Structural Behaviors of Non-Ductile Reinforced Concrete Frames with Engineered Cement Composite (ECC) Wing Wall Elements

2014 ◽  
Vol 597 ◽  
pp. 328-331
Author(s):  
Dae Hyun Kang ◽  
Won Gyun Lim ◽  
Hye Ran Kim ◽  
Mi Hwa Lee ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Cement Composite ◽  
Rc Frame ◽  
Test Results ◽  
Seismic Strengthening ◽  
Concrete Frames ◽  
Lower Beam ◽  
Pva Fiber ◽  
Structural Behaviors ◽  
Strengthening Method

In this paper, an experimental investigation was carried out to evaluate the application of engineered cement composite (ECC) wing wall elements for seismic strengthening of reinforced concrete (RC) buildings with non-ductile reinforcement details. The ECC is mixed with cement, silica fume, fly ash and polyvinyl alcohol (PVA) fiber. The ECC wing wall elements were fitted on three side of RC frame; upper beam, lower beam and column. Two specimens, non-ductile RC bare frame and RC frame strengthened with ECC wing wall, were made for this study. These specimens were made as a third scale for this study. The specimens were loaded through 1,000 kN actuator that consists of two cycles at a displacement level. The test results showed that the seismic strengthening method of ECC wing wall elements had a significant effect to improve seismic performance of non-ductile RC bare frame. As a result, the application of ECC wing wall elements in non-ductile RC bare frame may be effective alternative to seismic retrofit of non-ductile buildings.

Flexural Toughness of Sprayable Strain-Hardening Cement Composite (SHCC) for Seismic Retrofit of Non-Ductile Reinforced Concrete Frames

2013 ◽  
Vol 658 ◽  
pp. 34-37 ◽  
Author(s):  
Seung Ju Han ◽  
Hyun Do Yun
Keyword(s):  
Reinforced Concrete ◽  
Strain Hardening ◽  
Strong Influence ◽  
Volume Fraction ◽  
Cement Composite ◽  
Flexural Behavior ◽  
Test Results ◽  
Flexural Test ◽  
Concrete Frames ◽  
Flexural Toughness

This experimental study investigates the flexural behavior and toughness of sprayable strain-hardening cement composite (SHCC) developed to retrofit seismically reinforced concrete structures with non-ductile reinforcement details. Three SHCC mixtures with specified compressive strength of 50 MPa are mixed and tested. All SHCC mixes with different dosage and combination of admixtures such as superplasticizer and powder admixture were reinforced with 2.2 % polyvinyl alcohol (PVA) fibers at the volume fraction. This paper focuses on the flexural toughness based on the flexural test results for 100 x 100 x 400 mm prisms. The flexural toughness is evaluated in accordance with ASTM C 1018. The results indicated that less than 2.5 % dosage of hybrid superplasticizer and powder admixtures respectively provides excellent sprayability and flexural behavior of SHCC mixed in this study. A strong influence of hybrid superplasticizer and powder admixture on the flexural toughness of SHCC mixes was observed.

Design Forces for Drift and Damage Control: A Second Look at the Substitute Structure Approach

1994 ◽  
Vol 10 (2) ◽  
pp. 319-331 ◽  
Author(s):  
John F. Bonacci
Keyword(s):  
Reinforced Concrete ◽  
Damage Control ◽  
Dynamic Test ◽  
Frame Structures ◽  
Rc Frame ◽  
Test Results ◽  
Structure Approach ◽  
Maximum Displacement ◽  
Design Loads ◽  
Rc Frame Structures

This paper explores the development of a method that is useful for design of reinforced concrete (RC) frame structures to resist earthquakes. The substitute structure method, originally proposed in the 1970s, makes an analogy between viscously damped linear and hysteretic response for the purpose of estimating maximum displacement. The evolution of the method is retraced in order to emphasize its unique reliance on experimental results, which are needed to establish rules for assignment of substitute linear properties. Recent dynamic test results are used to extend significantly the calibration of the method, which furnishes design loads on the basis of drift and damage control.

scholarly journals Rapid Retrofit of Reinforced Concrete Frames after Progressive Collapse to Increase Sustainability

2019 ◽  
Vol 11 (15) ◽  
pp. 4195 ◽  
Author(s):  
Li ◽  
Shan ◽  
Zhang ◽  
Li
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Design Method ◽  
Numerical Models ◽  
Progressive Collapse ◽  
Frame Structure ◽  
Rc Frame ◽  
Concrete Frames ◽  
Before And After ◽  
Test Frame

A structural progressive collapse is usually a local failure, in which the damage is concentrated at beams that bridge the removal column and the column itself. In many cases, retrofitting the damaged structure is more economical and more sustainable than reconstructing the entire structure. A progressive collapse test of a 1/3 scale, four-bay by two-story reinforced concrete (RC) frame was conducted, after which the structure was retrofitted with carbon fiber reinforced polymer (CFRP) wraps and retested. The center column in the first story was removed and the frame was pushed down quasistatically under displacement control to investigate the progressive collapse performances of the retrofitted RC frame. The test results were represented systematically at different areas in terms of the resistance forces, crack developments, and local and global failure modes. Numerical models were built to verify the test frame before and after the retrofitting. A design method was proposed to retrofit an RC frame using CFRP wraps after a progressive collapse. The test frame was redesigned to improve the retrofitting and used as an example to demonstrate the rationality of the proposed retrofit design method. The results indicated that the proposed retrofitting technology rapidly restored the frame structure to its original capacity before the progressive collapse occurred, whilst consistently satisfying the priorities of being economical and sustainable.

