CAAnDoS _ Lecture 01 _ 06

7/25/2019 CAAnDoS _ Lecture 01 _ 06

1/22

uhammad

Ali

JInnah

University,

amabad

Campus

9/21/

Muhammad Ali Jinnah University, Islamabad CampusDepartment of Civil Engineering

CE6323Computer Aided Analysisand Design of Structures

Dr. Majid Ali


Introduction:

Teacher: Education: Civil Engg. (BSc, Taxila 2004; MSc, Taxila 2006; PhD, Auckland 2013) Experience: Total 11.5 years (5.5 years Teaching/research, 6 years professional) Publications: 24 (including 9 impact factor journal papers with cumm. IF >20) Awards: Gold Medal, HEC Approved Supervisor, Acad.& Professi. Honorariums etc

Education:

BSc Civil Engg, BSc Building & Arch. Engg., B. Tech., MSc Transportation Experience:

Total years = NIL 17 yearsNature = Contractor, Client, Academics, Consultancy/Design/Site


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uhammad

Ali

JInnah

University,

amabad

Campus

9/21/


Misc Information:

Class hr: 3

Reference Codes / Books:1. ACI 371R-08 / ACI 371R-982. ACI 350.3R3. ASCE 7-05 / ASCE-7-954. UBC-1997

5. BCP-20076. ACI-318-05


CLO-1: to recognize and explain different

Course Learning Outcomes:At the end of course, the student will be able:

advanced perspective (functions)of SAP, SAFE and AUTOCAD. (C2L) PLO-1 15%

CLO-2: to develop finite element models ofstructures (i.e. shell structures e.g.water tanks etc) using SAP, SAFE

,and to create structural drawingsusing AUTOCAD and manually. (P5H)

PLO-5

PLO-9 60%

CLO-3: to interpret as well as justifyanalysis and design of structures. (A3L) PLO-10 25%


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Ali

JInnah

University,

amabad

Campus

9/21/


Course plan (16 weeks teaching):Week Course outline

Quizzes/Presentation

BACKGROUND SUPERSTRUCTURE DESIGN

1Concepts of architectural dwgs; coordinate / grid system; structural layout;earthquake- resistant design; water tower; sloshing effect; code references.

SAP

2

SAP introduction; grids layout; material properties; member sizes, modifiers andother details; Geometry layout (beams, columns, shear walls, slabs); replication(linear, mirror, story); supports.Basic load cases (Dead, superimposed dead, live, roof live, soil (if any) andearthquake); mass-source.Factored load combinations (considering eccentricities in all directions and usingall code clauses)Applying basic loads (point, uniformly distributed, varying lateral and area loads).

Checking model errors; analysis options; model analysis.

4 Evaluation of analysis; performing concrete design. Quiz 1

SUPERSTRUCTURE DETAILING

5 AUTOCAD introduction.Structural drawings I.

6 Structural drawings II.7 Structural drawings III. Quiz 28 REVISION9 Midterm.


BACKGROUND FOUNDATION DESIGN

10Concepts of allowable bearing capacity (net, gross and effective) includingdesign examples .

SAFE

SAFE introduction; Exporting SAP file for SAFE foundation model; Importing

11SAP data/analysis; material and soil properties; foundation type and thickness;applying additional loads (if required); Preliminary foundation layout.Service and Factored load combinations (considering eccentricities in alldirections and using all code clauses).

Quiz 3

12Evaluation of analysis and design; checking bearing pressures and satisfyingfoundation sizes.

SUBSTRUCTURE DETAILING13 Structural drawings IV.

14 Structural drawings V. Quiz 4PRACTICING APPROACH

15 Alternate options for economical design

16 Project Presentations Presentations

17 REVISION18 Exam Preparation19

Final Exam20


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uhammad

Ali

JInnah

University,

amabad

Campus

9/21/


Marking criteria

CLOs CLO:1 CLO:2 CLO:3

Assessment

Modules

and

Explain)

and

Create)

and

Justify)

Presentation (20%) - 15% 5%

Quizzes (20%) 5% 10% 5%

Midterm Exam 20% 5% 10% 5%

Grading shall be as per rules in prospectus.

