How to build a besser block wall - APC
- 1. How to build a Besser Block Wall AUSTRALIAN PAVING CENTRE
- 2. Introduction Preface 2 Introduction 2 1.0 Retaining walls 3 1.1 Designs for reinforced retaining wall types 3 1.2 Loading Conditions 4 1.2.1 Retaining Walls 4 1.3 Material Specifications 4 1.4 Soil Classification 4 1.5 Wall Foundation 4 1.6 Infill Soil and Retained Soil 4 1.7 Drainage Systems 5 1.8 Water Penetration 5 1.9 Exploded View of Construction 5 1.10 How to Build the Wall 6 1.10.1 Preliminary 6 1.10.2 Base and Hob 6 1.10.3 Block Laying 6 1.10.4 Grouting 6 1.11 Tanking 6 1.12 Infill Soil and Drainage 6 1.13 Design Details for Wall Type 1 7 1.13.1 Level Surface Wall Layout 7 1.13.2 Sloping Surface up to 1 in 4 Wall Layout 8 1.13.3 Base and Key Sizes 9 1.13.4 Reinforcement Details 9 1.14 Design Details for Wall Type 2 10 1.14.1 Level Surface Wall Layout 10 1.14.2 Sloping Surface up to 1 in 4 Wall Layout 11 1.14.3 Base and Key Sizes 12 1.14.4 Reinforcement Details 12 2.0 Basement Walls 13 2.1 General 13 2.2 Drainage 13 2.3 Tanking 13 2.4 How to build the wall 13 2.5 Designs for reinforced basement wall types 13 2.6 Besser block basement wall design details for supporting a concrete floor 14 2.7 Besser block basement wall design details for supporting a timber floor 14 2.8 Basement walls 15 Glossary 15 Contents Preface The designs shown in the brochure are based on limit state design in accordance with the provisions of AS4678-2002 Earth retaining structures standard including Amendment 1, 2003. The designs are hereby certified by Adbri Masonry Building Products Pty Ltd ABN 31 009 687 521. The design details provided in this brochure have been prepared by Adbri Masonry specifically for Adbri Masonry blocks and are applicable only to retaining walls using Adbri Masonry products for residential or light commercial applications up to 3.0m high. For higher and/or more complex applications it is recommended reference be made to the Concrete Masonry Association of Australia document Reinforced Concrete Masonry Cantilever Retaining Walls – Design and Construction Guide MA51, Amended July 2003. Reinforced BESSER™ Block Retaining and Basement Walls consist of a reinforced concrete base which anchors the wall against overturning and sliding, and a stem of BESSER™ blocks. The stem is reinforced with steel bars placed vertically and horizontally, and all cores in the blocks are filled with semi-fluid concrete, known as ‘grout’. The vertical reinforcing bars in the cores are lapped with shorter ‘starter bars’ embedded firmly in the reinforced concrete base using a hob to correctly locate the bars. These short bars allow easier block laying, and the longer bars are put in after all blocks are laid and before grouting. The length of the lap is critically important and must be shown on the drawings.
