scholarly journals Analysis on the value of stiffness of the dual joint straightness notch joint of beams due to cyclic lateral load

2021 ◽  
Vol 921 (1) ◽  
pp. 012019
Author(s):  
M R Nur ◽  
H Parung ◽  
A A Amiruddin
Keyword(s):  
Control Method ◽  
Monolithic Column ◽  
Precast Concrete ◽  
European Convention ◽  
Building Structures ◽  
Earthquake Loads ◽  
Cyclic Lateral Load ◽  
Beam Type ◽  
Column Joint ◽  
Displacement Control Method

Abstract Precast concrete is an answer to the demands of building structures that save time, but cannot be used widely because of the reliability of the connection, especially during an earthquake, the desired earthquake-resistant building structure must have sufficient strength and rigidity. Stiffness is one of the factors that determine the response of a structure to earthquake loads. When connected with earthquake loads, a structure must have sufficient rigidity so that its movement during an earthquake can be limited. This study aims to determine and analyze the stiffness in the double columns straight joint beam notches due to lateral cyclic load. By dividing 3 (three) types of test specimens, namely Monolithic column Beam, Type 1 Column Joint (SBK), and Type 2 Column Beam Joint (SBK). The connection used is a double straight notch and using the grouting method. Testing and analysis using the Displacement Control Method with the European Convention for Constructional Steelwork (ECCS) 1986 standards. The results showed the monolith column Column (BK) specimens have a greater stiffness value compared to SBK 1 specimens and SBK 2 specimens.

Comparing the Seismic Performance of Beam-Column Joints with and without SFRC when Subjected to Cyclic Loading

2012 ◽  
Vol 626 ◽  
pp. 85-89 ◽  
Author(s):  
Kay Dora Abdul Ghani ◽  
Nor Hayati Hamid
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Experimental Work ◽  
Concrete Beam ◽  
Steel Fiber ◽  
Precast Concrete ◽  
Experimental Results ◽  
Column Joint ◽  
Initial Cracks

The experimental work on two full-scale precast concrete beam-column corner joints with corbels was carried out and their seismic performance was examined. The first specimen was constructed without steel fiber, while second specimen was constructed by mixed up steel fiber with concrete and placed it at the corbels area. The specimen were tested under reversible lateral cyclic loading up to ±1.5% drift. The experimental results showed that for the first specimen, the cracks start to occur at +0.5% drifts with spalling of concrete and major cracks were observed at corbel while for the second specimen, the initial cracks were observed at +0.75% with no damage at corbel. In this study, it can be concluded that precast beam-column joint without steel fiber has better ductility and stiffness than precast beam-column joint with steel fiber. However, precast beam-column joint with steel fiber has better energy dissipation and fewer cracks at corbel as compared to precast beam-column joint without steel fiber.

scholarly journals The Cartis Form for the Seismic Vulnerability Assessment of Timber Large-Span Structures

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 45
Author(s):  
Beatrice Faggiano ◽  
Giacomo Iovane ◽  
Andrea Gaspari ◽  
Eric Fournely ◽  
AbdelHamid Bouchair ◽  
...  
Keyword(s):  
Seismic Vulnerability ◽  
Precast Concrete ◽  
Structural Type ◽  
General Description ◽  
Seismic Zone ◽  
Building Structures ◽  
Timber Structures ◽  
Recent Past ◽  
Seismic Vulnerability Assessment ◽  
Large Span

Italy is located in a very active seismic zone, and many earthquakes have marked the country, some of them in the recent past. In order to take adequate measures of seismic prevention and protection, in the last decades, the Italian Civil Protection Department (DPC) initiated a survey and introduced a specific form for the quick and/or post-seismic assessment of buildings. This is useful to obtain statistics on the types of structures and their vulnerability and a judgement on the damage, leading to a decision about the possibility of reuse and/or the level of retrofitting to be applied. Those activities have been developed since the beginning of 2000. This task is currently carried out by the Italian DPC-ReLUIS project research, line WP2 on the inventory of building structures, setting up the CARTIS form for any structural type, like masonry, reinforced concrete, precast concrete, steel, and timber structures, the latter being mainly related to large span buildings, extensively used in Italy. In this context, the paper presents the first draft of the CARTIS form for large span timber structures that provides a general description for typical structural schemes, through the singular points commonly considered as seismic structural vulnerabilities. Moreover, the statistics on timber large span structures based on a sample of 10 buildings is presented.

