Influence Of Shear Span Ratio Research Articles

Experimental and numerical study on seismic behavior of special shaped steel truss and concrete composite shear wall

A steel truss-concrete composite (STCC) shear wall is fabricated by replacing the reinforcement of the shear wall by steel truss, which has high bearing capacity, good fire resistance, good seismic performance, and an easy construction. In order to investigate the seismic performance of special shaped composite shear wall, a quasi-static test was carried out on four T-shaped and two L-shaped composite shear walls. The results showed that the change of diagonal bracing form from strip steel to channel steel can improve the ductility and energy dissipation capacity of the shear wall and delay the strength degradation. Increasing the thickness of steel vertical supports can effectively improve the initial stiffness, while decreasing the thickness of diagonal braces will reduce the bearing capacity of the wall. The strength and stiffness of shear walls loaded along the web in the positive direction (flange in tension) is high, but the ductility is relatively poor when compared with walls loaded in the negative direction (flange in compression). Numerical models were established by ABAQUS, in which the steel hysteretic constitutive model was adjusted to simulate the influence of bond-slip effect. The influence of shear span ratio, axial load ratio, steel ratio of vertical support, volumetric ratio of diagonal brace, tilt angle of diagonal brace and horizontal force direction on the seismic performance of T & L shaped composite shear walls were analyzed. Finally, a design method was proposed, and the calculated results by the design method were in good agreement with the test.

Experimental study on shear performance of basalt fiber concrete beams without web reinforcement

In this study, we report the results of an experimental investigation conducted under a four-point bending loading in order to evaluate the shear performance of concrete beams reinforced with basalt fiber without web reinforcement. According to the experimental results, it is evident that the final failure morphology of concrete-basalt fiber concrete composite beams and conventional concrete beams was shear failure, whereas the failure morphology of concrete beams reinforced with full basalt fiber was bending failure. Moreover, the results also indicate that the cracking load and ultimate bearing capacity of concrete composite beams reinforced with concrete-basalt fiber are lower than those of conventional concrete beam. This is mainly due to the interface between ordinary post-cast concrete and concrete reinforced with hardened basalt fiber. Due to the superior tensile properties of fiber, composite beams and all basalt fiber concrete beams exhibit a higher degree of ductility than conventional concrete beams. Utilizing the existing calculation theory for concrete beams reinforced with fiber, it was calculated that the cracking load and ultimate load of basalt fiber beams were calculated, and the calculation results were consistent with the experimental results. Based on the results of the evaluation and the theoretical analysis, this study proposes a finite element modeling method for basalt fiber composite beams. The results of the analysis were consistent with the experimental results of all investigated beams. The established model was employed in order to investigate the influence of shear span ratio on the shear performance of basalt fiber beams.

Experimental Study on Shear Behavior of Reactive Powder Concrete Beam

In order to study the shear behavior of high-strength reinforced Reactive Powder Concrete (RPC) beams, eight test beams were designed and fabricated for the shear test under symmetrical concentrated load. By observing the development and failure mode of diagonal cracks, the influence of shear span ratio, stirrup ratio, and longitudinal reinforcement ratio on the cracking load, shear capacity, and deflection of the test beam is analyzed. The results show that: in a specific range, the shear capacity increases with the increase of stirrup ratio and longitudinal reinforcement ratio and decreases with the increase of shear span ratio. The shear span ratio has the most significant influence on the component’s failure mode and deformation capacity. The increase of the stirrup ratio can improve the deformation capacity of the component in a specific range. It is conservative to use the code to design concrete structures to calculate the shear capacity of high-strength reinforced reactive powder concrete beams. It is suggested that the shear calculation formula suitable for high-strength reinforced reactive powder concrete should be adopted to make the theoretical calculation results closer to the measured values.

