University Report: Analysis and Construction of Suspension Bridges

This report, focusing on suspension bridge construction, delves into the intricacies of bridge design and structural analysis. It examines the fundamental forces at play, including compression and tension, and explores the role of various components such as towers, cables, and road decks. Detailed drawings and design computations, including moment analysis, are presented to illustrate the engineering principles. The report further compares suspension bridges with cable-stayed bridges, highlighting their respective advantages and disadvantages, such as flexibility, load transfer capabilities, and construction time. Environmental factors like wind, temperature, and precipitation are also considered in the context of live, dead, and dynamic loads. The conclusion summarizes the key aspects of suspension bridge design, emphasizing the importance of considering factors like span length and lane capacity, and the overall construction mandates. The report is enriched with references to relevant literature.

Report about Suspension Bridge Construction
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Introduction
According to Larsen and Ostenfeld (2017) Suspension bridge mainly defined as a bridge type
constructed using the deck. The deck is positioned in the hung position below the parametric
suspension cables in line with the vertical suspenders. Preferably, it is important to note that the
first modern type of the suspended bridge was built in 1800s. Notably, the applications of the
simple suspensions bridges without vertical suspenders tend to have long history in line with the
analysis recorded for the mountainous parts worldwide. The suspension bridge type has
elementary cables often suspended between the existing towers. The suspended cables alongside
the vertical suspender cables necessitate the system to bear the deck weight. The process helps in
ensuring that the stability of the deck is obtained and thus, enabling the traffic crosses in long
run. Additionally, the process also aims at ensuring that the overall arrangement helps in
allowing for the leveling of the deck as well as for the clearance of the arc upward. It is
important to ensure that there is no false-work and practices during the construction of the
suspension bridge types. Subsequently, it is important to ensure that the anchoring of the
suspended cables mainly conducted and constructed at the bridge edges and this will help
transferring the tension loads to the main cables. Also, all the main cables should have the
network of continuity for the pillar sections and for the deck-level supports. Furthermore, it is
important to include the network of continued connections to the other aspects more so the
anchors and the ground. Conversely, it is important note that the connections and the support for
the roadway often regarded as the hangers. The roadway elements include rods as well as cables.
Uncertainty and the prevailing circumstances can lead to the construction and the erection of the
towers on the bluff and canyon sit edges. In such situations, roads may often be proposed to be
directed on the overall main span. Additionally, the bridge can also employ the technique of

having two smaller spans and these must run between the highways and the pair pillars.
However, in these situations the supports for the system often provided with the truss bridge or
the suspender cables. This mainly aims at ensuring that required stability is obtained in line with
the connection. In the cases whereby latter is applied, then little arc will be manifested in the
outboard of the main cables.
Structural Analysis
There are two main forces which one must incorporate in the designing of the suspended bridge
as far as the structural analysis is concerned. These two forces include the compression as well as
tension forces. Whereas the compression forces acts on the pillars, the tension force acts on the
cables. Preferably, the structural analysis demarcates that most of the forces acting on the pillars
poses vertically downwards as well as necessitated by the main cables in terms of the stability.
Thus, the pillars utilized in the process should be made of the slender materials as indicated in
the illustration below (Nader et al. 2017, September p. 2067).
Road deck in the suspended bridge mainly held in positions via the utilization of the towers and
the suspended cables. Essentially, the weight of the overall system mainly transferred from the
towers and later on into the ground. In situations in which the assumption is taken in line with
the weight as negligible, then the main cables will tend to form the parabola curves. Inn this
scenario, even the weight of the overlaying vehicles also equated as negligible in line with the
total weight of the bridge (Zarbaf and Ehsan 2018).

Detailed Drawings of the Suspended Bridge
The detailed drawings and analysis of the suspended bridge mainly illustrated as indicated in the
analysis below
Figure illustrating the Detailed Drawings and analysis of Suspended Bridge (Westgate, Koo and
Brownjohn 2014)
Design Computations
Moments are the essentials aspects which one must incorporate in the design and the overall
workability of the suspended bridge. The evaluation in line with the moment mainly indicated as
illustrated in the analysis below (Treyssède 2018 p.194).

Figure Showing the Illustration on the Moments in line with Suspended Bridge (Shi,Pan, Liu,
and Fan 2018)
Forces
There are three critical and vital forces which often operate and depicted in line with the any
bridge operations. The three forces include, live load, dynamic as well as dead load. Preferably,
dead loads relates to all the weights which are associated with the decisive weight of the bridge
itself. In essence, the weight of the bridge as far as the dead loads are concerned can cause the
bridge to collapse in line with the gravitational forces which tends to act on the bridge materials.