Study on Impaired Reinforced Concrete Beams Strengthening with Externally Steel Frame

2013 ◽  
Vol 438-439 ◽  
pp. 477-481
Author(s):  
Feng Lan Li ◽  
Xiong Huai Yu ◽  
Cheng Chen ◽  
Song Chen
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Concrete Beam ◽  
Steel Plate ◽  
Reinforced Concrete Beam ◽  
Steel Frame ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Externally Bonded ◽  
Strengthening Method

A large impaired reinforced concrete beam with cracks was strengthened under self-weight action by the externally bonded steel frame composed with bottom steel plate and side hoop steel belts. The normal service loading behaviors of this beam were tested to verify the effectiveness of this strengthening method specified in current Chinese design code. Based on the analyses of test results, it can be concluded that: the deformation of flexural cross section of this beam fitted the assumption of plain cross section, the steel plate could effectively enhance the flexural stiffness and decrease the deflection of this beam, no new cracks appeared under the normal service loads, the cracks at bottom of this beam were more confined by the steel frame than those at web zone. Therefore, other measure should be taken to avoid the opening of web cracks.

scholarly journals Effect of Different Bracing Systems in Reinforced Concrete Frames under Cyclic Loading

2020 ◽  
Vol 9 (7) ◽  
pp. 704-708
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Structural Parameters ◽  
Rc Frame ◽  
Concrete Frames ◽  
Element Analysis ◽  
Framed Structures ◽  
Rc Frames ◽  
Seismic Force ◽  
Rc Framed Structures

Reinforced concrete (RC) framed structures are widely used as load transferring system in residential and commercial buildings. Even though the RC frames are designed for gravitational and seismic forces, but they are week under severe seismic events. The main disadvantage of the framed structures is inefficient bracing systems designed in it. This investigation is conducted mainly to study the effective bracing system in the RC framed structure to transfer the seismic force. This research aims to study the seismic performance of RC frames influenced by the various types of cross bracings under cyclic loading. The finite element analysis software package ABAQUS is used to investigate the braced RC frames analytically. The research scheme consists of three RC frames; the bare frame, the bare frame with single X-bracing (X frame), double X bracing (D-X frame) along the height. The structural parameters include, load-displacement hysteresis envelope, stiffness degradation and energy absorption were studied to analyze the performance of bracings. The results showed that the X frame and D-X frame noticeably increased the lateral strength, stiffness and energy dissipation properties compared to the bare RC frame. The results also indicated that the addition of X bracing along the height significantly enhanced the structural parameters of the RC frame.

scholarly journals Deformable Polyurethane Joints and Fibre Grids for Resilient Seismic Performance of Reinforced Concrete Frames with Orthoblock Brick Infills

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2869
Author(s):  
Theodoros Rousakis ◽  
Alper Ilki ◽  
Arkadiusz Kwiecien ◽  
Alberto Viskovic ◽  
Matija Gams ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Masonry Wall ◽  
Rc Frame ◽  
Concrete Frames ◽  
Reinforced Concrete Frames ◽  
Horizon 2020 ◽  
Frame Building ◽  
Out Of Plane ◽  
Rc Frame Building ◽  
Very High

The behaviour of reinforced concrete frames with masonry wall infills is influenced a lot by the stiffness and strength difference between the frame and the infill, causing early detrimental damage to the infill or to the critical concrete columns. The paper reports the results from shake table seismic tests on a full-scale reinforced concrete (RC) frame building with modified hollow clay block (orthoblock brick) infill walls, within INMASPOL SERA Horizon 2020 project. The building received innovative resilient protection using Polyurethane Flexible Joints (PUFJs) made of polyurethane resin (PU), applied at the frame-infill interface in different schemes. Further, PUs were used for bonding of glass fibre grids to the weak masonry substrate to form Fibre Reinforced Polyurethanes (FRPUs) as an emergency repair intervention. The test results showed enhancement in the in-plane and out-of-plane infill performance under seismic excitations. The results confirmed remarkable delay of significant infill damages at very high RC frame inter-story drifts as a consequence of the use of PUFJs. Further, the PUFJ protection enabled the resilient repair of the infill even after very high inter-story drift of the structure up to 3.7%. The applied glass FRPU system efficiently protected the damaged infills against collapse under out-of-plane excitation while they restored large part of their in-plane stiffness.

scholarly journals Research on Hysteretic Models for Prestressed and Non-Prestressed Steel Reinforced Concrete Frames

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huihui Luo ◽  
Kun Wang
Keyword(s):  
Reinforced Concrete ◽  
Slenderness Ratio ◽  
Test Results ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Relevant Research ◽  
Steel Reinforced Concrete ◽  
Concrete Frame ◽  
Composite Frame ◽  
Load Displacement

The beam-column fibre model is used to simulate the entire hysteretic process of the prestressed and non-prestressed steel reinforced concrete frame, and the results are compared with the test results. Based on the analysis of a large number of parameters, the hysteretic curve characteristics of this kind of composite frame are discussed, and the load-displacement hysteretic models of single-storey and single-span composite frame are established. The models can comprehensively consider the influence of axial compression ratio and column slenderness ratio and can predict the hysteretic behaviour of this kind of composite frame under horizontal loads. The load-displacement hysteretic models are consistent with the numerical simulation results. Relevant research can provide reference for simplifying the elastic-plastic dynamic analysis of structures.

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