7.2 Design of minaret: Geometry:

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Reginald Dawson
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1 7. Design of minaret: Geometry: The figure below shows the longitudinal section in the minaret and the cross section will be shown when start calculate the self-weight of each section. Figure 7..1 Longitudinal section in minaret Minaret design 178

2 Analysis and Design: e should calculate the base shear from the wind and the earthquake load respectively And decide about the load combination which will be used in analysis and design procedure. Calculation of the base shear from the wind load: 1- Calculate design wind pressure According to UBC97 Code. As following: P C C q I e q s w A) Basic wind speed 1.61x90 1.9mph From table q s 0.079x KN From table A 1 B) For chimneys and solid tower : C q 0.8 for any direction. From table A 5 ( Appendix) D) For chimneys and solid tower I w 1 From table A 6 A 1( Appendix ) ( Appendix ) ( Appendix) E) Choose Exposure C for Mutah University Zone from table A-(Appendix). Height above average level of adjoining ground(m) C e for EXPOSURE C q(kn/m ) Table 7..1 Design wind pressure for exposure C Minaret design 179

3 ind Pressure Distribution 0 35 Height(m) q(kn/m) Figure 7.. Design wind pressure for exposure C Distribute the wind pressure for range of height as following: Height Range(m) Outer Diameter(m) Pressure (KN/m ) Distribution force (KN/m') * *Also use this for the elevated water tank (from 1-16) m Table 7.. Design wind pressure distribution over the range of height 3- Calculation of the Base shear: V.1 x (.1-0) x ( ) +.5 x ( ) x (3.5-19) x (5-3.5) x (8.75-5) + x ( ) 170.9KN Minaret design 180

4 After calculating the earthquake base we should decide about the load combination which will be used in analysis and design procedure, because according to UBC97 criteria, we should use the greatest of wind or earthquake load. Calculation of the base shear from earthquake load: 1- Calculate the weight of the structure: The minaret will be will be divided to more than one section according to the varying in the section area at each elevation as follow: Assume the footing is at elevation -3 below the ground level. Section No.1 Elevation from -3m to.1m From the architectural drawing thickness of the stone facing 10 cm. π π 1 + stone [ Dout Din ] γ + [ Dout Din ] γ stone stone π π KN [ ] [ ] ' I π π ( D D ) (.8 3. ) 19.5m out in Figure 7..3 Section No.1 Minaret design 181

5 Section No. Elevation from.1m to 17.5m and from 19m to 3.5m From the architectural drawing thickness of the stone facing 10 cm. 1 π I + stone π π π.6 π [ D D ] γ + [ D D ] out in π [.6 3. ] 5 + [.8.6 ] 3.6KN ' ( D D ) ( 3. ) 15.m out in out in stone γ Figure 7.. Section No. Section No.3 Elevation from 17.5m to 19m and from 3.5m to 5m π 1 [ Dout Din ] γ π KN π π I ( Dout Din ) (.0 3. ) 6m [ ] ' Minaret design 18

6 Figure 7..5 Section No.3 Section No. Elevation from 5m to 8.75m There is no stone facing but there are stone wall a round the section with more than one diameter. Use the average diameter of the stone wall and calculate the weight of the wall 1 + stone π π π [ D D ] γ + [ D D ] out in π [ 3.0. ] 5 + [.6 ] KN ' out in stone γ I π π ( D D ) ( 3.0. ).35m out in Figure 7..6 Section No. Minaret design 183

7 Section No.5 Elevation from 8.75m to 31m There is an empty space in this elevation because there are four windows with height equal to.5m. 1 total empty space L L π [ D D ] γ [ 3. ] KN ' π out 1 1 space rout Lout rin Lin γ π rout θ m 180 π rin θ m space KN / total in empty out in 3 empty 1 total empty space m π I π ( D D ) ( 3.0. ).35m out in 3KN ' ' Figure 7..7 Section No.5 Minaret design 18

8 Section No.6 Elevation from 31m to 3.5m π 1 [ Dout Din ] γ π KN π π I ( Dout Din ) ( 3.0. ).35m [ ] ' Section No.7 Figure 7..8 Section No.6 Elevation from 3.5m to 35.5m π 1 Dout Din π π π I D Din 3.0 [ ] γ [ ] KN ' ( ) ( 1.8 ) 3.6m out Figure 7..9 Section No.7 Minaret design 185

