ANALYSIS AND DESIGN OF PROJECTS (PROCEDURE)

Sunday, May 20, 2012

General approach Since the analysis procedure is basically numerical, and since it is based on the finite-element method, it will always ...

General approach

  • Since the analysis procedure is basically numerical, and since it is based on the finite-element method, it will always be required to endorse a finer mesh (one with more smaller elements) in order to yield more accurate results.


  • In the following, we will adopt a procedure that maintains that general understanding.



Vertical Loads

  • A story-by-Story analysis under the effect of dead and live loads shall be performed using SAP2000, taking into consideration the following:



    • A finer mesh shall be used.

    • Columns shall be includes in the analysis (not as knife-edge supports).

    • Walls loads shall be included as line loads.

  • Design of slabs and beams (under vertical loads) shall be done using the results of the analysis

  • Column and wall normal forces due to dead and live loads shall be summed up for all stories.

  • Columns and wall moments due to dead and live loads shall be recorded at this stage.



Lateral Load Analysis (The Etabs File)

  • Build the Etabs model, taking into consideration the following.


    • For columns, use frame elements

    • For walls, use a horizontal mesh of 0.5-0.8ms and a vertical mesh of 1.2-1.8ms (an element 0.6X1.2 seems appropriate, also may be 0.6X1.75). Don’t forget composite columns (if any). Group sum each wall and each core separately (pier forces) are required stories.

    • For slabs include slab limits and openings ignore small openings since they add more shell elements. Add beam elements at their locations as frame elements. Discretize slab with the finest mesh possible (less than or equal 2.5 x 2.5m, if) possible. Try to have the mesh as regular as possible All points within each horizontal level shall be included in a separate diaphragm.

    • Use reduced stiffness 0.35 for beams and 0.7 for columns and walls, and 0.25 for slabs.


  • For the dead loads, add dead load as a distributed load. It includes flooring and wall weight (A value of 0.3 - 0.5 seems usually reasonable). Include the self weight in the dead load. (Including the walls as a line load is an option?!)

  • For the live load, add live loads as a distributed load.


  • For the earthquake loads. Use UBC’97 loads in both directions with the following options:


    • Include eccentricity 0.05 in each direction.

    • Include Ct


      • First option: Ct = 0.02ft (user-defind)

      • This includes Ta as ct hn ¾ (Eq. 30-8)

      • Second option: Ct = 0.02ft (Program Calculated)

Calculate T using equation from code and compares it with Ta according to Eq. (30-8). You have to include dynamic analysis option for this option to work. Otherwise, program sometimes chooses T wrongly as We recommend using this second option.

Third option: Ta is user-defined as ct hn ¾.

There should be a match between the Eq. (30-8) first and third options.




    • R = 5.5 (or as per code)

    • Soil type = Sc (or per code)

    • Z = 0.15 (or as per code)

    • These loads are ultimate. To get working loads divide by 1.4

For the wind loads using BS 6399-95, use the following options!

  • Exposure extents from rigid diaphragm

  • Wind direction Oo (x-direction) and 90 (y-direction)

  • Front Coeff CP = 0.8

  • Rear Coeff CP = 0.3

  • Exposure height: Top STORY & BOT. Story (exclude basements)

  • Include parapets (if any)

  • Effective speed ve (m/sec) = 45 (or as per code)

  • Size effect factor, Ca = 1

  • Dynamic augmentation factor, Cr = 0.25

  • Exposure width (table)         Calculated from diaphragm extents. This wind loads option is recommended to be used.

For the wind loads using ASCE7-98, use the following options:

  • Exposure extents from rigid diaphragm

  • Direction angle Oo (x-direction) and 90o (y-direction)

  • Windward Cp = 0.8

  • Leeward Cp = 0.5

  • Exposure height: Top STORY & Bot. STORY (exclude basements)

  • Include parapets (if any)

  • Basic wind speed v= 100 mph

  • Exposure category = C

  • Importance factory, Iw=1

  • Kzt = 1

  • Kd = 0.85

  • Gust factor G = 0.85

  • Exposure width (tables)          calculated form diaphragm extents

For the winds loads using UBC-97, use the following options:

  • Exposure extents from rigid diaphragm

  • Direction angle Oo (x-direction) and 90o (y- direction)

  • Wind ward Cq = 0.8

  • Lee ward Cq = 0.5

  • Exposure height: Top STORY & Bot. STORY (exclude basements)

  • Include parapets (if any)

  • Basic wind speed v= 100 mph

  • Exposure type = C

  • Importance factory, Iw=1

  • Exposure width (tables)          calculated form diaphragm extents.