Size effect in shear failure of RC beams with stirrups: Simulation and formulation

The objectives of the present study are to discover the influences of stirrup ratio and shear-span ratio on the shear failure and size effect of reinforced concrete (RC) beams having different sizes, and to build a theoretical formula for quantitatively describing the size effect on shear failure of RC beams. A three-dimensional meso-scale simulation method for modelling the failure of RC beams is established, and it is utilized to explore the failure behavior of geometrically-similar RC beams. In addition, the influences of shear-span ratio and stirrup ratio on the size effect of shear failure was examined. Finally, a novel size effect law (SEL) for predicting the nominal shear strength of RC beams having different sizes is established and verified. The results indicate that, (1) the shear-span ratio has a great influence on the shear capacity of RC cantilever beams, but has ignorable effect on the size effect; (2) the increase of stirrup ratio increases the shear capacity of RC cantilever beams and weakens the size effect of the shear strength; (3) stirrups cannot increase the shear capacity of RC beams indefinitely, and the increase of shear strength is obvious under the condition of small stirrup ratio; (4) the developed SEL for shear failure of RC beams can well describe the quantitative influence of stirrup ratio and shear-span ratio, and it is consistent with the available test date.

Influence of shear span ratio on the seismic performance of L-shaped RC walls

Owing to their capability of meeting both structural and architectural demands, L-shaped reinforced-concrete (RC) walls are widely employed in low-rise and high-rise buildings. In spite of their popularity, the experimental data on the seismic performance of these walls is relatively sparse, especially with respect to their behaviour under lateral loads that are not parallel to the wall segments. In order to obtain improved understanding of such walls, quasi-static cyclic tests on six slender L-shaped RC walls were conducted under displacement control in Nanyang Technological University (Singapore). Through comparison with four squat L-shaped RC walls described in the literature, the influence of shear span ratio was highlighted in terms of cracking patterns, failure mechanisms, hysteretic responses, deformation components and strain profiles. Moreover, shear lag effect and effective stiffness were analysed using non-linear section analyses and methods available in the literature. The results showed the shear span ratio had a significant impact on the seismic performance of L-shaped RC walls, and should be addressed discretely in the design.

EXPERIMENTAL STUDY ON SEISMIC PERFORMANCE OF NEW-TYPE COMPOSITE SHEAR WALL

The composite shear wall structure is an industrialized and promising product in civil engineering. Its application in the industry is limted and not satisfying due to the tremendous difficulty in manufacturing the lattice reinforced shear walls and large amount of used steel. This paper proposes a new-type composite shear wall with easy fabrication process and decreased weight. The mechanical properties of the composite walls were studied by performing quasi-static experiments on four proposed composite shear walls and one conventional concrete shear wall. The influence of shear-span ratio, axial load ratio and interface connection on seismic behaviors of the composite structure were included by analyzing the bearing capacity, hysteresis and skeleton curves, stiffness degeneration, displacement ductility and energy dissipation capacity. Results show that the new-type composite shear wall shows good seismic performance and similar mechanical properties with the conventional wall; Shear studs installed at the interface between the precast fibergalss reinforced cement plate and cast-in-place concrete can improve the bonding performance, initial stiffness and energy dissipation capacity; Increasing the axial load ratio and reducing shear-span ratio can improve the bearing capacity of the shear wall. A formula was developed to calculate the bearing capacity of the normal section of such composite shear walls, which shows good agreement with the test results. This study may provide reference for design and engineering applications of the composite shear walls. Keywords: Composite shear wall, Seismic performance, Quasi-static test, Interface bonding, Shear studs

Experimental Study on Shear of Reinforced Concrete Beams with High Strength Rebars as Stirrups under Different Shear Span Ratios

To investigate the influence of shear span ratio for the shear behavior of reinforced concrete beam with HRBF500 high strength rebars as stirrups, an experiment was carried out, which included 8 simply supported beams with HRBF500 rebars as stirrups. Under concentrated loads, the crack, deflection, strain of rebars, bearing capacity and failure mode are observed under different shear span ratios. Some comparisons are made between test results and calculated outcome. It shows that the shear span ratio has very important influent on the shear behavior of reinforced concrete beam with HRBF500 high strength bars as stirrups. Formula in code for design of concrete structures can be used to calculate its shear capacity with enough safety.