- 3. 1.0 Retaining Walls 1.1 Designs for Reinforced Retaining Wall Types Retaining walls up to 3.0m high. 03 Boundary Retained soil Base Drain Drainage layer Infill soil Hob Reinforced block stem 45º Boundary Retained soil Base Drain Drainage layer Infill soil Hob Reinforced block stem 45º Wall Type 1 Wall Type 2 Note: Diagrams not to scale
- 4. 1.2 Loading Conditions 1.2.1 Retaining Walls These tables cover four loading conditions: • Level surface with 2.5 kPa surcharge for walls up to 1.5m high. • Level surface with 5.0 kPa surcharge for walls over 1.5m high. • Sloping surface up to 1:4 with 2.5 kPa surcharge for walls up to 1.5m high. • Sloping surface up to 1:4 with 5.0 kPa surcharge for walls over 1.5m high. Notes: • 300mm of soil or a private driveway imposes a load of approximately 5 kPa. • Sloping surface steeper than 1:4 is not included in this brochure. 1.3 Material Specifications In calculating these tables, the following material specifications were adopted: BESSER™ Block f’uc = 15 MPa in accordance with AS 4455 - 1997 Mortar Class M3 Cement 1 : Lime 1 : Sand 6 OR Cement 1 : Lime 0 : Sand 5 plus cellulose-based water thickener Concrete base f’c = 25 MPa Reinforcement Grade 500 N Grout f’c = 20 MPa with a pourable consistency and a cement content no less than 300 kg/m3 Where possible, use ready-mixed grout and specify when ordering that it is for filling blockwork. If the grout is mixed on site, use the following proportion: Cement 1 part Hydrated Lime Up to 1/10th part Mortar Sand 3 parts 10mm aggregate Up to 2 parts Notes: • 10mm aggregate should be rounded gravel where possible. • Grout should be mixed in a tilting drum paddle mixer and should flow freely without separation of the aggregate. 1.4 Soil Classification 1.4 Soil classification To simplify the following design tables only one type of soil has been used throughout for both infill soil and retained soil. It is classified as an average soil and would be typical of a wide range of insitu soils and would normally include; stiff sandy clays, gravelly clays, compact clayey sand and sandy silts, compacted clay fill (Class II). The characteristic soil property has been reduced by the uncertainty factors below and upon which the designs have been based: Uncertainty factor for drained cohesion, = uc 0.70 Uncertainty factor for drained internal friction angle, u = 0.85 ie: * = tan-1 ( u (tan ‘)) 1.5 Wall foundation The tables have been based on a foundation soil as described above and which must be excavated to sufficient depth to expose undisturbed material which is firm and dry. Should a designer wish to analyse a retaining wall built on a different foundation, base dimensions different from the tabulated values could be appropriate. If any of the following foundation conditions exist: softness, poor drainage, filled ground, organic matter, variable conditions, heavily cracked rock, aggressive soils, then experienced professional engineering advice should be obtained. 1.6 Infill soil and retained soil These tables have been calculated for infill soil and retained soil of soil classification shown above. Note: The following poor quality soils are not allowed for in the tables; soft and firm clay of medium to high plasticity, silty clays, loose variable clayey fill, loose sandy silts. If these soils are considered for use or aggressive groundwater exists an experienced professional engineer should be consulted and separate designs be obtained. Internal friction angle ‘ (degrees) Cohesion c’ (kPa) Characteristic soil parameters 27 3 Design soil parameters Internal friction angle * (degrees) Cohesion c* (kPa) 23 2 04
- 5. 05 Formwork to close cleanout openings. Tie to vertical bars with wire or support with temporary timber struts. Cleanout Blocks 20.61 or 20.45 Position vertical X and Y-bars to give 55mm clear cover on earth side. Cleanout Biscuit 20.45A Cleanout Block 20.45 Wall base Horizontal bars in wall can be laid on webs of H-blocks. Blocks type 20.48 Grout all cores Vertical X-bars (Stem) lapped with and tied to starter Y-bars Lap Base longitudinal bars Key Vertical starter Y-bars cast into base Grout Hopper Base transverse bars Hob Note: Where 15.42 or 20.42 blocks are in lieu of 20.48 blocks, lay alternative courses inverted and support horizontal reinforcement in the centre of the wall and 20 mm clear of the webs. Note: Diagrams not to scale 1.7 Drainage Systems It is essential that steps be taken to prevent the soil behind the wall from becoming saturated. These steps should include: • Sealing the soil surface – this can be done by covering it with a compacted layer of material with low permeability. The surface should be sloped towards an open drain. • A drainage system within the soil – this should preferably be achieved by placing gravel to a width of approximately 300mm immediately behind the wall with a continuous 100mm diameter slotted pvc agricultural pipe with geo fabric sock located at the base of the wall. The outlets from the pipe must be beyond the ends of the wall unless the pipe is connected to a proper storm water drainage system. For higher walls, or in cases where excessive ground water exists it may be necessary to provide another agricultural pipe drain at mid height of the wall. If it is not possible to discharge the drains beyond the end of the wall, weep-holes may be provided (see items for block laying following). In this case, a collecting system (e.g. spoon drains) must discharge the water into a drainage system to prevent saturation of the ground in front of the wall. A subfloor drainage system is advisable in basements to prevent hydrostatic pressure under the floor slab. 1.8 Water Penetration If considered necessary to reduce the passage of water through the wall, for aesthetic or other reasons such as aggressive ground water, the earth face of the wall should be treated using appropriate sealing techniques (see notes on tanking.) 1.9 Exploded View of Construction