For the response spectrum, use the following options:

  • UBC’97 response spectrum


    • Damping 5%

    • Scaling factor to equate base shear (may be you first need to run the program to get initial base shear values for response spectrum then calculate the scale factor)

    • Use Ritz vector.

    • Choose number of modes = 15

    • Use SRSS option for combination of modes.

Also, review these options before you run your file:

  • Mass per unit volume = 0.25 t/m3 (concrete)

  • Weight per unit volume = 2.5t/m3 (concrete)

  • Mass per unit volume = 0.785 t/m2 (Structural Steel)

  • Weight per unit volume = 7.85 t/m3 (Structural Steel)

  • Ec = 140000(fcu)1/2   t/m2  for a given fcu (concrete)

  • Es =  21000  t/m2                                 (Steel)

For the mass source data, use:

  • Mass defined from loads

  • Mass source data

  • Mass lateral lump mass from mass only at stories load No   Yes

  • Mass source loads

Load   multiplier

Dead       1

For the P-Delta effect, choose:

  • Number of iterations  =  2

  • P-Delta load combination = 1.2D + 0.5L


  • It is not recommended to perform a P-Delta analysis, unless a run is done without P-Delta to know that everything is ok, since P-Delta run takes more time.

No load combinations are recommended to be included. No design using Etabs is also recommended.

Consider reversibility of lateral loads
Results of all loads are working loads, except for earthquake load, which are ultimate.

Analysis Results & Design

Drift: drift values should not exceed 0.005h for lateral load cases

Slabs: slab design is basically dependent of item ‘2-vertical loads’. However, effect of lateral loads should be checked from step ‘3-lateral load analysis’, especially in case where framing in based on flat slab behavior, rather than connecting beams

Beams: Beam design is based on superposition of vl loads from ‘2-vertical loads’ and lateral loads from ‘3-lateral load analysis’.

Columns and walls

  • Vertical Loads (working loads)



  • Normal forces: from step ‘2-vertical loads’. Results of normal forces due to D.L and L.L from step ‘3-lateral load analysis’ should be overviewed only, since meshing is usually course (wide) and doesn’t produce accurate results and may be wall loads were not entered as line loads. Note that normal forces in columns and walls intersecting retaining walls drop in value in basements, due to interference of retaining walls.




  • Moments: use recorded values in step ‘2-vertical loads’ or from minimum sec (as per codes). Results of moments from step ‘3- lateral load analysis’ should be overviewed only, since meshing is usually course and doesn’t produce accurate results, in addition to other reasons mentioned above.



  • Lateral Loads (working loads)



  • Normal force and moments from ‘3-lateral load analysis’ for max. cases of wind, EQ, and response spectrum shall be used for design.




  • Note that EQ forces should be divided by 1.4 in order to be service loads.



  • Use PCA column with pervious service straining actions for column and wall design.


