Background to the fib Model Code 2010 shear provisions – part I: beams and slabs

Abstract

This paper examines the evidence for the one‐way shear model developed for the fib Model Code for Concrete Structures 2010 and provides examples of its application. For the design and analysis for shear, for members with and without shear reinforcement, the fib Model Code 2010 procedures have been developed from physical‐mechanical models that are based on observed behaviour at the meso‐scale level; they represent a significant advance over previous standardized empirical methods. In addition, an approach referred to as “level of approximation” (LoA) is incorporated where advanced models are simplified in a consistent and conservative way such that the designer can select the effort needed to justify their design. To illustrate the practical use of the models and the LoA approach, two examples are presented. The first is a deck slab of a cut‐and‐cover tunnel where design and possible refinements are discussed for a given configuration. The second is a prestressed concrete bridge girder, which is considered for the cases of design and for the analysis of an existing structure.

Background to fib Model Code 2010 shear provisions – part II: punching shear

“…Contrary to shear in beams and one-way slabs in the companion paper [32], where the relationship between strains (crack openings) and bending moments can be assumed as proportional after flexural cracking, the load-rotation behaviour of a slab is significantly non-linear [6,12,13,20].…”

Performance‐ and displacement‐based seismic design and assessment of concrete structures in fib Model Code 2010

“…Shear force action effects V E,d are determined through non-linear analysis for the combination of the applicable seismic action and the quasi-permanent gravity loads or, if linear analysis is used (see paragraph above), by capacity design calculations (see section 5.4). The design value of shear force resistance V R,d outside flexural plastic hinges is determined as for static loading [19]. Special rules, highlighted in section 7, apply for the value of V R,d in flexural plastic hinges under cyclic loading.…”

Experimental investigation on fatigue of concrete cantilever bridge deck slabs subjected to concentrated loads

“…The shear strength of reinforced concrete beams without shear reinforcement according to the fib-Model Code 2010 is based on the Simplified Modified Compression Field Theory [34]. For cantilever slabs under concentrated loads, the control section is located at d 6 a v =2 from the support and the shear force at that section is calculated by dividing the applied load by an effective width following a geometric rule [23].…”