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An-Najah National University Faculty of Engineering Civil Engineering Department. Al- Quds Open University -Nablus. Prepared by: Rana Adli Ramahi Supervised by: Eng. Imad Al- Qasim. Outline:. Introduction Slabs preliminary design Beams preliminary design
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An-Najah National University Faculty of Engineering Civil Engineering Department Al-Quds Open University -Nablus Prepared by: Rana Adli Ramahi Supervised by: Eng. Imad Al-Qasim
Outline: • Introduction • Slabs preliminary design • Beams preliminary design • Three-dimensional structural modeling • Columns design • Walls design • Footings design • Stairs design An-Najah National University
Chapter One: Introduction An-Najah National University
Project Description • The structure that designed is the building of Al-Quds Open University, Nablus-Palestine. • the land area is 3208 m2 • It consists of two Buildings, Academic & Administrative Buildings. • They consists of five floors over ground & join together in two basement floors. • The ground floor elevation is 4.5 m, all other floors are 3.5m elevated. An-Najah National University
Project Description • The academic building will be designed in this project • It’s divided by structural joints with thicknesses equal 10cm roughly into four parts: • Part A is the central entrance for the academic building • Parts B & C consists of garages in the second basement floor, lectures rooms in floors (B1-F3), & offices in the fourth floor. • Part D is an auditorium (it’s design not completed) An-Najah National University
Philosophy of analysis & design • The structure was analyzed & designed by one & two dimensional structural models for the elements manually & using SAP, then using three dimensional structural model SAP2000 14.2.4 An-Najah National University
Design code & load combinations • The structural design was according to American concrete institute code (ACI318-08) • Depending on the used code the load combinations are: • U1 = 1.4D • U2 = 1.2D+1.6L+1.6H • U3 = 0.9D+1.6H An-Najah National University
Materials • Structural materials used in the design are: • concrete: f’c=24 MPa for horizontal elements f’c=28 MPa for vertical elements • Steel(both longitudinal & transverse): fy=420 MPa Soil Bearing • Bearing capacity of the soil is 400 KN/m2 An-Najah National University
Loads: • Gravity loads: • Live loads: for all floors = 4 KN/m2 except the second basement floor which equal 5KN/m2 • Dead Load: In addition to own weight of the structural elements, • Superimposed dead load =4.36 KN/m2 • Perimeter walls load =20.6 KN/m ………………. for h=3.5m =26.5 KN/m …………..…... for h=4.5m • Lateral loads: Only soil pressure was taken into consider. An-Najah National University
Structural Systems: • Part B & Part C are designed as one way ribbed slabs in X-direction, with hidden beams generally • Part A & Part D are designed as two way solid slabs with drop beams. An-Najah National University
Chapter Two: Slabs Preliminary Design An-Najah National University
Thickness: • For Part (B) & Part (C): One way ribbed slab L max = 5.8 m Hmin=L / 18.5 = 5.8 / 18.5 = 0.314 m →Use h = 0.32 m • For Part (A) & Part (D): Two way solid slab Direct design method does not satisfied for this slab, so many trials for thicknesses done in the 3-d model to determine the suitable thickness. An-Najah National University
Loads estimation: • As a sample calculation Take the ribbed slab (rib1.1): • Own weight = 3.15 (KN/m) /0.55 = 5.73 KN/m2 • Superimposed dead load =4.36 KN/m2 • Total dead load = 5.73+4.36 = 10.2 KN/m2 • Live load = 4 KN/m2 →Wu (for rib) = 10.2 KN/m/rib An-Najah National University
Analysis using SAP: An-Najah National University
Reinforcement: • φVc = φ*0.1667*√24*150*290 = 26.67 KN > Vu No need for shear reinforcement • As min = 0.0033*150*290 = 143 mm2 An-Najah National University
Chapter Three: Beams Preliminary Design An-Najah National University
Thickness: • Take Beam B2 as a sample calculation: All spans of this beam have a length 5.6 m Hmin=L / 18.5 = 5.1 / 18.5 = 0.28 m →Use hidden beams (h=32cm) An-Najah National University
Loads estimation: • Wu from slab (5.7) =60.7 KN/m • Wu from slab (3.2) =29.6 KN/m • Factored O.W. of beam = 0.32 * 1 * 25 *1.2 = 9.6 KN/m • Total ultimate load on beam = 60.7 + 29.6 + 9.6 = 100 KN/m An-Najah National University
Using ACI-coefficient the moment diagram(KN.m),shear diagram (KN): • . • As =ρ*b*d An-Najah National University
Torsion • From ribs models in SAP, the moments in the supports of the slab act on the beams as torsion …….. • Tm = 16.96 KN.m/m • Tv(due to shear on the face of the beam from both sides)= 15.53 KN.m/m →Total factored torsion = 73.42 KN.m/m (64.58 at d from face of support) • Reduction for compatibility torsion to be 47.5 KN.m/m • No equilibrium torsion occur because the center of the beam same as the center of columns carry it An-Najah National University