- 6. 06 1.10 How to Build the Wall 1.10.1 Preliminary • Excavate to a satisfactory foundation. • Arrange for supply of materials to the specifications given previously. 1.10.2 Base and hob • Form the base and hob to the required dimensions and levels as shown in tables. • Place the base reinforcement as shown in the diagrams, securely fix the starter bars for the vertical reinforcement (Y-bars) 55mm from the back face of the wall, in the correct positions relative to the block cores to be reinforced by using the top front edge of the hob as a positioning reference point. • Place the base concrete, preferably using ready-mixed concrete, and compact thoroughly by rodding, spading or vibrating. Wood float finish any surface to be exposed permanently. Take care not to dislodge reinforcement. 1.10.3 Block laying Block laying procedure follows that of the normal practice for building unreinforced walls but, includes the additional requirement of locating the first course directly on top of a hob which is used to accurately locate the starter bars. The mortar mix used should be cement 1 part, lime 1 part, sand 6 parts or cement 1 part, sand 5 parts plus water thickener. These parts should be accurately measured by volume (e.g. a bucket). The sand used should be clean pit sand, masonry or plasterer’s sand. The use of plasticising additives is permitted. Where they are used, the dosage rate must not exceed that recommended by the supplier as this will drastically reduce the mortar strength. Detergent should never be used. Recommendations specifically applicable to reinforced concrete block retaining walls follow: • Cleanout openings should be provided in the bottom course using either 20.61 blocks plus timber formwork at the front or 20.45 blocks plus 20.45 A biscuits to permit removal of mortar fins and other debris, and to allow positioning and tying of vertical reinforcement. These openings must be closed before grouting. • Above the first course, the use of 15.48, 20.48 and 30.48 H-Blocks is recommended because they are easier to fill with grout and provide required protection of the reinforcement. 15.42 and 20.42 blocks may be used in lieu of H-Blocks and these blocks require less grout for filling. However, they must be laid with alternative courses inverted so as to provide grout cover to longitudinal reinforcement, which must be lifted 20mm clear of the web of the block by using stirrups or other supports (see diagram). • Mortar projecting into the cores should be removed, either as the blocks are laid, or by rodding after the mortar has set. Debris should be removed from the cores through the cleanout openings. • When the wall is to be tanked, the mortar joints on that face should be struck flush and cleaned. • Weepholes can be providing by passing 50mm diameter upvc pipes holes through the hob at 1200mm centres. • Reinforcement must be positioned accurately (refer to above), and tied securely before placing concrete or grout. Vertical reinforcing bars, including starter bars, should be as close to the back face of the wall as possible, consistent with 55mm cover requirements. 1.10.4 Grouting • Close cleanout openings. • Place grout. It is recommended that whenever available, ready-mixed grout to workability specifications given in AS3700 2001 should be used. Site-mixed grout, if used, should be mixed thoroughly in a tilting drum type paddle mixer to the same specification as ready-mixed grout. • All cores should be filled with grout, whether reinforced or not. This is essential to bond and protect horizontal reinforcement, and to give maximum weight for stability. • The grout should be compacted thoroughly so that voids are not left. Compaction may be by rodding with a plain round bar (do not use main vertical reinforcing bars or other deformed bars) or with a high frequency pencil vibrator, used carefully. • We recomend using “Coremasta” for corefilling your walls. “Coremasta” is a specially formulated block filler that gives superior grout penetration and requires minimal labour hours. Contact Hanson Construction Materials on 132 662 for more details. 1.11Tanking Where the wall is required to be waterproof, for example a basement wall, various proprietary tanking methods are available. One such method is a three coat liquid rubber compound incorporating a special reinforcing fabric for high stressed areas. Another method is a heavy duty, pliable, waterproof sheet membrane fixed to the wall surface. Surface coatings or sheet membranes must always be used in accordance with the manufacturer’s specifications. 1.12 Infill Soil and Drainage • Infill soil should not placed behind the wall until at least ten days after grouting. • Infill soil should be placed and compacted in layers not more than 200mm deep. The degree and method of compaction depends on the proposed use of the retaining wall. • The drainage system should be installed progressively as the infill soil rises. • The drainage system behind the wall should be connected to the main drainage system. • For the nominated infill soil in this brochure, it is advisable to seal off the top surface of the infill soil with a semi-impermeable layer of soil or earth. Compact and grade to a gutter to provide surface drainage.