Final Exam (40%) 5% 25% 10%

Total (100%) 15% 60% 25%


BACKGROUND

SUPERSTRUCTURE DESIGN


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Ali

JInnah

University,

amabad

Campus

9/21/


Architectural Drawings

important in order to imagine the structure help for precise structural FE models consist of

Plans Elevations Sections

Its better that the main structural

features can be seen in arch. dwgs

For detailed understanding, refer to related UG courses.


Coordinate / Grid System basically the reference lines primarily available in arch. dwgs is basically for layout may be improved by str. engr. during designphase helps in FEM geometry

,



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Ali

JInnah

University,

amabad

Campus

9/21/


Structural Layout

preliminary working of str. members on arch.dwgs to support structure i.e. to resistloadings should give proper consideration to types ofloading to be resisted should preferably visible in arch. dwgs

Framing plans

Reinforcement details (plans, sections etc)



Earthquake-resistant Design considers lateral loads due to strong groundmotions Mainly two types of analysis:

Dynamic Equivalent static force procedure

(used in this course)

requires some special material properties



7/22

uhammad

Ali

JInnah

University,

amabad

Campus

9/21/


Water Towers

important structures, even available aftermajor disasters thus have high importance factor in analysis have different types depending

on shapes (circular, square, rectangle,mushroom-type, etc) - ,shear walls, col.-beam with shear wall etc)

on fluid type

Shear wall supported mushroom-type water tower


Sloshing Effect oscillation of water surface additional loading effect because ofmovement of water due to strong groundmotion considered in analysis by few internationalcodes

needs proper free-board generates two components; convective andimpulsive


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Ali

JInnah

University,

amabad

Campus

9/21/


T=0 T=t1 T=t2

T=t3 T=t4 T=t5

T=t6 T=t7 T=t8

Figure 1: Sloshing effect in elevated water tank (one complete cycle)


Figure 2: Idealization of convective and impulsive components


9/22

uhammad

Ali

JInnah

University,

amabad

Campus

9/21/


Code References

ACI 371R-08 / ACI 371R-98Water tank design .

Water tank seismic designASCE 7-05 / ASCE-7-95

Seismic design (site specific acceleration)UBC-1997

Seismic designBCP-2007

Seismic design

ACI-318-05Concrete design and detailing


Report on Seismic analysis and designof water tower1. IntroductionElevated water tanks are commonly used for storingwater in public water distribution system and itshould be competent of keeping the expectedperformance during and after earthquake. It haslarge mass concentrated at the top of slendersuppor ng s ruc ure an ence ex reme yvulnerable against horizontal forces due toearthquake. They must be functional even afterearthquakes to ensure water supply is available inearthquake-affected regions.


10/22

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Ali

JInnah

University,

amabad

Campus

9/21/


Keeping in view the above stated importance of

elevated water tanks, seismic analysis and design ofelevated water tank need much attention to cater all

motions. In case of elevated water tank or evenground water tanks, sloshing effect (Figure 01) ofwater must be considered in addition to the lateralseismic forces. The sloshing effect generates dueto round motions and it re resents the oscillationof water surface. The stored water can be divided

into two parts, the upper oscillating part known asconvective component and the lower so-called solidpart known as impulsive component.


These two components along with tank structurecreate three objects (three degree of freedomsystem) to be considered for seismic analysis. Manyresearchers have suggested to combine theimpulsive component with tank structure, making ittwo degree of freedom system (Figure 2) which isrelatively easy to handle in calculations of dynamicanalysis. Whereas, in equivalent static force

,sloshing water is considered.


11/22

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Ali

JInnah

University,

amabad

Campus

9/21/


Seismic analysis can be performed by two methods:

i. equivalent static analysis and ii. dynamic analysis.Equivalent static analysis is easy and quick whereas, .

Equivalent static procedure is outlined in ACI 371Rand ASCE 7-05 but these codes suggest sitespecific acceleration amplification which make itdifficult to use ACI 371R strictly for Pakistanre ion. Therefore the conce t of e uivalent staticforce procedure is taken from ACI 371R and the

stepwise procedure to be adopted for Pakistanregion is outlined in this report (section 2).


