With SLC-4 we are starting to find evidence of more permanent infrastructure. The previous launch pads had portable launch platforms SLC-4 had permanent launch platforms, now dismantled, but the concrete bases can still be seen.
The SLC-4 area actually housed two launch pads: LC-4 which was used for 25 launches of Bomarc, Matador and Redstone missiles between 1952 and 1960; and LC-4A, which was used for three Bomarc launches between 1958 and 1959. These were both located on a single expanse of concrete.
SLC-4 also saw the introduction of safety infrastructure in the form of water hydrants with jet nozzles to combat any potential issues that may occur with the rockets and missiles whilst fuelling and in preparation for flight. These are known as monitors and are installed in diagonally opposing pairs across the launch pad.