Page 140 - Bridge and Highway Structure Rehabilitation and Repair

CHAPTER 3 BRIDGE FAILURE STUDIES AND SAFETY ENGINEERING 115

• Duress and job stress
• Lack of knowledge to perform a certain task effi ciently.
Hence, factors that contribute to unforeseen incidents need to be reduced or eliminated
through efficient planning and design:

Planning is the process of developing a product such as a bridge, formulating a program of
action, or structuring an orderly arrangement of activities for design and construction.
Design is the extension of planning when more detail and specifi c information is required.

3.18.2 Design Errors
1. Converting units of measure such as feet into inches.
2. Failure to include a correct factor of safety.
3. Use of a static force in place of a dynamic force.
4. Selection of the correct material.
5. Constructability issues resulting from design.
6. An incorrect estimate of the service life of a product.
7. Neglecting environmental effects such as thermal forces, vibration, corrosion, and
abrasion.
3.18.3 Production Errors

1. It is not always possible to construct the way it is shown on the drawing.
2. Changing fasteners or connectors because the sizes specified are not available can weaken

a structural joint.
3. Local overstress during shipping, erection, and handling.

3.18.4 Maintenance Errors
1. Inadequate maintenance or repair.
2. Poor access for inspection such as for bearings.
3. Lack of funds to carry out timely repairs.

3.18.5 Communication Errors (Figure 3.15)
1. Poor detailing.
2. Lack of construction coordination through responses to RFI (request for information).
3. DCN (design change notice) for resolving constructability issues.
4. Adjustments in dimensions due to site geotechnical conditions.
5. Access issues.
6. Availability of materials, etc. may contribute to failures.

Figure 3.15 The four components of communication.