9 Total gravity loads: gravity KN ( ( )) +.6 ( ) +.6 ( ) ( ) ( 5 3.5) ( ) ( ) ( ) ( ) - Quake force parameters: a) From Jordan seismic hazard map, Karak is on the B zone and for this zone get Seismic zone factor Z 0. from table (A-3) (Appendix) b) There is no available information about the soil, so use S D soil profile type from table (A-) (Appendix). c) The important factor I 1 from table (A-6) (Appendix). e) Response modification factor R: for Cast-in-place silos and chimneys having walls continuous to the foundations R 3.6 from table (A- 7) (Appendix). f) Seismic coefficient Ca and C v : based on the soil profile type and the seismic zone factor C a 0.8 and C v 0. from table and table (A- 8) and (A-9) (Appendix). g) Fundamental period T: for the non-building structure (self supporting structure) like chimney, silo, minaret, we should use method 1 as an initial fundamental period 3 / 3 / The initial fundamental period T C ( h ) ( 35.5) 0.71sec ond t n Minaret design 186

10 3- Quake force initial base shear: Based on the initial fundamental period T 0.75second Cv I 0. 1 V KN RT ( 0.11C I ) ( ) KN V a min.5c a I Vmax KN R 3.6 Extra load F t 0.07 T V KN It should be less than 0.5 V 0.5 x KN This base initial base shear (V) will be initially distributed over the height as shown in figure below: according to the following equation: Figure Lateral force distributed - Then calculate the exact fundamental period using the structural properties and deformational characteristics of the resisting elements in a properly substantiated analysis (method ). e prepare a computer program to calculate the exact fundamental period T that needs trail and error. From the computer program we get T 0.5 second. And the table as in the next page. Minaret design 187

11 Mass eight Accumulative i(kn) No. (KN/m') i(kn) I(m ) Elevation(m) Hi(m) i*hi Fi(KN) Table 7..3 (lateral force distribution) Sum Minaret design 188

12 Hi (m) Fx (KN) Accumulative Fx (KN) Moment (KN.m) Deflection (mm) Table 7..3 (cont.) Minaret design 189

13 From the table in previous page the accumulative Fi KN Compare to the wind load base shear 170.9KN the quake force will be used in analysis and design procedure. Compute the safety factor against overturning: Over turning moment KN.m Restoring moment restoring force x half the base width Self weight of the minaret (total gravity load) KN Assume footing dimension 10 x 10 x 1 eight of the soil surround by the minaret π π [ Dout Din ] 18 3 [.8 3. ] KN Self eight of column (0.6 x π) / x 5 x KN Total restoring weight x 10 x 1 x KN Restoring moment x KN.m Re storing moment 5115 Factor of safety against overtruning 1.7 > 1.5 overturning moment ok. Check the allowable deflection: From the above table the maximum deflection equal to 35.16mm The allowable deflection equal to h mm So it is ok. Minaret design 190

14 Design of minaret sections: From the table 7..3 we got the moment at each elevation and we will check the stresses and calculate the reinforcement required for each section as follow: Note: ' Allowable tensile strength of (f t ) 0.5 f c MPa ' Allowable compressive strength of (f ) 0.5 f c MPa Allowable shear strength of (V) 0.09 c ' f c MPa Elevation from -3m to.1m Vertical reinforcement: Maximum Moment (M) KN.m. at elevation -3 below the ground. eight above elevation -3 () KN. Eccentricity (e) M / / m M c ± ± ± A I ' 6.7KN.65MPa < 0.5 f it is ok. max c min 863.5KN.86MPa " Tension stress" The tensile stress is slightly greater than the allowable tensile strength of And the minimum reinforcement will be ok. Area of steel /m A g x (1000 x 700) 1050 mm The steel will be arranged into two layers Steel for one layer 1050 / 55mm Choose Ø1 15 spacing mm 55 Provide Ø1@ 50mm Horizontal reinforcement: V Applied shear stress 171.7KN 0.171MPa A 8 This is smaller than the shear strength of. So minimum horizontal reinforcement will be provided Area of steel /m 0.00 A g 0.00 x (1000 x 700) 100 mm The steel will be arranged into two layers Steel for one layer 100 / 700mm Choose Ø1 15 spacing mm 700 Provide Ø1@ 0mm Minaret design 191

