Systems Science and Engineering: FRP-Aluminum Bridge Design Analysis

This report provides a comprehensive analysis of the conceptual design phase for a hybrid FRP-aluminum space truss bridge, focusing on its application for emergency situations. The report begins by outlining the advantages of FRP materials in structural applications, particularly in bridge engineering, and highlights the need for lightweight, modular bridges suitable for rapid deployment. It then explores the stakeholder needs, specifically the demand for a two-rut vehicular bridge designed for manual erection and air transport. The conceptual design process is detailed, including the consideration of military bridge codes and the design requirements for carrying a 100KN four-wheel truck. The report discusses the selection of materials, including an aluminum bridge deck and FRP trussed members, and the use of pre-tightened teeth connections for joining components. Furthermore, the system requirements are outlined, including the dimensions, load-bearing capacities, and manufacturing processes. The report concludes by summarizing the design of a modular hybrid FRP-aluminum space truss bridge, emphasizing its potential for emergency applications and the innovative connection techniques used in its construction.

SYSTEMS SCIENCE AND ENGINEERING
By Name
Course
Instructor
Institution
Location
Date

Contents
INTRODUCTION...........................................................................................................................................2
SHAREHOLDER’S NEEDS..............................................................................................................................2
CONCEPTUAL DESIGN PROCESS...................................................................................................................3
Bridge Deck..............................................................................................................................................4
Trussed Members....................................................................................................................................5
Connections.............................................................................................................................................5
SYSTEM REQUIREMENTS.............................................................................................................................6
CONCLUSION...............................................................................................................................................7
REFERENCES................................................................................................................................................9

INTRODUCTION
Fiber-reinforced polymers which are also known as FRP materials are indeed very attractive
when it comes to the structural applications. This is due to their admirable properties like proper
resistance to corrosive agents, high strength as well as finally self-weight which is known to be
low. The FRP substances applications particularly in the engineering of the bridge either in the
construction of new bridges or in strengthening the already existing structures (Keller et
al.2013). Among the increasingly promoted areas include the construction of the bridge decks,
vehicular bridges which are light- traffic and even the pedestrian bridges. In some cases, there

has been the construction of heavily loaded bridges of the vehicle using FRP in the recent
engineering works.
It is possible to use FRP in the construction of bridges which are used for emergency purposes
instead of the conventional steel or concrete materials and assist in the satisfaction of its primary
requirements (Zhang et al. 2016). These primary requirements include modular feasibility,
lightweight facilities for transport and finally faster construction. The applications of the
materials made from FRP in the truss meant for space structure particularly for the case of major
members which bear primary load have actually be used increasingly in the previous years. It is
however regrettable that space truss application with the combination of such materials made
from composites which have never realized much fruits bearing angles in the case of the
construction of the vehicular bridge. Also, the research work on the mechanical performance and
feasibility of the composite space truss bridges are very few.
SHAREHOLDER’S NEEDS.
In this particular project, consideration has been given to the development and application of the
desired properties of FRP to meet the demand of the society. Taking the consideration of the
perfect form of the structure which is most cases is of the hybrid structure and commands the
other components of the space truss. The demand for modular bridges which are lightweight and
best suited for emergency purposes; there is a proposal of a bridge structure which is an
aluminum space truss which is a hybrid FRP component. The proposed structure of the bridge is
a structure of hybrid which is a two-rut vehicular bridge. Its erection should be done manually by
the laborers who are skilled and be used in the case of air transport. Its design was as a modular

bridge whose length span was meant to be 12m. The bridge had 8 structural units of truss which
were triangular.
These units were made up of FRP trussed members as well as aluminum bridge decks connected
by the use of the female jaws and male jugs (Yeh et al.2015). It is important to note that the
proposed bridge has its bridge decks welded into other members of the truss so that they form an
integer which can be observed as the chord on the upper section. The space truss which is
proposed as the bridge structure is different from other space structures which are analog in
which the trussed members are detached from the deck. Besides, the lower and upper chords are
never integral. Instead, they are connected by the use of pin joints as results of its modular
properties. The main aim of this particular paper is to comprehensively verify the viability of the
hybrid FRP-aluminum structure proposed as a space truss bridge. The conceptual design of the
bridge is therefore described.
PROCESS OF CONCEPTUAL DESIGN
For emergency particularly in the mountainous areas, a lightweight space truss bridge which is
structurally sound is desirable. The space truss bridge will be manually dismantled and erected
with the specific structural units. These units can be easily transported or further extended and be
installed elsewhere. The design utilized the general code for the military bridge in China. The
requirements of the design which were considered included the ability to effectively carry a four-
wheel truck whose weight is 100KN as per the code specifications. The design used a safety
factor of 1.5 in the case of the ultimate loading state. The admissible deflection for such structure
is actually between L/100 and L/50 in which L has been considered as the span length.

