I said this before and I am saying it again (and I'll probably say it again in the future): sidewalks are good places to find dead insects. This big brown beetle with long antennae and a spiny pronotum was also a recent sidewalk casualty. Its body is almost exactly 3 cm long.
If I am not mistaken, it is an Ortosoma brunneum, commonly known as the brown prionid. According to Lester & Papp's Common Insects of North America (1972), the 3 ridges on the elytra (wing covers), visible in the picture above, are characteristic of the species, as are the 3 teeth along the edges of the pronotum, visible in the picture below.
The larvae of O. brunneum feed on dead trees. This is one reason why we need to have more deadwood around. Otherwise, we will start losing the species that depend on dead trees.