- 7. 07 1.13 Design Details for Wall Type 1 1.13.1 Level Surface Wall Layout Wall Type 1 Note: Diagrams not to scale 75.10 Capping Tile if required 100 190 140 2.5 kPa surcharge N16 top course only 55 cover N12 @ 400 crs X-bars Y-bars Y-bars with 55 cover100 200 B 55 cover N16 @ 300 crs 500 lap Cleanout Block H 10.31 Capping Tile if required 100 H 700 lap N16 top course only 55 cover X-bars N12 @ 400 crs Y-bars 55 cover Cleanout Block Y-bars with 55 cover 100 250 B N16 @ 300 crs 240 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 190 10.31 Capping Tile if required 100 340 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 55 cover N16 top course only X-bars N12 @ 400 crs 55 cover to top of Y-bars Y-bars Y-bars 55 cover N16 @ 400 crs X-bars Cleanout Block Y-bars with 55 cover N16 @ 300 crs B 350 100 700 lap 700 lap 290 190 H Walls up to 1.2m high Walls over 1.8m and up to 3.0m high Walls over 1.2m and up to 1.8m high Note: All cores fully grouted Note: All cores fully grouted Note: All cores fully grouted
- 8. 07 1.13.2 Sloping Surface up to 1 in 4 Wall Layout Note: Diagrams not to scale 75.10 Capping Tile if required H 500 lap N16 top course only 55 cover X-bars N12 @ 400 crs Y-bars 55 cover Cleanout Block Y-bars with 55 cover 100 200 B N16 @ 300 crs 190 2.5 kPa surcharge 140 100 10.31 Capping Tile if required H 700 lap N16 top course only 55 cover X-bars N12 @ 400 crs Y-bars 55 cover Cleanout Block Y-bars with 55 cover 100 250 B W D N16 @ 300 crs 240 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m190 100 10.31 Capping Tile if required 100 340 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 55 cover N16 top course only X-bars N12 @ 400 crs 55 cover to top of Y-bars Y-bars Y-bars 55 cover N16 @ 400 crs X-bars Cleanout Block Y-bars with 55 cover N16 @ 300 crs W B D 350 100 700 lap 700 lap 290 190 H Walls up to 1.2m high Walls over 1.8m and up to 3.0m high Walls over 1.2m and up to 1.8m high Wall Type 1 Note: All cores fully grouted Note: All cores fully grouted Note: All cores fully grouted
- 9. 09 600 800 1000 1200 Wall height ‘H’ 1400 1600 1800 2000 2200 2400 500 600 700 850 Base width ‘B’ Surface slope 1000 - - - - - Key width ‘W’ Key depth ‘D’ Surface slope Level with Up to 1 in 4 with Up to 1 in 4 with 2.5 kPa surcharge 5.0 kPa surcharge 2.5 kPa surcharge 5.0 kPa surcharge 5.0 kPa surcharge 2600 - 2800 - 3000 - - - - - - 1300 1450 1650 1800 2000 700 800 1000 1200 1400 - - - - - 2100 - 2250 - 2450 - - - - - - 1800 2200 2400 2700 2900 - - - - - 200 200 300 300 300 3200 300 3400 300 3700 - - - - - 200 250 250 300 300 350 350 400300 1.13.3 Base and Key Sizes 600 800 1000 1200 Total wall height ‘H’ 1400 1600 1800 2000 2200 2400 600 800 1000 1200 Wall height Reinforcement - - - - - - Surface slope Surface slope Height of 150 series block Height of 200 series block Height of 300 series block Level X-bar 2600 - 2800 - 3000 - - - - - 1400 1600 1800 1800 1800 1800 - - - - - - - 200 400 600 1800 800 1800 1000 1800 1200 N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 N16 1:4 X-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 N16 Level Y-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 @ 200 N16 @ 200 1:4 Y-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 @ 200 N16 @ 200 1.13.4 Reinforcement Details Wall Type 1 Notes: 1. No key required for level surface slope walls. 2. All dimensions in millimeters. 3. 300mm of soil or a private driveway imposes a surcharge load of approximately 5 kPa. 4. 2.5 kPa surcharge applies up to 1.5m. 5. 5.0 kPa surcharge applies over 1.5m. Notes: 1. All bars are to be at 400mm centres unless otherwise stated. 2. All bars to have 55mm cover from outside concrete surface. 3. All dimensions in millimeters.