On the other hand, live loads mainly defined as the traffics which cause the movements across
the parametric bridge in association with the normal environmental conditions as well as factors.
Some of the key environmental factors which one needs to consider include winds, temperature
as well as precipitation. Finally, dynamic load also is another key element which one must
consider and these factors relates to the environmental factors which extends beyond the normal
prevailing weather conditions and elements (Huang, Feng and Qu 2017 p.2765).
Advantages and Disadvantages of Using the Cable-Stay Suspension Bridge Compared To
Suspended Arc Bridge
The use of cable-stay suspension bridges comes with numerous benefits in comparison with
suspended arc bridges. Some of these benefits mainly discussed as follows
First and foremost, Cable stay bridges have the capability of being flexible to accommodate one
tower or two whereas for the suspension bridges two towers are required. Second, it is an added
advantage for cable stay to support even curved bridges as opposed to the suspension bridges
which only require a straight bridge (Fairclough et al. 2018 p.34). Another important benefit the
cable stay has over suspended bridges is their ability to allow for load transfer to the tower
directly from the road via the cables and still maintains the balance for the tower. This is unlike
the suspension bridges in which only a portion of the load is transferred to the tower. The cable
stay bridges are stiffer compared to the suspension bridges. This ability makes the stay cables to
be stronger as compared to suspension bridges. This condition is possible due to the ability of the
stay cables to withstand a higher pressure than suspension cables. The cable stay bridges also
take a shorter duration to build therefore reducing construction time as compared to suspension
cables. These cables require less material therefore more economical as compared to suspension
cables (Acampora et al. 2014 p.90).

From this discussion it is necessary to talk about their disadvantages
The first in this study is that the cable stay bridges may not be too stable. Their lack of flexibility
contributes to this factor hence allows wind to act so much on them and make them lose stability.
The second point explains the difficulties in maintenance and inspection. The fact that their
major tension regions alongside the anchorage parts are hidden, this therefore makes their
inspection difficult to conduct from viewpoints. Lastly is the fact that the stay cables are not
recommended for too far distances as opposed to suspension cables. Thus, their maximum
distance is 1000 meters (Rosie 2018 p.342).
Conclusion
In summary, the analysis explored and examined the cable-stay suspension bridge in line with
the civil engineering works. The paper explored the report which aimed at explaining the various
aspects which the cable-stay suspension bridge often has and the construction mandatories which
one has to consider in the long run. This bridge often intended to have a span of at least 1350
meters with overall 6 lanes. Furthermore, this analysis also encompass on both the advantages
and the disadvantages.

References
Acampora, A., Macdonald, J.H.G., Georgakis, C.T. and Nikitas, N., 2014. Identification of
aeroelastic forces and static drag coefficients of a twin cable bridge stay from full-scale ambient
vibration measurements. Journal of Wind Engineering and Industrial Aerodynamics, 124, pp.90-
98.
Fairclough, H.E., Gilbert, M., Pichugin, A.V., Tyas, A. and Firth, I., 2018. Theoretically optimal
forms for very long-span bridges under gravity loading. Proc. R. Soc. A, 474(2217), p.20170726.
Huang, K., Feng, Q. and Qu, B., 2017. Bending aeroelastic instability of the structure of
suspended cable-stayed beam. Nonlinear Dynamics, 87(4), pp.2765-2778.
Larsen, A. and Ostenfeld, K.H., 2017. Bridge engineering and aerodynamics. In Aerodynamics of
Large Bridges (pp. 3-22). Routledge.
Nader, M., Baker, G., Patel, H., Shi, S. and Ingham, T., 2017, September. Design of the Cable-
Stayed Bridge Signature Span of the New Champlain Bridge. In IABSE Symposium Report (Vol.
109, No. 33, pp. 2067-2074). International Association for Bridge and Structural Engineering.
Rosie, G., 2018. Double Crossings: The Tangled Tale of the Forth Road Bridges. Scottish
Affairs, 27(3), pp.342-360.
Shi, Y., Pan, S., Liu, C. and Fan, S., 2018. The effect of seawater layer on cable-stayed bridge
under tri-direction spatial varying ground motions. Journal of Vibroengineering, 20(4).
Treyssède, F., 2018. Finite element modeling of temperature load effects on the vibration of local
modes in multi-cable structures. Journal of Sound and Vibration, 413, pp.191-204.
Westgate, R., Koo, K.Y. and Brownjohn, J., 2014. Effect of solar radiation on suspension bridge
performance. Journal of Bridge Engineering, 20(5), p.04014077.

Zarbaf, H.A.M. and Ehsan, S., 2018. Vibration-based Cable Tension Estimation in Cable-Stayed
Bridges (Doctoral dissertation, University of Cincinnati).