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10/9/2016

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Asst. Prof. Dr. Ferhat PAKDAMAR N Blok 1-17

Department of Architecture ARCH 261

Structural Analysis

Why do we need to be educated?

Almanya’da bir Lise Müdürü, her eğitim öğretim yılı başında öğretmenlerine şu mektubu gönderirmiş: “Bir toplama kampından sağ kurtulanlardan biriyim. Gözlerim hiçbir insanın görmemesi gereken şeyleri gördü. İyi eğitilmiş ve yetiştirilmiş mühendislerin inşa ettiği gaz odaları, iyi yetiştirilmiş doktorların zehirlediği çocuklar, işini iyi bilen hemşirelerin vurduğu iğnelerle ölen bebekler, lise ve üniversite mezunlarının vurup yaktığı insanlar. Eğitimden bu nedenle kuşku duyuyorum. Sizlerden isteğim şudur. Öğrencilerinizin insan olması için çaba harcayın. Çabalarınız bilgili canavarlar ve becerikli psikopatlar üretmesin. Okuma yazma, matematik, çocuklarınızın daha fazla insan olmasına yardımcı olursa ancak o zaman önem taşır.”

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Why Structural Science ?

Aim of the structural science engineering

Classifications of structural systems and Loads

Review of Statically Determinate Structures

Review of Truss Systems

Deflections

Analysis for Indeterminate Structures

Course Overview

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Course Overview

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21.09.2016 Assumptions in structural analysesLoads definitions and classification of structures

28.09.2016 Assumptions in structural analysesLoads definitions and classification of structures

05.10.2016 Equilibrium equations for frame systems Support conditions Statically determinate and indeterminate systems

12.10.2016 Shear and moment diagrams for statically determinate structures 19.10.2016 Analysis of statically determinate truss system 26.10.2016 Mid-term exam 02.11.2016 Deflections for statically determinate beams and frames 09.11.2016 Deflections for statically determinate trusses 16.11.2016 Analysis methods for statically indeterminate systems 23.11.2016 Moment distribution methods - 1 30.11.2016 Moment distribution methods - 2 07.12.2016 Reaction and member forces coefficients for trusses - 1 14.12.2016 Reaction and shear and moment coefficients for frames – 2 21.12.2016 Computer applications for structural analysis

Final exam

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Grading

Exam (1) : %25

: %25

Final Exam (1) : %50 Make-up Exam : %50

Attendance

(5)Homework (1) Quiz

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Materials

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Barry Onouye with Kevin Kane, Statics and Strength of Materials for Architecture and Building Construction.

Hibbeler, Structural Analysis.

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Structural Analysis vs Structural Design

Structural Analysis; Structural analysis is the prediction of the performance of a given structure under prescribed loads and/or other effects, such as support movements and temperature change.

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Structural Design; Structural design is the art of utilizing principles of statics, dynamics and mechanics of materials to determine the size and arrangement of structural elements under prescribed loads and/or other effects.

Buildings may have different functions: Residential: Housing, which includes low-rise (up to

2-3 floors), mid-rise (up to 6-8 floors) and high rise buildings.

Commercial: Offices, retail stores, shopping centers, hotels, restaurants.

Industrial: Warehouses, manufacturing. Institutional: Schools, hospitals, prisons, church,

government buildings.

Special: Towers, stadium, parking, airport, etc.

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Design of Structures - Safety - Esthetics - Serviceability - Environment - Economy

Idealization of Structures - Physical Model - Mathematical Model

Design Considerations;

Design of engineering systems is usually a trade-off between maximizing safety and minimizing cost.

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Structural Analysis; Given an existing structure subjected to a certain load

determine internal forces (axial, shear, flexural, torsional; or stresses), deflections and verify that no unstable failure can occur.

Thus the basic structural requirements are:

Strength: stresses should not exceed critical values: < f

Stiffness: deflections should be controlled: < max Stability: buckling or cracking should also be prevented

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A building structure safely transmits loads down to Earth

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Acceptances in Structural Analysis

1) The verifying systems are not depend on the loads.

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2) Deflections should be too small.

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3) Materials should behave linear-elastic.

4) The loads are assumed to be static.

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Two requirements must be imposed for the principle of superposition to apply :

1. The material must behave in a linear-elastic manner, so that Hooke.s law is valid, and therefore the load will be proportional to displacement.

2. The geometry of the structure must not undergo significant change when the loads are applied, i.e., small displacement theory applies. Large displacements will significantly change and orientation of the loads. An example would be a cantilevered thin rod subjected to a force at its end.

σ = P/A δ = PL/AE

5) Principle of Superposition

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End of the week 1

LOADS Loads are the external effects that cause stresses, deformations and displacement in structures.

The main purpose of a structure is to transfer load from one point to another: bridge deck to pier; slab to beam; beam to girder; girder to column; column to foundation; foundation to soil. There can also be secondary loads such as thermal

(in restrained structures), differential settlement of foundations, P-Delta effects (additional moment caused by the product of the vertical force and the lateral displacement caused by lateral load in a high rise building).

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LOADS

STATIC DYNAMIC

DEAD LOADS LIVE LOADS HYDROSTATIC

and SOIL PRESSURE

DEAD LOADS of STRUCTURAL COMPONENTS

FURNITURE

PEOPLE

SNOW

CONTINOUS IMPACT

EARTHQUAKE

WIND

Load Translation

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Loads

Roof Load (Snow, Rain, Wind) Slab Load

Wall Load

Beam

ColumnWind,Earthquake

Foundation

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Clasisfications of Structural Elements

For their geometry;

1. 1-d structural elements.

2. 2-d structural elements.

3. 3-d structural elements.

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1. Statically Determinate Systems (isostatic)

2. Statically Indetreminate Systems

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For the Analysis of structures

If support reactions and internal forces can be found only using equations of equilibrium then the structural systems, under various loading are called Isostatic or statically determinate systems.

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The aim of analyzing a system is to define;

Reaction forces, Internal Forces and Deflections

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Equations of Equilibrium

The equations of equilibrium in Static State are:

0X

0Y

0M

Newton's laws of motion First law: When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force.

Second law: F=ma The vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object.

Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

The three laws of motion were first compiled by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), first published in 1687

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Supports Connections Support connections - Structural members can be supported in a variety of methods, the most common are pin and fixed supports

A pin support prevents deflection; allows rotation

A fixed support prevents deflection and rotation

A roller support allows deflection and rotation

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Examples for Wrong Structural Design

Folder 01

Sources

1. H.Can, Çözümlü Örneklerle Yapı Statiği, Birsen Yayınevi,2008.

2. Özer E., Yapı Statiği Ders Notları

3. Kutaniş M., Yapı Statiği Ders Notları

4. 3. Çakıroğlu, A.,Çetmeli, E., Yapı Statiği I, Beta Yayım Dağıtım,İstanbul, 11. Baskı, 2001.

5. Hibbeler, R. C., “S