Unknown BS EN 15258 2008 ICS 91 100 30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Precast concrete products — Retaining wall elements This British Standard[.]
Material requirements
Production requirements
Concrete production
Hardened concrete
4.2.2.2 of EN 13369:2004 shall apply In addition, the minimum concrete compressive strength at the time of delivery shall be declared
The concrete class shall not be less than C25/30 for retaining wall elements.
Structural reinforcement
Finished product requirements
Geometrical properties
Surface characteristics
Mechanical resistance
4.3.3 of EN 13369:2004 shall apply except 4.3.3.4 which is not relevant
Complementarily to 4.3.3 of EN 13369:2004, 4.3.3.2 and 4.3.3.3 shall apply
4.3.3.2 Verification by calculation aided by physical testing
In the case physical testing on finished products is required to aid calculation according to 4.3.3.3 of
The EN 13369:2004, Annex C outlines a mechanical resistance testing method for the restraint (stem-base) of full-scale precast elements used in cantilever walls This testing can validate design assumptions or replace calculations when suitable models for specific details, such as gussets, are unavailable Additionally, sections 5.2(1), 5.2(2)P, and 5.2(3) of EN 1990:2002 are applicable.
The transient situations covered by this sub-clause relate to storage, handling, transport and installation
The strength and properties of the concrete retaining wall element to be considered in transient situations are those specified by the manufacturer at the time of delivery
Main and secondary transverse reinforcements in wall elements, along with those for lifting, must be designed to handle expected loadings during transient situations If needed, temporary props or safe mounting racks should be utilized to ensure precast elements remain in the correct position and shape, minimizing the impact of loadings.
Wall elements shall be installed in accordance with technical specifications provided by the manufacturer
Wall elements must be constructed with temporary supports or devices as specified by technical requirements to ensure their stability and resistance during the transitional phase, while also maintaining safe working conditions.
Where props or other temporary devices are required and specific provisions are necessary, they shall be provided with sufficient strength, thickness and design
Cast in situ concrete shall be designed, cast and cured according to design specification.
Acoustic properties
NOTE This clause is relevant only for specific applications.
Thermal properties
NOTE This clause is relevant only for specific applications.
Durability
Other requirements
Complementarily to 4.3.8 of EN 13369:2004, 4.3.8.1 and 4.3.8.2 shall apply
The manufacturer must declare the weight of each unit, ensuring that it does not deviate more than ± 5% from the stated value.
In case of specific applications the water vapour permeability, expressed in kg/(s.m.Pa), shall be determined by tests according to EN ISO 12572
Tests on concrete
Measuring of dimensions and surface characteristics
General
Complementarily to 5.2 of EN 13369:2004, 5.2.2 and 5.2.3 shall apply.
Position of reinforcement
Measurements must be conducted on the casting bed at the conclusion of the manufacturing process or in the stockyard, following the guidelines outlined in Annex A It is essential to ensure that all measurements are accurately recorded.
The results shall comply with the requirements and the tolerances of 4.3.1.
Wall element dimensions
Measurements must be conducted at the conclusion of the manufacturing process or in the stockyard, following the guidelines outlined in Annex A It is essential to document all measurement results.
The results shall comply with the requirements and the tolerances of 4.3.1.
Weight of the products
The method of determining the weight shall be either by weighing or by calculation, in accordance with 4.3.8.1.
Load test of elements
Annex C outlines a method for conducting mechanical resistance tests on the restraint (stem-base) of full-scale precast elements used in cantilever walls The purpose of this test is to assess the ultimate bending moment capacity of the bottom section of the wall panel in the precast element, as illustrated in Figures B.5 and C.1.
Clause 6 of EN 13369:2004 shall apply
For inspection schemes, specific rules are given in Annex A
Clause 7 of EN 13369:2004 shall apply
In production series of similar elements, the elements shall also be marked with the date of production
Technical documentation must detail geometrical data along with the complementary properties of materials and inserts This includes essential construction information such as dimensions, tolerances, reinforcement layout, concrete cover, and the anticipated transient and final support and lifting conditions.
The composition of technical documentation is given in Clause 8 of EN 13369:2004
General
The relevant subjects of Annex D of EN 13369:2004 shall apply Complementarily to these subjects, the following schemes shall also apply.
Process inspection
NOTE Table A.1 is complementary to D.3.2 of Table D.3 of EN 13369:2004
– position of main bars relative to concrete faces, and cover
– length of projection of protruding bars
Measuring according to 5.2.2 of this European Standard
Conformity with drawing and specified tolerances
Each day, a randomly selected wall element is tested, ensuring that different types are assessed when applicable The specified tests and frequencies can be modified or omitted if qualified equivalent information is obtained from the product or process An element is deemed a different type if it is produced using a different mold.
