How are runway lights constructed?
I presume you are asking about lights that are on the surface of the runway like centerline lights and touch down zone lights. The FAA has an AC that covers their design and installation which you can find here. Take a look at section 4.5 "In Pavement Light Fixture Testing". This section outlines some of the force requirements the light must be able to withstand. The FAA currently requires the light to be mounted in an L-868 base can which is imbedded in the runway during construction. There are also a bunch of size requirements laid out in section "3.4. Dimensional Requirements." that describe how the lights are to be built.