Structural dynamic properties of a reinforced concrete high-rise building during construction

1996 ◽  
Vol 23 (4) ◽  
pp. 950-972 ◽  
Author(s):  
Carlos E. Ventura ◽  
Norman D. Schuster

This paper presents the results of a study on the variability of the dynamic properties of an irregular high-rise building during its construction. Most of the knowledge about structural dynamics of high-rise reinforced concrete buildings is based on uniform structures. Hence, there is concern about extrapolating this knowledge to the behaviour of nonuniform building that emerge from current architectural trends. A clear example of these trends is the building selected for this study. This 30-storey reinforced concrete building is representative of the type of current construction in Vancouver, British Columbia. The lateral force resisting system in this structure is uniform in plan and elevation, while the distribution of storey mass is asymmetrical owing to its geometry as well as a major setback at one corner. Dynamic characteristics were determined by analyzing ambient vibrations of the structure. The objectives of this study included determining natural frequencies and corresponding mode shapes, determining the effect of architectural components, assessing base motion, and assessing the manner of the core's deformation. In addition, a three-dimensional dynamic analysis was performed to assess the accuracy of modeling techniques. Finally, base shears and overturning moments during different stages of construction were assessed in accordance with current building codes. Key words: structural dynamics, ambient vibration measurements, earthquakes, building construction, mode shapes and frequencies.

2004 ◽  
Vol 31 (2) ◽  
pp. 292-307 ◽  
Author(s):  
Timothy White ◽  
Carlos E Ventura

The purpose of the study discussed in this paper is to evaluate the seismic response of a modern building, designed according to the current building code and to extreme earthquake earthquakes from two different source mechanisms. To this end, a three-dimensional nonlinear dynamic response of a reinforced concrete high-rise building, typical of the type built in Vancouver, British Columbia, is investigated. According to current design practice, the building has been designed to resist lateral loads with a coupled shearwall system. A comparison of the responses of the building to crustal and subduction type earthquakes of similar magnitudes is presented and discussed. The ground motion records selected for this study were derived from recorded crustal and subduction events, which are both considered to be extreme, and beyond the code-based design requirements of the building. A part of this study includes an evaluation of how the dynamic properties of the building change as the building is being damaged by severe ground shaking. The results of the study show that the crustal earthquake imposes large upper levels displacements, and much plastic hinging near the base because the response of the building is governed mainly by the first mode of the "undamaged" system. The subduction earthquake results in displacements smaller than those from the crustal event and causes plastic hinging at mid-height and near the base as well as large torsional rotations, because the behaviour of the building is greatly influenced by the second mode of the "damaged" system.Key words: nonlinear dynamic analysis, seismic, high rise, reinforced concrete, coupled shearwall.


1999 ◽  
Author(s):  
Frederic Louarn ◽  
Pandeli Temarel

The dynamic behaviour of a WOR 60 is investigated using three dimensional hydroelasticity theory. Global structural responses (e.g. stresses) in waves are obtained corresponding to the upright as well as to the more realistic heeled sailing configurations, revealing the connection between the ballast keel and the hull as being a critical area of the structure. For the "dry hull" analysis, a global finite element model has been developed, incorporating the hull and deck shell, the internal structure, the ballast keel and the rig together with rigging loads. The modular nature of the model has been used to assess the relative influence of each of the aforementioned components upon the required characteristic dynamic properties (e.g. natural frequencies and principal mode shapes). Regarding the "wet hull" analysis, a three dimensional Green's function technique, using pulsating sources distributed over the wetted surface, provides a numerical solution to the case of the yacht sailing in regular waves at arbitrary heading. Principal coordinates for the rigid body motions and flexible distortions of interest are evaluated and the latter are used to obtain the dynamic stresses in waves using modal summation. This paper will describe the modelling techniques used and discuss the applicability / limitations of hydroelasticity theory regarding this type of structures in the light of the results obtained for the upright and heeled operational conditions, as well as from the point of view of design aspects such as "L" and "T" keel configurations. The ABS design criteria will provide a practical reference for comparing the results from the dynamic analysis.


Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 181 ◽  
Author(s):  
Boudjamaa Roudane ◽  
Süleyman Adanur ◽  
Ahmet Can Altunışık

The effects of seismic actions on reinforced concrete (RC) structures are strongly influenced by the dynamic behavior of their materials. It is crucial to find a simple definition of the natural frequencies of reinforced concrete buildings, particularly in relation to both principal and secondary elements constructing the reinforced concrete building type. This paper firstly presents a comparison with the ambient vibration surveys. An analysis model of different stages of construction of the reinforced concrete masonry wall was compared using the finite element software. In the second step, structural responses of the model were investigated by means of static analysis. Three main types were examined: Bare frame for one, two and three storeys; brick-walled; and coated cases. Modal analysis is carried out by ABAQUS software starting from the deformed building, to provide the natural frequencies and mode shapes. For the natural frequencies, a good agreement is obtained between analytical and experimental results. Furthermore, the comparison results between different cases show that the application of the plaster work increases the lateral stiffness and has significant effects on the dynamic response of the buildings.


2012 ◽  
Vol 39 (6) ◽  
pp. 631-642 ◽  
Author(s):  
Natthapong Areemit ◽  
Michael Montgomery ◽  
Constantin Christopoulos ◽  
Agha Hasan

As high-rise buildings increase with height and slenderness, they become increasingly sensitive to dynamic vibrations, and therefore the natural frequency of vibration and damping ratio are very important design parameters, as they directly impact the design wind forces. Recent advances in sensing and computing technology have made it possible to monitor the dynamic behaviour of full-scale structures, which was not possible in the past. Full-scale validation of the dynamic properties is useful for high-rise designers to verify design assumptions, especially since recent measurements have shown that damping decreases as the height of the building increases, and in situ damping measurements have been lower than many currently assumed design values, potentially leading to unconservative designs. A 50-storey residential building in downtown Toronto, with a reinforced concrete coupled shear wall lateral load resisting system with outriggers was monitored using current state-of-the-art sensing technologies and techniques to determine, in situ, the dynamic properties under real wind loads. The in situ measurements were then compared with results obtained using current state-of-the-art computer modelling techniques.


2016 ◽  
Vol 120 (1224) ◽  
pp. 271-290 ◽  
Author(s):  
M. Rohin Kumar ◽  
C. Venkatesan

ABSTRACTThe influence of the blade geometric parameters on the structural dynamic characteristics, response and loads of a helicopter rotor under hover condition in a whirl tower was investigated. A general geometry was considered for the rotor blade which included configuration parameters like root offset, torque offset, pre-twist, pre-cone, pre-droop, pre-sweep, tip-sweep and tip-anhedral. The option of placing concentrated masses at any location on the blade was also included. Natural frequencies and the corresponding mode shapes of the rotating blade were obtained by solving the linear, undamped structural dynamics model in the finite element domain. For calculating the response and loads on the rotor, the complete aeroelastic equation was solved in modal space. Aerodynamic models used in the aeroelastic loads calculations were Peters-He dynamic wake theory for inflow and themodifiedONERA dynamic stall theory for airloads calculations. From the study, the blade structural dynamic characteristics are found to be sensitive to variation in blade geometric parameters. Tip-sweep was found to have significant effects on root oscillatory moments. The moments at the tip junction with the straight portion of the blade were found to be substantially affected by tip-sweep and tip-anhedral.


2011 ◽  
Vol 255-260 ◽  
pp. 2355-2359
Author(s):  
Cheng Qing Liu ◽  
Xin Long Xiao ◽  
Rui Liang ◽  
Shi Chun Zhao

Based on the current methods of damage detection, a new detection damage model was proposed in order to search a more efficient detection method for reinforced concrete high-rise building damage induced by earthquake. This model is based on the regularity of change in the damping ratio of high-rise buildings, and the high order modes, mode participation coefficient and measure method of natural frequency, together with the type of structures, are taken into account in the model. The shaking test results for a model of reinforced concrete high-rise buildings show that the damage detection results based on the proposed model are close to the test results.


2010 ◽  
Vol 163-167 ◽  
pp. 1281-1285
Author(s):  
Bin Wang ◽  
Huan Jun Jiang ◽  
Jian Bao Li ◽  
Wen Sheng Lu ◽  
Xi Lin Lu

The reinforced concrete (RC) frame-tube structure considered in the study has two towers with lapping transfer columns. The lapping transfer columns, considering aesthetic requirement in elevation, lead to a complex vertical force transfer system. The large irregularity in elevation, according to Chinese code, necessitates a detailed study. A 1/15-scaled model of the high-rise building was tested on a shaking table to evaluate its seismic performance. The model was subjected to earthquake inputs representing frequent, basic, rare, and extremly rare earthquakes. The results of shaking table test in terms of the global and local responses as well as the dynamic properties are presented. The tests demonstrate that the designed structural system satisfies the pre-defined performance objectives and the lapping transfer columns have good seismic peformance. To better control seismic damages of the building, some suggestions for improving the design of this structure are also put forward at last.


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