Assessment of slenderness

Consider a 1.0 m vertical strip of wall acting as an isolated column. The effective height of a column I Bl , Zcol actual height of the column between centres of restraint 0 is a factor depending upon the coefficients kA and kB relating to the rigidity of restraint at the column ends. Assuming a constant modulus of elasticity for the concrete 1 x 0.23

Check by calculation

10.2.3.1 Calculation of steel stress and strain A area of reinforcement within the tensile zone area of concrete within tensile zone 1000 x 200 200 x 103 mm2 a coefficient taking account of stress distribution 1.0 for pure tension a coefficient allowing for the effect of non-uniform self-equilibrating stresses 0.8 for tensile stresses due to restraint of intrinsic deformations (h < 300 mm) tensile strength of concrete effective at first cracking 3.8 N mm2 (taking fctk Q95 but see Section...

Column B support moments

Analysis moment 198 kNm in both directions Column strip WSdcs 0.75 x 198 149 kNm BS 8110 Use 13T16 (2613 mm2) top in column strip. Provide 9T16 150 mm crs. in central 1.3 m and 2T16 300 mm crs. on either side Check whether minimum moment required for punching shear has been met. With -0.125 This is to be carried over a width of 0.3 . Since V includes for a loaded width of 5.2 m, it is assumed that the larger panel width may be used. By inspection reinforcement (9T16 in central 1.3 m) is...

For The Design Of Concrete Buildings

Based on BSI publication DD ENV 1992-1-1 1992. Eurocode 2 Design of concrete structures. Part 1. General rules and rules for buildings. This book of worked examples has been prepared by British Cement Association Ove Arup & Partners and The work was monitored by the principal authors A. W. Beeby BSc, PhD, CEng, MICE, MIStructE. FACI Professor of Structural Design, Dept of Civil Engineering, University of Leeds (formerly Director of Design and Construction, British Cement Association), R. S....

Info

Bars mark 8, which are located outside the web, must extend a further 150 mm - refer to Figure 2.8. Curtailment of the main reinforcement and arrangement of the link reinforcement are shown in Figures 2.6 and 2.7. Reinforcement details are shown in Figure 2.8 and given in Table 2.4. Figure 2.6 Curtailment diagram of main reinforcement Figure 2.6 Curtailment diagram of main reinforcement

Introduction And Symbols

1.1 Introduction 5 1.2 Symbols 5 2.1 Introduction 15 2.2 Basic details of structure, materials and loading 15 2.3 Floor slab 17 2.4 Main beam 20 2.5 Edge beam (interior span) 30 2.6 Columns 34 2.7 Foundation 39 2.8 Shear wall 43 2.9 Staircase 49 3.1 Introduction 53 3.2 Design methods for shear 53 3.3 Shear resistance with concentrated loads close to support 63 3.4 Design method for torsion 70 3.5 Slenderness limits 81 4.1 Solid and ribbed slabs 82 4.2 Flat slabs 109 5.1 Introduction 132 5.2...

Maximum concrete stresses

As the beam is a T-section, the values of Wx and Wb are not equal. By calculation it can be shown that I 6.79 x 109 mm4 and that the centroid of the section is at a height of 196 mm from the soffit. The calculation of the stresses under each load combination is not shown here. The method follows that given in the Post tensioned concrete floors Design handbook. The top and bottom concrete stress for transfer conditions are given in Table 9.3 and those after all losses are given in Table 9.4.

Nad

Basic span effective depth ratio (interpolating for p) 39.2 Table 7 Modification factor for steel stress - 1.19 Since flange width > 3 x rib width, a 0.8 modification factor is required. Since span > 7 m, no further modification is required. Permitted span effective depth ratio 39.2 x 1.19 x 0.8 37.3 > 25.9 OK For exposure class 1, crack width has no influence on durability and the limit 4.4.2.1(6) of 0.3 mm could be relaxed. However, the limit of 0.3 mm is adopted for this example....