Copyright © 2019 Strukts . All rights reserved.
Name

• compression couplers,1,• tension couplers,1,1997 UBC,1,56 days Concrete test,1,ADDICRETE,1,additives,1,administer computer networks,1,admixtures,1,Advises Subcontractors,1,alignment of the shafts,1,Allowable Stress Design,1,Anchor Bolts,1,Annual depreciation expense,1,approval of drawings,1,ASCE7,1,ASD,1,Assist in Quantity,1,Assist the Project Manager,1,Authority to Delegate,1,AutoCAD,2,AutoCAD to Etabs,1,bagger,1,bars,1,bars in a bundle,1,BASE ISOLATED DAMAGE,1,base plates,1,basement wall,1,Basic soil properties,1,basic wind speed,1,Beams Inspection Checklist,1,Bearing capacity,1,bell pile bottom,1,bent bars,1,Bitomeneous,1,Blockwork,1,Bowels,1,breaching spillway,1,BS 8007:1987,1,BS5400,1,BS6399,1,BS8007,1,BS8110-1997,1,building materials,1,buildings height,1,CALCULATION OF CRACK WIDTH,1,Canary Island Dates,1,cantilever footing,1,Carbon Equivalent,1,carbon test,1,cast in-situ,1,cast-in-place anchors,1,cast-in-place concrete pile,1,Cause-and-effect diagram,1,Chairs,1,Check sheets,1,Chemical Admixtures,1,Chute spillway,1,CIRIA,2,CIRIA Report 136,1,civil engineering,1,civil structures,1,Coal ash,1,collars,1,Collision Load,1,columns,3,columns and walls,1,Combination of combinations,1,combinations in Etabs,1,Company's Health,1,Compliant Towers platforms,1,compression test,1,compressive strength,1,concrete,4,concrete block buildings,1,CONCRETE IN HOT WEATHER,1,CONCRETE MOMENT FRAME,1,concrete pile,1,Concrete Rebound Hammer,1,Concrete Shrinkage,1,Concrete Slump Test,1,concrete walls,1,Construction and Stressing,1,Construction companies in Dubai,1,construction drawings,1,construction industry,1,Construction joints,1,Construction Manual,1,continuous external restraint,1,continuous slabs,1,contract planresponsibilities of QA/QC,1,Contracts Manager,1,cooling pipe system,1,Corner reinforcement,1,Cost Plus Award Fee,1,Cost-reimbursable,1,COUPLED SHEAR WALL,1,Couplers,1,couplers in columns,1,CP3,1,CRACK WIDTH,1,Creep,1,CURING,1,day to day work progress,1,Dead load and Self-weight,1,Deck,1,Deflection,1,Deflection discussion,1,Deflection in Prestressed,1,deformed bars,1,Demolition,1,design drawings,1,Design Requirements,1,designing a tall building,1,Designs projects,1,detailed review,1,detailing and implementation,1,Development length,1,different codes in one structure,1,Differential elastic shortening,1,dimensions,1,DIRECT TENSION,1,Draftsman responsibilities,1,drawings and specifications,1,Drift Limitations,1,Drop beams,1,dust loads,1,dust on roof,1,Dynamic Pile Head,1,dynamic wind pressure,1,Early age Crackwidth,1,early strength cement,1,Earth pressure,1,Earthquake Design,1,earthquakes,1,EBT adhesive sealant,1,Elastic Shortening,1,electrical and manual,1,elevator requirement,1,Elevators,1,Encasement of pipes,1,end plate connection,1,Energy dissipater,1,engineering design,1,Environmental procedures,1,epoxy compound,1,Epoxy grout,1,equipment performance records,1,Error and warning free model,1,Errors in Etabs,1,establishment of construction,1,Estimating Flow Standard,1,Etabs,2,Etabs Design,1,ETABS to ROBOT,1,excavation,1,Excavation slopes,1,external concrete surfaces,1,Finishing of slip-forms,1,Fire,1,Firm Fixed Price,1,Fixed platforms,1,Fixed Price Incentive Fee,1,Fixed Price with Economic,1,Flexible Joints,1,Flexible pipes,1,floors,1,Flow charts,1,Fly ash,1,Foundation analysis,2,Foundations,2,framed openings,1,Free over fall spillway,1,FRP,1,FRP advantages,1,FRP disadvantages,1,FRP technology,1,full length bar,1,General Notes,1,Geophone sensor,1,Hammer