Concrete beams

Carbon Fiber Reinforced Plastics has recently has been recognized as an alternative to conventional steel reinforcement in concrete due to its excellent resistance to corrosion. Four rectangular concrete beams and four concrete columns reinforced with CFRP bars were cast for the study of the long term behavior under uniform sustained loading. The beams were simply supported and subjected to uniform sustained loading. The columns were arranged in a steel reaction framework. The beams and columns were instrumented and monitored to observe the change in the behavior due to the creep and shrinkage of concrete. An analytical method is developed to predict the long term behavior of CFRP reinforced concrete members. The calculated deformations compare reasonably with the experimental values. A modified equation for the calculation of the long term deflection is proposed for CFRP reinforced concrete beams. A simplified equation for the calculation of the creep coefficient is also proposed.

This thesis presents an analytical and experimental investigation
of the remaining impact strength of concrete beams with corroding
reinforcement. Concrete beams were subjected to impact using a
centrally loaded instrumented dropweight system. Three different
amounts of steel corrosion were used to simulate ten, twenty, and thirty
years of seawater exposure.
The first part in the analytical investigation involved the use of
the finite element code ADINA. The second included development of three
physical models; the first based on a beam impact equation of forced
vibration for a pin-ended beam with center span impact, the second a
two-degree-of-freedom model, and the third a three-degree-of-freedom
model taking into account the stiffness of the supports for the impacted
beam specimens.
The different analytical results showed good correlation with the
test values of the impact energies. Also, the energy values for the
different corrosion periods obtained from the ADINA analysis compared
well with experimental ones.

This study presents and illustrates a methodology to calculate the capacity of an existing reinforced concrete bridge under a non-conventional blast load due to low and intermediate pressures. ATBlast program is used to calculate the blast loads for known values of charge weight and stand off distance. An excel spreadsheet is generated to calculate ultimate resistance, equivalent elastic stiffness, equivalent elastic deflection, natural period of the beam, the maximum deflection, and the maximum rotation in the support for a simple span solid slab and T-Beam bridges. The allowable rotation could be taken as to two degrees. Naval Facility Engineering Command (NAVFAC) approach was adopted, where the inputs were material properties, span length, and area of reinforcement. The use of the Fiber Reinforced Polymer for increasing the capacity of an existing bridge is also presented in this study. Parametric studies were carried out to evaluate the performance of the solid slab and T-Beam bridges under the assumed blast load.