scholarly journals Moment-Curvature Behavior of PP-ECC Bridge Piers under Reversed Cyclic Lateral Loading: An Experimental Study

2020 ◽  
Vol 10 (12) ◽  
pp. 4056
Author(s):  
Yi Jia ◽  
Hexian Su ◽  
Zhengcong Lai ◽  
Yu Bai ◽  
Fuhai Li ◽  
...  
Keyword(s):  
Plastic Hinge ◽  
Polypropylene Fiber ◽  
Axial Loading ◽  
Lateral Loading ◽  
Bridge Piers ◽  
Failure Patterns ◽  
Vertical Loading ◽  
Design Variables ◽  
Negative Effect ◽  
Reversed Cyclic

In the study, the moment–curvature relations of bridge piers constructed with polypropylene-fiber-reinforced engineered cementitious composite (PP-ECC) and reinforced concrete (RC) at the potential plastic hinge regions were performed experimentally. The bridge pier specimens were subjected to a combination of constant axial vertical loading and reversed cyclic lateral loading. The test variables include the reinforcement stirrup ratio, axial compression ratio, and height of the PP-ECC regions. Strain gauges were installed at the plastic hinge regions to determine the curvature. PP-ECC and RC bridge piers presented similar shapes of moment–curvature hysteretic curve. Regardless of the concrete type for the pier, the maximum moment and curvature were located near the bottom of the pier, which was consistent with the observed failure patterns. As greater peak moments and larger areas of hysteretic curves were observed for PP-ECC piers, this indicated that the use of PP-ECC at the potential plastic hinge regions significantly improved the deformation capacity and damage tolerance of bridge piers. Regarding the design variables, it was found that the axial loading ratio has a negative effect on enhancing the rotation capacity and plastic deformability, while the height of the PP-ECC portion and the amount of reinforcement stirrups displayed the opposite trend. Moreover, the contribution of stirrups in PP-ECC piers was more significant than that of RC ones.

Seismic behavior of steel reinforced ECC columns under constant axial loading and reversed cyclic lateral loading

2016 ◽  
Vol 50 (1) ◽  
Author(s):  
Chang Wu ◽  
Zuanfeng Pan ◽  
R. K. L. Su ◽  
C. K. Y. Leung ◽  
Shaoping Meng
Keyword(s):  
Seismic Behavior ◽  
Axial Loading ◽  
Lateral Loading ◽  
Reversed Cyclic

scholarly journals Seismic Performance of Bridge Piers Constructed with PP-ECC at Potential Plastic Hinge Regions

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1865
Author(s):  
Yi Jia ◽  
Renda Zhao ◽  
Fuhai Li ◽  
Zhidong Zhou ◽  
Yongbao Wang ◽  
...  
Keyword(s):  
Axial Compression ◽  
Seismic Performance ◽  
Compression Ratio ◽  
Damping Ratio ◽  
Plastic Hinge ◽  
Bridge Piers ◽  
Major Influence ◽  
Equivalent Viscous Damping ◽  
Vertical Loading ◽  
Axial Compression Ratio

This work presents an experimental investigation on the seismic performance of bridge piers constructed with polypropylene fiber reinforced engineered cementitious composite (PP-ECC) at potential plastic hinge regions. Eight solid square bridge piers are tested under a combination of reversed cyclic lateral loading and constant axial vertical loading. The test variables include the reinforcement stirrup ratio (0 vol.%, 0.46 vol.%, and 0.79 vol.%), axial compression ratio (0.1 and 0.3) and height of the PP-ECC regions (0, 250, and 500 mm). Seismic performance of eight specimens is presented and interpreted, including the failure mode, hysteretic curves, loading–resistance capacity, ductility, stiffness degradation, energy dissipation, and equivalent viscous damping ratio. The material test on the PP-ECC plate specimen suggests that the PP-ECC has obvious strain-hardening behavior and multiple fine-cracking characteristics, with the tensile strength and strain capacity greater than 3.2 MPa and 2.6%, respectively. The PP-ECC material applied at the potential plastic hinge regions notably improves the seismic performance and damage tolerance of bridge piers. The influence of the aforementioned crucial parameters has also been investigated in detail. The axial compression ratio and the height of PP-ECC region have a major influence on the seismic performance of PP-ECC piers. In comparison, the stirrup ratio has a limited effect on the seismic behavior of PP-ECC piers. The experimental findings shed light on the mechanism of the PP-ECC that contributes to the seismic performance of bridge piers and provide some valuable guidance in the seismic design of PP-ECC piers.

scholarly journals Numerical Modelling of Reinforced Concrete Slender Walls Subjected to Coupled Axial Tension–Flexure

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Cheng ◽  
Haoyou Zhang
Keyword(s):  
Reinforced Concrete ◽  
Plastic Hinge ◽  
Element Model ◽  
Lateral Loading ◽  
Design Parameters ◽  
Seismic Behaviour ◽  
High Rise ◽  
Ultimate Deformation ◽  
Axial Tension ◽  
Plastic Hinge Length

