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An-Najah National University Faculty of Engineering Civil Engineering Department Graduation Project: 3D Dynamic Soil Structure Interaction Design For Al-Manar Building Supervised By Dr: Imad AL-Qasem. Prepared by: Ayman Naalweh Mustafa Mayyaleh Nidal Turkoman.
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An-Najah National University Faculty of Engineering Civil Engineering Department Graduation Project: 3D Dynamic Soil Structure Interaction Design For Al-Manar Building Supervised By Dr: Imad AL-Qasem Prepared by: Ayman Naalweh Mustafa Mayyaleh Nidal Turkoman
3D’s For Al-Manar Building GRADUATION PROJECT December 2010
Abstract Chapter One : Introduction Chapter Two : Slab Chapter Three : Beams Chapter Four : Columns Chapter Five : Footing Chapter Six : Checks Chapter Seven : Dynamic Analysis Chapter Eight : Soil Structure Interaction SUBJECTS TO BE COVERED
Abstract • AL-Manar building composed of seven stories office building. Each floor is composed of equal surface area of 1925 m2 with 3.5 meter height and long spans. • The building analyzed under static loads using SAP 2000v12. • After that the building was analyzed dynamically. • Finally it was designed based on Soil Structure Interaction (SSI).
INTRODUCTION • About the project: (AL-Manar) building in Ramallah, is an office building consists of seven floors having the same area and height, the first floor will be used as a garage. • Philosophy of analysis & design: • SAP2000 V12 is used for analysis and ultimate design method is used for design of slab, the slab are carried over drop beams.
INTRODUCTION • Materials of construction: • Reinforced concrete: (ρ) = 2.4 ton/m3 , The required compressive strength after 28 days is fc= 250 kg/cm2, For footings fc =280 kg/cm2 For columns fc = 500 kg/cm2 Fy =4200 kg/cm2 • Soil capacity = 3.5 kg/cm²
INTRODUCTION • loads: • Live load: LL=0.4 ton/m2 • Dead load: DL=(Calculated By SAP) , SID= 0.3 ton/m2 • Earthquake load: its represents the lateral load that comes from an earthquake.
INTRODUCTION • Combinations: Ultimate load= 1.2D+1.6L • Codes Used: • American Concrete Institute Code (ACI 318-05) • Uniform Building Code 1997 (UBC97)
SLAB • One way solid slab is used : • Thickness of slab: t = Ln/24 =12.9 cm use 15 cm ,d=12 cm • Slab consists of two strips (strip 1 & 2)
SLAB • ANALYSIS AND DESIGN FOR SLAB : • STRIP 1 :
SLAB M+ve. = 1.28 ton.m ρ= 0.0024 As bottom = ρ* b* d = 2.8 cm2 • Ast = ρ shrinkage * b*h = 0.0018*100*15= 2.7 cm2 • Use 1 ф 12 mm /30 cm
SLAB M –ve= 1.75 ton.m ρ= 0.0028 Ast top = 3.66 cm2 Use 1 ф 12 mm/ 25cm Shrinkage steel = 1 ф 12 mm / 30 cm Check shear : Vu= 2.95 ton at distance d from face of column. Ф Vc = ф (.53)(10) (b) (d) =0.75*0.53**10*1.0*0.12 = 7.54 ton > 2.95 ton. Ok
BEAMS • BEAMS SYSTEM: Beams will be designed using reaction method(Loads from slab reactions) in this project, all the beams are dropped, multi spans and large space beams.
BEAMS • DESIGN OF BEAM 1:
BEAMS • DESIGN OF BEAM 1:
BEAMS • DESIGN OF BEAM 1: • Positive moment on beam 1: • M+ve = 38.44 ton.m • =0. 00624 • As bottom = ρ* b*d = 14.4 cm2 • As min = 0.0033*b*d=0.0033.*30*76=7.54 cm2 < 14.4 cm2 • Use 4 ф 22 mm
BEAMS • DESIGN OF BEAM 1: Negative moment on beam 1: M -ve= 40.34 ton.m ρ = 0.0066 As top = 15.01 cm2 Use 4 ф 22 mm Min. beam width = ndb +(n-1)S+2ds+2* cover b min = 4(2.2)+ 3(2.5)+2(2.5) +2(1) =23.3 cm < 30 cm ok
COLUMNS • Columns System : • Columns are used primarily to support axial compressive loads, that coming from beams that stand over them. • 24 columns in this project are classified into 2 groups depending on the ultimate axial load and the shape. • The ultimate axial load on each column is calculated from 3D SAP, and the reaction of beams as shown in next table :
COLUMNS • Design of columns: • the capacity of column: ФPn max = ф λ {0.85𝒇'c (Ag - Ast) + ℱy Ast} Ast = 0.01 Ag (Assumed) • All columns are considered as short columns .
