Safety factor for the punching shear resistance model in 2nd Generation of Eurocode 2

2022 ◽  
Vol 46 ◽  
pp. 103788
Author(s):  
Jaroslav Halvonik ◽  
Jana Kalická ◽  
Lucia Majtánová ◽  
Mária Minárová
Keyword(s):  
Safety Factor ◽  
Shear Resistance ◽  
Punching Shear ◽  
2Nd Generation ◽  
Eurocode 2 ◽  
Resistance Model

scholarly journals Theoretical prediction of punching shear capacity of flat slabs without shear reinforcement strengthened by concrete topping

2021 ◽  
Vol 1203 (2) ◽  
pp. 022108
Author(s):  
Daniel Čereš ◽  
Katarína Gajdošová
Keyword(s):  
Shear Resistance ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Model Code ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract The main reasons for strengthening flat slabs are the change of the use of a building, increase in the value of loads, degradation of the concrete cover layer, or insufficient reinforcement. This paper is focused on the assessment of punching shear capacity of the strengthened flat slabs without shear reinforcement. One of the possibilities how to enhance punching shear capacity is the addition of reinforced concrete topping. The main goal of this paper is to compare the possibilities for calculation of the increase in the punching shear capacity by investigation of the influence of different thicknesses of concrete toppings and different reinforcement ratio. A reference specimen is represented by a fragment of a flat slab with the thickness of h = 200 mm supported by circular column with the diameter of 250 mm. Three different thicknesses (50 mm, 100 mm, 150 mm) of concrete toppings were considered together with three different reinforcement ratios for each thickness of concrete overlay. Theoretical predictions of the punching shear resistance of flat slabs were evaluated by design guidelines according to the relevant standards: Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of the second generation of Eurocode 2 (prEN 1992-1-1). The differences in the influence of reinforcement ratio are significant. In Model Code 2010 the reinforcement ratio in concrete topping was considered in equation of moment of resistance. This is unlike in both of the mentioned Eurocodes, where the reinforcement ratio was assumed as a geometric average value of the original reinforcement ratio in the slab before strengthening and of the reinforcement ratio of concrete topping. All the predicted theoretical calculations are based on the perfect connection and bond between the original and new layer of concrete. These predictions should be verified by experimental investigation, which is going to be prepared shortly. By the additional increase in the thickness of concrete topping or in the amount of added reinforcement the attention should be payed to the limitation of the punching shear resistance by the value of the maximum punching shear resistance in the compression concrete strut.

scholarly journals Punching shear resistance of reinforced concrete footings: evaluation of design codes

2018 ◽  
Vol 11 (2) ◽  
pp. 432-454
Author(s):  
D. F. A. SANTOS ◽  
A. F. LIMA NETO ◽  
M. P. FERREIRA
Keyword(s):  
Reinforced Concrete ◽  
Progressive Collapse ◽  
Shear Resistance ◽  
Test System ◽  
Shear Capacity ◽  
Experimental Results ◽  
Punching Shear ◽  
Complex Method ◽  
Shear Design ◽  
Eurocode 2

Abstract Punching is a possible failure mode for slender footings and it may lead a structure to ruin through progressive collapse. Although footing present different geometric characteristics, their punching shear design is based on the empirical methods used for flat slabs. This paper uses experimental results from 216 tests to evaluate the performance of design code recommendations presented by ACI 318 (2014), ABNT NBR 6118 (2014) and Eurocode 2 (2010) to estimate the punching shear resistance of reinforced concrete footings. Great dispersion between theoretical and experimental results was observed, being evident that the test system affects the punching shear capacity of footings. The more complex method proposed by Eurocode 2 resulted in a better correlation with experimental results.

scholarly journals Strengthening flat slabs without shear reinforcement against punching shear by concrete overlay

2021 ◽  
Vol 1209 (1) ◽  
pp. 012056
Author(s):  
D Čereš ◽  
K Gajdošová
Keyword(s):  
Parametric Study ◽  
Shear Crack ◽  
Shear Resistance ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Flat Slab ◽  
Model Code ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract Research in this paper presents a theoretical study of increasing in punching shear capacity of the strengthened flat slab by concrete overlay. The parametric study is based on comparison of three different relevant standards design models and presents results how Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of second generation of Eurocode 2 (prEN 1992-1-1) take into account strengthening by concrete overlay. A reference specimen is represented by a fragment of a flat slab supported by circular column. Influence of concrete toppings depends on thickness and also on reinforcement ratio. In Eurocode 2 and new generation of Eurocode 2 the increase of punching shear resistance of the slab with concrete topping can be taken into account only by reinforcement ratio and thickness of the slab considering the perfect connection and bond between the original slab and new layer of concrete overlay. Model Code 2010 is based on Critical shear crack theory and the reinforcement ratio in concrete topping was considered in equation of moment of resistance and punching shear resistance is calculated by considering the rotation and deformation of the slab. Estimation of results by parametric study are compared by non-linear model from Atena software.

scholarly journals Slabs strengthened for punching shear with post-installed steel and CFRP connectors

2019 ◽  
Vol 12 (3) ◽  
pp. 445-478
Author(s):  
M. J. M. PEREIRA FILHO ◽  
M. V. P. FREITAS ◽  
D. F. A. SANTOS ◽  
A. J. C. NASCIMENTO ◽  
M. P. FERREIRA
Keyword(s):  
Shear Resistance ◽  
Experimental Results ◽  
Punching Shear ◽  
Design Codes ◽  
Shear Reinforcement ◽  
Shear Strengthening ◽  
Flat Slab ◽  
Design Recommendations ◽  
Eurocode 2 ◽  
Shear Failures

Abstract Structural accidents due to punching shear failures have been reported in flat slab buildings. Design recommendations presented by codes can lead to entirely different punching shear resistance estimates for similar situations. Furthermore, design codes do not present guidelines for the design of punching shear strengthening of existing slabs. This paper uses a database with 118 experimental results to discuss the performance of theoretical estimates of punching shear resistance using ACI 318, Eurocode 2 and ABNT NBR 6118 in the case of slabs without shear reinforcement. Another database with results of 62 tests on slabs strengthened with post-installed steel and CFRP dowels is used to evaluate the performance of these strengthening techniques and to propose adaptations in codes to allow their use in punching shear strengthening situations of existing slab-column connections.

The Analysis of Shear Forces Flow around the Supports of Flat Slabs

2020 ◽  
Vol 309 ◽  
pp. 216-221
Author(s):  
Simona Šarvaicová ◽  
Viktor Borzovič
Keyword(s):  
Cross Section ◽  
Shear Resistance ◽  
Linear Analysis ◽  
Punching Shear ◽  
Shear Forces ◽  
Flat Slab ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Non Linear ◽  
Linear Shear

This paper deals with both linear and non-linear analysis of shear forces distribution in the area near the supports of the flat slabs. With a cross-section ratio of cmax / cmin > 3, the main amount of the shear stress is concentrated near the column or wall corners bases. As a consequence of this phenomenon, it is necessary to reduce the control perimeter when evaluating the punching shear resistance of a flat slab. The fragments of the flat slabs with the thickness of 200 mm supported by a wall with various loading conditions were analyzed. The results according to the Eurocode 2 were compared to a non-linear shear resistance evaluation that was calibrated based on the results from the previous experiments. Based on thus evaluated punching shear resistances, the theoretical reduced control perimeter was determined and subsequently it was compared to design model Eurocode 2. The physical basis for determining reduced control perimeters is based on the shear force concentration near the support.

PREDICTION OF PUNCHING SHEAR RESISTANCE OF PRESTRESSED CONCRETE FLAT SLABS

2011 ◽  
Vol 14 (1) ◽  
pp. 180-196
Author(s):  
A M Elshihy ◽  
H A ShehabEldeen ◽  
O Shaalan ◽  
R S Mahmoud
Keyword(s):  
Prestressed Concrete ◽  
Shear Resistance ◽  
Punching Shear ◽  
Flat Slabs

Zur maximalen Durchstanztragfähigkeit von Einzelfundamenten mit einer neuartigen Durchstanzbewehrung/Maximum punching shear resistance of footings with a new punching shear reinforcement

Bauingenieur ◽  
2016 ◽  
Vol 91 (11) ◽  
pp. 435-445
Author(s):  
Josef Hegger ◽  
Alexander Stark ◽  
Marcus Ricker ◽  
Dominik Kueres
Keyword(s):  
Shear Resistance ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Eine Hohe

Aufgrund der geringeren Schlankheit und der Belastung durch Bodenpressungen stellt sich bei Fundamenten und Bodenplatten ein Lastabtrag ein, der infolge der steileren Druckstrebenneigung höhere Durchstanztragfähigkeiten ermöglicht als bei Flachdecken. Die steileren Schubrisse führen jedoch dazu, dass vertikale Durchstanzbewehrungselemente weniger effizient sind als in Flachdecken. Aus diesem Grund scheinen geneigte Bewehrungselemente geeigneter für den Einsatz in Platten mit größerer Bauteildicke und geringerer Schlankheit. Aufbauend auf den Ergebnissen vorhandener experimenteller Untersuchungen an durchstanzbewehrten Einzelfundamenten wurde daher ein neues Durchstanzbewehrungselement mit geneigten Bewehrungsstäben entwickelt.   In einer ersten Versuchsserie wurden sieben Versuche an Einzelfundamenten mit der neuartigen Durchstanzbewehrung und einem Versagen innerhalb des durchstanzbewehrten Bereichs durchgeführt. Die Versuche wurden in Anlehnung an eine bereits bestehende Versuchsserie an Einzelfundamenten ohne und mit Bügeln als Durchstanzbewehrung geplant und zeigten im Vergleich eine erhebliche Steigerung der Durchstanztragfähigkeit.   Aufbauend auf den Ergebnissen der ersten Versuchsserie wurde eine zweite Versuchsserie durchgeführt, um die maximale Durchstanztragfähigkeit von Fundamenten mit der neuartigen Durchstanzbewehrung zu untersuchen. In den sieben Versuchen wurden die Betondruckfestigkeit, die Schubschlankheit, der bezogene Stützenumfang und die Anordnung der Durchstanzbewehrungselemente variiert. Der Vergleich der Bruchlasten der neu durchgeführten Versuchsserie mit der Durchstanztragfähigkeit nach DIN EN 1992-1-1+NA(D) belegt eine hohe Effizienz der neuartigen Durchstanzbewehrung.

Parametric analysis on punching shear resistance of reinforced-concrete continuous slabs

2019 ◽  
Vol 71 (20) ◽  
pp. 1083-1096
Author(s):  
Beatrice Belletti ◽  
Aurelio Muttoni ◽  
Simone Ravasini ◽  
Francesca Vecchi
Keyword(s):  
Reinforced Concrete ◽  
Parametric Analysis ◽  
Shear Resistance ◽  
Punching Shear
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