By Wang Bin, Li Rong, Central Research Institute of Building and Construction Co., Ltd., MCC Group
The application of FRP in civil engineering is an inevitable trend
High-performance fiber reinforced polymers (FRP for short) are irreplaceable structural and functional materials for aerospace and ammunition and have also been more and more important in civil fields such as rail transportation, energy and power and construction engineering. Thanks to their high specific strength, high specific modulus, good durability, low electromagnetic induction, and processing easiness, FRPs can solve technical problems that traditional materials cannot solve and meet the requirements of integration of structure and function of new buildings. The application of FRPs is an inevitable trend for improving the energy efficiency, quality and construction efficiency of civil engineering, and is also an important direction for technological change in the international civil engineering industry.
FRP in civil engineering innovation
In the field of civil engineering, FRPs are mainly applied in the reinforcement of existing structures and the construction of new structures.
1. Reinforcement of existing structures
FRPs have advantages like wide application range, obvious reinforcement/seismic effect, low construction energy consumption, low pollution emission, and high efficiency, hence being ideal for the enforcement of existing structures, especially for earthquake relief and post-earthquake reconstruction. They will also have important economic values in the sectors of cultural relics protection, rapid reinforcement and maintenance of important existing structural facilities, and emergency rescue.
At present, the international civil engineering FRP research and development is mainly concentrated in the field of structural reinforcement and repairing. Advanced FRP automatic molding technology, 3D printing and AI reinforcement are development trends. The application fields are building structures, bridges, tunnels, underground structures, hydraulic structures, ports, docks, and pipelines.
2. Construction of new structures
With the substantial reduction of manufacturing costs and the continuous maturity of design and manufacturing technology, the structural and functional advantages of FRPs and their components continue to improve, letting them play an advantage role in new structures.
(1) FRP cable and super-long-span structure
The FRP cable, made by the pultrusion process, has a similar appearance to the steel cable, but its strength, modulus and durability are much superior to the steel cable. The use of FRP rebar/cable can greatly reduce the weight of the structure, thus having outstanding advantages in super long span structures.
(2) FRP profile and special equipment
FRP profiles, made by pultrusion process, are able to be prefabricated and quickly established and have characteristics of light weight, strong bearing capacity, environmental corrosion resistance and good electromagnetic performance. In military field, FRP profile bridge decks and full FRP structured bridges have unique advantages in rapid transportation and emergency bridge building. In the field of electromagnetic communication, FRP profiles are indispensable structural materials for communication equipment radomes, high-power electromagnetic equipment supporting devices and geomagnetic observation stations.
(3) FRP functional panels, curved panels and functional buildings
FRPs can be made into ribbed, hollow or sandwich panels, and can be easily corrugated, curved, spherical, and specially shaped, hence achieving the integration of nonlinear architectural aesthetics and structural functions. Some typical functional buildings, such as the Chanel Pavilion, have extensively used such materials.
(4) Interdisciplinary design and construction and conceptual structure
In recent years, cross-disciplinary collaboration of bio-bionics, intelligent manufacturing, and 3D printing has provided more possibilities for FRP innovative design and construction.
Problems and challenges
There is a manufacturing technology system for FRP, and its research and application in the field of civil engineering has made many achievements. However, there are very few types of products, with insufficient stability and high manufacturing cost. Civil engineering FRPs’ structural-functional integration design is insufficient. The key technologies such as connection anchoring, long-term reliability assessment and verification, and extreme environment construction are still not perfect. It is the fundamental guarantee for the in-depth application of FRP in the field of civil engineering to fully understand and absorb the innovative technologies of superior disciplines, work together to break through the technical barriers of the entire industrial chain of FRP engineering application, and form a complete set of technologies and standard systems for the design and application of civil engineering FRP.
Comprehensively promoting the coordinated development of key technologies in the entire process of integrated manufacturing, characterization evaluation, application construction, safety monitoring and life evaluation of FRP can enhance the technical innovation of FRP and civil engineering and ensure the construction of national economy and national defense security.
