Table 12.1 Loading on wall A per metre run ©2004 Taylor & Francis Table 12.1 (Contd) ©2004 Taylor & Francis ©2004 Taylor & Francis Table 12.2 Loading on wall B per metre run; inner leaf ©2004 Taylor & Francis ©2004 Taylor & Francis walls will provide the resistance to wind loading. In an actual design, the designer must of course check that the structure is safe for wind blowing east-west and vice versa. In the calculation below it has further been assumed that the walls act as independent cantilevers; and hence moments or forces are apportioned according to their stiffness. 12.5.2 Wind loads These are calculated according to CP 3, Chapter V: Part 2. We have Using ground roughness category 3, Class B, with height of the building=21.0m, from Table 3, CP3, Chapter V: Part 2 Therefore design wind speed is and dynamic wind pressure is From Clause 7.3, CP3, Chapter V: Part 2, total wind force The total maximum bending moment is total max. BM=F×h/2 where h is the height under consideration. Total BM just above floor level is given for each floor by: • 6th floor C f qA e ×h/2=1.1×(1269/10 3 )×21×3×3/2=131.9kNm • 5th floor 1.1×(1269/10 3 )×21×6×3=527.6kNm • 4th floor (1.1×1269×21/10 3 )×9×9/2=1187.20kNm • 3rd floor 29.313×(12×12/2)=2110.54kNm • 2nd floor 29.313×(15×15/2)=3297.70kNm ©2004 Taylor & Francis Fig. 12.3 The variation of the factor S 2 and the wind velocity along the height of the building. (Assumptions made in the design shown in full lines.) ©2004 Taylor & Francis • 1st floor 29.313×(18×18/2)=4748.71kNm • ground floor 1.1×(1269/10 3 )×21×21×21/2=6463.2kNm In the calculation the factor S 2 has been kept constant (Fig. 12.3), which means the design will be a bit conservative. However, the reader can vary the S 2 factor as given in Fig. 12.3 taken from Table 3 (CP 3) which means the wind speed will be variable depending on the height of the building. 12.5.3 Assumed section of wall resisting the wind moment The flange which acts together with the web of I-section is the lesser of • 12 times thickness of flange+thickness of web • centre line to centre line of walls • one-third of span (a) Wall A For wall A (Fig. 12.4), neglecting the outer skin of the cavity wall flange, the second moment of area is (b) Wall B The flange width which acts with channel section has been assumed as half of the I-section. For wall B (Fig. 12.5), neglecting the outer skin of the cavity wall flange, ©2004 Taylor & Francis Table 12.3 Distribution of bending moment stresses and shear force in walls ©2004 Taylor & Francis ©2004 Taylor & Francis [...]... dead+wind, and the design load is (1 .96 ×102.5×103)/103=201kN/m 12.6.4 Selection of brick and mortar for inner leaf of wall B The design vertical load resistance of the wall is (ßtfk)/␥m (clause 32.2.1) The value of ß depends on the eccentricity of loading; hence the value of e needs to be evaluated before design can be completed 12.6.5 Calculation of eccentricity The worst combination of loading for obtaining... the design load=3.17×102.5×103/103=324.9kN/m 12.7.1 Selection of brick and mortar combination for wall A: according to EC6 Design vertical load resistance of wall on eccentricity and slenderness ratio 12.7.2 , where depends Calculation of eccentricity Figure 12 .9 shows the worst combination of loading for obtaining the value of eccentricity Axial load ©2004 Taylor & Francis Fig 12 .9 Calculation of. .. Chapter 6 for wind loading 12.7 DESIGN CALCULATION ACCORDING TO EC6 PART 1–1 (ENV 199 6–1: 199 5) To demonstrate the principle of design according to EC6, the wall A in the ground floor will be redesigned The dead and live loading is taken as calculated before and as in Table 12.1 The bending moments and shear forces due to wind loading are given in Table 12.3 The category of manufacturing and execution... for obtaining the value of e at top of the wall is shown in Fig 12.6 Axial load P=(0 .9 78.54+1.6×7. 29) (Gk and Qk from Table 12.2) =(70. 69+ 11.66)=82.35kN/m First floor load P1=(1.4×6.48+1.6×2.025) (see Table 12.2) =12.31kN/m ©2004 Taylor & Francis BM at centre of the panel=627.8×(Cpe+CPi)h2×0.104×1.4 =627.8×(1.1+0.2)×(2.85)2×0.104×1.4 =96 4.6Nm/m (Cpe and Cpi from CP3, Chapter V: Part 2) (BM coefficient... the design ©2004 Taylor & Francis 12.6.6 Calculation of characteristic compressive stress fk for wall B (inner leaf) 12.6.7 Design of the outer leaf of the cavity wall B in GF Load combination: • Windward side ©2004 Taylor & Francis • Leeward side The design is similar to the inner leaf and will not be considered any further The slight tension which is developing is of no consequence, since 6 to 10% of. .. in BS 5628 is higher than in the Eurocode, but it does not make much difference to the design 12.8 DESIGN OF PANEL FOR LATERAL LOADING: BS 5628 (LIMIT STATE) To explain the principle of the design only panel B between sixth floor and roof will be considered The low precompression on the inner leaf is ignored in this design Assume: • Inner leaf 102.5mm brickwork in 1:1:6 mortar • Outer leaf 102.5mm brickwork... 1:¼:3 mortar may be used, provided that it satisfies the lateral load design The grade of mortar is kept the same as for the inner leaf Characteristic flexural strength: (Table 3) Design characteristic shear as in inner leaf: Instead of the conventional design calculations described in this chapter a more sophisticated analysis of the structure is possible by idealizing it as a frame with vertical... Selection of brick and mortar combinations for wall A:BS 5628 Design vertical load resistance of wall is (ßtf k)/g m (clause 32.2.1), eccentricity Hence ß=0.67 ©2004 Taylor & Francis (Table 7 of BS 5628), ␥m=3.5 (see section 12.3) The design loads from the previous subsection and the characteristic strengths are shown in Table 12.4 along with the suitable brick/mortar combinations Check for shear stress: design. .. value of shear force is taken from Table 12.3 For the sixth floor For the ground floor There is no need to check at any other level, since shear is not a problem for this type of structure The BS 5628 recommends gA as the design vertical load per unit area of wall cross-section due to vertical load calculated from the appropriate loading condition specified in clause 22 The critical condition of shear... loading for obtaining the value of eccentricity Axial load ©2004 Taylor & Francis Fig 12 .9 Calculation of eccentricity of the loading (not to scale) ©2004 Taylor & Francis EC6 allows the use of the value from the national code Hence 50N/mm2 brick in mortar will be sufficient In the absence of test data a formula as given below is suggested for use: or Therefore, 100N/mm2 bricks are required which is much . floor C f qA e ×h/2=1.1×(12 69/ 10 3 )×21×3×3/2=131.9kNm • 5th floor 1.1×(12 69/ 10 3 )×21×6×3=527.6kNm • 4th floor (1.1×12 69 21/10 3 ) 9 9/ 2=1187.20kNm • 3rd floor 29. 313×(12×12/2)=2110.54kNm • 2nd floor 29. 313×(15×15/2)=3 297 .70kNm ©2004. Selection of brick and mortar for inner leaf of wall B The design vertical load resistance of the wall is (ßtf k )/ ␥ m (clause 32.2.1). The value of ß depends on the eccentricity of loading;. hence the value of e needs to be evaluated before design can be completed. 12.6.5 Calculation of eccentricity The worst combination of loading for obtaining the value of e at top of the wall is