Suspension Bridges

Introduction

Amazed by the tall skyscrapers, mesmerized by the intricate designs of the infrastructures, and got exhausted in crossing the bridges – it seems like the modern engineering already perfected the combined art and function. Civil works became one of the highest paid jobs in the world because of the knowledge, skills, and talent that steered in the profession. In the modern day, there is an addition on the requirements and that is to provide the appropriate approach among the issues involve, whether in managerial, safeness, cost efficiency, and many others which makes the continuous development in the profession. Based on the history, engineering starts even in the Stone Age, where the early people learned to build their own bridges. In this era of civilization, bridges are also used as part of the daily transportation owed from the professional engineers.

Society of Civil Engineers

Civil engineering is referred to as the oldest branch in engineering. The continuous development of the profession originated from the knowledge of mathematical and physical sciences that are gained through the study, experience, and practice. All of these factors are used to apply in judgment to develop ways to economically utilize the materials and forces (both human and environment) in the progression of human beings. The application of knowledge is assumed to be responsible in constructing one project that is beneficial for the entire society. The work and responsibility of an engineer may be difficult and they should perform according to the functions of investigations and survey, planning and design, construction, research, and facilitating, control and management (USOPM, 1998). The most common position that a civil engineer might acquire is in the public works in which the service is dedicated for the public good. Suspension bridge is one of the major types of project that continuous to serve the people even after 10 years.

Suspension Bridges

Suspension bridges are a typical infrastructure that can deteriorate but cannot be easily replaced or easy to break. In San Diego (California), the Spruce Street Suspension Bridge remains the only suspension foot-bridge since its construction in 1911. The structure of the bridge was facilitated by the professional engineers. The combination of the knowledge and technology made it possible to build. However, since changes occur in all sides of the earth, monitoring and reconstruction is the attention given to the suspension to continue its service. On the inspection of the bridges most repairs are for broken flanges that connect hand rail cables to the bridge deck, because people rock the bridge and the flanges break. This is great evidence that ordinary people do not understand the functions of the bridge and mistakenly understood as the place to have fun (Brownlee, 1984). Obviously, a suspension bridge represents a significant capital investment and plays an important role in the transportation system. It is true that the parts of the bridge can be maintained and/or replaced but it might the reason to carry the heavy traffic (Nickerson, 2003).

Safeness of Suspension Bridges

As the response of the civil engineers in the needs of people, the safeness and reliability of the suspension bridges are firstly measured. Because of the complex structures involve in the work of engineers, the evaluation is addressed to measure the flutter reliability of a suspension bridge. Uncertainties such as the material properties, geometric parameters, wind velocity, structural site, and other elements are considered. It is important to determine the safeness of the project of suspension bridge (Cheng, et al., 2005). The primary concern of safeness in suspension bridges is that the collapse of structures in the case of high magnitude earthquake, which is placed as the top priority of the engineers – assuring that the construction is safe and such dilemma can be prevented. The earliest form of bridges was made from woods and ropes which the safeness is questionable. Other countries also spend time in building bridges through the use of twisted grasses and other materials that can be found in their place and is available (Schafer, 2002). As a replacement, the civil engineers provided the materials that maybe difficult to administer and costly but can support the load-carrying capability. Because of the importance and capital investment, the suspension bridges are usually designed to functions for 100 years or more. And because of the cost and time involved in the monitoring and evaluation technique, it is usually done only after a bridge has been in service for many years (Nickerson, 2003).

Conclusion

There should be applicable guidelines and techniques that the engineers should apply to avoid failure in the construction of suspension bridges. Furthermore, it is better if the inspection can be done in an interval years to maintain the safeness of the bridges.

References:

Brownlee, J.C., (1984) "Bull Strong, Horse High, and Hog Tight:" The Work and Character of Edwin M. Capps, The Journal of San Diego History 30(3) [Online] Available at: https://www.sandiegohistory.org/journal/84summer/capps.htm [Accessed 16 July 2010].

Cheng, J., Cai, C.S., Xiao, R., & Chen, S.R., (2005) Flutter Reliability Analysis of Suspension Bridges, Journal of Wind Engineering and Industrial Aerodynamics 93:757–775 [Online] Available at: http://www.engr.colostate.edu/~schen/flutter.pdf [Accessed 16 July 2010].

Nickerson, R., (2003) Safety Appraisal of Suspension Bridge Main Cables [Online] Available at: http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_w20.pdf [Accessed 16 July 2010].

Schafer, B., (2002) Civil Engineering Structures [Online] Available at: ce.jhu.edu/whatis2/lecture/Civil Engineering Structures.ppt [Accessed 16 July 2010].

USOPM, (1998) Civil Engineering Series GS-0810 Workforce Compensation and Performance Service Classification Programs Division, United States Office of Personnel Management [Online] Available at: http://www.azguard.gov/hro/documents/standards/gs_standards/gs0810.pdf [Accessed 16 July 2010].