California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 6 - Elevator Safety Orders › Group II - Elevator Installations for Which the Installation Contract Was Signed Before October 25, 1998 › Article 18 - Design Data, Formulas, Tests on Approved Devices, and Electrical Regulations › Section 3103 - Hydraulic Elevator Car Frame and Platform Stresses and Deflections

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) General
						Requirements. The stresses and deflections in car frame and platform members
						shall be based on the data and formulas listed in this section. For cars with
						corner-post or subpost car frames, the formulas and data do not generally apply
						and shall be modified to suit the specific conditions in each case.
(1) The maximum stresses in car frame
						uprights which are normally subject to compression shall be such that the
						quantity [(fa/Fa) +
						(fb/Fb)] does not exceed unity.
Where:
Fa = Allowable axial compressive
						  unit stress (not exceeding
						  17,000-0.485(L/R)2).
Fb = Allowable bending unit
						  stress (15,000 psi if area basis is gross section or 18,000 psi if area basis
						  is net section).
fa = Actual axial compressive
						  unit stress based on gross section.
fb = Actual bending unit
						  stress.
L = Free length of uprights in inches (distance from
						  lowest fastening in crosshead to top fastening in plank).
R = Least radius of gyration of section in
						  inches.
(2) The stresses in
						the car frame crosshead shall be based on the total load, if any, supported by
						the crosshead.
The moment of inertia in the crosshead shall be not
						  less than twice that of the stile section about an axis parallel to that of the
						  crosshead section. The connection between the crosshead and the stile shall
						  have sufficient rigidity to transmit the bending moment in the stile into the
						  crosshead.
(3) The normal
						stresses in the car frame plank for elevators having a single plunger shall be
						based on a load equal to ½ the maximum static load on the plunger
						concentrated at each end of the plank with the plunger force applied at the
						middle. Where multiple plungers are used, the stresses shall be analyzed for
						the specific case. Stresses resulting from oil buffer engagement shall be
						calculated in accordance with Design Section
						3101(d).
(4) The stresses in each car frame upright
						due to compression and bending and the slenderness ratio of each upright and
						its moment of inertia shall be determined in accordance with the following
						formulas:
(A) Stresses due to bending.
fb = KL/4HZu
where:
fb = The bending stress in each
						  upright in the plane of the frame due to the live load W on the platform for
						  the class of loading A, B, or C for which the elevator is to be used.
K = Turning moment in inch-pounds as determined by the
						  class of loading by the following formulas:
1. For Class A freight loading or passenger
						loading:
K = WE/8
2. For class B freight loading:
K = W [E/2 - 48] or K = WE/8
whichever is greater
3. For Class C freight loading:
K = WE/4
For explanation of symbols L, H, and
						  Zu see Design Section
						  3101(g).
(B) Stresses due to compression:
fa = Compressive stress in each
						  upright.
(C) Slenderness
						Ratio:
The slenderness ratio L/R for uprights subject to
						  compressions other than those resulting from buffer action shall not exceed
						  120.
EXCEPTION: Where the upper side-brace connections on
						  passenger elevator car frame uprights are located at a point less than 
						  2/3 of L
						  from the bottom (top fastening in car frame plank), a slenderness ratio of L/R
						  not exceeding 160 shall be permissible.
(D) Moment of Inertia.
The moment of inertia of each upright shall be not less
						  than determined by the following formula:
I = KL3/18EH
For explanation of symbols see Design Section
						  3101(g).