Presentation on theme: "Analysis and Design of a Multi-storey Reinforced Concrete Building"— Presentation transcript:
1Analysis and Design of a Multi-storey Reinforced Concrete Building United Arab Emirates University College of Engineering Civil and Environmental Engineering Department Graduation Project IIAnalysis and Design of a Multi-storey Reinforced Concrete BuildingPreparedSultan Saif Saeed AlneyadiSultan Khamis AL-shamsi Hasher Khamis AL-azizi Rashed Hamad AL-Neyadi Abdulrahman Abdulla JarrahAdviserDr. Usama EbeadSecond Semester 2007/2008
2Outline Objectives Summary General Approach Building Types Concrete Structural ElementsSlabsFlat SlabDesign of Flat SlabColumnsRectangular ColumnsDesign of Rectangular ColumnsShear wallsDesign of Shear WallsFoundationsPile GroupDesign of Pile GroupEconomic ImpactEnviromental ImpactConclusion
3Objectives The Objectives of the Project are:- Carrying out a complete analysis and design of the main structural elements of a multi-storey building including slabs, columns, shear walls and foundationsGetting familiar with structural softwares ( SAFE ,AutoCAD)Getting real life experience with engineering practices
4SummaryOur graduation project is a residential building in Abu- Dhabi. This building consists of 12 repeated floors.
5General ApproachObtaining an architectural design of a regular residential multi-storey building.Al-Suwaidy residential building in Abu Dhabi.Establishing the structural system for the ground, and repeated floors of the building.The design of column, wind resisting system, and type of foundations will be determined taking into consideration the architectural drawings.
6Types of building Buildings are be divided into: Apartment building Apartment buildings are multi-story buildings where three or more residences are contained within one structure.Office buildingThe primary purpose of an office building is to provide a workplace and working environment for administrative workers.
9Concrete MixturesConcrete is a durable material which is ideal for many jobs.The concrete mix should be workable.It is important that the desired qualities of the hardened concrete are met.Economy is also an important factor.
10Structural Elements Any reinforced concrete structure consists of : SlabsColumnsShear wallsFoundations
11Flat Slab Structural System Flat slab is a concrete slab which is reinforced in two directionsAdvantagesDisadvantages
13Defining properties Slab thickness = 23 cm Concrete compressive strength = 30 MPaModules of elasticity of concrete = 200 GPaYielding strength of steel = 420 MPaCombination of loads (1.4Dead Load Live Load)
14ACIACI contains the current code requirements for concrete building design and construction.The design load combinations are the various combinations of the prescribed load cases for which the structure needs to be checked.1.2 DL LL
15Flat Slab Analysis and Design Analyzing of flat slab mainly is done to findShear forces.Bending moment.Deflected shape.Reactions at supports.15
19ColumnsIt is a vertical structural member supporting axial compressive loads, with or with-out moments.Support vertical loads from the floors and roof and transmit these loads to the foundation.
20Types of column Tied Columns Over 95% of all columns in building in non-seismic regions are tied columnsSpiral ColumnsSpiral columns are generally circular. It makes the column more ductile.Spiral columnRectangular column
21Steel Reinforcement in Columns The limiting steel ratio ranges between 1 % to 8 %.The concrete strength is between 25 MPa to 45 Mpa.Reinforcing steel strength is between 400 MPa to 500 Mpa.
22Design procedure 1. Calculate factored axial load Pu 2. Select reinforcement ratio3. Concrete strength = 30 MPa, steel yield strength = 420 MPa4. Calculate gross area5. Calculate area of column reinforcement, As, and select rebar number and size.
24Guidelines for Column Reinforcement Long ReinforcementMin. bar diameter Ø12Min. concrete covers 40 mmMin. 4 bars in case of tied rectangular or circularMaximum distance between bars = 250 mmShort Reinforcement ( Stirrups)Least of:(16)×diameter of long barsleast dimension of column(48)×diameter of tiesAspSdc
27Shear wallsA shear wall is a wall that resists lateral wind loads which acts parallel to the plane of the wall.