Finished product inspection
NOTE Table A.2 is complementary to D.4.1 of Table D.4 of EN 13369:2004
– flatness of the moulded face if necessary for aesthetic reasons
Measuring according to 5.2.2 and 5.2.3 of this European Standard and Annex J of
Conformity with drawing and specified tolerances Every week, one wall element taken at random, every time a different type b if applicable
Visual inspection Appearance for aesthetic reasons For each production run
3 Weight (only if determined by weighing) Weighing Conformity with declaration and specified tolerances
Each week, a randomly selected wall element is tested, ensuring that different types are assessed when applicable The specified tests and frequencies can be modified or omitted if reliable equivalent information is obtained from the product or process An element is deemed a different type if it is produced using a different mold.
Examples of retaining wall elements
This annex provides examples of precast elements for cantilever retaining walls as defined in the European Standard, specifically in section 3.1 While the figures illustrate various shapes, it is important to note that this list is not exhaustive, as numerous other designs exist Additionally, some of these precast elements may be subject to patent protection.
The main reinforcement to be added in situ is not shown in the figures
1 back view 5 "in situ" footing
2 left side view 6 two stiffening ribs
3 wall panel 7 single stiffening rib
Figure B.1 — Precast elements with base slab for cantilever walls and bridge abutments (example)
1 back view 5 "in situ" footing
2 left side view 6 two stiffening ribs
3 wall panel 7 single stiffening rib
NOTE The stiffening ribs may be in the downstream face
Figure B.2 — Precast elements with base slab for cantilever auxiliary walls in bridge abutments
1 side view 4 back wall panel
2 isometric view 5 footing wall panel
Figure B.3 — Precast element with footing wall plate for cantilever walls (example)
1 side view 3 back wall panel
2a front wall panel concrete finishing 4 prop for installation
2b front wall panel finished with stones 5 "in situ" footing
Figure B.4 — Precast elements with different finishing on the front wall plate for cantilever walls
Figure B.5 — Precast elements with base slab for cantilever walls (example)
Mechanical resistance test of the restraint (stem-base) of precast elements for retaining cantilever walls
This annex outlines a mechanical resistance testing method for the restraint (stem-base) of full-scale precast elements used in cantilever walls The primary objective of the test is to assess the ultimate bending moment capacity at the base of the precast wall panel.
The tests can be made only after a sufficient age when the material properties have reached the necessary levels
For accurate predictions of structural behavior and the interpretation of measured data, it is essential to use the actual values of material properties at the time of testing, without applying any safety factors.
The concrete compressive strength will be evaluated using special samples made from the same material as the element or by testing cores drilled directly from the element itself.
The strength of reinforcing steel should be tested only under conditions that approach failure, necessitating the collection of special samples from the materials involved.
Prior to conducting the load test, it is essential to prepare a comprehensive report that includes all calculations required to monitor the behavior of the element during loading operations and to facilitate the interpretation of results in relation to the objectives of the experimental investigation.
To ensure the reliability of design models and manufacturing processes, test specimens must be constructed from the same materials and utilize similar technology as the final products.
This article focuses on the mechanical resistance behavior of the restraint (stem-base) of elements subjected to horizontal loads, where deformations and failure modes are primarily influenced by bending moments.
Only short term behaviour is investigated, so the loading and unloading operations are to be done within a short time (e.g within a day)
The element is arranged in a stable configuration, closely resembling its final position within the structure, as illustrated in Figure C.1 It rests on a continuous sand bedding with an average thickness of 2 cm A locking system secures the base to prevent overturning, while additional blocking is implemented to avoid slipping Figure C.1 also depicts a test setup for a cantilever wall element with an incorporated footing, which can similarly be arranged for cantilever wall elements featuring “in situ” footings.
A monitoring system is essential for accurate measurements, requiring the recording of displacements at one or multiple points of the element It is crucial to utilize proper instrumentation that offers adequate scale accuracy and sufficient travel range.
All instruments, for the measurement of forces/weights, of displacements and of other quantities, should be correctly calibrated
For a clear survey of cracking a white paint may be previously applied to the element
In the installed condition, the earth pressure is assumed to follow a triangular distribution, resulting in the pressure equivalent total force acting at one-third the height of the wall (H/3) To accurately simulate this force, a test load is applied.
Loading should be applied gradually, with a minimum time interval of 5 minutes between each step To enhance the interpretation of results, loads must be increased proportionally, allowing the subsequent deflection to be attributed to a single parameter.
The load is gradually increased in increments of at least five steps until it reaches the anticipated service load, with each increment stabilized for five minutes During this process, all cracks are documented along with the specific step at which they occur The load continues to rise in steps until failure is reached, at which point the failure load is recorded, and both the cracks and the mode of failure are noted.
The position of the reinforcement can also be checked and compared with the detailing
Clauses of this European Standard addressing the provisions of the EU
ZA.1 Scope and relevant characteristics
This European standard has been prepared under the mandate M/100 "Precast Concrete Products" 1) given to CEN by the European Commission and the European Free Trade Association
The clauses of this European standard shown in this Annex meet the requirements of the mandate given under the EU Construction Products Directive (89/106/EEC)
Adhering to these clauses establishes a presumption of suitability for the retaining wall components outlined in this annex for their specified applications; relevant information should be referenced accordingly.
WARNING : Other requirements and other EU Directives, not affecting the fitness for intended uses, may be applicable to the retaining wall elements falling within the scope of this standard