- 10. 10 1.14 Design Details for Wall Type 2 1.14.1 Level Surface Wall Layout Note: Diagrams not to scale 75.10 Capping Tile if required 100 190 140 2.5 kPa surcharge N16 top course only 55 cover N12 @ 400 crs X-bars Y-bars Y-bars with 55 cover SL72 Mesh100 200 D B W 55 cover 55 cover N16 @ 300 crs 500 lap Cleanout Block H 10.31 Capping Tile if required 100 H 700 lap N16 top course only 55 cover X-bars N12 @ 400 crs Y-bars 55 cover Cleanout Block SL72 mesh Y-bars with 55 cover 100 250 D B 55 cover N16 @ 300 crs W 240 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 190 10.31 Capping Tile if required 100 340 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 290 190 55 cover N16 top course only N12 @ 400 crs 55 cover to top of Y-bars Y-bars Y-bars Y-bars with 55 cover W B 55 cover N16 @ 300 crs 100 350 D 55 cover N16 @ 400 crs X-bars Cleanout Block SL72 mesh X-bars 700 lap 700 lap H Walls up to 1.2m high Walls over 1.8m and up to 3.0m high Walls over 1.2m and up to 1.8m high Wall Type 2 Note: All cores fully grouted Note: All cores fully grouted Note: All cores fully grouted
- 11. 11 1.14.2 Sloping Surface up to 1 in 4 Wall Layout Note: Diagrams not to scale 75.10 Capping Tile if required 100 190 140 2.5 kPa surcharge N16 top course only 55 cover N12 @ 400 crs X-bars Y-bars Y-bars with 55 cover SL72 Mesh100 200 D B W 55 cover 55 cover N16 @ 300 crs 500 lap Cleanout Block H 10.31 Capping Tile if required 100 H 700 lap N16 top course only 55 cover X-bars N12 @ 400 crs Y-bars 55 cover Cleanout Block SL72 mesh Y-bars with 55 cover 100 250 D B 55 cover N16 @ 300 crs W 240 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m190 10.31 Capping Tile if required 100 340 2.5 kPa surcharge up to 1.5m 5.0 kPa surcharge over 1.5m 55 cover N16 top course only X-bars N12 @ 400 crs 55 cover to top of Y-bars Y-bars Y-bars 55 cover 55 cover N16 @ 400 crs X-bars Cleanout Block Y-bars with 55 cover SL72 mesh N16 @ 300 crs W B D 350 100 700 lap 700 lap 290 190 H Walls up to 1.2m high Walls over 1.8m and up to 3.0m high Walls over 1.2m and up to 1.8m high Wall Type 2 Note: All cores fully grouted Note: All cores fully grouted Note: All cores fully grouted
- 12. 12 600 800 1000 1200 Wall height ‘H’ 1400 1600 1800 2000 2200 2400 500 800 800 1000 Base width ‘B’ Surface slope 1100 - - - - - Key width ‘W’ Key depth ‘D’ Surface slope Level with Up to 1 in 4 with Level 1 in 4 Level 1 in 42.5 kPa surcharge 5.0 kPa surcharge 2.5 kPa surcharge 5.0 kPa surcharge 2600 - 2800 - 3000 - - - - - - 1600 1900 2000 2200 2400 700 900 1100 1400 1500 - - - - - 2700 - 2900 - 3100 - - - - - - 2200 2400 2600 2900 3200 - - 150 200 200 350 400 400 500 550 3500 600 3700 600 4000 150 150 200 300 350 500 550 550 600 700 750 800 900700 - - 200 300 300 500 600 600 700 800 900 900 100 200 300 400 500 700 800 800 900 1000 1100 1200 13001000 1.14.3 Base and Key Sizes 600 800 1000 1200 Total wall height ‘H’ 1400 1600 1800 2000 2200 2400 600 800 1000 1200 Wall height Reinforcement - - - - - - Surface slope Surface slope Height of 150 series block Height of 200 series block Height of 300 series block Level X-bar 2600 - 2800 - 3000 - - - - - 1400 1600 1800 1800 1800 1800 - - - - - - - 200 400 600 1800 800 1800 1000 1800 1200 N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 N16 1:4 X-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 N16 Level Y-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 @ 200 N16 @ 200 1:4 Y-bar N12 N12 N12 N12 N16 N16 N16 N16 N16 N16 N16 N16 @ 200 N16 @ 200 1.14.3 Reinforcement Details Wall Type 2 Notes: 1. All dimensions in millimeters. 2. 300mm of soil or a private driveway imposes a surcharge load of approximately 5 kPa. 3. 2.5 kPa surcharge applies up to 1.5m. 4. 5.0 kPa surcharge applies over 1.5m. Notes: 1. All bars are to be at 400mm centres unless otherwise stated. 2. All bars to have 55mm cover from outside concrete surface. 3. All dimensions in millimeters.