AbstractUnder strong earthquakes, reinforced concrete (RC) walls in high-rise buildings, particularly in wall piers that form part of a coupled or core wall system, may experience coupled axial tension–flexure loading. In this study, a detailed finite element model was developed in VecTor2 to provide an effective tool for the further investigation of the seismic behaviour of RC walls subjected to axial tension and cyclic lateral loading. The model was verified using experimental data from recent RC wall tests under axial tension and cyclic lateral loading, and results showed that the model can accurately capture the overall response of RC walls. Additional analyses were conducted using the developed model to investigate the effect of key design parameters on the peak strength, ultimate deformation capacity and plastic hinge length of RC walls under axial tension and cyclic lateral loading. On the basis of the analysis results, useful information were provided when designing or assessing the seismic behaviour of RC slender walls under coupled axial tension–flexure loading.

Resistance of Reinforced Concrete Frames with Masonry Infill Walls to In-Plane Vertical Loading

2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Progressive Collapse ◽  
Lateral Loading ◽  
Masonry Walls ◽  
Reinforced Concrete Frame ◽  
Masonry Infill ◽  
Concrete Frame ◽  
Vertical Loading ◽  
Infill Masonry

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.

Robustness evaluation of CSMM based finite element for simulation of shear critical hollow RC bridge piers

2019 ◽  
Vol 37 (1) ◽  
pp. 313-344
Author(s):  
Vijay Kumar Polimeru ◽  
Arghadeep Laskar
Keyword(s):  
Finite Element ◽  
Earthquake Engineering ◽  
Bridge Piers ◽  
Fe Model ◽  
Content Type ◽  
Aspect Ratios ◽  
Linear Behavior ◽  
Non Linear ◽  
Reversed Cyclic ◽  
Rc Bridge Piers

Purpose The purpose of this study is to evaluate the effectiveness of two-dimensional (2D) cyclic softened membrane model (CSMM)-based non-linear finite element (NLFE) model in predicting the complete non-linear response of shear critical bridge piers (with walls having aspect ratios greater than 2.5) under combined axial and reversed cyclic uniaxial bending loads. The effectiveness of the 2D CSMM-based NLFE model has been compared with the widely used one-dimensional (1D) fiber-based NLFE models. Design/methodology/approach Three reinforced concrete (RC) hollow rectangular bridge piers tested under reversed cyclic uniaxial bending and sustained axial loads at the National Centre for Research on Earthquake Engineering (NCREE) Taiwan have been simulated using both 1D and 2D models in the present study. The non-linear behavior of the bridge piers has been studied through various parameters such as hysteretic loops, energy dissipation, residual drift, yield load and corresponding drift, peak load and corresponding drift, ultimate loads, ductility, specimen stiffness and critical strains in concrete and steel. The results obtained from CSMM-based NLFE model have been critically compared with the test results and results obtained from the 1D fiber-based NLFE models. Findings It has been observed from the analysis results that both 1D and 2D simulation models performed well in predicting the response of flexure critical bridge pier. However, in the case of shear critical bridge piers, predictions from 2D CSMM-based NLFE simulation model are more accurate. It has, thus, been concluded that CSMM-based NLFE model is more accurate and robust to simulate the complete non-linear behavior of shear critical RC hollow rectangular bridge piers. Originality/value In this study, a novel attempt has been made to provide a rational and robust FE model for analyzing shear critical hollow RC bridge piers (with walls having aspect ratios greater than 2.5).

scholarly journals Does Customer Demotion Jeopardize Loyalty?

2009 ◽  
Vol 73 (3) ◽  
pp. 69-85 ◽  
Author(s):  
Tillmann Wagner ◽  
Thorsten Hennig-Thurau ◽  
Thomas Rudolph
Keyword(s):  
Negative Impact ◽  
Positive Impact ◽  
Loyalty Programs ◽  
Negative Consequences ◽  
Managerial Decision ◽  
Design Variables ◽  
Negative Effect ◽  
Loyalty Intentions ◽  
The Impact ◽  
Scenario Study

Hierarchical loyalty programs award elevated customer status (e.g., “elite membership”) to consumers who meet a predefined spending level. However, if a customer subsequently falls short of the required spending level, firms commonly revoke that status. The authors investigate the impact of such customer demotion on loyalty intentions toward the firm. Building on prospect theory and emotions theory, the authors hypothesize that changes in customer status have an asymmetric negative effect, such that the negative impact of customer demotion is stronger than the positive impact of status increases. An experimental scenario study provides evidence that loyalty intentions are indeed lower for demoted customers than for those who have never been awarded a preferred status, meaning that hierarchical loyalty programs can drive otherwise loyal customers away from a firm. A field study using proprietary sales data from a different industry context demonstrates the robustness of the negative impact of customer demotion. The authors test the extent to which design variables of hierarchical loyalty programs may attenuate the negative consequences of status demotions with a second experimental scenario study and present an analytical model that links status demotion to customer equity to aid managerial decision making.

