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In th e N am e o f A llah ,th e M o st B en e ficen t, th e M ost M erc ifu l
Welcome to HRC Bagh
Workshop on Safer Building Through Improving
Steel Detailing
Objective• To understand the recommended practices
with reference to earthquake resistant techniques to make their houses safe;
• To improve steel detailing in in building construction;
• To sensitize the stakeholders to adopt earthquake safer techniques;
• To ensure the effective technology transfer to the target groups.
WELCOME
Bagh Seismic zone
Destruction In Earthquake
7
RC Frame Buildings
DHQH Bagh
8
RC Frame Buildings
9
RC Frame Buildings
Margalla Tower
Earthquake 2005
Ring Spacing
Ring Problem
Our Practice?
Spacing of StirrupsEffects
Common Practice
New
Recommended Spacing
Ring Spacing= 4″
Recommended Shape of Seismic Stirrup
3″
135°
Such stirrups do not open even during strong shaking
Column “L” AND Base
Deficient Length of “L”
19
Proper Column Base
“L” Should be= 12 inch
Beam To Column Joint
Wrong Practices
Results
Beam To Column Joint at lintel Level
Our Practice
MistakeResult
Interior Beam-Column Joint
Beam long bar should passed from the center of column
0‘-6"
Wrong Practice
Is it ok?
Proper Plinth Corner Joint
Band To Column Joint at corner
Right way at middle/ Junction
Minimum= 2 Feet
OVERLAPPING
31
Length of vertical bar not Length of vertical bar not sufficient for 2sufficient for 2ndnd Storey Storey
Practice still continued
Why column fails?
Proper way of Lapping
Min 4‘-0"
Sufficient lapping lengthSufficient lapping length
Within lapping length, Within lapping length, stirrups at closer spacingstirrups at closer spacing
Location at mid Location at mid heightheight
Not more than 50 % bars Not more than 50 % bars lapped at a sectionlapped at a section
Our Practice (New)
Lap length is 15”
Overlapping in Beam
Recommended Overlap should be equal to= 60 x D
Identify Reasons?
Framing around opening
NewAfter Remedy
Infill Walls Connection With? Before OCT 2005
39
Tie-up of Walls
40
Tie-up of Walls
Why crack develop?Beam bar not bent up near support to overcome negative movement
Why crack develop?
Bent up bars
What is Our Practice
Construct beam and slab togetherConstruct beam and slab together
Commonly used steel reinforcementCommonly used steel reinforcementMild Steel Mild Steel High Strength Deformed Bar High Strength Deformed Bar
Should be free from loose mill scale, loose Should be free from loose mill scale, loose rust, coat of paints and oils, cracks, rust, coat of paints and oils, cracks, surface flaws, laminations etcsurface flaws, laminations etcShould comply with requirement of Should comply with requirement of dimension and weight dimension and weight Should not break while bendingShould not break while bending
Steel ReinforcementSteel Reinforcement
Simple Steel Quality Test
Making close hook 4d and bent the bar at 180 degree then straight it. Good quality bar doesn't break, while bad quality steel breaks.
SpacersConcrete Cover
Column= 1.5″
Beam= 1.5″
Slab=3/4″
Foundation=3″
Thank You!!!