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Introduction Introduction Tasks achieved in GP I Tasks achieved in GP I Earthquake load Earthquake load Alternative # 2 Alternative # 2 Design of compression.

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Presentation on theme: "Introduction Introduction Tasks achieved in GP I Tasks achieved in GP I Earthquake load Earthquake load Alternative # 2 Alternative # 2 Design of compression."— Presentation transcript:

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2 Introduction Introduction Tasks achieved in GP I Tasks achieved in GP I Earthquake load Earthquake load Alternative # 2 Alternative # 2 Design of compression & zero force members Design of compression & zero force members Design of tension members Design of tension members Design of end beams & columns Design of end beams & columns Design of welded connection Design of welded connection Design of bolted connection Design of bolted connection Material cost Material cost Comparison and final design Comparison and final design Conclusion Conclusion 2 Outline

3 Introduction Currently, Al Ain International Airport is under extension work due to: Currently, Al Ain International Airport is under extension work due to: o Growth in the passenger flights o Increase in the airline traffic to Al Ain Our graduation project was motivated by the ongoing expansion of Al Ain International Airport. Our graduation project was motivated by the ongoing expansion of Al Ain International Airport. The roofing system of a typical airports terminal was selected, analyzed and then designed. The roofing system of a typical airports terminal was selected, analyzed and then designed.

4 The major objective was to utilize the theory of structures principals and the Load and Resistance Factor Design concepts to; The major objective was to utilize the theory of structures principals and the Load and Resistance Factor Design concepts to; o Model o Analyze o Design the steel elements and connections forming the main supporting element of the long-span roofing system. Objective

5 Comprehensive literature review was conducted on common construction material, structural systems, and dimensions of existing or proposed airport terminals. Two alternative architectural designs were selected. A general structural layout was generated using the AutoCAD software to describe all the components of the first alternative system. 5 GP I Summary

6 The initial computer model was developed for the first alternative system using the structural analysis software SAP2000. The various design loads acting on the first alternative system including dead loads, roof live loads and wind loads were calculated based on the latest American standards developed by the American Society of Civil Engineers (ASCE7-05). A detailed 3D model was developed using SAP2000 to simulate the behavior and response of the selected structural system under the computed loads. 6 GP I Summary

7 First Alternative: Multi-Curvature Arch Generation of the Alternatives

8 Second Alternative: Traditional Single-Curvature Arch Second Alternative: Traditional Single-Curvature Arch Generation of the Alternatives

9 9 An earthquake is a shake of the earth's surface usually occurred by the release of underground stress along fault lines. This release causes movement in masses of rock and resulting seismic waves. Earthquake Load

10 10 Severe Lateral load Severe Lateral load Very complex & uncertain Very complex & uncertain Potentially more damaging than wind loads Potentially more damaging than wind loads Earthquake Load Earthquake Load Earthquake Load

11 Designing buildings to resist earthquakes requires that ground motions be translated into forces acting upon a building. Earthquake forces are called lateral forces. Designing buildings to resist earthquakes requires that ground motions be translated into forces acting upon a building. Earthquake forces are called lateral forces. The magnitude of earthquake load depends on the mass of the structure and on the horizontal acceleration imparted from the ground shaking. The magnitude of earthquake load depends on the mass of the structure and on the horizontal acceleration imparted from the ground shaking. 11 Earthquake Load Earthquake Load Earthquake Load

12 Case # 1 Case # 2 Earthquake Load Calculations

13 The procedure of calculating the earthquake load acting on the building structure is in accordance with ASCE7-05/IBC 2009 standards. o Required values, factors and coefficients : Earthquake Load Calculations

14 S s Values: Abu Dhabi = 0.6 Dubai = 0.83 Al Ain = Seismic activity in UAE (MCE) Abu Dhab i Dubai Al Ain

15 Abu Dhabi Dubai Al Ain S 1 Values: Abu Dhabi = 0.24 Dubai = 0.33 Al Ain = 0.27 Seismic activity in UAE (MCE)

16 Long - Period Transition Period : T L = 8 Seismic activity in UAE

17 Earthquake Load Calculations Base Shear (V b ) ; the total lateral load caused by the earthquake at the base of the structure. V b = C s W Where V b ; the seismic base shear. W ; the effective seismic weight the total dead load of the entire building. C s ; the seismic response coefficient 17

