Escalator support structure

Escalator support structure

escalator scissors

According to EN 115-1: 2017, we have tried to describe the escalator truss and its requirements in detail below

An escalator has a structural support called the “escalator truss” on which all the mechanisms are located and attached. The escalator truss is divided into three main sections: Upper Section, Incline Section, and Lower Section. Usually, the Upper and Lower sections are fixed, while the center section can be modified to provide variable heights.

The escalator truss has two support angles at each end where it is inserted into the structural beams of the building. The support angles are not fixed (not welded, bolted, etc.) and are held only by their own weight. Underneath the support angles is a layer of high-density rubber that prevents the truss from vibrating.

The escalator truss material is made of various steel alloys and shapes (rectangular steel, angle steel and channel steel) and their combinations of different sizes.

A 5 millimeter thick steel plate called “soffit” is attached to the bottom of the truss.

The escalator truss must be designed so that the structure is free from oscillation and misalignment, and this is accomplished by using joint welding, which provides high quality joints while keeping the parts stationary.

Hot dip galvanized materials are used to coat indoor escalator trusses for longer paint life, semi-open, fully open and heavy escalators (to BS 729 – ISO1461) with a minimum thickness of 85 microns.

The escalator truss must be able to support its own weight as well as a structural design load of 5000 N/m2 in accordance with EN 1993-1-1:2005, and the maximum deflection must not exceed 1/750 of the horizontal length between two structural beams. . In case the horizontal length of the escalator truss is too long and causes a greater deflection of the truss than allowed, a center support(s) should be used.

To facilitate the movement of long escalators, the truss may be divided into two or more sub-sections. Hexagon socket bolts must be used to assemble the sub-sections during assembly where they are designated and pre-drilled in the connection plates at the factory.

Perforated plates called “lifting lugs” are welded to the corners of the escalator girder and are used for lifting to move and assemble the escalator truss. If the escalator truss is split, each corner must also be provided with lifting lugs. The eyelet facilitates the connection of tow ropes to the unit. Lifting the escalator or moving it from unauthorized points and directions may cause irreparable bending or defects in the operation of the device.

In accordance with EN 115-1:2017, the escalator truss shall, after installation, be completely covered with suitable non-perforated panels called “external cladding”. The cladding must be able to withstand 250 N at right angles at all points on a circular or square area of 2500 mm2 without collapsing. In addition, any gaps or openings for ventilation grilles on the panels must be less than 4 millimeters away from moving parts that are at risk of contact.