S

Minimum area 0.0015bd 5.4.2.1.1 The reinforcement details are shown in Figure 2.15 and given in Table 2.8. COVER to outer bars - N1 i.0 , F1 20 COVER to outer bars - N1 i.0 , F1 20 Figure 2.15 Shear wall reinforcement details Table 2.8 Commentary on bar arrangement Table 2.8 Commentary on bar arrangement

Combined footing

Design a combined footing supporting one exterior and one interior column. An exterior column, 600 mm x 450 mm, with service loads of 760 kN dead and 580 kN imposed and an interior column, 600 mm x 600 mm, with service loads of 1110 kN dead and 890 kN imposed are to be supported on a rectangular footing that cannot protrude beyond the outer face of the exterior column. The columns are spaced at 5.5 m centres and positioned as shown in Figure 7.2. The allowable bearing pressure is 175 kN m2, and...

Pilecap design example using truss analogy

Pile Cap Design

A four-pile group supports a 500 mm square column which carries a factored load of 2800 kN. The piles are 450 mm in diameter and spaced at 1350 mm centres. Assume a pilecap depth of 800 mm. Allow the pilecap to extend 150 mm beyond the edge of the piles, to give a base 2.1 m square as shown in Figure 7.7. Use 2.1 m x 2.1 m x 0.8 m deep pilecap For components in non-aggressive soil and or water, exposure class is 2 a . Minimum concrete strength grade is C30 37. For cement content and w c ratio...

Twoway spanning solid slabs

EC2 1 permits the use of elastic analysis, with or without redistribution, or plastic analysis for ultimate limit state design. Elastic analyses are commonly employed for one-way spanning slabs and for two-way spanning slabs without adequate provision to resist torsion at the corners of the slab and prevent the corners from lifting. Plastic analyses are commonly used in other situations. Tabulated results for moments and shears from both types of analysis are widely available. Care is necessary...

Concrete Nib Design

Nib Reinforcement

lt 0.0015 x 1000 x 81 122 mm2 Check minimum area of reinforcement for crack control 0.4 x 0.8 x 3.0 x 52.5 x 103 460 110 mm2 No further check for crack control Is necessary as h 105 lt 200 mm. Maximum bar spacing 3h 315 lt 500 mm The reinforcement details are shown in Figure 8.5. Figure 8.5 Nib reinforcement details Figure 8.5 Nib reinforcement details Check shear in nib, taking into account the proximity of the concentrated load 4.3.2.3 to the support. 0 2.5dlx 2 5 X 81 1.69 Eqn 4.17

Concrete grades

Concrete Cube Cylinder Strength

EC2 1 uses the cylinder strength, fck, to define the concrete strength in design equations, although the cube strength may be used for control purposes. The grade designations specify both cylinder and cube strengths in the form C cylinder strength cube strength, for example C25 30. It may occasionally be necessary to use cube strengths which do not exactly correspond to one of the specified grades. In such instances a relationship is required between cylinder and cube strength in order to...

Symmetrically reinforced rectangular columns

Ec2 Reinforced

Figures 13.2 a to e give non-dimensional design charts for symmetrically reinforced columns where the reinforcement can be assumed to be concentrated in the corners. The broken lines give values of K in Eqn 4.73 of EC2. Eqn 4.73 Where the reinforcement is not concentrated in the corners, a conservative approach is to calculate an effective value of d' as illustrated in Figure 13.3.

Comparison with spaneffective depth ratio

The procedure for limiting deflections by use of span effective depth ratios is set out in EC2 Section 4.4.3. 100 4 100 x 2410 o _ UU 0.37 Therefore the concrete is lightly stressed, p lt 0.5 The NAD 1 introduces a category of nominally reinforced concrete corresponding to p 0.15 Basic span effective depth ratio for a simply supported beam, interpolating for p 0.37 For flanged beams where M gt w gt 3.0 the basic span effective depth ratio should be multiplied by a factor of 0.8 The span...

References

Eurocode 2 Design of concrete structures. Part 1. General rules and rules for buildings together with United Kingdom National Application Document . DD ENV 1992-1-1 1992. London, BSI, 1992. 254 pp. 2. British standards institution. Structural use of concrete. Part 1 Code of practice for design and construction. Part 2 Code of practice for special circumstances. Part 3 Design charts for singly reinforced beams, doubly reinforced beams and rectangular columns. BS...