Schmidt Type,1,HDP,1,Health and Safety procedures,1,helical piering,1,helical piles,1,High Early Strength Portland Cement,1,High quality additives,1,high rise / tower,1,highly effective,1,Histograms,1,hooked bars,1,Horizontal steel,1,Human Comfort,1,hydraulic,1,hydraulic jump,1,Hydraulic resistance,1,Hydro technical tunnels,1,IBC/ASCE,1,immediate reaction,1,importance of Plasticizers,1,Importing,1,IMS,1,Inspection Checklist,6,INSTRUMENT CALIBRATION,1,inter-story drift,1,interest payments,1,IT engineer responsibilities,1,Jack-up Platforms,1,Jacking Systems,1,Japanese code for escalators,1,Kicker,1,largest man-made machine,1,largest man-made machine on earth,1,largest oil platform,1,lateral forces,1,lateral loads,1,LFD,1,lifting hooks,1,Load Factor Design,1,load resisting elements,1,load-bearing wall,1,Loading,1,Loads and Resistances,1,LRFD,1,Maintain contract database,1,Maintains close scrutiny,1,maintenance cost,1,Makes recommendations,1,manage,1,manufacturer,1,manufacturing process,1,Maximum allowable slopes,1,maximum deflection,1,maximum difference,1,maximum pressure,1,maximum reinforcement,1,maximum temperature,1,Mechanical couplers,1,Mechanical damage,1,membrane floors,1,Metal sleeves swaged,1,Method of dissipation,1,METHOD OF TESTING,1,Method statement,2,Mineral Admixtures,1,minimize the seepage,1,minimizing the cost,1,minimum eccentricity moment,1,Minimum reinforcement,1,mixing concrete,1,modelling in Etabs,1,Monitors performance,1,monthly invoice,1,Monthly Safety Report,1,Most Useless Megaprojects in the World,1,multi-storey buildings,1,multistory buildings,1,Natural frequency,1,Necessity of tunnel lining,1,new structural systems,1,O&M,1,of concrete block buildings,1,office buildings,1,Office Tall Buildings,1,offshore platforms,1,oil platform,1,oil rigs,1,on beams from loaded slab can be achieved by defining the slab as a membrane,1,opening reinforcement,1,ordinary Portland cement,2,Other bars,1,Overlap,1,overlap locations,1,Oversee and review,1,palm trees weight,1,parallel threads,1,parapet,1,Perform data backups,1,Performance Bonds,1,Performs design drafting,1,physical properties,1,pile cap,1,Pile Dynamic Test,1,Pile Head Preparation,1,Pile Integrity Testing,1,Pile Shaft Overbreak,1,piles foundations,1,Pindos,1,Pipe Classifications,1,PLACING,1,Placing boom,1,Plan and prioritize work,1,Planning Engineer,1,plant and equipment,1,Plant and Equipment Engineer,1,plaster walls,1,Platform types,1,pneumatic,1,Post-Tensioning Grouting,1,Pour strip,1,precast panel,1,Prepares monthly report,1,Pressure Ratings,1,Prestressed Concrete,1,prevent uplift,1,principal load resisting,1,procedure of fixing,1,Project Coordinator,1,Project manager assignment,1,project schedule,1,project's compliance,1,Provides technical expertise,1,provisional Sum,2,PT slabs,2,pump,1,PVC,1,QA,1,QA/QC Engineer,1,QC,1,Quality,1,quotes,1,Quotes of Engineers,1,raft foundations,1,Raft Slab Inspection Checklist,1,reaction as an engineer,1,rebound hammer,1,recommended tests,1,Recorded experience,1,Reinforced concrete columns,1,reinforcement,1,Reinforcement at openings,1,reinforcing bars,2,reinforcing-steel,1,Residential Tall Buildings,1,RESISTING SYSTEMS DAMAGE,1,Retaining Wall Inspection Checklist,1,Retaining walls,1,retarder,1,Review contract documents,1,review contracts,1,review expiring contracts,1,Reviews accidents,1,reviews contract drafts,1,Reviews shop drawings,1,Reviews the terms and conditions,1,Rice husk ash,1,rigid foundation,1,Rigid pipes,1,Road layers,1,Robot Millennium,1,Rock Strata and Excavation,1,Roles and