Seismic Retrofitting of Rectangular Bridge Columns with Composite Straps

1997 ◽  
Vol 13 (2) ◽  
pp. 281-304 ◽  
Author(s):  
H. Saadatmanesh ◽  
M. R. Ehsani ◽  
L. Jin
Keyword(s):  
Plastic Hinge ◽  
Poor Performance ◽  
High Strength ◽  
Bridge Columns ◽  
Absorption Capacity ◽  
Seismic Retrofitting ◽  
Frp Composites ◽  
Reinforced Polymer ◽  
Seismic Forces ◽  
Reversed Cyclic

Behavior of typical rectangular bridge columns with substandard design details for seismic forces was investigated. The poor performance of this type of column attested to the need for effective and economical seismic upgrading techniques. A method utilizing fiber reinforced polymer (FRP) composites to retrofit existing bridge columns is investigated in this paper. High-strength FRP straps are wrapped around the column in the potential plastic hinge region to increase confinement and to improve the behavior under seismic forces. Five rectangular columns with different reinforcement details were constructed and tested under reversed cyclic loading. Two columns were not retrofitted and were used as control specimens so that their hysteresis response could be compared with those for retrofitted columns. The results of this study indicated that significant improvement in ductility and energy absorption capacity can be achieved as a result of this retrofitting technique.

Experimental and numerical investigation on failure behavior of ring joints in precast concrete shear walls

2019 ◽  
Vol 23 (1) ◽  
pp. 118-131
Author(s):  
Jian Zhou ◽  
Xudong Zhi ◽  
Feng Fan ◽  
Anliang Jiao ◽  
Hongliang Qian
Keyword(s):  
Bearing Capacity ◽  
Precast Concrete ◽  
Critical Role ◽  
Axial Loading ◽  
Shear Walls ◽  
Yield Ratio ◽  
Failure Behavior ◽  
Displacement Ductility ◽  
Failure Patterns ◽  
Pull Out

Precast shear wall structures have been widely used due to their outstanding features, and the joints between precast members play a critical role in complete structures, specifically for vertical joints. The ring joint is a new connection method used for the vertical connection. Few studies and related regulations were traced; therefore more detailed studies are required. In order to study the anchoring performance and failure behavior, an experimental model was designed and tested under monotonic axial loading, taking the composite height of ring rebars, concrete specifications, diameter of the horizontal rebars, relative position of the ring rebars, diameter of the ring rebars, and number of horizontal rebars into consideration. The failure phenomena were observed and the data were collected. The failure pattern, bearing capacity, yield ratio, displacement ductility coefficient, and other performance parameters were analyzed. The study indicated that the failure patterns are divided into ring rebar pull-out and ring rebar fracture. Increasing the composite height of the ring rebar, the concrete specifications and the number of horizontal rebars could improve the bearing performance, and the contribution of the horizontal rebar diameter was limited, and interlocking ring rebars arranged uniformly are not optimal. In the case of joint failure, the yield ratio is relatively small and the displacement ductility coefficient is larger, which shows the bearing capacity reserve is better. A numerical model was established to analyze the internal behavior, and the results were in good agreement with the experimental results, important for us to understand the failure behavior. Design recommendations will promote its application.

scholarly journals Out-of-plane instability of reinforced masonry uniaxial specimens under reversed cyclic axial loading

2017 ◽  
Vol 44 (5) ◽  
pp. 367-376 ◽  
Author(s):  
Nazli Azimikor ◽  
Svetlana Brzev ◽  
Kenneth J. Elwood ◽  
Donald L. Anderson ◽  
William McEwen
Keyword(s):  
Axial Loading ◽  
Shear Walls ◽  
Reinforcement Ratio ◽  
Design Parameters ◽  
Key Factors ◽  
Cyclic Tension ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Tension And Compression ◽  
Reversed Cyclic

Results of a study performed on the out-of-plane instability of reinforced masonry shear walls (RMSW) under seismic loading are presented. The study was conducted to gain understanding of the out-of-plane instability mechanism and the key factors influencing its development through the testing of five reinforced masonry uniaxial specimens under reversed cyclic tension and compression. The specimens represented the end zone of a RMSW. The design parameters considered in the study included longitudinal reinforcement ratio and height-to-thickness ratio for the test specimens. It was found that onset of out-of-plane instability is strongly influenced by the level of tensile strains developed in the specimens, the reinforcement ratio, and the bar size. In this case, out-of-plane instability occurred when out-of-plane displacements exceeded the critical value equal to half the wall thickness. A study on full-scale RMSW specimens subjected to reversed cyclic loading, also undertaken under this research program, is expected to verify the findings of this study and contribute towards development of design criteria for out-of-plane stability of RMSW.

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