scholarly journals Accounting for horizontal torsional vibrations of foundations when calculating seismic load

2021 ◽  
Vol 31 (4) ◽  
pp. 66-78
Author(s):  
Yu. T. Chernov ◽  
J. Qbaily
Keyword(s):  
Seismic Hazard ◽  
Structural Design ◽  
Transfer Functions ◽  
Seismic Load ◽  
Torsional Vibrations ◽  
Building Structures ◽  
Different Types ◽  
Seismic Forces ◽  
Structural Solutions ◽  
Outer Plane

The article presents a method for calculating in-plane vibrations of building structures under seismic load taking into account the possibility of foundation displacement, which is similar to horizontal torsional vibrations when calculating earthquake forces. The method is illustrated by the structural design of a seven-storey tower-like building with a massive foundation. We develop transfer functions for a massive rigid body, which are subsequently used for calculating the response of the foundation subject to base shears and moments applied to the outer plane of the foundation under seismic forces. The structural calculations conducted for ductile structures with the first frequency of ~2.4 Hz and for more rigid structures with the first frequency of 7.1 Hz showed that, depending on the building stiffness, reduced seismic forces increase by 1.5–2 times. According to the results obtained, when designing structures in areas of high seismic hazard, account should be taken of possible foundation flexibility effects depending on different types of soil and structural solutions of particular buildings.

Probabilistic Assessment of Reliability and Risk Values by Certification Results

2020 ◽  
pp. 52-67
Author(s):  
Vladimir A. Lapin ◽  
Erken S. Aldakhov ◽  
S. D. Aldakhov ◽  
A. B. Ali
Keyword(s):  
Seismic Risk ◽  
Housing Stock ◽  
Seismic Resistance ◽  
Probabilistic Assessment ◽  
Quantitative Estimates ◽  
Different Types ◽  
Reduce Risk ◽  
First Time ◽  
Structural Solutions ◽  
Practical Recommendations

For the first time in Almaty full passport of apartment stock of multiapartment building was carried out. The structure of the housing stock was revealed with the allocation of groups of buildings according to structural solutions and assessment of their seismic resistance. Based on the results of certification, quantitative estimates of failure probability values for different types of buildings were obtained. Formulas for estimation of quantitative value of seismic risk are obtained. The number of deaths in the estimated zem-shakes was estimated. The results of the assessments will be used for practical recommendations to reduce risk and expected losses in possible earthquakes.

The effect of element strength assignment on the torsional response of stiffness-eccentric systems

2013 ◽  
Vol 40 (7) ◽  
pp. 655-662
Author(s):  
George K. Georgoussis
Keyword(s):  
Structural Design ◽  
Shear Force ◽  
Ground Motions ◽  
Building Structures ◽  
Centre Of Mass ◽  
Base Shear ◽  
Structural Behaviour ◽  
Torsional Response ◽  
Building Models ◽  
Storey Building

Building structures of low or medium height are usually designed with a pseudostatic approach using a base shear much lower than that predicted from an elastic spectrum. Given this shear force, the objective of this paper is to evaluate the effect of the element strength assignment (as determined by several building codes) on the torsional response of inelastic single-storey eccentric structures and to provide guidelines for minimizing this structural behaviour. It is demonstrated that the expected torque about the centre of mass (CM) may be, with equal probability, positive (counterclockwise) or negative (clockwise). This result means that the torsional strength should also be provided in equal terms in both rotational directions, and therefore the base shear and torque (BST) surface of a given system must be symmetrical (or approximately symmetrical). In stiffness-eccentric systems, appropriate BST surfaces may be obtained when a structural design is based on a pair of design eccentricities in a symmetrical order about CM, and this is shown in representative single-storey building models under characteristic ground motions.

scholarly journals Approaches to the Mechanical Properties of Threaded Studs Welded to RHS Columns

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1429
Author(s):  
Ismael García ◽  
Miguel A. Serrano ◽  
Carlos López-Colina ◽  
Fernando L. Gayarre ◽  
Jesús M. Suárez
Keyword(s):  
Mechanical Properties ◽  
Tensile Tests ◽  
Efficient Solutions ◽  
Bolted Joints ◽  
Building Structures ◽  
Static Behavior ◽  
Steel Tubes ◽  
Punch Test ◽  
Different Types ◽  
The Face