Responsibilities,8,Roller bucket,1,Rough Order of Magnitude,1,Rules of thumb,1,saddle beams,1,Safe 14,1,Safety Manager,1,sample letter,3,sand,1,SAP2000,1,Schmidt Hammer,1,Seismic,1,Seismic Design Principle,1,Seismic force,1,SEISMIC RESISTING SYSTEMS,1,seismic zone factor,1,Semi-structural welding,1,Semi-submersible Platforms,1,Senior Architect,1,Senior Contracts Engineer,1,Sequential Loading,1,Set work program,1,Seven Basic Quality Tools,1,shallow foundation,1,Shell,1,Ship-board Rigs platforms,1,shop drawings,1,shortening of columns,1,Shrinkage,1,Shrinkage and Temperature,1,Side channel spillway,1,simply supported,1,Site engineer responsibilities,1,site facilities,1,Site Investigation,1,SK Gosh,1,Ski-jump,1,slab assignment,1,slabs,2,Slabs Inspection Checklist,1,slings,1,slip forms,1,Slip-form,1,Slip-form construction,1,slip-forming,1,smooth finish,1,soffit slabs,1,Soil classification,1,Soil Sloping Systems,1,Soil Testing,1,speed of erection,1,Spring Force,1,standard size bolts,1,Static load,1,Static load multiplier,1,steel beam,1,Steel Columns,1,steel quantity,1,steel stress,1,Stiffness,1,stiffness and resistance,1,stilling basin,1,Strap footing,1,Strength and Stability,1,Stress on soil in etabs,1,Stressing sequence,1,Striking formworks,2,Strip footing,1,Strong Column,1,structural construction process,1,structural design spreadsheet,1,Structural Details,1,structural engineers,1,Structural Provisions,1,structural purposes pipes,1,strukts spreadsheets,1,Subcontract Agreement,1,Super-plasticizers,2,surfactants,1,Tack welding,1,Tall Building,1,tall buildings,1,taper-cut threads,1,Tdr Test Accuracy,1,Technical Engineer,1,technical submittals,1,test hammer,1,Test on Piles,1,Test specimens,1,TESTING,1,Thermal Expansion,1,threaded rods with nuts,1,time for completion,1,Top bars,1,torsion-load test,1,Total Shortening,1,tower cranes,1,Tower cranes installation,1,Transform AUTOCAD drawings,1,trough spillway,1,Trump Tower,1,Tunnel,1,tunnel lining,1,type of concrete,1,Types of contracts,1,types of foundation,1,Types of shallow foundation,1,Types of spillways,1,Types of waterproofing,1,Ultra Ever Dry,1,Uniform loads Safe 14,1,uniform thickness,1,Uplift Force,1,uplift test lateral-load test,1,vertical load resisting,1,Voided Biaxial Slabs,1,wall openings,1,walls,2,Warning,1,Water curing,1,Weak Beam Concept,1,Wedge locking sleeves,1,weekly and monthly program,1,weekly and monthly report,1,Welding of reinforcement,1,Welding procedures,1,What teachers never taught us,1,wind and seismic,1,Wind loads,1,Wind simulation,1,WOOD SHEAR WALL,1,workability,2,workshop drawings,1,Workshop repair,1,
ltr
item
Strukts: ANALYSIS AND DESIGN OF PROJECTS (PROCEDURE)
ANALYSIS AND DESIGN OF PROJECTS (PROCEDURE)
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7wlpTZWRne-joYiPhLR9QytDOdiR-tyO_1R0ki8qGDmfNIx5tDZAt4XyrJYOsZNR45ImE9ftAA1PQnrQH_Gg3-rBRK1CozwuuptgvdgLV8gfcKKAQMIf1qnhUx6wov5kS3wHy7UpUXlI/s320/index.jpg
https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7wlpTZWRne-joYiPhLR9QytDOdiR-tyO_1R0ki8qGDmfNIx5tDZAt4XyrJYOsZNR45ImE9ftAA1PQnrQH_Gg3-rBRK1CozwuuptgvdgLV8gfcKKAQMIf1qnhUx6wov5kS3wHy7UpUXlI/s72-c/index.jpg
Strukts
https://www.strukts.com/2012/05/analysis-and-design-of-projects_77.html
https://www.strukts.com/
https://www.strukts.com/
https://www.strukts.com/2012/05/analysis-and-design-of-projects_77.html
true
7606260228666216043
UTF-8
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share to a social network STEP 2: Click the link on your social network Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy