Experimental tests on shear capacity of naturally corroded prestressed beams

2020 ◽  
Vol 21 (5) ◽  
pp. 1777-1793
Author(s):  
Beatrice Belletti ◽  
Jesús Rodríguez ◽  
Carmen Andrade ◽  
Lorenzo Franceschini ◽  
Javier Sánchez Montero ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Shear Capacity ◽  
Prestressed Beams

Punching shear behaviour of flat slabs with different reinforcement schemes: openings and rectangularity effects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Donia Salman ◽  
Rabab Allouzi ◽  
Nasim Shatarat
Keyword(s):  
Structural Engineering ◽  
Experimental Tests ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Cross Sectional ◽  
Content Type ◽  
Flat Slabs ◽  
Reinforced Concrete Slabs ◽  
Rectangular Columns

PurposeThe main goal is to investigate the effect of size and location of opening and column size on the punching shear strength. Openings are often needed in order to install mechanical and electrical services. This process takes away part of the concrete volume which is responsible for resisting the shear forces and any unbalanced moment. Furthermore, the application of rectangular columns in flat slabs is commonly used in practice as they provide lateral stiffness to the building. They are also utilised in garages and multi-storey buildings where these elongated cross-sectional columns reduce the effective span length between adjacent columns.Design/methodology/approachThis research is a numerical-based investigation that is calibrated based on a thirteen previously tested and numerically calibrated slab specimens with no openings. A parametric study is conducted in this study to consider the effect of other parameters, which are the size and location of opening and the rectangularity ratio of column in order to evaluate their effect on the punching shear capacity. A total of 156 models are developed to study these factors. Additionally, the predicted shear carrying capacity of the simulated slabs is calculated using the ACI318–19 and Eurocode (EC2-04) equation.FindingsThe presence of openings reduced the punching shear capacity. The small opening's location and orientation have almost no effect except for one slab. For slabs of large openings, the presence of openings reduced the punching capacity. The punching capacity is higher when the openings are farther from the column. The numerically obtained results of slabs with rectangular columns show lower punching capacity compared to slabs of squared columns with the same length of the punching shear control perimeter. The punching capacity for all slabs is predicted by ACI318–19 and Eurocode (EC2-04) and it is found that Eurocode (EC2-04) provided a closer estimation.Originality/valueThe slabs considered for calibration were reinforced with four different punching shear reinforcement configurations, namely; ordinary closed rectangular stirrups, rectangular spiral stirrups, advanced rectangular spiral stirrups and circular spiral. Generally, there has been limited research on concrete flat slabs with openings in comparison with other subjects related to structural engineering (Guan, 2009) and no research on punching shear with openings of slabs reinforced with these reinforcement schemes. The available research focussed on the effects of openings on the flexural behaviour of reinforced concrete slabs includes Casadei et al. (2003), Banu et al. (2012) and Elsayed et al. (2009). In addition, experimental tests that examined slabs supported on rectangular columns are very limited.

scholarly journals Shear Strengthening of Deep T-Section RC Beams with CFRP Bars

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6103
Author(s):  
Zheng-Nan Jing ◽  
Rong-Gui Liu ◽  
Gui-Hua Xie ◽  
Dan Liu
Keyword(s):  
Design Theory ◽  
Experimental Tests ◽  
Economic Benefits ◽  
Shear Capacity ◽  
Shear Strengthening ◽  
Engineering Structures ◽  
Near Surface ◽  
Strut And Tie ◽  
Beam Design ◽  
Strut And Tie Model

Deep T-section beams have been widely used in engineering structures due to their high bearing capacity, high construction efficiency and economic benefits, while the current beam design theory can hardly interpret reasonably the mechanical behaviors of deep beams. The performance features of the deep T-beam were investigated, involving in strain distribution and principal stress trace using experimental tests. Different near surface mounted (NSM) reinforcement schemes were proposed for deep T-beams aiming at improving the shear capacity. The results show that the behaviors of deep T-beams dissatisfy the assumption of plane cross-section, and the ‘strut-and-tie’ model is applicable in such structures. The reinforcement systems can significantly relieve the strain concentration, mid-span deflection and crack width in deep T-beams, consequently improving the shear capacity range from 45 to 65%. The scheme is preferential for the reinforcement of deep T-beams when the applied angles, positions and lengths of CFRP bars are optimized based on the ‘strut-and-tie’ model.

scholarly journals Shear Behavior of RC Deep Beam Strengthened by V-Shaped External Rods

2020 ◽  
Vol 10 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Pramod Rai ◽  
Kitjapat Phuvoravan
Keyword(s):  
Experimental Test ◽  
Shear Failure ◽  
Experimental Tests ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Deep Beam ◽  
Nominal Strength ◽  
Rod System ◽  
Strengthened Beam ◽  
Strengthening Technique

This research investigated the shear strengthening technique of Reinforced Concrete (RC) deep beams using a V-shaped external rod system. Shear behavior, the stress in an external rod, and the shear capacity at the diagonal shear failure of a strengthened beam were focused mainly. Experimental tests of control and two strengthened beams were carried out to observe the effect of the external rod on shear behavior of RC deep beam. A theoretical approach to compute the stress in the external rod and the nominal strength of the strengthened beam in the diagonal shear failure were examined based on the experimental test results and verified using Finite Element Method (FEM) in ABAQUS. The computed nominal shear strength of the strengthened beam was 10% higher than the experimental test. The strengthening technique shifted the brittle shear failure to ductile shear failure and improved the performance of RC deep beam.

scholarly journals Width and Edge Beam Effects on the Ultimate Behaviour of RC Bridge Overhangs

2019 ◽  
Vol 61 (2) ◽  
pp. 131-152
Author(s):  
José Javier Veganzones ◽  
Costin Pacoste ◽  
Raid Karoumi
Keyword(s):  
Bearing Capacity ◽  
Experimental Tests ◽  
Shear Capacity ◽  
Critical Section ◽  
Effective Width ◽  
Ultimate Capacity ◽  
Loading Process ◽  
Arch Effect ◽  
Shear Distribution ◽  
Transition Area

Abstract The bearing capacity of RC overhangs under concentrated loads can be dependent on the width of the slab. The goal of this paper is to investigate the effect of different widths using tests from the literature and non-linear FE-simulations as a reference. Shear force redistributions along the loading process and the shear concrete capacity are analysed. The shear effective width and the influence of an edge beam are also addressed. The results show that the bearing capacity of RC overhangs increase with the width until a transition area is reached and the increase flattens. An increased shear distribution sideways and posterior redistributions under the loading process are enabled. The shear capacity of concrete increases with the width and for loads close to the root an arch effect is observed. The edge beam contributes to a further increase of the ultimate capacity for wide enough overhangs. The effect of the width and the edge beam is not only quantitative but also qualitative since the failure mode and the critical section are influenced. Existing formulation for shear effective widths should be revisited. Experimental tests used for this purpose should consider wide enough specimens to capture the real behaviour of a bridge overhang slab.

Shear Behavior of CFRP Prestressed Concrete Beams without Stirrups

2011 ◽  
Vol 266 ◽  
pp. 126-129 ◽  
Author(s):  
Zuo Hu Wang ◽  
Xiu Li Du ◽  
Jing Bo Liu
Keyword(s):  
Prestressed Concrete ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Beams ◽  
Shear Behavior ◽  
Shear Capacity ◽  
Shear Span ◽  
Compression Failure ◽  
Concrete Members ◽  
Prestressed Beams

Five beams were tested up to failure to study the shear behavior of concrete beams prestressed with fiber reinforced polymer (FRP). Different factors were taken into consideration: the type of prestressing tendons and the shear span ratio. The shear failure modes and the influence of different factors on shear behavior were investigated in details. The test results showed that FRP prestressed beams without stirrups had two shear failure modes: diagonal compression failure and shear compression failure; the shear span ratio was the most important factor to determine the failure mode and shear capacity of the prestressed beams. The shear capacity of concrete members prestressed with FRP tendons was lower than that of concrete beams prestressed with steel cables.

Strength and Ductility of Embedded Steel Composite Coupling Beams

2003 ◽  
Vol 6 (1) ◽  
pp. 23-35 ◽  
Author(s):  
W. Y. Lam ◽  
R. K. L. Su ◽  
H. J. Pam
Keyword(s):  
Energy Absorption ◽  
Experimental Tests ◽  
Preliminary Test ◽  
Shear Capacity ◽  
Coupling Beam ◽  
Coupling Beams ◽  
Diagonal Reinforcement ◽  
Beam Design ◽  
Steel Composite ◽  
Strength And Stiffness

The stringent requirements on dimensions, ductility, energy absorption, strength and stiffness of coupling beams have resulted in much research on various alternative coupling beam designs, which include the use of diagonal reinforcement, rhombic arrangement of main bars and steel composites. Experimental results showed that each of these designs offered better performance than the conventional type but had its own limitations. A new embedded steel composite coupling beam design is therefore proposed. This paper presents the findings from the experimental tests of a coupling beam fabricated with this proposed design and a conventionally reinforced coupling beam, which serves as the reference. The preliminary test results showed that the embedded steel coupling beam with relatively large span-to-depth ratio ( l/h = 2.5) had excellent shear capacity (∼10MPa) and very good energy absorption.

scholarly journals Flexural Behavior of UHPC Beams Prestressed with External CFRP Tendons

2021 ◽  
Vol 11 (19) ◽  
pp. 9189
Author(s):  
Li Jia ◽  
Zhi Fang ◽  
Zhengmeng Huang ◽  
Kypros Pilakoutas ◽  
Qiwu Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Loading Condition ◽  
High Performance Concrete ◽  
High Strength ◽  
Shear Capacity ◽  
Utilization Efficiency ◽  
Flexural Behavior ◽  
Flexural Capacity ◽  
Deformation Ability ◽  
Prestressed Beams

This paper presents an experimental investigation on the flexural behavior of ultra-high-performance concrete (UHPC) beams prestressed with external carbon fiber-reinforced polymer (CFRP) tendons. A total of eight T-shaped beam specimens were fabricated and tested, and the effects of the effective prestressing stress, partial prestressing ratio, deviated angle, and loading condition on the flexural behavior were analyzed. The experimental results indicate that the fully prestressed beams experienced a brittle failure, and the shear capacity of these beams was mainly controlled by the effective prestressing stress in CFRP tendons and the ultimate tensile strength of UHPC, whereas the partially prestressed beams failed in a ductile manner. The presence of internal steel reinforcement could significantly improve the flexural capacity and deformation ability. Thus, internal reinforcements should not be omitted from UHPC beams with CFRP tendons. A higher effective prestressing stress resulted in enhanced cracking load and flexural capacity. The deviated angle enhanced the utilization efficiency of high strength CFRP tendons. The loading condition exerted a slight influence on the flexural behavior of the specimens. Moreover, a method considering the effect of steel fibers was proposed and verified to predict the flexural capacity of UHPC beams prestressed with external CFRP tendons.

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