The design life of fiberglass pipe is 50 years. In order to ensure long service life of fiberglass pipe, long-term properties under service conditions is the most important performance. According to the polymer matrix composite material with viscoelastic properties, adopt equivalent principle and shift factors method combined with experiments to study the long term performance of fiberglass pipe, established a relatively simple for fiberglass pipes long-term performance prediction method. The experiments show that compliance of fiberglass pipe with all hoop winding increased by 148% after 50 years in 60% stress level.

The interface properties of carbon fiber(CF) within the composite material has a great effect to its functional characteristics. The work is focused on the research of CF electro-mechanical response after its surface modification using acetone and nitric acid oxidation. With characterization by XPS and SEM, there exist the various changes on the CF surface not only the chemical elements or chemical groups. With changing CF’s resistance under uniaxial tension, the CF has differerent electro-mechanical response to loading force. Through statistical analysis, the research shows the sensibility of CF to the electro-mechanical effect can be improved by the surface modification with acetone process or nitric acid oxidization.

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The paper aims to sense strains of structures in two-dimension stress states and to perform a large-region strain monitoring. Polymer-matrix Carbon Fiber Smart Stripes (CFSS) distributed in two ways are stuck on a bending plate to detect strains using the piezoresistivity of CFSS. Monotonous tests are conducted to calibrate the surface piezoresistivity of the CFSS and then cyclic tests are conducted to measure the strains of the structure using the constitutive relation of CFSS. Results show the experimental values by CFSS fairly good with those by gage factors.

Earth pressure can be divided into three kinds of load form by Spangler theory: vertical earth pressure, bed reaction and horizontal lateral pressure. According to Spangler theory, the level of static earth pressure presents a parabolic distribution in central angle bon both sides of the tubes. Used the glass steel pipe as the specific research object, Spangler theory applied to the three-dimensional buried tube model for finite element analysis, the analysis is divided into two situations: (1) the same soil, finite element analysis of different pipe diameter; (2) the same tube diameter, finite element analysis of different soil. This method can reasonably reflect the interaction of soil and structure, it is feasible. The complicated process of the finite element simulation of tube soil interaction can be avoided.