Page 103 - Bridge and Highway Structure Rehabilitation and Repair

78 SECTION 1 ADMINISTRATIVE ISSUES

5. Failure during construction: A surprising number of failures have occurred during construc-
tion due to a lack of skilled labor, failure of lifting equipment and cranes, fabrication errors,
or instability during erection.

3.1.5 Detailed Objectives
Failures are like open books.
There is an old saying that “failures are the pillars of success.” It is based on deductive
reasoning that if you identify, eliminate, or minimize the reasons for failure step by step, you
have reduced the risk and probability of failure, thereby leading to eventual success.
Primary objectives of our study are to identify all causes of failure and to understand the
technical issues and reasons behind failure.
The knowledge and experience gained from failure analysis can be applied:
1. To save lives and property.
2. To study failure mechanisms, formation of plastic hinges, andmodes of failure.

3. To develop analytical methods and efficient design codes; perform post design checks.
4. To study actual load combinations leading to collapse.
5. To study the behavior of materials.
6. To refi ne ultimate load methods of design including load factors, distribution factors, and
resistance factors.
7. To improve construction practices and to implement reconstruction methods correctly.
8. To resolve disputes for insurance claims during forensic engineering.

3.2 THE ROLE OF FORENSIC ENGINEERING
3.2.1 Combining Science, Engineering, and Legal Requirements
1. Forensic engineers explain how and why failures occur. The forensic process gets to the roots
of the problem. It gives a clear insight into structural behavior and lack of maintenance,
providing an independent account of deficiencies that lead to loss of life and/or damage.

Conducting forensic engineering involves:
• Expert witnessing
• Technical knowledge
• Detective skills
• Legal aspects of the damage caused.
2. The basic procedures of conducting a forensic engineering investigation are applied following
a failure.Ultimately, based on the knowledge gained from past experiences, the engineer is
better prepared technicallyto successfully facethe challenges that will arise in the future.
3. A forensic engineer knows that if design and reconstruction criteria were correctly imple-
mented a failure could be prevented. As a routine, bridges get demolished from sabotage,
fatigue and fracture, old age, inherent defects, or a lack of compliance to normal functions.
In addition, they may fail unexpectedly or due to continued neglect.
4. Collapse due to earthquake could be delayed when standard details, such as ductile moment
resistance connections are used. The expected life of 75 years or more for modern bridges
and their components may not be achieved without regular inspection, structural evaluation,
preventive action, and timely rehabilitation.

3.2.2 Documentation for Various Phases of Investigation
1. The structural forensic engineer, who is called in following a collapse, plays a crucial role
in determining what the first steps of an investigation should be. He is the most qualifi ed