§1604.7. Overhead Beams, Foundations, and Flooring Over Hoistway.

(a) Overhead Beams and Foundations.

Overhead beams and foundations for the direct support of the machinery or sheaves, or both, shall conform to the following requirements:

(1) Beams and Supports Required.

Machines, machinery, and sheaves shall be so supported and maintained in place as to effectually prevent any part from becoming loose or displaced under the conditions imposed in service.

Supporting beams, if used, shall be of steel or reinforced concrete. Beams are not required under machines, sheaves, and machinery or control equipment which are supported on floors, provided such floors are designed and installed to support the load imposed thereon.

(2) Overhead Beams, Floors, and Their Supports.

Overhead beams, floors, and their supports shall be designed for not less than the sum of the following loads:

(A) The load resting on the beams and supports which shall include the complete weight of the machine, sheaves, controller, governor, and any other equipment, together with that portion, if any, of the machine room floor supported thereon.

(B) Twice the sum of the tensions in all wire ropes supporting the car, passing over sheaves or drums supported by the beams, with rated load in the car.

(3) Foundations, Beams, and Floors for Machinery and Sheaves Not Located Directly Over the Hoistway.

For machines and sheaves located below, or at the sides of, the hoistway, the foundation for the machine and sheave beams and their supports shall be designed to withstand loads as follows:

(A) The foundation shall support the total weight of the machine, sheaves, and other equipment, and the floor, if any.

(B) The sheave beams and the foundation bolts shall withstand twice the vertical component of the tensions in all hoisting ropes passing over sheaves or drums on the foundation or beams, less the weight of the machine or sheaves.

(C) The sheave beams and the foundation bolts shall withstand twice the horizontal component, if any, of the tensions in all hoisting ropes passing over sheaves or drums on the foundation or beams.

(D) The foundation shall withstand twice the overturning moment, if any, developed by the tensions in all the hoisting ropes passing over sheaves or drums on the foundation or beams.

(4) Securing of Machinery and Equipment to Beams, Foundations, or Floors.

(A) Overhead Beams and Floors.

Machinery or equipment shall be secured to, and supported on or from the top of, overhead beams or floors.

EXCEPTIONS:

1. Secondary or deflecting sheaves of traction hoists.

2. Devices and their accessories for limiting or retarding car speed.

(B) Beams or Foundations Supporting Machinery and Sheaves Not Located Directly Over the Hoistway.

Machines and sheaves located below, or at one side of, a hoistway shall be anchored to beams, foundations, or floors with bolts, shall conform to American National Standard Specification for Low-Carbon Steel Externally and Internally Threaded Standard Fasteners, G38.5-1969 (ASTM A307-68), and shall be of sufficient size and number to withstand the applicable load conditions specified under Section 1604.7(a)(2). Based on these initial loads, total tension in anchor bolts shall not exceed 12,00 lb./in.2 of net section, and the total shear shall not exceed 8,600 lb./in.2 of actual area in the shear plane. Where bolts are used through sloping flanges of structural shapes, the bolt heads shall be of the tipped or beveled-head type or shall be fitted with beveled steel washers, and nuts on sloping flanges shall seat on beveled steel washers.

EXCEPTION: Bolts made of steel having a greater strength than that specified by American National Standard G38.5-1969 (ASTM A307-68) may be used and the maximum allowable stresses increased proportionally based on the ratio of the ultimate strengths. Elongation must conform to the requirements of the corresponding American National Standard.

(C) Overhead Hoisting Rope Hitches.

Where hoisting ropes are secured to the structure above a hoistway, the hitch plates and hitch plate blocking beams, where used, shall be secured to, and mounted on top of, overhead beams, machine beams, or on top of auxiliary beams connected to the webs of overhead beams. Hitch plates, blocking beams or auxiliary beams shall be secured by bolting, riveting, or welding, and shall be so located that the tension in the hoisting ropes will not develop direct tensions in the bolts or rivets. Bolts shall conform to American National Standard G38.5-1969 (ASTM A307.68), American National Standard Specification for High Strength Bolts and Structural Steel Joints, Including Suitable Nuts and Plain Hardened Washers, G38.6-1972 (ASTM A325-71a), or American National Standard Specifications for Quenched and Tempered Alloy Steel Bolts for Structural Steel Joints, G24.19-1972 (ASTM A490-71). Rivets shall conform to American National Standard Specification for Steel Structural Rivets, G42.2-1968 (ASTM A502-65). Welding shall conform to American Welding Society, Structural Welding Code D1.1. Where bolts and rivets are subject to shearing stresses due to tensions in the hoist ropes, the total shear shall not exceed 8,600 lb./in.2 of actual area in the shear plane. Except where friction-type connections are used in accordance with American National Standard G38.6-1972 (ASTM A325-71a) and American National Standard G24.19-1972 (ASTM A490-71), the allowable stresses per Section 1604.7(a)(5)(A) shall be used.

The stresses in welds due to tensions in the hoisting ropes shall not exceed 12,000 lb./in.2 based on the throat area of the weld.

The hitch plate supporting beams shall be designed to withstand twice the sum of the tension in all hoisting ropes attached to the hitch plates.

Total stresses in tension plus bending in hitch plates and hitch plate shapes shall not exceed 12,000 lb./in.2

EXCEPTION: Bolts made of steel having a greater strength than specified by American National Standard G38.5-1969 (ASTM A307-68) may be used and the maximum allowable stresses increased proportionally based on the ratio of the ultimate strengths. Elongation must conform to the requirements of the corresponding American National Standard.

(D) Cast Metals in Tension or Bending.

Cast metals having an elongation of less than 20% in a length of 2 inches, which are subject to tension or bending, shall not be used to support machinery or equipment from the underside of overhead beams or floors.

(5) Allowable Stresses for Machinery and Sheave Beams, or Floors and Their Supports.

The unit stresses for all machinery and sheave beams, and floors and their supports, based on the loads computed as specified under Section 1604.7(a)(2), shall not exceed 80 percent and the unit stresses in tower or mast structures shall not exceed one hundred percent of those permitted for static loads by the following standards:

(A) Structural Steel.

AISC Specification for the Design, Fabrication and Erection of Structural Steel for Building.

(B) Reinforced Concrete.

Building Code Requirements for Reinforced Concrete ANSI A89.1 (ACI 318).

Where stresses due to loads other than hoist loads, supported on the beams or floor, exceed those due to the hoist loads, 100 percent of the permitted stresses may be used.

(b) Flooring Over Hoistway.

Where the hoisting machine is installed at the top of the hoistway, a solid floor shall be provided for maintenance, inspection, and lubrication. The floor shall be of 2-inch plank, or the equivalent, secured against movement with guardrails installed on all open sides. Where the hoisting machine is located at the bottom of the hoistway suitable access shall be provided for maintenance, inspection, and lubrication of top cathead and sheaves.

Go Back to Article 14 Table of Contents