On the other hand, there are many models availableby which the dynamic analysis can be performedwhich make it difficult to select a more accurate

. ,rigorous method of dynamic analysis, ACI 350.3 inits Appendix A suggests GENERAL PROCEDURE fordynamic lateral forces, pressure distribution,overturning moments, vertical accelerations and

stresses for water tank. There are man researchesstill going on (even in 2015) for understanding thereal dynamic behavior of water tanks under strongground motions. Therefore it is recommended to useequiv. static force procedure (outlined in section 2)for design of water tanks to be on safe side.


12/22

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Ali

JInnah

University,

amabad

Campus

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2. Equivalent Static Force Procedure

The sloshing, horizontal and vertical eccentricitieseffects (5.1.2.4.1, G in 5.1.2.2 and 5.1.2.9,,

equivalent static analysis. Effective seismic weight(used in calculating base shear) should include alldead load of tank structure, convective andimpulsive weight of water, 25% of live load and 20%of snow load where flat roof snow load exceeds30psf (ACI 371R). The weight of convective and

impulsive component can be calculated using ACI350.3 (Figure 9.6 for circular tanks and Figure 9.2for rectangular tanks).


A close approximation for convective and impulsivemasses of axisymmetric, other than cylindrical,tanks may be obtained from an equivalent cylindrical

axisymmetric tank and a depth that results in thesame volume as the axisymmetric tank. The restprocedure may be adopted in a same manner as thatin analysis of buildings with the exception that

i. the res onse modification factor R (2.2) and im ortancefactor I (1.25)should be taken for tanks.ii. the load combinations as per PBC should also consider theadditional parameters (if governing) mentioned in loadcombinations as per ACI 371R (e.g. G=eccentric load effectdue of dead and water load, S=snow load and T= temperatureand shrinkage effects) for analysis of tanks.


13/22

uhammad

Ali

JInnah

University,

amabad

Campus

9/21/


For external stability checks, the in-house built

excel sheet can be used whereas for internalanalysis, FEM using STAADPRO, ETABS or SAP.

checked using clause 15.6.5.1 of ASCE 7-05. Thetime period of the empty and full tank shouldpreferably be calculated using Method B,particularly for internal analysis.


Snap shotsfromreferred

5.1.2.4.1 fromACI 371R-08

codes


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Ali

JInnah

University,

amabad

Campus

9/21/


5.1.2.2 fromACI 371R-08


5.1.2.9 fromACI 371R-08


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Ali

JInnah

University,

amabad

Campus

9/21/


Figure 9.6from.


Figure 9.2from

.


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University,

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15.6.5.1from-


1630.1.1from


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Ali

JInnah

University,

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9/21/


1612.2from


1630.2.1from


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JInnah

University,

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Campus

9/21/


Method Bfrom UBC


Table data from UBC 1997


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Ali

JInnah

University,

amabad

Campus

9/21/




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Ali

JInnah

University,

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Ali

JInnah

University,

amabad

Campus

9/21/



Computer Aided Analysis and Designof Structures

(Elevated Water Tank 50,000 Gallons)

A mashroom-type elevated water tank(EWT) of 50,000 gallons capacity is to bedesigned. A minimum hydraulic head of60'-0" was required by the ServicesEngineer to cover the area/buildings. Thestructura ana ys s an es gn wasstarted based on concrete outline with60'-0" minimum hydraulic head. SAP /SAFE softwares were used to analyzeand the design the EWT.


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Ali

JInnah

University,

amabad

Campus

9/21/


Final Geo-Technical Recommendations

The recommendations for the site soil by theGeotechnical Engineer are as under: ' "- . -

below N.S.L

-Effective allowable bearing capacity = 0.90 TSF

at 10'-0" below N.S.L

-No increase in allowable bearing capacity due to

seismic loading is permitted

-Soil profile type "SE- Sliding coefficient = 0.4


Architectural drawings

Documents

CAAnDoS _ Lecture 01 _ 06