18 Earthquake Load Calculations The lateral seismic force (F xf ) ; F xf = C vfx V b The calculated base shear is distributed among all floors with respect to: o the heights of the building o their effective weight Vertical distribution factor (C vxf ) ; C vfx =( W xf h xf k / Σ i=1 n W i h i k )(C t h n x ) 18

19 19 Alternative # 1Results

20 20 Results Results JointW (KN)h (m)hkWhkCvfxFxfFINAL Fxf (KN) Case #1 Case #2 Alternative # 2 Results

21 Joint #a1a1 a2a2 Dead Load (Ib)Dead Load (Kips)Dead Load (KN) The various design loads calculations were performed based on [ASCE/SEI 7-05]. The various design loads calculations were performed based on [ASCE/SEI 7-05]. Dead Load Calculations Results Results

22 Live load acting on a typical truss joint: Live load acting on a typical truss joint: Results Results Joint #x1x1 x2x2 Live Load (Ib)Live Load (Kips)Live Load (KN) Live Load Calculations

23 Direction #1: Perpendicular to 204 m Direction #2: Perpendicular to 118.5m The main equation The main equation In wind load calculations, it is important to divide the system itself to different sections. Wind Loads Calculations

24 24 Wind direction Results Results Jointθ (deg)θ (rad)P (KN)Px (KN)Pz (KN) Wind Loads Calculations

25 The design of the airport roofing system using AutoCAD software Computer Model m 31 m 4 m Systems Material Steel (A572-G50) Roofing System Type Space Truss The different joints and elements were labeled in an Excel spreadsheet to be used as an input in SAP2000 Software

26 26 Computer Model Horizontal Structural Elements Beams & Columns Supports (Hinges)

27 Assigning Structural Loads in SAP2000 To simulate the behavior and response of the structural system under the computed loads. To simulate the behavior and response of the structural system under the computed loads. To conduct full structural analysis of the entire system. To conduct full structural analysis of the entire system. Assignment of the dead load Assignment of the live load

28 Assignment of the wind load Assignment of the earthquake load Assigning Structural Loads in SAP2000

29 The analysis was carried out according to 11 loads combinations Analysis Stage 1.2D +1.6L 1.2D + 1.6W + 0.5L 1.2D + 1E + 0.5L Truss 3Truss 24 Steel Section Circular cross-section

30 30 SAP 2000 Output Table : Sample SAP2000 Output FrameStationOutputCaseCase TypeP TextinText Kip D+LCombination D+LCombination D+LCombination D+LCombination D+LCombination D+E1+LCombination57.957

31 o The major objective of this phase is to insure the safety and economy of the system by comparing the element's resistance with the applied load. o A comparison was done between the two units based on the tension and compression forces for each of the combination. Final Design Process Type of load Comparison Design for Compression only-Compression Tension only-Max. Tension Compression or TensionCompression > TensionMax. Compression Compression or TensionCompression < Tension Max. Tension & Max. Compression (Consider the biggest section)

32 o Based on the type of load, the structural elements were classified as: Zero force members Zero force members Compression members Compression members Tension members Tension members Final Design Process o Design of Zero-Force Members Zero-force members are special members that are designed to satisfy stiffness criterion only (i.e.; strength is not an issue). These members should be designed following stiffness requirement of compression members.

33 Design of Compression Members o Steel is known to be sensitive to buckling and, therefore, special attention should be given to buckling behavior of these elements. Data obtained from LRFD manual o Procedure of designing the compression members

34 Design of Compression Members

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36 Tension members Tension members are structural elements that are subjected to axial tensile forces. 36 Design of Tension Members Failure mode #1 Design of steel due to yielding in the gross section. Failure mode #2 Design of steel due to tensile rupture in net sections

37 Design of tension members

38 Specifications and Final Design After designing the different elements, the appropriate steel section was selected for each element.

