IDENTIFYING TYPE OF CRACKS IN STRUCTURES!!

IDENTIFYING TYPE OF CRACKS IN STRUCTURES

CRACKS MAY DEVELOP DUE TO

1. ·         DETERIORATION OF CONCRETE.
2. ·         NATURAL CALAMITIES
3. ·         CORROSION OF REBARS DUE TO POOR CONDTRUCTION PRACTICES
4. ·         INAPPORPRIATE SELECTION OF CONSTRUCTION MATERIALS.
5. ·         TEMPERATURE AND SHRINKAGE EFFECTS.
6. ·         SETTLEMENT OF SUPPORTS.

TYPES OF CRACKS

Ø  STRUCTURAL CRACKS

§  Cause – Incorrect Design, Faulty Construction and Overloading

Ø  NON-STRUCTURAL CRACKS

§  Cause – Stresses induced internally by construction materials.

IDENTIFYING STRUCTURAL CRACKS

THESE TYPE OF CRACKS APPEAR ON STRUCTURSL ELEMENTS SUCH AS BEAMS, COLUMNS,SLABS,ETC.THESE ARE: 

      1.    FLEXURAL CRACKS IN BEAM

2.    SHEAR FLEXURE CRACKS IN BEAM

3.    TORSIONAL CRACKS IN BEAM

4.    TENSION CRACKS IN TIE BEAMS

5.    CRACKS IN COLUMNS

6.    CRACKS IN SLABS

7.    CRACKS DUE TO SETTLEMENT OF FOUNDATION

IDENTIFYING NON-STRUCTURAL CRACKS

1. ELASTIC DEFORMATION-Non uniform Distribution of loads,Excessive Deflection
2. MOISTURE CHANGE
   
   
   
   
   
   
   
3. THERMAL MOVEMENT-Depends on thermal coefficients and dimensions of elements
4. CREEP- Depends on W/C ratio,materials used and shape and size of components.
5. FOUNDATION MOVEMENT AND SETTLEMENT OF SOIL-Due to unequal bearing capacities
6. GROWTH OF VEGETATION-Dehydration is caused by roots leads to settlement
7. CHEMICAL REACTION-Sulphate attack,carbonation,corrosion and alkali aggregate reaction.
   

INSTRUMENTS FOR MEASUREING CRACKS

·         DIGITAL CRACK GAUGE

·         MEASURING MAGNIFIER

·         LOMARO MICROSCOPE

·         CRACK SCOPE