CI/SfB. (Ff2) June 2007 CIVIL E NGINEERING PRODUCTS STEPOC SYSTEM. innovators in masonry

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1 CI/SfB (Ff2) June 2007 CIVIL E NGINEERING PRODUCTS STEPOC SYSTEM innovators in masonry

2 STEPOC SYSTEM THE FASTER, MORE E CONOMICAL WAY TO BUILD WALLS WITH EXCEPTIONAL STRENGTH Stepoc is a system of highly-engineered and dimensionally co-ordinated building modules which are designed to readily accept horizontal reinforcement for use where structural performance is the prime consideration. Stepoc combines the ease of blockwork with the versatility of in-situ concrete, and yet is faster to apply than both, making it an ideal component in fast-track construction for: Retaining walls Sheer wall Laterally-loaded panels Blast panels Bund walls Basement walls and any applications that require higher compressive or lateral loads than those achievable with standard masonry. The standard Stepoc system is available in two widths 190mm and 256mm and comprises four units a full length and a third length standard block and a full length and third length plain end block for use at corners and ends of walls. Built dry, with no mortar joint, and requiring no special on-site skills or techniques, as each unit weighs less than 20 kgs, the blocks are laid to a running bond, in a combination of third and full lengths. Corners, T-junctions and cross junctions are created using a combination of all four units and specific data sheets are available to illustrate these. FULL LENGTH BLOCK 1/3 LENGTH BLOCK FULL LENGTH PLAIN END 1/3 LENGTH PLAIN END

3 LAYING STEPOC IS FAST AND EASY When casting the foundation, vertical reinforcing bars may be positioned, as appropriate thereof. Data sheets are available for details at corners, stop ends etc. Check that the base is level Lay the first course, bedding in mortar to a stretched line. Walls should generally start at a corner with the open ends of the block running towards the centre of the wall. The open ends of the blocks should engage the ribbed full end of the adjacent block Position horizontal reinforcement to engineer s requirements. Stack blocks dry to a 1 / 3 rd or 1 / 2 running bond, depending on the block chosen, and to a height not exceeding 2.25m before the first pour. Check vertical faces for plumb on completion of alternate courses. 7 Pump in concrete, directing the hose along the block in order to reduce the risk of displacing the units. To allow initial setting, 24 hours should elapse between infills of concrete. Concrete should finish 50-75mm below the top of the block to provide a key for subsequent courses..

4 DESIGNING WITH STEPOC Strength Tests undertaken by Ceram Research yielded high values for characteristic compressive strength (fk) for Stepoc walls. The 256mm Stepoc achieved an fk of 18N/mm 2 and 190mm Stepoc achieved 14N/mm 2. Pending test data, the 325 Basement Block has been conservatively assumed to have the same value of fk as 256 Stepoc. For axially loaded stocky walls not subject to the effects of buckling, the 256mm Stepoc wall provides a higher vertical load resistance than a 3mm wall constructed from standard format bricks, with a compressive strength of 70 N/mm 2, laid in a class III mortar in accordance with BS 56: Part 1: Similarly, 190mm Stepoc provides a higher vertical load resistance than a 215mm wall constructed from standard format brickwork, with a compressive strength of 50 N/mm 2 laid in class III mortar. Design Chart This chart is intended to display the range of strengths attainable when Stepoc walls are designed in accordance with BS 56 Code of Practice for Use of Masonry The design loads referred to are at ultimate limit state, i.e. factored. For unreinforced Stepoc, a partial safety factor of 3.1 for material strength should be used, to account for the special category of manufacturing control operated by Forticrete. For reinforced Stepoc, the partial factor of safety should be taken as 2 and 1.15 for steel in accordance with part 2 of the masonry code and Forticrete s quality control procedures. Example Stepoc strength bending from lateral load By reference to the laterally loaded wall chart, to sustain a bending moment of 55kNm, 1250mm 2 /m of high yield vertical reinforcement is required within the voids of 256mm Stepoc. From the reinforcement table, it can be seen that this is easily provided by T16 bars at 1mm c/c. Design Moment KNM per metre (factored) Laterally Loaded Wall (reinforced) Max Moment knm STEPOC WALL Max Moment 68.5 knm STEPOC WALL Max Moment 30.5 knm STEPOC WALL Area of high yield reinforcement (mm2/m) Area of reinforcement (mm 2 /m) for various bar diameters to coincide with void pattern Bar Bar centres diameter 1mm 162mm 266mm 325mm 399mm Bar Centres for 190 & 256 Stepoc Bar Centres for 325 Basement Block NB The use of this chart is intended for guidance only at a preliminary stage. A full design check should be undertaken by the designer in accordance with BS 56: part 2: 1995 Structural use of Reinforced and Pre-stressed Masonry, accounting for ultimate and serviceability limit states as required.

