I I

Eurocode 2 Design of shear connection at the interface between concrete cast at different times

Description:
Calculation of required shear connection reinforcement and verification of concrete strength at the interface between concrete cast at different times
According to:
EN 1992-1-1:2004+AC2:2010 Section 6.2.5
Supported National Annexes:
Nationally Defined Parameters (NDPs) automatically filled for supported countries
All Calculations
Input
MPa
e.g. 30 MPa for concrete class C30/37. For a list of concrete classes see Table of Concrete Design Properties
MPa
See table below for interface classification
Classification of interface according to EN1992-1-1 §6.2.5(2)
Very smoothA surface cast against steel, plastic or specially prepared wooden moulds (c = 0.025 to 0.10, μ = 0.5)
SmoothA slipformed or extruded surface, or a free surface left without further treatment after vibration (c = 0.20, μ = 0.6)
RoughA surface with at least 3 mm roughness at about 40 mm spacing, achieved by raking, exposing of aggregate or other methods giving an equivalent behaviour (c = 0.40, μ = 0.7)
IndentedA surface with indentations complying with EN1992-1-1 Figure 6.9 (c = 0.50, μ = 0.9)
The provided value is applied as a multiplier for the concrete bond coefficient c. A value of 1.0 leads to no adjustment. According to EN1992-1-1 §6.2.5(5) under fatigue and dynamic loads a value of 0.5 should be considered. For bridges according to EN1992-2 §6.2.5(105) under fatigue and dynamic loads a value of 0.0 should be considered.
MPa
Stress per unit area caused by the minimum external normal force across the interface that can act simultaneously with the shear force (positive when compressive)
kN
Transverse shear force acting on the composite cross-section (see figure below)
m
In the shear analysis of reinforced concrete with small axial force, the approximate value z = 0.9d may normally be used, according to EN1992-1-1 §6.2.3(1) where d is the effective depth of the cross-section to the centroid of tensile reinforcement
m
Width of the interface where shear forces are transferred between old and new concrete. See figure below for typical cases.
Ratio of the longitudinal force in the new concrete area to the total compressive or tensile longitudinal force for the section considered. When the longitudinal force in the new concrete is compressive the total compression force of the cross-section is considered. When the longitudinal force in the new concrete is tensile the total tension force of the cross-section is considered, resulting from the tension forces of the longitudinal reinforcement. A value of β=1 is always conservative.
°
An angle of 90° corresponds to the bars being perpendicular to the plane of the interface. Values less than 90° mean that the bars are in tension due to the shearing action on the interface.
Examples of shear interfaces between concrete cast at different times
Examples of shear interfaces between concrete cast at different times (reproduced from EN1992-1-1 Figure 6.8)
Nationally Defined Parameters
According to EN1992-1-1 §3.1.6(1)P and the National Annex.
According to EN1992-1-1 §3.1.6(2)P and the National Annex.
According to EN1992-1-1 §2.4.2.4 and the National Annex.
According to EN1992-1-1 §2.4.2.4 and the National Annex.
Note: Always verify the validity of the Nationally Defined Parameters. Please inform us of any discrepancy using our Contact Form