Discussion: Floor vibration due to occupants and reliability-based design guidelines

1996 ◽  
Vol 23 (2) ◽  
pp. 571-572
Author(s):  
Donald M. Onysko
Keyword(s):  
Design Guidelines ◽  
Reliability Based Design ◽  
Floor Vibration

Floor vibration due to occupants and reliability-based design guidelines

1995 ◽  
Vol 22 (3) ◽  
pp. 471-479 ◽  
Author(s):  
Ricardo O. Foschi ◽  
Greg A. Neumann ◽  
Felix Yao ◽  
Bryan Folz
Keyword(s):  
Close Agreement ◽  
Analytical Study ◽  
Coupled System ◽  
Design Guidelines ◽  
Vibrational Response ◽  
Reliability Based Design ◽  
Floor Vibration ◽  
Coupled Dynamical System ◽  
Commercial Applications ◽  
Acceptability Criteria

Lightweight floors for residential or commercial applications may exhibit annoying levels of vibration under occupancy loading. This paper presents an experimental and analytical study of the vibrational response of wood floors to impact produced by occupants. The results show that, for the analysis of this type of floors, it is necessary to consider the coupled dynamical system of floor and occupants. It is also shown that occupants may be modelled with simple oscillators, and that the dynamic analysis of the coupled system can produce close agreement with tests. Acceptability criteria are used to study design guidelines, combining the variability in floor stiffness with the variability in human tolerance to vibrations. Floors considered use 2 × 8 SPF joists and I-joists. Key words: vibrations, serviceability, occupancy loads, wood floors, reliability.

Reply: Floor vibration due to occupants and reliability-based design guidelines

1996 ◽  
Vol 23 (2) ◽  
pp. 572-572
Author(s):  
R. O. Foschi ◽  
G. A. Neumann ◽  
F. Yao ◽  
B. Folz
Keyword(s):  
Design Guidelines ◽  
Reliability Based Design ◽  
Floor Vibration

Numerical and Experimental Study on the Dynamic Behavior of an Innovative Steel-Concrete Composite Hollow Waffle Floor

2020 ◽  
Vol 20 (08) ◽  
pp. 2050087
Author(s):  
Xi Zhang ◽  
Qing Li ◽  
Yousan Wang ◽  
Qiming Wang
Keyword(s):  
Experimental Study ◽  
Structural Parameters ◽  
Design Guidelines ◽  
Element Analysis ◽  
Long Span ◽  
Vibration Serviceability ◽  
Floor Vibration ◽  
Walking Tests ◽  
Vibration Performance ◽  
Hollow Beams

The U-shaped steel-concrete composite hollow waffle (CHW) floor is an innovative slender large-span floor composed of a thin slab and bidirectional orthogonal steel-concrete composite hollow beams. Large vibrations may occur under human excitations, and vibration guidelines for CHW floors are still lacking. Thus, this paper undertook a parametric and experimental study to explore the vibration performance of the CHW floors. First, the modal properties and vibration response under walking tests considering the varying frequencies and routes were obtained from the measurements, which validated the accuracy of the finite element analysis (FEA). Then, the influence of the structural parameters on the floor vibration was investigated by numerical modeling. The parametric study shows that the medium-sized long-span (MLS) (28[Formula: see text]m) CHW floors present the best vibration serviceability, the small-sized long-span (SLS) (14[Formula: see text]m) CHW floors vibrate substantially under walking excitation, and the large-sized long-span (LLS) (42[Formula: see text]m) CHW floors are vulnerable to resonance. Finally, this paper provides recommendations for design guidelines for CHW floors and indicates that controlling the span-to-height (SH) value and beam spacing (BS) at a small value are the most effective methods of vibration control.

The Development of Reliability-Based Design Guidelines and Prototype Design of Super Long-Span Bridges

2012 ◽  
Vol 18 (14) ◽  
pp. 1096-1103
Author(s):  
Ho-Kyung Kim ◽  
Myeong-Jae Lee ◽  
ByungHong Yang ◽  
Byeong-Hoon Song ◽  
HaeSung Lee ◽  
...  
Keyword(s):  
Design Guidelines ◽  
Long Span Bridges ◽  
Reliability Based Design ◽  
Long Span ◽  
Prototype Design

scholarly journals Vibration serviceability assessment of office floors for realistic walking and floor layout scenarios: Literature review