5 325 BASEMENT BLOCK The new 325 Basement Block enables the fast construction of single skin retaining walls up to 3.8 metres high and, at 325mm wide, it is dimensioned to carry 2 x 100mm leaves plus insulation and cavity. Available in full length; half-length and plain end/corner units, 325 Basement Block is laid to half running bond and yet retains all the smooth filling benefits of the traditional system. 325 Basement Block s unique design enables horizontal reinforcement to be placed adjacent to either block face, or both if required, to ensure that maximum strength is achieved just where it s needed. And, at less than 20kg, each 325 Basement Block is well within the HSE guidelines for a single man repetitive lift. Proven in use on applications the length and breadth of the UK, this is a truly Modern Method of Construction. CONCRETE INFILL & SPECIFICATION Stepoc is bonded with concrete, which is poured down through the inter connected cavities in the blocks. The blocks unique design creates a cascade or waterfall filling effect which ensures a smooth filling of the poured concrete, forcing out air and eliminating segregation, to create walls which have immense compressive and lateral strength. The concrete should possess the characteristic strength specified by the structural engineer, but not less than 35N/mm 2, and in accordance with BS EN 206 Part 1:2000. It should be designed to be suitable for the specific means of delivery to be used, possessing a slump of no less than 150mm. The maximum aggregate size should not exceed 10mm and the mix should contain no less than 300kg of Ordinary Portland Cement per cubic metre of fresh concrete. Filling is best accomplished by a concrete pump or a skip with a flexible hose attached. Alternative methods to pumping may be used, provided that the fresh concrete can flow in a similar manner to pumped concrete and that the method of transportation and placing does not incur an additional risk to the stability of the wall. Mechanical vibration is unnecessary, and should not be used. CONCRETE INFILL Stepoc Block 190mm = 0.11 m 3 per m 2 of wall Stepoc Block 256mm = 0.15 m 3 per m 2 of wall Basement Block 325mm = 0.19 m 3 per m 2 of wall 325 FULL LENGTH BLOCK 325 1/2 LENGTH BLOCK 325 FULL LENGTH PLAIN END

6 SPECIFICATIONS TYPE COMPOSITION AND MANUFACTURE Forticrete Stepoc blocks are manufactured to fine tolerances using aggregates which satisfy BS 882 and cement to BS12. They are manufactured at a plant which is registered under the BSI Registered Firms Scheme, a third party quality assurance scheme based on BS EN ISO 9001:2000. DIMENSIONS Forticrete Stepoc blocks are available in three standard sizes: 400 x 225 x 190mm 400 x 225 x 256mm 325 x 225 x 325mm TYPICAL WEIGHTS Stepoc Block 190mm = 16.5kg Stepoc Block 256mm = 19.8kg Basement Block 325mm = 19.8kg MANUFACTURING TOLERANCES Height: +2, -2 Length: +2, -2 Width: +2, -2 Fire Resistance Minimum fire resistance: 2 hours. For specific applications refer to BS 8110 Part Agrément Approval The British Board of Agrément has approved Stepoc for use as set out in Agrément Certificate No. 98/3450. Resistance to Frost Damage The Stepoc system is resistant to the freeze-thaw conditions that are likely to occur below a damp proof course. Resistance to Sulphate Attack Stepoc has adequate resistance to Class 3 sulphate ground conditions. SALES ENQUIRIES Forticrete Ltd, Hillhead Quarry, Harpur Hill, Buxton, Derbyshire SK17 9PS Tel: Fax: engsales@forticrete.com Information or advice can also be obtained using the Forticrete Technical Hotline: FREEPHONE: or by to technical@forticrete.com Information on the complete range of Forticrete products can be found on the Internet at FM x 225 x 190 standard TYPE x 225 x 256 standard 325 BASEMENT BLOCK Forticrete Ltd FORTICRETE is a registered trademark of Forticrete Ltd. CRH is a registered trademark of CRH plc. Innovators in masonry is a trademark of Forticrete Ltd / / /245 35/40 125/ / /112 Delivery and Offloading Stepoc blocks are supplied on pallets for offloading by forklift truck or crane. Blocks should be stored on reasonably dry, firm, level ground with protection from rain and snow. If blocks are accidentally wetted, provision should be made for free circulation of air round the stack so that the units may dry out prior to being used. Blocks should not be stacked directly on sulphate-bearing ground, clinker or ashes, unless precautions are taken to prevent chemicals being drawn into them by rising moisture, nor should they be stacked on newly-cast slabs until the concrete is fully matured. Mechanical handling should not be used after the blocks have been offloaded from the wooden pallet x 225 x 190 1/3 length x 225 x 256 1/3 length 325 x 225 x 325 standard 162 x 225 x 325 1/2 length EMS The information contained within this publication is as accurate as possible at the time of going to press. However, this document does not form part of any contract and Forticrete cannot accept liability for any errors or omissions. In order to maintain its position as a market leader, Forticrete operates a policy of continuous product development and therefore reserves the right to alter specifications without notice. innovators in masonry