The AASHTO specification does not specify the analysis method for base-plate design of span-wire traffic signal poles. The study reported here consisted of full-scale testing and finite element analysis of a number of existing signal poles to examine their behavior and evaluate their structural adequacy. A simplified analysis method has been developed because present procedures were found to be unreliable. This method is consistent with the working stress design concept in the current code. It decomposes the base plate into three elementary components corresponding to three critical regions of maximum stress. The subsequent analyses become straightforward on the basis of these modelings, with the assistance of empirically determined coefficients to reach equivalent section capacities with respect to critical stresses. Hand calculation is adequate for applications of this method in routine design.

Traffic-signal poles that are span-wire mounted (referred to here simply as" signal poles") currently are designed according to the AASHTO specification (J). Provisions are given for analysis and design of the post and anchor bolts, but no method is specified for analysis of the base plate. This study examined structural adequacy of the base plates of signal poles supplied to New York State. As a result, a semiempirical method was developed for analyzing base plates because the current procedures were found to be unreliable. This method is intended to be consistent with the working stress design adopted by the current code and may be included in the specification for design applications. In New York State, a typical signal pole consists of a round or polygonal steel post with changing diameter welded to a square steel base plate. The base plate is anchored to a concrete footing by four bolts. A reinforced hand hole is provided in the post. Typical pole details are shown in Figure 1. Dead, wind, and ice loads are required to be covered in pole design (1, 2). Their combinations and corresponding strength requirements are provided by the code (1). In this paper signal poles are identified by the first letter of the manufacturer's name, design load in kips, and height in feet. For example, C530 is a pole manufactured by Carlan Manufacturing Company, with a design load of 22.2 kN (5 kips), that is 9.14 m (30 ft) tall. Two critical loadings are considered here: parallel loading, in which the wire runs parallel to a side of the square base plate, and diagonal loading, in which the wire runs along a diagonal of the base plate.