Identification of Cracks

Identification of Cracks

INTRODUCTION:-

• Earthquakes are the most destructive natural hazards throughout human history. 
• Building cracks are most common problem found in any type of building.
• We all love to have a house which structurally safe and beautiful but it is not so easy, one has to overcome natural calamity, soil failure, construction faults, improper design, and inadquate joints causings to develop cracks on the building.Though the cracks in concrete cannot be prevented entirely but they can be controlled by using adequate material and technique of construction and specific design criteria.On timely identification of such cracks and adopting preventive measure are essential.
• Active cracks causes seriously problem and they need special attention as they are structurally hazardous. So, it is important to understand the types of cracks,crack patterns and their causes and the preventive measures to be taken to control the cracks.

Question 1:- What is the mode of failure or damage of the beams in the figure below? Are the damages repairable? Elaborate

 AIM:- To determine  the mode of failure or damage of the beams in the pictures and determination of  the damages repairement

INTRODUCTION:-

We all already know that  the failures occurs in the beam and columns or structural members which we will find out in this project with observation of the images provided 

TYPES OF FAILURES IN THE BEAMS AND COLUMNS ARE AS BELOW:-

• Flexural Tension Failure
• Flexural Compression Failure
• Shear failure
• Diagonal Tension Failure
• Shear Compression Failure
• Splitting Shear Failure
• Anchorage Failure
• Failure Due to Pure Compression
• Failure Due to Combined Compression and Bending
• Failure due to Inelastic Inability

a)

OBSERVATION FROM THE IMAGE :-

1. As we can see that,Concrete crushed and the reinforcement is fully visible 
2. Concrete fall upto the rebars which may be a sign of rupture
3. Beam top portion looks safe because of the flange advantage from slab 
4. The crack developes from bottom to top means rebar yeilding occurs in support bottom only  

ANSWER:-

1. Its form of flexural failure due to reverse of stress during earthquake as we can see in the elloborate image obove 
2. During stress reversal reversal, support top experiences compression and bottom experiences tension 
3. Top compression is managed by slab advantage. Bottom tension was not satisfied by the provided reinforcement 

REPAIR PROBABILITY :-

• As the reinforcement got exposed ,and get upto yeilding , it can not be repaired 

b)

OBSERVATION FROM THE IMAGE :-

1. As we observed Cracks along Beam- Column edge
2. Cracks seem to have developed through the structure as it looks much wider
3. Beam looks separated from the column at joints
4. Concrete is not fully (severally) crushed

ANSWER:-

1. Its a Beam pull out failure due to insufficient development length of reinforcement in joints 
2. During earthquake, the horizontal movement of structure makes this condition worse and detached the beam member from column 

REPAIR PROBABILITY :-

• Providing anchorage length between two existing concrete is very difficult.So its not repairable

c)

OBSERVATION FROM THE IMAGE :-

1. As we observed,Cracks are exactly at the joint of column and  Beam
2. Cracks in Beam developed through its entire width
3. we can see the cracks in the slabs in the direction of the beam width

ANSWER:-

1. Its a plastic hinge failure, as we know plastic hinge failure occured only at the joints
2. The damage occured only in the joint zone first of all
3. Cyclic lateral loading and stress reversal at the joints led to damage
4. Even the slab participated to its best to handle the tension . Slab is severly cracked means it has undergone tension with its flange condition.But unable to control the damage 

REPAIR PROBABILITY :-

The joint can be strengthed therefore repairable.

Question 2:-

a) 

OBSERVATION FROM THE IMAGE :-

1. As we observed ,Concrete damaged at top of the column 
2. Concrete damaged all round the column face 
3. Beams are safe as they we seem no damage to them
4. As the image shown the brighter environment at left it definately a outer column or to be specific column lies edge of the building 
5. No walls are built along the column means it is probably at ground floor, to be specific it is may be parking lots area 

ANSWER:-

• Its a soft story failure, Technically plastic hinge formation
• Due to absence of walls at the ground floor,The plastic hinge forms at the top of ground story column during lateral movement

REPAIR PROBABILITY :-

Based on the development of crush of concrete it can be either repairable or non repairable(it fully depwnd on the severaty of the plastic hinge failure , if it in severe it cannot be repair or vice versa)

b)

OBSERVATION FROM THE IMAGE :-

1. As we can observed ,The concrete is fully crushed
2. The rebars are fully visible ,in it affect on the whole structure
3. Concrete developed complete breakage diagnolly 
4. The reinforcement is intact but the by the time  it may be  buckeled as the rebars doesnt have a binding material
5. Shear reinforcement spacing looks wider which means probably lesser shear rebar provided

ANSWER:-

1. Its a pure shear failure
2. Inadequate shear reiforcement compels concrete takes all the shear stresses

 REPAIR PROBABILITY :-

As the shear occurs (tranfered) only in from concrete it somehow repairable

c)

OBSERVATION FROM THE IMAGE :-

1. As we can observed ,Column failed completely
2. Failure at top of column is visible 
3. There are two slabs connected to columns , probably one at mid of the column
4. There is not a single bonding of any member to the column is visible 
5. The wooden rods may be added as a failure support after column failed, providing temporary prop to avoid collapse of the entire structure 

ANSWER:-

• Its a short column failure
• An additional slab or a beam connected to a column in mid height leads to its effects
• This leads to failure especially if the connection is unintentional and not accounted in designs

 REPAIR PROBABILITY :-

AS because it completly shear failure it cannot be repairable