2019 ◽  
Vol 23 (6) ◽  
pp. 1238-1255
Author(s):  
Márcio S Gonçalves ◽  
Aleksandar Pavic ◽  
Roberto L Pimentel
Keyword(s):  
Design Guidelines ◽  
Design Criterion ◽  
Embodied Energy ◽  
Human Gait ◽  
Vibration Source ◽  
Structural Elements ◽  
Single Person ◽  
Vibration Serviceability ◽  
Floor Vibration ◽  
Vibration Performance

Over the last two decades, office floors have been built progressively lightweight with increasing spans and slenderness. Therefore, vibration performance of office floors due to walking dynamic loads is becoming their governing design criterion, determining their size and shape, and therefore overall weight and embodied energy of the building. To date, floor design guidelines around the world recommend walking load scenarios in offices featuring some or all of the following standard characteristics: (a) walking loads are assumed to be periodic dynamic excitation represented by the Fourier series, including harmonics corresponding to up to the first four integer multiples of the pacing frequency of which at least one is exciting the floor at a resonant frequency and (b) single person walking. However, the literature surveyed provides evidence that such assessment methodology is potentially an over-simplification which does not reflect real walking load scenarios, since crucial features of the floor vibration source, path and receiver are missing. First, in terms of vibration source, realistic scenarios need to feature (a) moving rather than stationary walking forces, (b) stochastic nature of human gait, (c) simultaneous multi-person walking and (d) human–structure interaction. Second, for the transmission path (i.e. office floor structure), two features are needed to consider: (a) realistic office floor layouts and (b) presence, or absence, of non-structural elements. Finally, for the vibration receivers (i.e. floor occupants), (a) vibrations calculated at floor locations occupied by users (instead of at the potential highest response location which may not be occupied), (b) actual period over which occupants feel vibration due to such excitation and (c) assessment of vibration levels based on their probability of occurrence. This study therefore addresses these seldom considered but increasingly important features and discusses realistic approaches to floor design for vibration serviceability.

Duration of load in wood: Canadian results and implementation in reliability-based design

1993 ◽  
Vol 20 (3) ◽  
pp. 358-365 ◽  
Author(s):  
Felix Z. Yao ◽  
Ricardo O. Foschi
Keyword(s):  
Design Guidelines ◽  
Fatigue Load ◽  
Load Duration ◽  
Reliability Based Design ◽  
Theoretical Approaches ◽  
Timber Construction ◽  
Adjustment Factors ◽  
Load Effects ◽  
Accumulation Of Damage ◽  
Duration Of Load

This paper summarizes some Canadian experimental results for duration of load effects in wood, and discusses the theoretical framework utilized for their interpretation and implementation in design guidelines. The theory is based on a model for accumulation of damage, and it is used in the context of reliability assessment of a structure under load over its service life. The paper also compares results from other theoretical approaches. Finally, the background to currently recommended design adjustment factors for duration of load is discussed. Key words: fatigue, load duration, reliability, timber construction, wood.

Reliability Based Design Criteria for Installation of Pipelines in the Bay of Campeche, Mexico: Part 1

2002 ◽  
Author(s):  
Robert Bea ◽  
Tao Xu ◽  
Ernesto Heredia-Zavoni ◽  
Leonel Lara ◽  
Rommel Burbano
Keyword(s):  
Limit State ◽  
Companion Paper ◽  
Design Guidelines ◽  
Design Criteria ◽  
Ultimate Limit State ◽  
Reliability Based Design ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Ultimate Limit ◽  
Allowable Stress Design

Studies have been performed to propose reliability based design criteria for the installation of pipelines in the Bay of Campeche, Mexico. This paper summarizes the reliability formulations that were used to develop Allowable Stress Design and Load and Resistance Factor Design guidelines for Ultimate Limit State conditions, background on the target reliabilities that were used in the development, and the methods that were used to characterize the demands (loads, displacements) induced in pipelines during their installation. This paper summarizes data that was gathered during the installation of pipelines in the Bay of Campeche to help define the Biases (actual stresses/calculated stresses) associated with the analytical model used to predict installation demands. These results are compared with those published previously based on other field and laboratory tests. A companion paper details the analyses of pipeline Ultimate Limit State capacities and the Biases associated with these capacities.

Reliability-Based Design Guidelines for Fatigue of Ship Structures

2002 ◽  
Vol 114 (2) ◽  
pp. 113-138 ◽  
Author(s):  
Bilal M. Ayyub ◽  
Ibrahim A. Assakkaf ◽  
David P. Kihl ◽  
Michael W. Siev
Keyword(s):  
Design Guidelines ◽  
Ship Structures ◽  
Reliability Based Design

Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Limit State ◽  
Design Guidelines ◽  
Design Tool ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Concrete Members ◽  
Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

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