39 The design of the first upper cord is identical to the second one and same for the diagonals. Alternative #1 Alternative #2 Steel sections

40 End columns and beams are secondary elements that are intended to withstand self weight of cladding sheets. They should be able to provide adequate strength for moments resulting from wind loads. Alternative #1 Design of end beams and columns

41 Alternative #2

42 Steel members are usually connected in the fabrication shop by welding. Steel members are usually connected in the fabrication shop by welding. In the construction site either welding or bolting could be used; however, bolting is more recommended for quality control, ease and safety reasons. In the construction site either welding or bolting could be used; however, bolting is more recommended for quality control, ease and safety reasons. 42 Connections

43 There is a practical limit on the maximum length of steel members that could be carry to the construction site and that is about 12 to 14 meters There is a practical limit on the maximum length of steel members that could be carry to the construction site and that is about 12 to 14 meters 43 Connections Alternative #1Alternative #2

44 Welding process; The elements are heated and fused with molten metal added to the joint The most commonly used welding techniques are : (1) Shielded Metal Arc Welding (SMAW), used for field welds. (2) Submerged Arc Welding (SAW), used for shop welds. The SAW process provides more penetration into the base metal and higher strength than the SMAW process. Type of Weld: Fillet Welds Fillet Welds (about 80% of all welds), those welds placed in a corner formed by two parts in contact (the parts to be welded) Welded Connections

45 Type of Weld: Fillet Welds About 80% of all welds, those welds placed in a corner formed by two parts in contact (the parts to be welded) Types of length weld; Longitudinal Welds (Welds that are perpendicular to direction of the load applied) Transverse Welds (Welds that are parallel to the direction of the applied load) Welded Connections

46 The procedure for designing Welded connections Welded Connections Rn/in = 0.75(0.6 F EXX ) (te) (1.5) L w = P u /( Rn/in) L w = P u /( Rn/in) L w,min = 4Sw L w,min = 4Sw L w,max = 100Sw L w,max = 100Sw

47 Connections for tension members, such as truss members, are classified as concentric shear connections, since the centroid of the connector group (fasteners or bolts) coincides with the centroid of the member. Bolted Connections Concentric connections

48 Two main load transfer mechanisms control such connections: 1.Bearing-Type Connections: Transfer of loads depends on the Bearing at bolt holes. The most commonly used bolts are A325 and A Friction-Type (Slip-Critical) Connections: Load transfer depends on the friction between connected parts. Bolted Connections

49 The procedure for designing bolted connections Bolted Connections ØR n/bolt = 0.75 A b F t N b = P u /(ØR n/bolt ) Smin = 0.67d Smax = the smaller of [24t, 12] S = π D / N b

50 To calculate the overall cost of the project, the weight of the overall structural elements must be calculated. The truss is divided to; Lower cord elements Upper cord elements Diagonals Upper diagonals and Horizontal elements Purlins Cost Estimation Number of elements 39 SectionPipe2SH40 Weight (Ib/ft)3.66 Total Length (in) Length (ft) Weight (Ib) Weight (ton)0.850 Data obtained from LRFD manual Data obtained from LRFD manual Horizontal elements (AL#2)

51 Truss Part Lower Chord Upper Chord Diagonal Upper Diagonal Horizontal Element Purlin Total Cost (Dhs/ton) Total weight (ton) Order (10%) Truss (Dhs/ton) ,144.1 System (Dhs/ton) ,952,704 Cost Estimation Alternative #1 Alternative #1

52 Cost Estimation Truss Part Lower Chord Upper Chord Diagonal Upper Diagonal Horizontal Element Purlin Total Cost (Dhs/ton) Total weight (ton) Order (10%) Truss (Dhs/ton) ,043.3 System (Dhs/ton) ,608,584 Alternative #2 Alternative #2

53 The projects objective: to utilize the theory of structures principals and the load and resistance factor design concepts to model, analyze and design the steel elements and connections that make up the main supporting element of the long-span roofing system. For two different systems : For two different systems : Full analysis and design. Cost estimation. Conclusion

54 The second alternative was found to be more efficient since it costs less than the first alternative. This result meets our expectation since the second alternative is a single curvature arch which is more efficient in carrying loads as compared to the first alternative. Some gained skills: Some gained skills: Calculating the different types of load according to the detailed analytical procedures presented by ASCE7-05, utilizing recent data such as the maps used in earthquake load calculations. Using structural analysis software (SAP2000) to model and analyze the roofing system. Employing the project advisors and coordinators feedback to improve our performance and learn from our mistakes. Solving problems, overcome difficulties and acceptable time management. Enhancing team work.

55 Finally, this project was very helpful and challenging at the same time. One remark among many is to conduct more projects and researches in the same field and other fields in Engineering to gain more experience, to develop our performance and to apply what we learnt in our career.

56 Thank You


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