Design and Behavior of Coped Beam

J. J. Cheng, J. A. Yura, and C. P. Johnson


The behavior of coped beams with various coping details was examined by conducting a theoretical parametric study using the elastic and inelastic finite element programs BASP and ABAQUS. The design models and recommendations for different types of coped connections (top, bottom and double coped) are made according to behavior results of the analytical studies. In addition to yielding, coped beams can fail in two distinct instability modes, lateral-torsional buckling over the span and local web buckling at the cope region. Cope length, cope depth and span length were found to have a significant influence on the buckling capacity.

Simple interaction equations, which utilize the individual lateral buckling capacities of the coped regoin and the uncoped length, were developed for design of lateral buckling of top (compression) flange coped beams and double coped beams. Copes on the bottom (tension) flange reduced the lateral buckling capacity 10 percent of the uncoped case. A plate buckling model was developed to check for web buckling in compression flange coped beams and a lateral buckling model was adopted for web buckling in double flange coped beams.

A series of sixteen full scale tests, 14 rolled sections and two plate girders, was used to check the reliability of the design recommendations. Six of the tests considered lateral-torsional buckling. The remainder were for local web buckling. The test results indicate that the proposed design recommendations for both lateral-torsional buckling and local web buckling give conservative and reasonable results.

Various types of reinforcement at the cope region were studied to determine their effectiveness in improving the strength of coped beams.

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