised by: Automation of production is a function of the capital value, to be invested in the factory machinary and equipment. Locrete elements are produced in steel pallets, with each pallet able to produce up to 34 sqm per casting. Up to 54 pallets of Locrete elements can be produced in 8-9 hours of work. Annual production can be doubled if double shift work system is adopted. Slab elements are reinforced with 7.94 mm strands, with wall elements are reinforced with 5 mm wires. Slab elements are reinforced with 7.94 mm strands, with wall elements are reinforced with 5 mm wires. Thermal curing rooms are part of the production line. The pallets are stacked in curing rooms by means of a specially designed and fabricated lifting overhead crane. The pallets are lifted from the curing rooms and placed in lines for de-tensioning and emptying. The elements are emptied from the pallets by labour force. Bundles of Locrete elements are compiled and strapped for easy transportation to construction sites. Post emptying the pallets are cleaned and oiled and recharged with the plastic dividers and the strands or wires for re-concreting. Components of a typical production facility include: Batching and mixing plant (30 m3 / hour) 54 pallets Pedestals and pallets pushing motors Casting and concrete vibration equipment Overhead lifting cranes Curing rooms Tensioning and de-tensioning jacks and clamps Locrete elements handling, lifting and loading 6 Locrete Production
8 Production Facility
A solid slab at six metres span can take up to 250kg dead load and 250kg live load, apart from its own weight. Load bearing tests Tests conducted by VTT of Finland, Labortech of Italy and the Kuwait Institue for Scientific Research found Locrete to be compliant with ACI code 318. 9 Locrete Testing
The World Federation of Technical Assessment Organisation (WFTAO) identied six essential requirements for fitness for intended use of construction products: Mechanical resistance and stability Safety, in case of fire Non-threat to hygiene, health and environment Safety in use Protection against noise Locrete is made of concrete, which is: Easily and economically produced for different purposes and to fulfil specified classifications concerning fire-resistance. Durable, exceeding the durability of most other common building materials without requiring additional surface treatment. Highly resistant to moisture and other weather conditions and does not corrode or decay, thus reducing overall maintenance costs. Capable of storing heat which, in turn, helps reduce energy consumption and provides a comfortable indoor climate. This helps insulate building environments from fluctuations in outdoor temperatures. Offers good sound insulation properties. This property finds increased application in certain specialised structures (i.e. highway noise barriers). 10 Locrete Testing
Load bearing capacity as a function of span and topping thickness. 11 Structural Results
12 Building with Locrete
Wall elements are fitted into a pre-fabricated steel shuttering system which forms the caston-site columns. Each column is fitted with the structurally required reinforcement. The walls are built in two planes with 5 cm thick insulation panels fitted into the cavity. After the construction of the walls to the levels specified in the drawings the columns are then concreted and left to dry with the result being a load bearing wall with rigid connections at the column points. The shuttering system is fabricated by the builder according to the design specifications. The specially designed shuttering system for Locrete columns allows for the wall elements, internally and externally, to be constructed to the required heights prior to casting the columns. If building a double wall, 5 cm insulation material in the cavity is enough to meet the heat insulation and energy saving requirements of the construction. This layer can be increased to any thickness to meet required standards of energy saving. Pictured is a section of a Locrete structure with shuttering system still in place. 13 Shuttering System
Locrete suspended beams are formed by keeping the central panel independent from the corner columns of the shutter. The custom designed shuttering system for Locrete columns allows the construction of the external and internal walls to the required heights prior to casting the columns. The reinforced concrete columns, once cast, will permanently and rigidly hold the wall elements in position. The inner shutter elements are levelled to the suspended slab level. 14 Shuttering System