- 13. 13 2.0 Basement Walls 2.1 General The foundation slab of a basement can be modified to provide an efficient footing for a retaining wall. In addition, a concrete floor slab will provide a ‘prop’ to the top of the wall, simplifying the wall details compared to a timber floor. All infill materials must be with granular material. Details of typical basement walls are shown in the following figures. 2.2 Drainage As with all retaining walls it is critical that the soil is prevented from becoming saturated. Steps to be taken to achieve this include: • A drainage system within the soil. This should preferably take the form of a 300 mm width of gravel immediately behind the wall with a continuous agricultural pipe located at the base of the wall. The pipe must discharge beyond the ends of the wall. • Sealing the soil surface. This can be done by placing a compacted layer of low-permeability material over the soil and sloping the surface away from the house. It is also important to prevent hydrostatic pressure under the floor slab. Where there is the possibility of groundwater under the slab, then a subfloor drainage system is advisable. 2.3 Tanking Where it is required that the basement be kept dry, a proper tanking system needs to be installed behind the wall before backfilling (refer Chapter 10). An alternative to this is to provide a drain and a false wall in front of the wall (refer alternative detail). 2.4 How to Build the Wall Building a Basement wall is essentially the same as building a retaining wall. Please refer to section 1.10 for details on how to build a basement wall. 2.5 Basement Walls Basement Retained soil Base Drain Drainage layer Infill soil Timber floor Reinforced block stem 45º Basement Retained soil Base Drain Drainage layer Infill soil Concrete floor Reinforced block stem 45º Unpropped or partially propped wall Basement walls up to 2.7m high. Propped wall Note: Diagrams not to scale
- 14. 14 2.6 BESSER™ Block Basement Wall Design Details For Supporting a Concrete Wall Floor slab reinforcement N12 at 200 crs False wall Drained cavity Note: N12 at 200 crs may be used instead of N16 at 400 crs Note: No tanking required Starter bar to match wall reinforcement above One-course bond beam with N12 bar Note: Wall blocks and reinforcement as for ‘Typical Details’ - fully propped walls 20.48 ‘H’ blocks Vertical reinforcement N16 at 400 crs, central Horizontal reinforcement N12 at 400 crs 20.20 knock-out block saw-cut at floor soffit level Tanking to back face of wall Ag. drain Ag. drain 190 thick blockwork N16 at 400 crs N12 at 400 crs 55 cover 200 200 1000 2700 max. Floor slab reinforcement Timber floor Timber floor140-thick blockwork 190-thick blockwork False wall Drained cavity Note: N20 at 400 crs may be used instead of N16 at 200 crs Note: No tanking required Pole plate fixed to bond beam One-course bond beam using 20.20 knock-out block with 1-N12 bar Note: Reinforcement as for ‘Typical Details’ 290-thick blockwork 20.48 ‘H’ blocks Vertical reinforcement N16 at 400 crs, central Horizontal reinforcement N12 at 400 crs 55 cover to back face Tanking to back face of wall 55 cover to back face Ag. drain Ag. drain 190 thick blockwork 290 thick blockwork 30.48 ‘H’ blocks Floor slab reinforcement N16 at 200 crs N12 at 400 crs 55 cover 300 300 1500 2700 max. to ground level 1200 Note: Diagrams not to scale Typical details - Fully-propped walls Typical details - Unpropped or partially-propped walls Alternative details Alternative details 2.7 BESSER™ Block Basement Wall Design Details For Supporting a Timber Floor