The use of Rectangular Hollow Sections (RHS) as columns in steel construction includes important advantages like higher mechanical strength and fire resistance. However, the practical demountable bolted joints between beams and columns are not easy to execute, due to impossibility of access to the inner part of the tube. The use of threaded studs welded to the face of the tube and bolted to the beam by means of angle cleats is one of the cheaper and most efficient solutions to obtain beam–column joints with a semi-rigid behavior, as is usually sought in building structures. Nevertheless, it is important to point out that the stud-diameter and the stud-class selection may affect the mechanical properties of the welded parts of the joint. In this paper, 8MnSi7 (with a commercial designation K800) and 4.8 threaded studs were welded to RHS steel tubes and mechanical properties on the weld, the Heat Affected Zones (HAZ), and the base metal were obtained in two different ways: through a correlation with the Vickers hardness and by means of the Small Punch Test (SPT). A study of the microstructure and tensile tests on the threaded studs and in the columns was also carried out. The research involved different types of stud qualities, tube wall thicknesses, and stud diameters. The work presented in this paper proved that in most cases, the welded joint between these studs and the RHS steel tubes present a reasonable static behavior that fulfils the requirements for the beam–column joints under static loading.

Observed Natural Frequencies, Damping Ratios, and Mode Shapes of Vibration of a 30-Story Building Excited by a Major Earthquake and Typhoon

2010 ◽  
Vol 26 (2) ◽  
pp. 371-397 ◽  
Author(s):  
Kun-Sung Liu ◽  
Yi-Ben Tsai
Keyword(s):  
Natural Frequencies ◽  
Transfer Functions ◽  
Measurement Data ◽  
Spectral Ratio ◽  
Transverse Mode ◽  
Structural Vibration ◽  
Mode Shapes ◽  
Building Structures ◽  
Ambient Vibrations ◽  
Frequency Changes

The safety of building structures and contents, as well as the comfort of occupants, under such strong forces as earthquakes and typhoons remain major engineering concerns. In order to improve our understanding of building structural responses, records of a structural array in the 30-story PS Building in Taipei from the M7.6 Chi-Chi earthquake and Typhoon Aere are analyzed. In addition, wind data measured at the Taipei Meteorological Station are also used. First, the field measurement data clearly demonstrate that serviceability of the PS Building met the criteria for occupant comfort during Typhoon Aere. Secondly, several structural vibration parameters of this highrise building, including the transfer functions, natural frequencies, damping ratios and mode shapes, excited by the Chi-Chi earthquake, Typhoon Aere, and ambient vibrations are also determined and compared. The results show the frequency of the first mode for the longitudinal components is approximately 8.6% lower for the earthquake than the ambient vibrations. The transverse mode frequencies behave similarly. In contrast, frequency changes from the typhoon to ambient vibrations are in the third decimal (1.3% and 0.9% lower in the longitudinal and transverse directions, respectively), indicating little nonlinearity. The damping ratios of the PS Building apparently increase with vibration amplitudes. Finally, results of a spectral ratio analysis of the Chi-Chi earthquake data do not indicate significant SSI effects in the longitudinal and transverse directions.

SMALL CATAMARANS: DESIGN APPROACHES AND CASE STUDIES

2015 ◽  
Vol 157 (B1) ◽  
Author(s):  
A Nazarov
Keyword(s):  
Structural Design ◽  
Special Interest ◽  
Applied Research ◽  
Comparison Of Methods ◽  
Theoretical Methods ◽  
Seakeeping Performance ◽  
Different Types ◽  
Shape Selection ◽  
Vertical Accelerations ◽  
Design Experience

The paper presents the review of design experience and applied research of catamaran craft, up to 30m in length, of total over 30 catamaran designs, developed by ‘Albatross Marine Design’ and launched during recent years. Architecture of catamarans is discussed; typical catamaran hull shapes are reviewed and their suitability for different applications and desired speeds are studied. Recommendations are given for hull shape particulars selection. Performance issues are studied using available theoretical methods and sea-trials data of number catamarans. Components of resistance of catamarans and methods of their prediction are reviewed. Comparison of methods is presented and samples of their applications for hull shape selection are shown. Seakeeping performance is discussed in terms of vertical accelerations. Results of full-scale measurements of vertical accelerations on number of craft are presented. Controllability discussion is based on turning track measurements for power catamarans of different configurations at different speeds. Structural design issues are reviewed with special interest in composite craft and their improvements. Perspective applications of catamaran concept for different types of craft are indicated. Presented are samples of catamaran designs for special, small commercial and pleasure catamarans.

scholarly journals The effect of the type of fixators reinforcement on strength and deformation characteristics of reinforced concrete

2019 ◽  
Vol 97 ◽  
pp. 02034
Author(s):  
Evgenij Borisyuk
Keyword(s):  
Reinforced Concrete ◽  
Crack Resistance ◽  
Steel Reinforcement ◽  
Low Grade ◽  
High Grade ◽  
Building Structures ◽  
Deformation Characteristics ◽  
Reliable Operation ◽  
Different Types ◽  
Strength And Deformation

