EN 15050 is a candidate 'harmonised' European standard and fully takes into account the requirements of the European Commission mandate M/100, Products related to precast concrete products, issued under the EU. This document (EN A1:2012) has been prepared by the Technical Committee CEN/TC 229 “Precast concrete products”, whose secretariat is provided by AFNOR and was examined and agreed with a joint working group appointed by the Liaison Group CEN/TC 229 -CEN/TC250, mainly due to its compatibility with structural Eurocodes. The installation of some structural precast concrete products is covered in ENV 13670-1: Execution of concrete structures – Part 1: Common rules, which currently has the status of a European pre-standard.
EN 1168, Precast concrete products — Hollow core slabs EN 12794, Precast concrete products — Foundation piles EN 12843, Precast concrete products — Poles and beams EN 13224, Precast concrete products — Ribbed floor elements EN 13225, Precast concrete products — Linear structural elements. EN 13693, Precast concrete products — Special roof elements EN 13747, Precast concrete products — Floor slabs for floor systems EN 13978, Precast concrete products — Precast concrete garages EN 14843, Precast concrete products — Stairs. EN 14991, Precast concrete products - Foundation elements EN 14992, Precast concrete products - Wall elements EN 15050, Precast concrete products - Bridge elements.
The conformity assessment given in this European Standard refers to the finished precast concrete elements for bridges delivered to the market and covers all the production operations carried out in the factory. This European Standard applies to precast concrete structural elements produced in a factory and used in bridge construction, such as deck elements."
Material requirements
Production requirements
General
- Application of prestressing
When protecting the ends of debonded strands, a soft material should be used so that the end protection is not destroyed as the beam continues to creep. This soft covering (eg, a bead of foam) should also be used even when the wire is to be cast into a diaphragm.
Finished product requirements
- Geometrical properties
- Surface characteristics
- Mechanical resistance
- Resistance and reaction to fire
- Acoustic properties
- Thermal properties
- Durability
- Other requirements
The minimum dimensions of structural members are defined by the structural calculations, by providing the values of coverage required by EN 1992-1-1, EN 1992-2 and by this European Standard. Defects of limited importance can be treated after the transfer of prestress, preferably with non-shrink mortar or prestress, after a surface cleaning of the defect area. Recesses deeper than 8 mm (5 mm for external surfaces of edge beams or upper surfaces of bottom flanges) must be filled with an appropriate mortar of strength not less than the concrete of the prefabricated element.
In this case, and if authorized by the customer, the repair should only be carried out after a technical assessment of the problem and its severity has been carried out. The appearance of the elements is considered acceptable if there is no honeycomb structure, broken edges or too many voids in the surface; cracks must be assessed on a case-by-case basis. To define the characteristics of the elements, structural connections transferring longitudinal shear between precast and cast-in-place concrete shall comply with 6.2.5 of EN and the following additional requirements.
Minimum reinforcement for vertical displacement and flange displacement in the prefabricated elements must be provided. When verification of the resistance to fire is required or appropriate due to special situations, the procedures in 4.3.4 of EN shall apply.
Tests on concrete
Measuring of dimensions and surface characteristics
General
Beams
Measure the maximum distance of the beam soffit from the straight line connecting the beam axis. It is obvious that if the design base of the beam is curved, the distance will be determined from the theoretical position of the base of the beam.).
Other elements
Weight of the products
Scope
Decks with precast beams as main structural elements
In types a) to c) thin floor slabs are often used as permanent formwork for the cast-in-place concrete slab (see B.6).
Solid slabs
Segmental decks
Scope
Dimensions in the bearing zone
Transfer of prestressing
Anchorage of the main reinforcement at supports
Change of the restraint conditions after the application of loads
Skewed ends
Deck layout
4 web hole at the end of the beam, for diaphragm reinforcement 5 local square end to beam.
General
Connecting reinforcement
Connection to beams
Connection between adjacent floor plates
When the ends of the prestressing steel on the floor slabs are not embedded by the cast-in-place concrete, they should be protected.