The structure of hybrid FRP-aluminum was designed as a single-span that was supported simply
on just one- Lane Bridge. The length of the span was taken as 12m. This was corresponding to a
two-rut load of the traffic. The total width of the structure was taken at 3.2 meters. The two ruts
had a clearance of 0.8metres between them (Mukhopadhyay et al.2015). The designs of the two
ruts were such that they form a triangular cross-section with 0.85-m depth and 1.2-m width.
These elements were linked up by the use of the transverse braces. Every unit was having 4
standard structural units that are connected by female jaws and male jugs. Every unit had a
length of 3m and was made up of a deck from aluminum material. The deck was supported by
the FRP and other members of the aluminum truss. The entire bridge has a total weight of 12KN
with every unit of the total 8 units having only 1.5KN.
Bridge Deck
On top of the structure of the bridge was an aluminum deck of the bridge. This deck was made
up of thin plate whose thickness was 5mm with a series of "I" beams welder to the structure of
integer. The integer component was also known as orthotropic bridge deck. Besides the major
longitudinal beams of the two units adjacent to each other were just connected by the use of pin
joints and were never meant for the transfer of the bending moments experienced at the point of
connectors. The secondary longitudinal beam and thin plate are never continuous in the axial
direction over the entire bridge as a result of its modular properties. Also, the connection of the
main longitudinal beam has been achieved just by the use of pin joints (Zhu and Lopez 2014).
This implies that they will not be required to participate in the transfer of loads of bending
moments. In other perspectives, the approximation of the upper chord truss can be used as a
reflection of the bridge properties. This implies that the bridge deck made from aluminum can
show better compressive response as opposed to the FRP composite deck. This is because it

allows for the distribution of load over the whole structure as it comes in the form of stressed
induced load and as a concentrate wheel load. The design thus chose wrought aluminum.
Trussed Members
In this particular proposed bridge of the space truss, there was a selection of the aluminum
profiles and pultruded FRP for the structural applications as members. The use of the pultruded
FRP was for the case of the lower members of the chord to provide the desired stiffness of the
structures besides being cost-effective. In the case of the members of the diagonal web that has a
weak impact on the structure stiffness, there was a selection of GFRP that have low values of
elastic modulus as low as 31.5 GPa. Ultimately there was a selection of wrought aluminum alloy
7A05 to be used in the members of the vertical web as a result of 0.95m insufficient length. This
allowed the application of the connection of pre-tightened teeth to be used in weight control
functions.
Connections
This particular paper has employed pre-tightened teeth connection (PTTC that has very high
efficiency of connection to assist in connecting aluminum profiles and e FRP tubes of the
structure of the proposed hybrid bridge. This is because it had been discovered that there would
be a likelihood of having low connection efficiency when using connection technique of FRP
tubes in the conventional composite material (Liu and Pantelides 2013). The efficiency of the
compressive connection as well as the efficiency of tensile connection will be as 66.3% & 58.4%
respectively. Interestingly, only 40% of the connection efficiency would be achieved by the use
of conventional composite connections (Ghasemi et al.2016). The connection of the pre-
tightened teeth utilized stripe-shaped tooth structure for composite materials grooved at the ends
of the connections that were properly matched on the pieces of the aluminum. After the assembly

of composite components and external aluminum tube, there will be compression of the external
aluminum tube into the tube of the composite before it is subjected to expansion. This is done
because the internal aluminum tube's diameter is larger than the composite tube's internal
diameter (Rakoczy and Nowak 2013). This will lead to the production of positive radial stress on
the teeth of the composite material. Hence the external load will be transferred through shearing
stress of the composite teeth on the bottom layer.
SYSTEM REQUIREMENTS
There was grooving of stripe-shaped teeth or ring at the point of the connection end as well as
the outside surface of the tube of the composite. The external tube was then cut into the length of
the design. On this length, there was grooving of corresponding teeth at the outside surface and
end of the tube. This was done in a manner which allowed for the proper matching of external
aluminum tube and the composite tube. There was manual screwing of the composite tube into
the external aluminum tube. After assembling composite components and external aluminum
tube, the internal aluminum tube will be compressed into the tube of the composite material by
the use of a hydraulic jack (de Freitas, Kolstein and Bijlaard, 2013). Finally, there will be a
combination of all different tubes into a whole structure so that it will allow for the transfer of
the external load. It is expected that during the period of manufacture, there will be no use of
bonds between the surfaces of different tubes.
In the proposed bridge design, there will be the manufacture of 3 and 7 spiral teeth on both sides
of GFRP and HFRP tubes respectively (Dey et al.2016). The teeth have a width of 12mm and a
depth of 2mm for the case of FRP tubes. The corresponding values on external aluminum tube
included 2mm and 8mm. To get the ultimate bearing capacity in the designed pre-tightened teeth
connection, there was the preparation of 6 coupons (3 for HFRP and 3 for GFRP). The ultimate