Rebar fixators of various types (plastic and concrete) became widespread with manufacturing of building structures of precast and monolithic reinforced concrete in order to fix steel reinforcement cage in strictly design position and to exclude the probability of its displacement during concreting. Such sufficiently rigid fixing is necessary for the following reliable operation of the structure in the building, as well as for the preservation of steel reinforcement which protected by a necessary layer of concrete from corrosion. Information available in the literature does not allow us to judge about the effects that different types of fixators apply to exploitative properties (such as strength and crack resistance) of reinforced concrete. The experiments, according to the accepted method, showed that these characteristics are slightly worse for the samples with plastic fixators and fixators made of low grade concrete than for the samples without fixators or fixators made of high grade concrete. On the base on the research results it becomes possible to substantiate the distinction between the areas of application of plastic and concrete fixatives

scholarly journals Country-scale InSAR monitoring for settlement and uplift damage calculation in architectural heritage structures

2020 ◽  
pp. 147592172094212
Author(s):  
Anastasios Drougkas ◽  
Els Verstrynge ◽  
Koenraad Van Balen ◽  
Michal Shimoni ◽  
Thibauld Croonenborghs ◽  
...  
Keyword(s):  
Ground Movement ◽  
Analytical Models ◽  
Building Structures ◽  
Architectural Heritage ◽  
Damage Classification ◽  
General Applicability ◽  
Combined Use ◽  
Building Geometry ◽  
Different Types ◽  
The Common

The article proposes a methodology for assessing the development of damage in building structures, subjected to differential settlement and uplift, using the analysis of Interferometry Synthetic Aperture Radar (InSAR) data. The proposed methodology is targeted towards general applicability, capable of providing assessment results for measurements over wide geographic areas and for varying structural typologies. The methodology is not limited to ground movement measurements linked to tunnelling, as is the common case. Instead it extends to the monitoring of arbitrary movement in buildings, for example, due to ground consolidation, water table changes or excavation. The methodology is designed for use alongside patrimonial building databases, from which data on individual building geometry and typology are extracted on a region or country scale. Ground movement monitoring data are used for the calculation of the building deformation, expressed in different types of deformation parameters. The combined use of this data with analytical models for settlement damage classification in building structures enables the assessment in patrimonial building structures, at a country scale. The methodology is elaborated and applied on the patrimonial inventory of Belgium for the evaluation of potential settlement and uplift damage on buildings over a period of nearly three decades. The analysis results are compared to on-site observations.

Recorded Responses of Building Structures during the 2011 Tohoku-Oki Earthquake with Some Implications for Design Practice

2013 ◽  
Vol 29 (1_suppl) ◽  
pp. 245-264 ◽  
Author(s):  
Izuru Okawa ◽  
Toshihide Kashima ◽  
Shin Koyama ◽  
Masanori Iiba
Keyword(s):  
Structural Design ◽  
Earthquake Response ◽  
Building Structures ◽  
Design Practice ◽  
Large Earthquakes

During the 2011 Tohoku-oki earthquake, a large number of response records from various types of buildings were obtained. The records give us the actual motions of buildings during the exceptionally large earthquakes that are considered comparable with design earthquakes. Various types of earthquake response records have been collected, and their properties with several buildings that will exhibit implications for structural design are discussed.

Estimation of Dynamic Wind Pressure for Multi-Span Greenhouse Structural Design

2012 ◽  
Vol 446-449 ◽  
pp. 878-882
Author(s):  
De Fa Sun
Keyword(s):  
Structural Design ◽  
Dynamic Pressure ◽  
Practical Method ◽  
Structure Design ◽  
Wind Pressure ◽  
Wind Loads ◽  
Building Structures ◽  
Gust Factor ◽  
Relative Safety ◽  
Contrast Analysis

Based on the contrast analysis of loads provided in foreign and China standards, analysis and discussion are mentioned about the definition and estimation of dynamic wind pressures for multi-span greenhouse structural design in details. Meanwhile, taking advantage of past experience in greenhouse structural design a practical method which can be used in greenhouse design was given for wind loads. Under the present conditions, it is relative safety in calculation wind loads according to Load code for the design of building structures (GB 50009-2001), yet it is unnecessary to make modification of statistical reappearing factor in calculation wind load-dynamic pressure when considering the coefficients of wind pressure depending on height and the gust factor according to Greenhouse structure design load (GB/T 18622-2002).

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