- 15. 2.8 Basement Walls These designs are based on a level surface with 5 kPa surcharge. Walls designed as propped must not be backfilled before the concrete floor at the top of the wall is in place. Important Notes No loadings should be applied (e.g. from footings), within the area of infill soil other than those loadings referred to above. The area of infill soil is bounded by a line at 45° to the rear of the base as illustrated in chapter 1. Only one typical soil case is presented. These tables may not provide an ideal solution in a particular case. For situations other than those covered by the tables, or if there is doubt as to: • The strength and stability of the foundation material the drainage system needed • An experienced professional engineer should be consulted for advice. Load and Limit States: Dead load* The self-weight of the structure, infill soil, retained soil or rock. Live load* Loads that arise from the intended use of the structure, including distributed, concentrated, impact and inertia loads. It includes construction loads, but excludes wind and earthquake loads. Surcharge A uniformaly distributed external load. For retaining walls under 1.5m a minimum load of 2.5 kPa. For retaining walls over 1.5m a minimum load of 5 kPa. Stability limit state A limit state of loss of static equilibrium of a structure or part thereof, when considered as a rigid body. Strength limit state A limit state of collapse or loss of structural integrity of the components of the retaining wall. Serviceability limit state A limit state for acceptable in-service conditions. The most common serviceability states are excessive differential settlement and forward movement of the retaining wall. Components: Concrete masonry units Concrete blocks manufactured to provide an attractive, durable, stable face to a retaining wall. The recommended block types are the 15.48, 20.48 and 30.48 ‘H’ blocks. Retained soil The natural soil, intended to be retained by a retaining wall. Foundation soil The natural soil material under a retaining wall. Infill soil The soil material placed behind the retaining wall facing. Often retained soil is used for this purpose. * This brochure uses the terminology ‘dead load’ to indicate permanent loads and ‘live load’ to indicate imposed loads. This terminology is consistent with the convention adopted in AS 4678-2002. Glossary Flinders Park 284 Grange Road, Flinders Park, SA 5025 phone: (08) 8234 7144 I fax: (08) 8234 9644 Gawler Cnr Main North & Tiver Rd, Evanston, SA 5116 phone: (08) 8522 2522 I fax: (08) 8522 2488 Gepps Cross 700 Main North Road, Gepps Cross, SA 5094 phone: (08) 8349 5311 I fax: (08) 8349 5833 Holden Hill 578 North East Road, Holden Hill, SA 5088 phone: (08) 8369 0200 I fax: (08) 8266 6855 Kadina 86 Port Road, Kadina, SA 5554 phone: (08) 8821 2077 | fax: (08) 8821 2977 Lonsdale 13 Sherriffs Road, Lonsdale, SA 5160 phone: (08) 8381 2400 I fax: (08) 8381 2366 Mount Barker Westbourne Park 4 Oborn Road, Mount Barker, SA 5251 455 Goodwood Rd, Westbourne Park, SA 5041 phone: (08) 8391 3467 fax: (08) 8398 2518 phone: (08) 8299 9633 I fax: 08) 8299 9688 Mount Gambier Whyalla 6 Graham Road, Mount Gambier West, SA 5291 132 Norrie Ave, Whyalla Norrie, SA 5608 phone: (08) 8725 6019 I fax: (08) 8725 3724 phone: (08) 8644 0918 I mob: 0412 810 056 Hallet Cove 9-11 Commercial Road, Sheidow Park, SA 5158 phone: (08) 8381 9142 I fax: (08) 8381 7666 Streaky Bay 18 Bay Road, Streaky Bay, SA 5680 phone: (08) 8626 7011 I mob: 0427 263 050