Torsion • Check section adequacy for beam OK, Good section • Av/s +AT/s = 2.09 mm2/mm • Use 1φ12/100mm • Longitudinal steel at each support = 510 mm An-Najah National University
Total reinforcement (manual design) An-Najah National University
Model in SAP • The beam was modeled in SAP with fixed ends firstly & pin ends also, then the average of loaded was used for the design Pin ended fix ended An-Najah National University
Model in SAP • The average moment (KN.m): • The total (torsion & flexure) longitudinal reinforcement: An-Najah National University
Section in beam B2 An-Najah National University
Chapter Four: Three Dimensional Structural Modeling An-Najah National University
General • A three dimensional structural modeling done using SAP2000(v14.2.4) • Many verification checks must be achieved, serviceability, equilibrium, compatibility, & stress-strain relation ship. An-Najah National University
Serviceability Long Term Deflection Check • Take Part (C) & Part (B) as sample calculation, the check occurs for many spans, the critical one is the span between H-G&15-17 • SAP information: • Mu=10.3 KN.m • ∆D = 0.0094, ∆D+L = 0.0114 • Calculations summery: • ∆allowable = L/480 = 2.9/480 = 0.00604 m • ∆LT = ∆L +α ∆D+α T ∆Ls = 0.0226 >∆all ,find Ig/Icr An-Najah National University
Ig = 7.03*104 cm4 • Icr = 8277 cm4 • . • . • ∆L = ∆D - ∆D+L = 0.125 mm • ∆LT = ∆L +α ∆D+α T ∆Ls = 0.001 < ∆all=0.006 OK An-Najah National University
Check Compatibility • From start animation in SAP, the compatibility(structure work as one unit) was verified An-Najah National University
Check Equilibrium • Take Part (B) as sample calculation • Dead load (own weight) An-Najah National University
Dead load (Superimposed dead load) • Live load An-Najah National University
Comparing results: • Error (own weight) = 2.4% OK • Error in SID = 2.64% OK • Error in live load = 0.33% OK An-Najah National University
Check stress-strain relationship • Take Part (B) as sample calculation, check for span 5-6 in beam B4 (1m*0.32m) & Wu =92 KN/m • +ve M = Wu*Ln2/16 = 92*3.92/16 = 87.46 KN.m • -ve M =127.2 KN.m at each support & avg is 127.2KN.m • 1-D model: (+ve M) + [(–ve MR + -ve ML)/2] = 214.67 KN.m • 3-D model: M = 233 KN.m • Error = 8.7………………….. OK An-Najah National University
Slab Design • Take Part (B) as sample calculation, design slab thickness 32cm (ribbed slab R1) & cover 3cm. • Bending moment diagram for rib 1 (KN.m/m) An-Najah National University
Beam Design • Take Part (B) as sample calculation, design beam on grid (F) An-Najah National University
Chapter Five: Columns Design An-Najah National University
Preliminary Design • Take group G2 as sample • Pu = 2000 KN , • assume ρ = 0.01 • Pu = 0.65 * 0.8 * [0.85* f’c *(0.99Ag) + Fy*(0.01Ag)] → Ag = 0.1523 m2 , use section b*h = 0.5 m *0.5 m As = ρ * Ag = 0.01 *0.25 = 2.5*10-3 m2 = 2500 cm2 So, use 8φ20 mm An-Najah National University
(3-D)Design • Take group G2 as sample( Pu = 1727.8KN & M2=47 KN.m &M1=29.66 KN.m), design for axial, flexure & shear • Check buckling, depend on stiffness's of column & related beams: • K factor =0.82 (Non-sway) An-Najah National University
K*Lu/r = 0.82*4.2/0.15 = 22.96 • Check slenderness: 34 – 12(M1/M2) >22.96 (neglect slenderness) • δns = 0.92, use δns = 1 →Md=Mu = 47 KN.m • Using interaction diagram(f’c=28, fy=420, ƴ=0.75) →ρ=0.015, As=30 cm2 → Use 8φ22 mm • Use φ10/200 mm • Vn<Vc/2 …………… no shear reinforcement An-Najah National University
Chapter Six: Walls Design An-Najah National University
Bearing wall design • Take wall 6as sample, design for axial loads. • average axial load=337 KN An-Najah National University
Thickness: • Section used has a thickness =25 cm • = 1952KN > Pu OK • Reinforcement (minimum) • Vertical reinforcement = 0.0012*Ag (Use 1φ10/300 mm) • Horizontal reinforcement = 0.002*Ag (Use 1φ10/300 mm) An-Najah National University
Basement wall design • Take wall 11 as sample, design for axial loads & soil load. • Vu (from sap) = 122 KN • φVc = 127KN>Vu OK • From SAP: • Vertical Moments: • M +ve max = 55 KN.m/m (ρ=0.004) → (1φ14/250mm) • M-ve max = 30 KN.m/m (ρ=0.0033) → (1φ14/250mm) • Horizontal Moments: • M +ve max = 33 KN.m/m (ρ=0.003) → (1φ12/300mm) An-Najah National University
Chapter Seven: Footings Design An-Najah National University
Footing system • Footings that used in this project can be classified into three types: • Wall footing • Single footing • Combined footing • No need for using mat foundation because the soil has high bearing capacity. • The footings was grouped into 27 group, depending on the column load, dimension, shape, adjacency. An-Najah National University