Strands of Locrete elements overlap with the column reinforcement which enhances the rigidity of hinging Locrete wall elements with the column. The inner shutter elements are levelled to the suspended slab level. Once the reinforced columns are cast permanently, and the shuttering removed, the resulting columns form a rigid hold cementing the wall elements in position. The Locrete system requires the vertical shuttering of the columns only. This allows for designing a flexible and user friendly shutter system that has various applications. Investment in a shuttering system is mandatory but is offset considering the savings in environmental impact, cost of shuttering material, shutter installation, time and effort. 15 Shuttering System
Locrete walls are constructed by stacking cut-to-length Locrete elements that are delivered with the wire strand extending 5-10 cm on each end. Door and window openings are accounted for during the production process and the Locrete elements that are delivered are already cut to size and ready for installation. There should be no need to cut Locrete elements on site except for odd shapes or for post-construction modifications. Door and window openings can be framed with precast concrete panels, marble, plastered in frame or as part of internal and/or external wall plastering. Cantilevered slabs are also possible using the Locrete system. 16 Exterior Walls
Locrete elements can be cut on-site with a hand tool. The elements on exterior plane of the double wall - or single wall with a beam - can be cut at the existing slab level to allow resting new slab elements for expansion of the structure. Wall elements can be cut, after casting, to allow modification of partitions and opening of doorways, subject to leaving enough elements at the higher level to support the suspended slab units. Single wall partitions are built along with the exterior walls in the manner previously described. A Locrete beam is introduced to take the loads of the slab elements that are suspended and resting on a single beam. The beams are always filled with reinforced or plain concrete depending on the structural calculations. 17 Exterior Walls
Locrete wall elements span up to six metres. In all cases, the elements must be hinged on at least one end into cast-on-site reinforced concrete columns. Walls have horizontal joints which can be closed by plastering the walls or by placing bituminous lining between consecutive elements or by lining the joint with chemically treated cementation lining mix. 1 cubic metre of concrete renders 15.75 m 2 in single-wall area 1 cubic metre of concrete renders 7.875 m 2 in double-wall area A 1 metre high wall requires 15 elements Sound insulation value (STC rating) is 47 db per square metre 18 Locrete Walls
Internal partitions are mostly a single layer of Locrete elements with a total thickness that does not exceed 80mm. 19 Internal Partitions
Locrete slabs are made by resting the Locrete elements, cut to the required length, on opposite walls or beams. The slab element bundled and lifted to slab level are stacked side by side. Slab elements are best propped up temporarily when spans are 3-6 metres. Minimal thickness reinforcement steel mesh is installed and the services networks are built above the Locrete elements to counter the effect of shrinkage. Bathroom slabs can be lowered in level to allow for the installation of the services. Plain concrete is cast over the Locrete elements to form a structural suspended slab. The load bearing capacity varies according to span and the thickness of the topping layer, amongst other factors. 20 Slabs
Slanted roof with cantilever and flat slabs. Slanted roof with insulation. 21 Slabs
Six metre Locrete slab over six metre Locrete beams. 22 Slabs
The Locrere Building System makes it easy to introduce architectural modifications to existing buildings, including: 1. Adding window openings by simply cutting through the elements to the width between the jointing columns at a suitable height without jeopordizing the integrity of the structure. 2. Extension of the roof slabs in any direction. One way this can be achieved is by diskcutting the outer two elements at the level of the existing slab or any other preferred level to allow supporting the extension elements on the existing wall elements and then casting the concrete topping. 3. Vertical extensions which can be built with minimal effort or destruction to the existing structure. 23 Adaptability for Expansions
Electric conduits are normall flush mounted. Conduit routes in internal partitions are chased out by cutting with a concrete-cutting disk mounted on a hand tool. Pipes are installed in the external wall cavity of the double walls. Service conduits are installed simultaneously with the construction of walls. In slabs, networks are installed prior to casting the plain concrete topping. 24 Service Installation
Proposed design for an hospital in The Comoros 25 Photo Gallery
Private housing project in Iraq. 27 Photo Gallery
Proposed design for a water resorvoir. 28 Photo Gallery
30 Photo Gallery
31 Photo Gallery
Highway barrier. 32 Photo Gallery
34 Photo Gallery