Study on control of cracks in a Structure through Visual Identification & Inspection

Study on control of cracks in a Structure through Visual Identification & Inspection

Abstract:

Structural Cracks are a common occurrence in all types of buildings. To ensure the longevity of the structure, engineers are often required to look into their causes and carry out suitable repairs and remedial measures. For repairs and remedies to be effective, it is essential that the engineer should have a proper understanding of various causes of occurrence of cracks. For investigating the causes it is necessary to observe carefully the location, shape, size, depth, behavior and other characteristics of the cracks, and to collect information about specifications of the job and time of construction. It is also necessary for the engineer to keep track of when the cracks first came to notice. This paper talks about how visual inspection of cracks can be helpful in order to identify and categorize them with respect to various parameters by taking case study of an institutional building.

Keywords:

1. Cracks, 
2. Shrinkage,
3. Structural Failure,
4. Stresses and 
5. Grouting.                                                                                                             INTRODUCTION AND BACKGROUND STUDY                                                            Cracks in buildings are of common occurrence. A building component develops cracks whenever stress in the component exceeds its strength. Stress in a building component could be caused by externally applied forces, such as dead, live, wind or seismic loads, or foundation settlement or it could be induced internally due to thermal variations, moisture changes, chemical action, etc. Cracks could be broadly classified as Structural and Non-Structural. Structural cracks which are due to incorrect design, faulty construction or overloading and Non-structural cracks are mostly due to internally induced stresses in building materials and these generally do not directly result in structural weakening. These are due to penetration of moisture or thermal variation. Cracks may appreciably vary in width from very thin hair cracks barely visible to naked eye (about 0.01 mm in width) to gaping cracks 5 mm or more in width. A commonly known classification of cracks, based on their width is:
   (a) Thin — less than 1 mm in width,
   (b) Medium — 1 to 2 mm in width, and
   (c) Wide — more than 2 mm in width.

   Cracks may be of uniform width throughout or may be narrow at one end, gradually widening at the other. Cracks may be straight, toothed, stepped, map pattern or random and may be vertical, horizontal or diagonal.Cracks may be only at the surface or may extend to more than one layer of materials.                                                                                                                                                                   Author Information:                                                                                               Kishor Kunal, Namesh Killemsetty                                                                      Department of Civil Engineering, O.P. Jindal Institute of Technology ,India     IOSR Journal of Mechanical and Civil Engineering                                      (IOSR-JMCE) e-ISSN: 2278-1684,p-ISSN: 2320-334X,                                Volume 11, Issue 5 Ver. VI (Sep-Oct. 2014), PP 64-72                                                 www.iosrjournals.org