DS CEN/TR 15728:2016

Projektimi dhe përdorimi i pajisjeve për ngritjen dhe mbajtjen e elementëve prej betonit të parapërgatitur

Design and use of inserts for lifting and handling of precast concrete elements

Scope

1.1 General
This Technical Report provides recommendations for the choice and use of cast-in steel lifting inserts, hereafter called 'inserts' for the handling of precast concrete elements. They are intended for use only during transient situations for lifting and handling, and not for the service life of the structure. The choice of insert is made according to the lifting capacity of their part embedded in the concrete, or may be limited by the capacity of the insert itself and the corresponding key declared by the insert manufacturer.
The report covers commonly used applications (walls/beams/columns and solid slabs and pipes). The range of these applications is further limited to prevent other types of failure than concrete breakout failure (cone failure), bond failure, failure of reinforcement or failure in the steel insert.
Due to lack of information this report does not cover double shell walls, floor plates and beams for beam-and-block floor systems.
The safety levels are given for information and are intended for short-term-handling and transient situations.
This Technical Report applies only to precast concrete elements made of normal weight concrete and manufactured in a factory environment and under a factory production control (FPC) system (in accordance with EN 13369:2013, 6.3) covering the insert embedment.
This Technical Report does not cover:
- the design of the lifting inserts independently placed on the market;
- lifting inserts for permanent and repeated use.
This Technical Report is prepared based on the fact that the anchorage in the concrete of parts of the lifting assembly is governed by the Construction Products Regulation. Lifting accessories independently placed on the market are governed by the Machinery Directive.
1.2 Types of inserts for lifting and handling
This Technical Report applies to the embedment of lifting inserts. Devices made by the precaster may consist of smooth bars, prestressing strands, steel plates with anchorage or steel wire ropes. The system devices may be e.g. internal threaded inserts, flat steel inserts and headed inserts.
Lifting loops of ribbed bars are not covered.
1.3 Minimum dimensions
This Technical Report applies in general to inserts with a minimum nominal diameter of 6 mm or the corresponding cross section. In general, the minimum anchorage depth should be hef = 40 mm.
Wire ropes of diameter less than 6 mm are not covered.