Design of concrete structures

Centric axial strain in uniaxially restrained precast reinforced concrete floor slabs

Any floor slab whose shortening is obstructed by stiffening components, such as building cores or walls, will be subject to strain caused, for instance, by shrinkage. In this scenario, reinforced concrete floor slabs are thus subject to a combined action of service loading and strain forces. The impact of the loading component leads to flexural cracks in certain areas of the slab that, in turn, result in a partial reduction of the strain. Physically nonlinear FEM models currently provide the only option to realistically simulate superimposed service loading and strain forces as well as their interactions.

TU Kaiserslautern and Bochum University of Applied Sciences jointly conducted a research project funded by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR). Its first phase included a comprehensive program of short-term and fatigue tests of precast floor slabs carried out at TU Kaiserslautern. After completion of these tests, a team of researchers at Bochum University of Applied Sciences performed corresponding computations to replicate the test results and to calibrate the parameters required for non-linear FEM simulations. In the next step, a parametric study involving all relevant parameter combinations was conducted.

The outcomes of the structural component tests and of the parametric study were used to develop verified design tools that permit realistic calculations of the longitudinal strain forces acting on uniaxially restrained precast reinforced concrete floor slabs.

Related articles:

Issue 2020-02 Reinforced-concrete floor slabs in multi-story building construction

Concentric strain due to shrinkage and/or temperature variations

Constraint forces occurring in reinforced-concrete members are often difficult to determine. This particularly applies to reinforced-concrete floor slabs in multi-story building construction, which...

Issue 2019-09

Precast floor slab and method for forming a flooring deck and building formed of precast floor slabs

(11) EP 3 517 698 Al (22) 29.01.2019 (43) 31.07.2019 Bulletin 2019/31 (57) The invention relates to a floor slab, which is intended to form a flooring deck. The floor slab (26) in­cludes cast...

Issue 2022-06

Experimental investigations on punching shear of flat slabs made of carbon-reinforced concrete

So far, European standards do not stipulate generally applicable verification rules for the punching shear of slabs made of carbon-reinforced concrete. In addition, regulations on the structural...

Issue 2008-12

December 2008

Issue 2013-02 Precast floor slabs with an in-situ concrete toping

Verification of the lap joint detailing

Two-way precast floor slabs require an overlapping joint of the load carrying reinforcement in both directions. As the overlapping reinforcement lies within the in-situ concrete, special detailing of...