capacities of bearing included GFRP and HFRP connections of the trussed members with values
as 320kN and 730kN respectively.
According to the pre-tightened teeth connections, the constructional elements at the junction
aluminum with the trussed profiles of FRP could be realized easily. It is anticipated that
technology of welding will be used of the aluminum profile junctions and GFRP/HFRP –areas
with relatively small stresses. A flange joint will be used for the tubes of HFRP with the female
jaws or male jugs in areas where there are larger stresses (Dey et al.2015). The process will
utilize 3 spiral teeth with 2mm depth. This will be meant to restrain connection C-6 sliding along
the lower member of the chord. The two structural unit joints were created by female jaws and
male jugs that will be fixed by the use of a flanged connection. This will involve the use of 8
high stressed bolts for the members of the lower chords. There will be a rivet connection for the
main "I" beam that was longitudinal as per (C-1, C-3) format.
CONCLUSION
There was the design of a hybrid FRP-aluminum space truss structure as a bridge of modular
type which could be used for emergency. The designed bridge had a span of 12m and was
containing other 8 structural units. The units consisted of the aluminum deck that was supported
by the material of FRP tubes and connected by the use of female jaws and male jugs on a
technique of novel connection known as pre-tightened teeth connection (PTTC). As per the
proper selection of the materials used which included aluminum materials and hybrid FRP which
were combined with pre-tightened teeth connection (PTTC) approach, the space truss proposed
had a lightweight of approximately 1.2 tons (Blaga et al.2015). This implied that every unit out
of the total 8 structural units had only 0.5 tons. It was possible to have the bridge transported
easily and be manually erected quickly as a result of the utilization of the pre-fabricated units of

the modular lightweights. The qualities were found to be very suitable in meeting the design
requirement of operation in the mountainous places during emergency responses.

REFERENCES
Blaga, L., Dos Santos, J.F., Bancila, R. and Amancio-Filho, S.T., 2015. Friction Riveting
(FricRiveting) as a new joining technique in GFRP lightweight bridge construction. Construction
and Building Materials, 80, pp.167-179.
de Freitas, S.T., Kolstein, H. and Bijlaard, F., 2013. Lightweight reinforcement systems for
fatigue-cracked orthotropic bridge decks. Structural Engineering International, 23(4), pp.458-
467.
Dey, P., Sychterz, A., Narasimhan, S. and Walbridge, S., 2016. Performance of pedestrian-load
models through experimental studies on lightweight aluminum bridges. Journal of Bridge
Engineering, 21(8), p.C4015005.
Dey, T.K., Mukhopadhyay, T., Chakrabarti, A., and Sharma, U.K., 2015. The efficient
lightweight design of FRP bridge deck. Proceedings of the Institution of Civil Engineers-
Structures and Buildings, 168(10), pp.697-707.
Dey, T.K., Srivastava, I., Khandelwal, R.P., Sharma, U.K., and Chakrabarti, A., 2013. Optimum
design of FRP rib core bridge deck. Composites Part B: Engineering, 45(1), pp.930-938.
Ghasemi, S., Zohrevand, P., Mirmiran, A., Xiao, Y. and Mackie, K., 2016. A super lightweight
UHPC–HSS deck panel for movable bridges. Engineering Structures, 113, pp.186-193.
Keller, T., Rothe, J., De Castro, J. and Osei-Antwi, M., 2013. GFRP-balsa sandwich bridge deck:
Concept, design, and experimental validation. Journal of Composites for Construction, 18(2),
p.04013043.

Liu, R. and Pantelides, C.P., 2013. Shear strength of GFRP reinforced precast lightweight
concrete panels. Construction and Building Materials, 48, pp.51-58.
Mukhopadhyay, T., Dey, T.K., Chowdhury, R., Chakrabarti, A., and Adhikari, S., 2015.
Optimum design of FRP bridge deck: an efficient RS-HDMR based approach. Structural and
Multidisciplinary Optimization, 52(3), pp.459-477.
Rakoczy, A.M., and Nowak, A.S., 2013. Resistance Model of Lightweight Concrete
Members. ACI Materials Journal, 110(1).
Yeh, F.Y., Chang, K.C., Sung, Y.C., Hung, H.H. and Chou, C.C., 2015. A novel composite
bridge for emergency disaster relief: Concept and verification. Composite Structures, 127,
pp.199-210.
Zhang, S., Shao, X., Cao, J., Cui, J., Hu, J. and Deng, L., 2016. Fatigue performance of a
lightweight composite bridge deck with open ribs. Journal of Bridge Engineering, 21(7),
p.04016039.
Zhu, J. and Lopez, M.M., 2014. Performance of a lightweight GFRP composite bridge deck in
positive and negative bending regions. Composite structures, 113, pp.108-117.