Effect of higher modes on the seismic response and design of moment-resisting RC frame structures

Maniatakis, Charilaos A.; Psycharis, Ioannis N.; Spyrakos, Constantine C.

doi:10.1016/j.engstruct.2013.05.021

Cited by 47 publications

(23 citation statements)

References 32 publications

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“…62. It has been found that the higher mode effects on seismic response of floor acceleration are non-negligible even for first-mode dominated structures, but that inter-story drifts are affected significantly less [80]. Here, we simplify the design problem by only considering the maximum inter-story drift ratio from the first mode shape…”

Section: Dynamic Responses Of Structure-cladding Systemmentioning

confidence: 99%

Variable friction cladding connection for seismic mitigation

Gong

Cao

Laflamme

et al. 2019

Engineering Structures

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Cladding systems are conventionally designed to serve an architectural purpose and provide environmental protection for building occupants. Recent research has been conducted to enhance structural resiliency by leveraging cladding systems against man-made and natural hazards. The vast majority of the work includes the use of sacrificial cladding panels and energy dissipating connectors. These passive protection systems, though effective, have typically targeted a single hazard one-at-a-time because of their limited frequency bandwidths. A novel semi-active friction connection has been previously proposed by the authors to leverage the cladding motion for mitigating blast and wind hazards. This semi-active friction device, termed variable friction cladding connection (VFCC), is designed to laterally connect cladding elements to the structural system and dissipate energy via friction. Its variable friction force is generated onto the sliding friction plates upon which a variable normal force is applied via actuated toggles. Because of its semi-active capabilities, the VFCC could be used over wide-band excitation frequencies and is thereby, an ideal candidate for multiple hazard mitigation. The VFCC in its passive in situ mode has been previously designed to mitigate air-blast effects towards the structure and its semi-active scheme has been applied to wind hazard mitigation. In this paper, a motion-based design (MBD) procedure is developed to apply the VFCC to seismic hazard mitigation, completing its application against multiple hazards. The MBD procedure begins with the quantification of seismic load and performance objectives, and afterwards, dynamic parameters of the cladding connection are selected based on non-dimensional analytical solutions. Simulations are conducted on two example buildings to verify and demonstrate the motion-based design methodology. Results show the semi-actively controlled VFCC is capable of mitigating the seismic vibrations of structures, demonstrating the promise of the semiactive cladding system for field applications.

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Section: Dynamic Responses Of Structure-cladding Systemmentioning

confidence: 99%

Variable friction cladding connection for seismic mitigation

Gong

Cao

Laflamme

et al. 2019

Engineering Structures

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“…Therefore, frame shear force in the frame pin‐supported wall structure can be designed based on the fundamental mode. This is different from a conventional frame, where higher mode effects play an important role in shear force distribution . The pin‐supported wall tends to force the frame to vibrate in the first mode (specifically, rocking mode) and suppress higher mode responses in the frame.…”

Section: Higher Mode Effects In An Example Modelmentioning

confidence: 86%

Higher mode effects in frame pin‐supported wall structure by using a distributed parameter model

Pan

Zhang

2016

Earthq Engng Struct Dyn

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Frame pin-supported wall structure is a kind of rocking structure, which releases constraints at the bottom of the wall. The wall is affiliated to the frame and can rotate around the hinge. Previous studies have investigated seismic performance (such as deformation pattern and plastic hinge distribution) of frame pin-supported wall structure. Strength demand of this system was investigated through static pushover analysis. However, dynamic characteristics, especially higher mode effects, remain to be quantified. As demonstrated in several researches, higher mode effects have non-negligible effects on seismic response. For this purpose, a distributed model for analyzing higher mode effects in frame pin-supported wall structure was proposed, where the pin-supported wall and the frame were simplified as a bending beam and a shear beam, respectively. The model was solved by differential equations derived from equilibrium and compatibility. Displacement and inner force distribution of frame pin-supported wall structure in higher modes were quantified according to the model. Influence of critical parameters, such as wall stiffness and structure period, was assessed on higher mode effects. It was demonstrated that response in higher modes cannot be neglected in the design of frame pin-supported wall structure. Capacity design based on the fundamental mode is not conservative, especially in the wall. Furthermore, pin-supported walls tend to force the frame to vibrate in the rocking mode and suppress higher mode effects in the frame. n and T n are related to the relative stiffness λ, bending stiffness of pin-supported wall E w I w , shear stiffness of frame K, and the total height of the structure H, while λ is determined by E w I w , K, and H.

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“…As an attempt to accurately estimate the higher‐mode response of ductile structures, Sullivan et al proposed a new modal superposition scheme for RC frame‐wall buildings that uses modified modal properties for higher vibration modes. Maniatakis et al proposed a modified procedure based on the determination and application of actual response modification factor and displacement amplification factor for each vibration mode. However, this procedure requires to perform the multimode pushover analysis of an inelastic structural model and, therefore, can also be viewed as a simplification of the modal pushover analysis (MPA) proposed by Chopra and Goel …”

Section: Background and Motivationmentioning

confidence: 99%

A modified response spectrum analysis procedure to determine nonlinear seismic demands of high‐rise buildings with shear walls

Najam

Warnitchai

2017

Structural Design Tall Build

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SummaryThe standard response spectrum analysis (RSA) procedure prescribed in various design codes is commonly used by practicing engineers to determine the seismic demands for structural design purpose. In this procedure, the elastic force demands of all significant vibration modes are first combined and then reduced by a response modification factor (R) to get the inelastic design demands. Recent studies, however, have shown that the response of higher vibration modes may experience much lower level of nonlinearity, and therefore, it may not be appropriate to Over last few decades, the structural design against earthquakes has passed through a continuous process of evolution. The story that started from a simple mass-proportional lateral load resisted by elastic action has now evolved into an explicit consideration of design earthquakes applied to the detailed nonlinear finite-element models. The exponential growth in computational power in recent years is continuously narrowing the industryacademia gap by providing the cutting-edge research and technology to practicing engineers at their doorstep. As a result, the structural designers nowadays are equipped with far more aids and tools compared to a couple of decades ago. Moreover, recent advancements in nonlinear modeling techniques have also opened a whole new research area dealing with constructing computer models with close-to-real behaviors. With such a range of options available, the choice of modeling scheme and the analysis procedure for design decision making often becomes a matter of "the more the sweat; the more the reward" for designer. However, this is not a complete depiction of this story. If on one side, these advancements are bringing more sophistication to design process (in terms of better structural idealization and faster numerical solvers), they are also making the process complex, extra skill-demanding, and sometimes unnecessarily intricate. From design point-of-view, the real purpose of structural analysis is not merely to simulate the detailed 3D models and compute design demands, but also to understand the complex structural behavior. This understanding may not always guaranteed by complicated modeling techniques or analysis procedures and faster numerical solvers. In fact, it can be more effectively developed using convenient methods capable of simplifying and clearly explaining the complex response in terms of its components. This insight should then help in devising the most efficient design scheme in terms of reduction in cost, time, effort, and other

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Effect of higher modes on the seismic response and design of moment-resisting RC frame structures

Cited by 47 publications

References 32 publications

Variable friction cladding connection for seismic mitigation

Variable friction cladding connection for seismic mitigation

Higher mode effects in frame pin‐supported wall structure by using a distributed parameter model

A modified response spectrum analysis procedure to determine nonlinear seismic demands of high‐rise buildings with shear walls

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