28Shear walls Wind results in a pressure on the surface of the building Pressure increases with heightPositive Pressure, acts towards the surface of the buildingNegative Pressure, acts away from the surface of the building (suction)
29Wind pressure q = Velocity pressure (Wind speed, height and exposure condition)G = Gust factor that depends on the building stiffnessCp = External pressure coefficient
30Gust G Factor & External pressure Cp coefficient for Stiff Structures take G =0.85Windward Wall, Cp = +0.8Leeward Wall, Cp = varies between -0.2 & -0.5Depending on the L/B RatioL/B = m /26.18 m = < 1 then , Cp = -0.5
31Velocity Pressure V = 160 km/h Kz = To be determined from the equationsKzt = 1 (level terrain adjacent to the building – not on hill)Kd = 0.85 (rectangular building)I = 1 (use group II)
37Design of the wind pressure 37qb = qz (at the top of the building)G0.85Cp (windward)0.8Cp (leeward)-0.5B (m)26.18LevelHeight (z) mTributary Height (ht ) mKzqz (kn/m2)Design Wind Pressure(KN/m^2)Design Wind Force (KN)wind ward (qz G CP)lee ward (qb G CP)wind ward (qz G CP)(B)(ht )lee ward (qb G CP)(B)(ht )Total (floor level)Moment(KN.m)12431.751.361126.96.36.19910361.31932.51.288291.25725.51.226221.18518.51.144151.09311.51.0320.9514.50.85sum37
38Computing total moment acting toward N-S Direction 38M = total floor level *height (z)38
39W-E Direction Computation 39L= 26.18B= 18.84LevelHeight (z) mTributary Height (ht ) mKzqz (kn/m2)Design Wind Pressure(KN/m^2)Design Wind Force (KN)wind ward (qz G CP)lee ward (qb G CP)wind ward (qz G CP)(B)(ht )lee ward (qb G CP)(B)(ht )Total (floor level)Moment(KN.m)12431.751.361188.8.131.5210361.31932.51.288291.25725.51.226221.18518.51.144151.09311.51.0320.9514.50.85sum39
40Design of Shear Wall40East west directionNorth south direction40
43FoundationsFoundations are structural components used to support columns and transfer loads to the underlying Soil.FoundationsDeepShallowIsolated Combined Strap wall Raftfooting footing footing footing footingCaissons Piles
44Pile foundationOur building is rested on a weak soil formation which can’t resist the loads coming from our proposed building, so we have to choose pile foundation.Pile capPilesWeak soilBearing stratum
45Pile foundationPiles are structural members that are made of steel, concrete or timber.
46Function of pilesAs with other types of foundation, the purpose of a pile foundation is:To transmit a foundation load to a solid groundTo resist vertical, lateral and uplift loadPiles can beTimberConcreteSteelComposite
47Concrete piles General facts Advantages Disadvantages Usual length: 10m-20mUsual load: 300kN-3000kNAdvantagesCorrosion resistanceCan be easily combined with a concrete superstructureDisadvantagesDifficult to achieve proper cutoffDifficult to transport
48Pile foundation Piles can be divided in to two major categories: End Bearing PilesIf the soil-boring records presenceof bedrock at the site within a reasonable depth,piles can be extended to therock surfaceFriction PilesWhen no layer of rock is present depth at a site, point bearing piles become very long and uneconomical. In this type of subsoil, piles are driven through the softer material to specified depths.
49Pile Cap Reinforcement Pile caps carrying very heavy point loads tend to produce high tensile stresses at the pile cap.Reinforcement is thus designed to provide:Resistance to tensile bending forces in the bottom of the capResistance to vertical shear
50Design of the pile cap Rs = α ⋅ Cu ⋅ As .L bearing capacity of one pile:Rs = α ⋅ Cu ⋅ As .LLength of pile penetration L = 18 metersAdhesion factor of soil (clay) α = 0.8Untrained shear strength Cu = 50Diameter = 0.9 mFor piles with diameter 0.9 mRs = KN
51First typeThis section shows how pile caps are designed to carry only vertical load, and the equation used to determine the resistance of cap isWhereP is the strength of the pile cap per one pileQ is the total force acting on the pile capn is the number of piles used to support the pile cap
52Columns layout & Reactions ( Vertical Load ) Total ReactionkN1129.632246.852962.28382.6610393.3821458.355500.223400.854810.224627.7425384.1430158.31899.632355.26
53Design of pile cap (Vertical Load only) Reaction = kNPile diameter = 0.9 mCapacity for one pile = 0.8 * 50 * 18 * π * 0.9 = KNNeed 3 pilesLength between piles = (2*0.3) + (3*0.9) + (2*0.9)*2 =6.9 mWidth = 1.5 metersActual forces on each pile = = kN
54Second type Second type This section shows how pile caps are designed to carry vertical load and lateral loads ( Bending Moment), and the equation used to determine the resistance of cap is
55Shear walls layout & reactions M (KN.m)N (KN)W1W2W3W45719.5W54128W61899.6W10W11W13W143297.6W152040W165470.2W17W18
56Design of pile cap (Vertical Load & moment) Shear wall # (1):M =Q =Assume 8 piles
57Economical impactReinforced concrete is proven to be a very economical solution in the UAE.the most affordable solution for multistory building such as the one we are making the analysis and design for.
58Environmental impactAlthough the cement production is environmentally challenging, the final product of a reinforced concrete building is environmentally friendly.
60ConclusionWe have applied our gained knowledge during our graduation projectWe are able to use structural software ( SAFE )We have practiced real life engineering practicesThis GP enables us to go into the market with an excellent background regarding design of RCAt this point, we would like to thank all instructors, engineers, and Al Ain Consultant Office for their grateful effort.