Direct adaptive algorithm for seismic control of damaged structures with faulty sensors

2017 ◽  
Vol 24 (24) ◽  
pp. 5854-5866 ◽  
Author(s):  
Amin Hosseini ◽  
Touraj Taghikhany ◽  
Arash Yeganeh Fallah
Keyword(s):  
Adaptive Control ◽  
Seismic Response ◽  
Structural Damage ◽  
Control Method ◽  
Control Strategies ◽  
Magnetorheological Damper ◽  
Main Concern ◽  
Building Structures ◽  
Steel Moment Resisting Frames ◽  
Seismic Control

In recent decades, the application of semi-active control strategies has gained much attention as a way to reduce the seismic response of civil infrastructures. However, uncertainty in the modeling process of systems with possible partial or total failure during an earthquake is the main concern of engineers about the reliability of this strategy. In this regard, adaptive control algorithms are known as an effective solution to adjust control parameters with different uncertainties. In the current study, the efficiency of the simple adaptive control method (SACM) is investigated to control the seismic response of building structures in the presence of unknown structural damage and fault in the sensors. The method is evaluated in 20-story steel moment resisting frames with different arrangement of smart dampers and sensors with various damage and fault scenarios. The results show that the SACM control system can effectively reduce the maximum inter-story drift of the structure in all different assumed magnetorheological damper arrangements. Furthermore, combination of a Kalman–Bucy filter with the SACM improves robustness of the controller to the uncertainties of sensors faults and damages of structural elements.

scholarly journals CYCLIC PERFORMANCE OF HDR HOOK-END PRECAST BEAM-COLUMN JOINT: A FINITE ELEMENT ANALYSIS

2019 ◽  
Vol 81 (6) ◽  
Author(s):  
Kai Siong Woon ◽  
Farzad Hejazi ◽  
Mohd Saleh Jaafar ◽  
Farah Nora Aznieta Abd. Aziz
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Precast Concrete ◽  
Concrete Cover ◽  
Numerical Results ◽  
Cyclic Performance ◽  
Element Analysis ◽  
Finite Element Software ◽  
Column Joint ◽  
Dowel Bar

Small concrete cover to dowel’s diameter reduces the cyclic performance of precast concrete frame with pinned dowel beam-column connection due to brittle concrete splitting failure around the dowel joint. Besides, utilisation of bearing pad thicker than half of dowel’s diameter causes the dowel bar to sustain greater tensile stress and plastic elongation up to their breaking point due to larger inclination of the dowel bar, particularly under the action of cyclic loading. Hence, a new precast beam-column joint with hook-end configuration and utilizing the advantage of high damping rubber (HDR), was proposed as the alternative for precast structures. Therefore, this study presented the horizontal and vertical cyclic performances of the precast frames with the proposed joint, through numerical analysis using finite element software. The numerical results were compared with a numerical modelled single pinned dowel connected precast frame, which was verified with the experimental results under horizontal cyclic loading. In terms of accumulative energy dissipation capacity, the numerical results showed that precast frames with the proposed joint demonstrated approximately 230% and 120% of improvement at 40 mm of horizontal cyclic level and 7 mm of vertical cyclic level, respectively, than the precast frame with single pinned dowel connection. It indicates that the viscoelastic behavior of HDR has contributed the benefit in this improvement.

Experimental study of precast beam-to-column joints with steel connectors under cyclic loading

2020 ◽  
Vol 23 (13) ◽  
pp. 2822-2834
Author(s):  
Xian Rong ◽  
Hongwei Yang ◽  
Jianxin Zhang
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Load Capacity ◽  
Precast Concrete ◽  
Displacement Ductility ◽  
Reversed Cyclic Loading ◽  
Column Joint ◽  
Energy Dissipation Capacity ◽  
Reversed Cyclic ◽  
The Web

This article investigated the seismic performance of a new type of precast concrete beam-to-column joint with a steel connector for easy construction. Five interior beam-to-column joints, four precast concrete specimens, and one monolithic joint were tested under reversed cyclic loading. The main variables were the embedded H-beam length, web plate or stiffening rib usage, and concrete usage in the connection part. The load–displacement hysteresis curves were recorded during the test, and the behavior was investigated based on displacement ductility, deformability, skeleton curves, stiffness degradation, and energy dissipation capacity. The results showed that the proposed beam-to-column joint with the web plate in the steel connector exhibited satisfactory behavior in terms of ductility, load capacity, and energy dissipation capacity under reversed cyclic loading, and the performance was ductile because of the yielding of the web plate. Therefore, the proposed joint with the web plate could be used in high seismic regions. The proposed joint without the web plate exhibited similar behavior to the monolithic specimen, indicating that this joint could be used in low or moderate seismic zones. Furthermore, the utilization of the web plate was vital to the performance of this system.

