ultimate strength design

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Presentation Description

The presentation covers the design of beams for flexure. The beam types covered are singly reinforced beam, doubly reinforced beam, and t-section. In the end, the USD method is compared with working stress design method.

Comments

By: harris.waheb (15 month(s) ago)

That's really nice slide show regarding to the RCC, Please UPLOAD more

By: paktiawaal (19 month(s) ago)

quite useful. great share mate!!!!

By: Arificial (19 month(s) ago)

@paktiwaal: Thanks. (This was my third year presentation for our Reinforced Concrete Design course.)

 

Presentation Transcript

please wait .. . : 

Arificial intelligence || Slides please wait .. .

ULTIMATE STRENGTH DESIGN : 

A Cube ULTIMATE STRENGTH DESIGN in flexure. 2010

Contents : 

Contents Ultimate Strength Design Introduction Assumptions Beam design Advantages

Introduction : 

Ultimate Strength Design || an introduction Introduction Method of the determine the dimension of structure based on Ultimate load Ultimate section

Slide 5: 

Ultimate Strength Design Historical Background Being used since 1957.

HISTORY : 

Ultimate Strength Design || History HISTORY Ultimate strength design method was first permitted in Britain in 1957 USA in 1956 USSR in 1935 The ACI code of 1963 put equal emphasis on both ultimate strength design and working stress design While the ACI codes 1971 ,1977,1983, emphasized ultimate strength

Slide 7: 

Ultimate Strength Design Assumptions Assumptions simplify analysis.

Assumptions : 

Ultimate Strength Design || Assumption Assumptions Bars at the same level, provided that the bond between the concrete and steel is adequate Is linearly proportional to the distance from the neutral axis. Modulus of elasticity for all grades of steel is taken as Es = 29 x 10 ^ 6 psi Plane cross sections continue to be plane after bending Concrete's tensile strength is about 1/10 of its compressive strength Cracked concrete is assumed to be not effective Before cracking, the entire cross section is effective in resisting the external moments At high stresses, non-elastic behavior is assumed, which is in close agreement with the actual behavior of concrete and steel Maximum strain at the extreme compression fibers 0.003 by ACI code Compressive stress distribution may be assumed to be rectangular, parabolic or trapezoidal.

Beam Types : 

Ultimate Strength Design Beam Types Singly reinforced section Doubly reinforced section T-section

Slide 10: 

n w Ultimate Strength Design designing beam .. .

Slide 11: 

Ultimate Stress Design Singly Reinforced Beam A singly reinforced beam has only tension reinforcement.

Singly Reinforced Beam : 

Ultimate Stress Design || Singly Reinforced Beam Case 1 Case 2 Case 3 Singly Reinforced Beam b d b No information given ρ and d given b and d given

Case 1 : 

Case 1 No information given Step 1: Decide steel ratio Step 2: Determine beam width effective depth b d Table 4.1 (Nadeem Hasoun) Ultimate Strength Design || Singly Reinforced Beam

Case 1 : 

Case 1 Step 2: Determine effective depth beam width Ultimate Strength Design || Singly Reinforced Beam

Case 1 : 

Case 1 Step 1: Decide steel ratio Step 2: Determine beam width effective depth Step 3: Calculate As and number of bars Step 4: Find bar spacing Ultimate Strength Design || Singly Reinforced Beam

Case 2 : 

Ultimate Strength Design || Singly Reinforced Beam Case 2 ρ and b given b b Step 1: Find Ru Step 2: Determine effective depth Step 3: Calculate As and number of bars Step 4: Find bar spacing d

Case 3 : 

Ultimate Strength Design || Singly Reinforced Beam Case 3 b and d given b d b d Step 1: Find ρ Step 2: Calculate As and number of bars Step 3: Find bar spacing Step 4: Check Compression steel not required. Compression steel required.

Slide 18: 

Ultimate Strength Design Doubly Reinforced Beam A doubly reinforced beam has both tension and compression steel.

Slide 19: 

Ultimate Strength Design

Slide 20: 

Ultimate Strength Design T-Section A singly reinforced beam is . . . .

T-Section basics : 

Ultimate Stress Design || T-section T-Section basics

T-Section behaviours : 

Ultimate Stress Design || T-section T-Section behaviours T-section behaving as rectangular section t-section

Rectangular Section design : 

Ultimate Stress Design || T-section Rectangular Section design Step 1: Find steel ratio Step 3: Calculate As and number of bars Step 4: Find bar spacing

T-Section design : 

Ultimate Stress Design || T-section T-Section design

Slide 25: 

Ultimate Strength Design Advantages There are many reasons why Ultimate Strength design is preferred over working stress design.

Advantages : 

Ultimate Stress Design || Advantages Advantages Better predicts strength Requires lesser material Easier to compute More rational approach Accounts for uncertainties in load.

Slide 27: 

Comparison || Working vs Ultimate Quantitative Comparison #8 bar has been used in all beams.

ULTIMATE STRENGTH DESIGN : 

A Cube ULTIMATE STRENGTH DESIGN Wins The End. Arificial intelligence || Slides