Today, in this article we are going to tell you what is structural integrity and why it is that important. Structural integrity is an engineering field that plays a fundamental part of ensuring that structures are fit to do what they are designed under normal operational conditions, and are safe when conditions exceed the original design intent. This includes supporting its own weight. Its aim is to prevent deformation, breaking, and catastrophic failure of a structure due to load, allowing the structure to perform its duty reliably throughout its predicted lifetime.
Integrity is not a case of good design as long as it needs to be maintained for the life of a structure. Of course, structural integrity needs inspection and maintenance at periodic intervals. Engineers ensure structures are safe, reliable, and perform their designed function throughout their lifetime.
Causes of Structural Failure
Read on the chapter if you want to learn more about the causes of structural failure, and reasons. Structural failure can occur from a range of different sources. The type of failure is often associated with the industry, environment, and application of the structure. The primary reasons for failure are as follows:
- Weak structures
- Structural deterioration
- Manufacturing errors
- Defective material
- Improper environmental considerations
- Improper operational conditions
The structure is not strong enough to withstand the load to which it is subject. This is usually due to inappropriate geometric design or material choice. Materials that just aren't strong enough to withhold the load. But there are cases when workers make mistakes even when they are given the right materials, they may mix concrete incorrectly or something else. Another reason for creating a weak structure is when the load is heavier than it was expected.
The structure deteriorates due to corrosion, fatigue, wear, rot, or creep. Fatigue failures often begin when cracks form at regions of high stress. These cracks grow when subject to cyclic loading, resulting in sudden failure. This is usually due to inappropriate geometric design, material choice or maintenance
This includes using the wrong materials or not following manufacturing procedures or standards. It can also result from poor workmanship or components being out of tolerance, etc.
The materials don't conform to standards, resulting in a lower load-bearing capacity than designed.
Improper environmental considerations and operational conditions
This is when engineers may neglect mitigating features for certain environmental conditions, such as natural disasters, and when the structure is not used for its intended purpose.
Structural integrity assessment is a process by which we determine how reliable an existing structure is able to carry current and future loads and fulfill the task for a given time period. In structural monitoring, periodic measurement of displacement, strains, stresses, damage evaluation, and vibration characteristics are carried out with the sole objective of either detecting the changes that have taken place in the structure or where the structure appears to be at risk to plan for its evacuation.
Determining the Condition
When there are noticeable defects in the structure such as visible cracks in a building, a study to determine the condition of the building is carried out. Such investigation should identify the type of defect such as cracking and subsidence, settlement or movement of the structure. Technical expertise and an understanding of building construction is essential to correctly identify the cause of building defects and the remedial measures required to put the defects right.
Building inspection is a general surface examination of those parts of a property which are accessible. In order to carry out the inspection, the surveyor requires some basic equipment to be used during the survey. In general four types of inspection are distinguishable: these include visual inspection, concealed object inspection, Dampness inspection, stress, and strain survey.
In visual inspection, the equipment includes a digital camera, binoculars, magnifying glass, video recorders, etc. Concealed object inspection may be carried out by the use of cover meter, fibrescope, endoscope, and so on. Dampness inspection may be carried out using a digital thermometer, hydro test kit, wheel, etc.
Stress and Strain Test
What is the stress and strain test and why your buildings need them? Stress and strain tests are carried out to test the structural integrity of various components of the building structure. They enable the detection of sources of bending, cracks, and displacement in the structures. Some of the types of equipment for this test include:
- Strain gauge
- Geodetic survey methods
Cracks develop in a building or sections of a building whenever stress in the component exceeds its strength.
Stress in the building component may be caused by externally applied forces such as dead and live load or foundation settlement or it could be induced internally by thermal variation, moisture changes, chemical actions, and others.
A proper understanding of the type of movement that has caused the crack, and the rate at which this movement is to be expected in the future, is a key step in analyzing and providing specifications for the repairs of the cracks. Buildings can move in several directions and this movement can be in various forms.
It could be the building moving, or a small portion of it, or it could be the soil on which the building is built or a small portion of it. Therefore, crack is not the cause, but rather the sign that shows that the building is undergoing movement. There are two major reasons why buildings move, and they include movement as a result of conditions below the ground and movement as a result of conditions above ground.
Structural Integrity Inspection
Engineers combining an array of considerations into the design process, for example, stress analysis, materials performance, and fracture mechanics and etc, can calculate the integrity of structures. Once built, a construction will need inspection and maintenance to maintain its integrity. During a structural integrity inspection engineers may do the following:
- Carry out inspections to identify damage. This might involve the use of non-destructive testing (NDT)
- Check that a structure has been built according to the appropriate designs, procedures, and standards
- Check that a structure is being used appropriately for the environment designed for
- Recommend and design modifications to address areas of concern.