Semi-rigid––simply supported shear deformable pultruded GRP beams subjected to end moment loading: comparison of measured and predicted deflections

A single span shear deformable beam is analysed. One end is simply supported and subjected to an external moment and the other is supported by a semi-rigid joint with a linear moment––rotation characteristic. An expression for the mid-span deflection is derived in order to predict deflections recorded in tests on pultruded GRP beams with four types of semi-rigid joint. Using rotational stiffnesses derived from moment––rotation tests on similar joints it is shown that semi-rigid, shear deformable beam analysis is generally able to predict the measured deflections to within less than 10%. The mid-span deflection formula is recast to allow a back analysis to be carried out to determine the actual stiffness of two of the semi-rigid joints. It is shown that the joint tests significantly under-estimate the rotational stiffness of the bolted web cleat joint, whereas the predicted stiffness of the bolted web and flange cleat connection differs only by about 20% from that determined in one of the joint tests on this connection.