Scope
Continuity of bridge decks
Hogging moments at supports
Long term sagging moments at supports
The aspect ratio is defined as the ratio of skew span to the width of the tire. Continuity reinforcement is carried out in the slab and at the top and bottom of bridge beams. Reinforcement corresponds to type 1 and 2 depending on the cross-section of the stage 1 crosshead.
There is no continuity reinforcement between ends of beams and there is no moment continuity between spans. The strap reinforcement at mid-depth of the slab is detached for a short length on either side of the joint to allow decrotation. The dissolution element must act as a barrier to moisture, and must be continuous over its full length and through the joint seal.
Slabs between spans are separated using compressible joint fillers, but the waterproofing and deck surfaces are continuous and special seals are applied over the joint for double protection.
General
Infilled beams with a thin topping
For this type of construction, the lower transverse reinforcement through holes in the beams is not required, provided that: .. a) the total depth of the deck is at least twice the depth of the precast beams; The transition situation during on-site casting must be verified and, if necessary, support for the precast beams must be provided. Special attention must be paid to the protection of the post-tensioning steel in the connections, especially in the match-cast box beam system.
The performance of the connections between elements affects the way the structure works, as there is discontinuity in the passive reinforcement. This is usually achieved by using the surface of the adjacent segment as a mold (match casting method). The production mold system must be designed so that necessary adjustments can be made in the mold position to ensure deck alignment.
All this will be carried out with a topographic control of the position of each segment. The water tightness of the channels must be checked by means of a pressurized water injection. The clauses of this European standard presented in this annex meet the requirements of the mandate given under the EU Directive on Construction Products (89/106/EEC).
Compliance with these clauses provides a presumption of suitability of the precast concrete bridge elements covered by this Annex for the intended uses specified herein; reference is made to the information accompanying the CE marking. In order to meet the provisions of the EU Construction Products Directive, these requirements must also be complied with when and where they apply. The requirement for a particular property does not apply in those Member States (MS) where there are no legal requirements for that property for the intended use of the product.
Verification of the conformity of precast concrete bridge elements, for the essential characteristics indicated in Table ZA.1, will be based on the assessment of the conformity procedure indicated in Table ZA.3, resulting from the application of the clauses of this or other European standards. shown there. The aforementioned declaration and certificate shall be presented in the official language or languages of the Member State in which the product is to be used. The manufacturer or his authorized representative located in the EEA is responsible for affixing the CE mark.
The design values of the mechanical ultimate strength of the element and the resistance to fire class shall be calculated using, for the nationally determined parameters, the recommended values in EN 1992-1-1 and EN 1992-1-2, or the given values in the National Annex of the EN Eurocodes applicable to the works.
Infilled beams with a thick topping
Scope
This annex deals with decks formed using side-by-side, cast-in-place slabless precast beams.
Transverse prestressing by post-tensioning
Reinforced joints
General
- Description
- Joints
- Keys
- Post-tensioning
In many cases it is necessary to apply a temporary tension to hold the segments in their position or to provide the necessary pressure in the case of glued joints.
Design
- Assembly stage
- Final situation
- Checking of joints
- Local transverse bending
- Discontinuity regions
The effective area for shear strength is the area of the lamellae and the part of the plate located at an angle of 45° from the lamellae. When there is a partial opening in the joints in the box section, there is a change in the torsional strength with a significant increase in the tangential stresses, see EN. When determining the design width for the transverse deflection caused by the concentrated load, its position relative to the joints, the stress state in the joints and the effects of shear keys must be taken into account.
In the case where the joint is open under the design forces, the transmission of forces through it should not be considered. In the case of shear key joints in longitudinal compression plates, the design width may be calculated as for a monolithic structure.
Production
Building assembly
- Segment positioning
- Segment sealing
- Post-tensioning
- Closing segment
System 2+ : See VPO Annex III-2 (ii) First possibility, including certification of the factory production control by an approved body based on initial inspection of the factory and of factory production control as well as of continuous supervision, assessment and approval of factory production control.
