Cal. Code Regs. tit. 8 § 3909
All supporting structures used in connection with amusement rides shall be designed and constructed to carry safely with the appropriate factors of safety as defined by the nationally accepted standards and with proper allowance for wind forces, dynamic effects of the equipment, load reversals and repetitions all loads to which such structures may normally be subjected. All rides shall be placed on solid footings and be anchored to prevent shifting or tipping. Sandbags may be used on cement surfaces. Use of shim blocks shall be kept to a minimum. Depressions in the ground near the ride footings shall be filled and tamped and adequate means of drainage provided to prevent water from collecting and softening supporting areas in case of rain. The area surrounding the ride shall be cleared and kept free from trash and tripping hazards.
Cal. Code Regs. Tit. 8, § 3909