The Analysis of Judging Criterion and the Influence of Shear-Span Ratio to the Failure Model in Frame Short Column

In architectural design, the discrimination to the frame short column has two judging criteria: the judging criterion with the shear-span ratio λ«2 and the judging criterion with the height-width ratio H/h«4 . Whether they have consistency has been raised attention by the engineering personnel. Through the analysis of two judging criteria, We get that: the judging criterion λ«2 has extensive applicability; the judging criterion H/h«4 is the simple calculation method, and needs certain limitations. Meanwhile, by the analysis of the relationship between the shear-span ratio and the mechanical properties in frame short column, it is concluded that the shear-span ratio has the directly affect to the failure model, and the circular cross-section frame column has better mechanical properties.

Performance index limits of high reinforced concrete shear wall components

The deformation performance index limits of high reinforced concrete (RC) shear wall components based on Chinese codes were discussed by the nonlinear finite element method. Two typical RC shear wall specimens in the previous work were first used to verify the correctness of the nonlinear finite element method. Then, the nonlinear finite element method was applied to study the deformability of a set of high RC shear wall components designed according to current Chinese codes and with shear span ratio λ≥2.0. Parametric studies were made on the influence of shear span ratio, axial compression ratio, ratio of flexural capacity to shear capacity and main flexural reinforcement ratio of confined boundary members. Finally, the deformation performance index and its limits of high RC shear wall components under severe earthquakes were proposed by the finite element model results, which offers a reference in determining the performance status of RC shear wall components designed based on Chinese codes.

Performance Index Limits of Medium-Height RC Shear Wall Components

In order to determine the deformation performance index limits for medium-height RC shear wall components based on Chinese codes with the shear span ratio between 1.0 and 2.0, the reliability of the nonlinear finite element method was first verified by four typical medium-height shear wall components experiments in some literatures. Then, the nonlinear finite element method was applied to analyze a set of medium-height RC shear wall components designed according to current Chinese codes. Parametric studies were made of the influence of shear span ratio λ, axial compression ratio μ and main flexural reinforcement ratio of confined boundary members ρflex. Finally, the deformation performance index and its limits of the medium-height RC shear wall components under severe earthquakes are presented by the finite element model results.

Experimental Study on the Shear Behaviors of the SRHSHPC Composite Frame Columns

The shear behaviors of steel reinforced high strength and high performance concrete (SRHSHPC) composite frame columns are studied through the test on a number of SRHSHPC specimens with grade of concrete strength varied from C80 to C120 subjected to constant axial compression and cyclically varying horizontal load. Four influencing factors, namely, shear span ratio, axial compression ratio, stirrup ratio and concrete strength, are taken into consideration in the test, and strain gauges are respectively placed on steel web, stirrups as well as reinforcement bars to study the shear mechanism of SRHSHPC composite columns. According to test results, the shear failure patterns and shear mechanism of the specimens are discussed. By analyzing the contribution of the steel web, concrete, stirrups and reinforcement bars to the shear capacity, the shear mechanism of the SRHSHPC composite columns is figured out. Therefore, the influence of shear span ratio, axial compression ratio, stirrup ratios and concrete strength on shear behaviors of the SRHSHPC frame columns is clear. Finally, concrete truss model and principle of accumulation are applied to discuss the shear capacity and a calculation model for shear strength of the SRHSHPC composite columns is established. It is indicated that the shear behaviors of the SRHSHPC frame composite columns are excellent, and the calculated results of shear strength have good conformity with test results.

The influence of shear span ratio on load capacity of fibre reinforced concrete elements with various steel fibre volumes

Abstract This paper analyses the influence of steel fibre volume and shear span ratio on the strength of fibre reinforced concrete elements in various states of stress. 36 beams with three different shear spans (a/h = 1, 1,5, and 2 %) and three different fibre volumes (1, 1,5, and 2 %) were tested to examine how these factors influence the behaviour of such elements. Test results suggest that steel fibre volume and shear span can increase load capacity, plasticity and cracking. Experimental research showed that steel fibre volume has different influence at different shear span ratios. Regression analysis of experimental data was carried out and empirical approach showing different effect of these factors was proposed. Furthermore, test results were compared with different theoretical and empirical approaches of other authors.