COLUMNS • Columns Groups :
Let COLUMNS = 1 • Design columns in group (1): Pu = 980 ton Check buckling: The column is short K: The effective length coefficient (=1 braced frame ) Lu: unbraced length of the column r: radius of gyration of the column cross section Let = 1 , = 16.67 < 22 → ok short column. • ФPn max = ф λ {0.85𝒇'c (Ag - Ast) + ℱy Ast}
Let COLUMNS = 1 • Design columns in group (1): → Ag = 4073 cm2 Use 70*70 → Ag = 4900 cm2 → Ast = 0.01× 4900 = 49 cm2 (use 20 Ф18) Spacing between stirrups: Spacing between stirrups shall not exceed the least of the following: 1) At least dimension of the column = 70cm 2) 16db = 16*1.8 = 28.8 cm 3) 48ds = 48*1.0 = 48 cm use Ties (1 ф 10 mm/25 cm c/c)
COLUMNS : • Summary:
FOOTING : • FOOTING SYSTEM: • All footings were designed as isolated footings. • The design depends on the total axial load carried by each column. • Groups of footings :
FOOTING : • Summary :
FOOTING : • Group 2 using sap :
FOOTING : • Group 2 using sap : • Moment per meter in x& y =395.66/4.7= 84.18 ton.m/m • Compare it with hand calculation Mu= 88.73 ton.m • % of error = 88.73-84.18/84.14 = 5.4 %
FOOTING : • Tie Beam Design: • Tie beams are beams used to connect between columns necks, its work to provide resistance moments applied on the columns and to resist earthquakes load to provide limitation of footings movement. • Tie beam was designed based on minimum requirements with dimensions of 30 cm width and 50 cm depth. • Use minimum area of steel , with cover = 4 cm.
CHECKS • Check Compatibility: This requires that the structure behave as one unit, so the computerized model should achieve compatibility, to be more approach to reality.
CHECKS • Check of equilibrium: • Dead load: Columns :
CHECKS Slab : Area of slab =1846.2m Weight of slab = 1846.2*2.4*0.15*7 = 4652.42 ton Beams :
CHECKS Super imposed dead load: Super imposed dead load = area of slab* Super imposed on slab = 1846.2*0.3*7 = 3877.02 ton Total dead load = columns +slabs +beams +super imposed = 794.41+4652.42+3877.02+4359.18= 13683.03 ton Results from SAP: Dead load = 13947.82 ton Error in dead load: % of error = (13947.82-13683.03)/ 13683.03 = 1.9% < 5% ok
CHECKS Live load: Live load = area of slab* live load = 1846.2*0.4*7 = 5169.36 ton Results from SAP: Live load = 5169.36 Error in live load: % of error =(5169.36 -5169.36)/5169.36 = 0% < 5% ok
CHECKS Check stress strain relationship: Taking beam 1 as example: Stress –Strain relationship is more difficult check compared with others, because of the large difference between values of 1D and 3D model, which usually appears during check .
DYNAMIC ANALYSIS • Period of structure : Fundamental period of structure depends on the nature of building, in terms of mass and stiffness distribution in the building . (Define area mass for building)
DYNAMIC ANALYSIS Check the modal response period from Sap by Rayleigh method Approximate method calculation: Rayleigh law: period = 2 , Where: M = mass of floor = displacement in direction of force (m) F: force on the slab (ton)
DYNAMIC ANALYSIS Rayleiph method calculation for 7 stories in x- direction :
DYNAMIC ANALYSIS Response spectrum : Analysis input: IE: seismic factor (importance factor) = 1.0 R: response modification factor (Ordinary frame) = 3 PGA: peak ground acceleration = 0.2 g According to seismic map for Palestine (Ramallah city) Soil type: SB (Rock) Ca: seismic coefficient for acceleration = 0.2 Cv: seismic coefficient for velocity = 0.2 Scale factor = = 3.27
DYNAMIC ANALYSIS Definition of response spectrum function :
DYNAMIC ANALYSIS Define of earthquake load case in x-direction :
DYNAMIC ANALYSIS Base reaction for Response Spectrum :
DYNAMIC ANALYSIS Summary:
SOIL STRUCTURE INTERACTION (SSI) • The process in which the response of the soil influences the motion of the structure and the motion of the structure influences the response of the soil is termed as soil-structure interaction (SSI). • Neglecting SSI is reasonable for light structures in relatively stiff soil such as low rise buildings, however, The effect of SSI becomes prominent for heavy structures resting on relatively soft soils .
SOIL STRUCTURE INTERACTION (SSI) • Soil structure model from SAP
SOIL STRUCTURE INTERACTION (SSI) • ANALYSIS AND DESIGN FOR BEAMS: • Beam 1:
SOIL STRUCTURE INTERACTION (SSI) • M+ ext. = 32.73 ton.m • ρ= 0.0053 • As bottom = ρ* bw* d = 12.0 cm2