Pseudo-Dynamic Testing Method Based on External Displacement Control

2012 ◽  
Vol 204-208 ◽  
pp. 2428-2432
Author(s):  
Da Peng Wang ◽  
Shi Zhu Tian
Keyword(s):  
Control Method ◽  
Dynamic Testing ◽  
Fast Response ◽  
Displacement Sensor ◽  
Internal Displacement ◽  
Displacement Control ◽  
Loop Control ◽  
Testing Technology ◽  
Hydraulic Servo ◽  
Displacement Control Method

In order to accelerate the velocity and improve the accuracy of the pseudo-dynamic testing，the external displacement control method is put forward based on the hardware control. The internal displacement sensor of the actuator is invalid on control and substituted by the LVDT displacement sensor connected with the specimen. The process of the feedback displacement and command error compensation is quickly implemented by the internal closed-loop control of the actuator. Compared with the iteratively approximate load control, this method not only makes the testing velocity fast, but also enables the error between command and feedback to be “zero”. The fast pseudo-dynamic testing about a cantilever beam is carried out by applying appropriate PID parameters of the actuator. The testing result shows that although this method has rather high requirements in the control system and electro-hydraulic servo load device, and the risk to some extent, the fast response of the actuator can be firmed by applying appropriate PID control parameters. This method provides a fast testing technology for velocity-dependent structures or specimens.

Seismic Response Control for Four High-Rise Building Structures Using Connected Control Method

2007 ◽  
Author(s):  
Kazuto Seto ◽  
Chinori Iio ◽  
Shigeru Inaba ◽  
Shingo Mitani ◽  
Fadi Dohnal ◽  
...  
Keyword(s):  
Seismic Response ◽  
Active Control ◽  
Control Method ◽  
Control Force ◽  
Building Structures ◽  
Response Control ◽  
Control Approach ◽  
Seismic Response Control ◽  
High Rise ◽  
Lq Control

This paper presents a vibration control method for multiple high-rise buildings against large earthquake motion. This method is called as “Connected Control Method (CCM)” and has the merit of obtaining enough control force to protect high-rise buildings from large earthquakes using passive and semiactive devices. In this paper, first a modeling approach for four scaled building structures is shown and effectiveness of the CCM using LQ control approach for them is demonstrated by seismic response control results. Next, in order to reduce the supplied power, a semi-active control approach in place of active control is applied for the CCM. For this purpose, a new MR damper is developed and designed to have a close performance with results of the LQ control. This performance is verified by measured frequency responses.

scholarly journals Numerical Derivation of Buckling Knockdown Factors for Isogrid-Stiffened Cylinders with Various Shell Thickness Ratios

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Han-Il Kim ◽  
Chang-Hoon Sim ◽  
Jae-Sang Park ◽  
Keejoo Lee ◽  
Joon-Tae Yoo ◽  
...  
Keyword(s):  
Shell Thickness ◽  
Control Method ◽  
Computation Time ◽  
Initial Imperfection ◽  
Equivalent Model ◽  
Detailed Model ◽  
Buckling Loads ◽  
Global Buckling ◽  
Displacement Control Method ◽  
Factor Function

This study is aimed at providing a numerical derivation of the shell knockdown factors of isogrid-stiffened cylinders under axial compressive loads. The present work uses two different analysis models such as the detailed model with modeling of numerous stiffeners and the equivalent model without modeling of stiffeners for isogrid-stiffened cylinders. The single perturbation load approach is used to represent the geometrically initial imperfection of the cylinder. Postbuckling analyses using the displacement control method are conducted to calculate the global buckling loads of a cylinder. The shell knockdown factor is numerically derived using the obtained global buckling loads without and with the initial imperfection of the isogrid-stiffened cylinder. The equivalent model is more efficient than the detailed model in terms of modeling time and computation time. The present knockdown factor function in terms of the shell thickness ratio (radius to thickness) for the isogrid-stiffened cylinder is significantly higher than NASA’s knockdown factor function; therefore, it is believed that the present knockdown factor function can facilitate in developing lightweight launch vehicle structures using isogrid-stiffened cylinders.

Post-Buckling Behavior of Z-Shaped Columns under Variables of Lengths and Initial Imperfections

2013 ◽  
Vol 437 ◽  
pp. 62-65
Author(s):  
Ji Nao Zhang
Keyword(s):  
Failure Modes ◽  
Control Method ◽  
Three Dimensional ◽  
Initial Imperfection ◽  
Maximum Load ◽  
Element Analysis ◽  
Initial Imperfections ◽  
Solution Methods ◽  
Post Buckling ◽  
Displacement Control Method

This paper conducts three-dimensional, nonlinear finite element analysis to investigate the results of using different solution methods and the influence of initial imperfections and material plasticity on failure modes and maximum load of various Z-shaped column lengths; it also compares the column buckling responses between various lengths, each with different initial imperfections. Further analyses include investigating the element suitability and computational costs. Results showed that both displacement control method and Riks method are fully capable of receiving promising results from this analysis. In terms of the effects of initial imperfection and material plasticity on the maximum load that column could carry, the imperfection is the major contributing factor when the column is long whereas the plasticity is the major contributing factor when the column is short.

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