15 Elevation from.1m to 17.5 m Maximum Moment (M) KN.m. at elevation.1m eight above elevation.1 () 578.5KN. Eccentricity (e) M / / m A ± M c ± ± I max 77.55KN.8MPa < 0.5 f ' c it is ok. min 758.1KN.76MPa " Tension stress" The tensile stress is slightly greater than the allowable tensile strength of And the minimum reinforcement will be ok. Area of steel /m A g x (1000 x 600) 900 mm Choose Ø1 15 spacing mm 900 Provide Ø1@ 150mm at the center of the section Horizontal reinforcement: V Applied shear stress 176.3KN 0.176MPa A 7.5 This is smaller than the shear stress of. So minimum horizontal reinforcement will be provided Area of steel /m 0.00 A g 0.00 x (1000 x 600) 100 mm Choose Ø16 00 spacing mm 100 Provide Ø16@ 160mm Note: Use these horizontal Reinforcements for all other sections. Minaret design 19

16 Elevation from 19m to 3.5 m Maximum Moment (M) 5311.KN.m. at elevation 19m eight above elevation () 176KN. Eccentricity (e) M / / 176. m A ± M c ± 88.6 ± 79.7 I max KN 1.1MPa < 0.5 f ' c it is ok. min KN 0.50MPa " Tension stress" There is a Tension stress and it is less than the allowable tensile strength of So minimum reinforcement will be provided. Area of steel /m A g x (1000 x 600) 900 mm Choose Ø1 15 spacing mm 900 Provide Ø1@ 150mm at the center of the section Elevation from 17.5m to 19 m Maximum Moment (M) 63.57KN.m. at elevation 17.5m eight above elevation 17.5 () 38.7KN. Eccentricity (e) M / / m A ± M c ± ± 15.5 I max KN.8MPa < 0.5 f ' c it is ok. min 189.KN 1.9MPa " Tension stress" There is a Tension stress and it is less than the allowable tensile strength of So minimum reinforcement will be provided. Area of steel /m A g x (1000 x 300) 50 mm Choose Ø1 113 spacing mm 50 Provide Ø1@ 50mm at the center of the section Minaret design 193

17 Elevation from 3.5m to 5.5 m Maximum Moment (M) 589.5KN.m. at elevation 3.5m eight above elevation 3.5 () KN. Eccentricity (e) M / / m A ± M c I ± ± max KN 1.MPa < 0.5 f ' c it is ok. min 57.7KN 0.53MPa " Tension stress" Provide Ø1@ 50mm at the center of the section Note: For the vertical reinforcement: It is obvious that tension stress is small and the can take it, so minimum reinforcement of A g will be provided for all sections. Reinforcement Details: Dimension Section Vertical Horizontal Outer inner No. Reinforcement Reinforcement Diameter (m) Diameter (m) layerø1@50mm layerø1@ 0mm layer Ø1@150mm Ø16@ 160mm layer Ø1@50mm Ø16@ 160mm layer Ø1@50mm Ø16@ 160mm layer Ø1@50mm Ø16@ 160mm layer Ø1@50mm Ø16@ 160mm layer Ø1@150mm Ø16@ 160mm Table 7.. Minaret sections Reinforcement details Minaret design 19

18 This is a sample of the Reinforcement of the section (section No.1) Figure Reinforcement of section No.1 Minaret design 195

19 7.3 Design of footing for minaret The footing maybe subjected to moment from all direction, so the footing will be designed to resist this moment by choosing square footing e assumed the footing dimension to be 10m x 10m x 1m Loads: The normal force KN Bending moment KN.m Check stress: M e. 98m P L m 6 6 Because e > L/ 6, so tension stress will be occurred P Mc ± ± A I KN /.75KN / 85 m Figure Pressure distribution 80 m hen e > L/6, the length of the triangular distribution decreases to 1.5L _ 3e and the maximum pressure rises to: P qmax KN < 00KN Ok. 1.5B( L e) (10.98) As in figure Put because we still have negative stress under the footing of the minaret and we should find any way to reduce it to zero or +ve value and we have two ways as follow: 1- Increase the size (Dimensions) of the footing: and this way isn t economic - Use the pile foundation instead of the single footing and this is economic way and the design of the pile foundation for the Minaret as shown in Appendix B Minaret design 196

DESIGN AND DETAILING OF COUNTERFORT RETAINING WALL

DESIGN AND DETAILING OF COUNTERFORT RETAINING WALL When the height of the retaining wall exceeds about 6 m, the thickness of the stem and heel slab works out to be sufficiently large and the design becomes