scholarly journals Effect of Competent Caliche Layers on Measuring the Capacity of Axially Loaded Drilled Shafts Using the Osterberg Test

2020 ◽  
Vol 10 (18) ◽  
pp. 6169
Author(s):  
Rouzbeh Afsharhasani ◽  
Moses Karakouzian ◽  
Visar Farhangi
Keyword(s):  
Field Tests ◽  
Cost Effective ◽  
Full Scale ◽  
Drilled Shaft ◽  
Hydraulic Jack ◽  
Top Down ◽  
Shaft Length ◽  
Finite Element Software ◽  
Reliable Interpretation ◽  
Pile Resistance

This study investigates the effect of the location of an O-cell hydraulic jack along the length of a drilled shaft in a full-scale Osterberg test performed in soils containing layers of caliche. The location of the hydraulic jack with respect to caliche layers influences the measurements obtained from the Osterberg test and the subsequent interpretation of drilled shaft capacity. In this study, drilled shaft capacities were derived utilizing data from 30 Osterberg full-scale field load tests in soils containing caliche layers. The hydraulic jack was placed at the midpoint of the drilled shaft length. Additionally, the Osterberg test data was used to calibrate a numerical model by Plaxis finite element software for drilled shaft analysis. Using the calibrated model, several scenarios of hydraulic jack location were simulated. The scenarios included hydraulic jack locations at several distances above and below a caliche layer. The results of the simulations indicate that in cases where the O-cell was installed far from the caliche layer, the Osterberg tests results showed lower pile resistance capacity compared to the top-down test. However, in cases where the O-cell was installed close to the caliche layers, the Osterberg tests results showed comparable pile resistance capacity compared to the top-down tests. This study recommends installing the hydraulic jack as close as possible to the caliche layers for more reliable interpretation of the Osterberg field tests which leads to a cost-effective design approach by reducing the required shaft length.

Full‐scale shake‐table tests on two unreinforced masonry cavity‐wall buildings: effect of an innovative timber retrofit

2021 ◽  
Author(s):  
Marco Miglietta ◽  
Nicolò Damiani ◽  
Gabriele Guerrini ◽  
Francesco Graziotti
Keyword(s):  
Seismic Vulnerability ◽  
Concrete Slab ◽  
Cost Effective ◽  
Unreinforced Masonry ◽  
Full Scale ◽  
Cavity Wall ◽  
Masonry Walls ◽  
Shake Table ◽  
Earthquake Excitation ◽  
Reinforced Concrete Slab

AbstractTwo full-scale building specimens were tested on the shake-table at the EUCENTRE Foundation laboratories in Pavia (Italy), to assess the effectiveness of an innovative timber retrofit solution, within a comprehensive research campaign on the seismic vulnerability of existing Dutch unreinforced masonry structures. The buildings represented the end-unit of a two-storey terraced house typical of the North-Eastern Netherlands, a region affected by induced seismicity over the last few decades. This building typology is particularly vulnerable to earthquake excitation due to lack of seismic details and irregular distribution of large openings in masonry walls. Both specimens were built with the same geometry. Their structural system consisted of cavity walls, with interior load-bearing calcium-silicate leaf and exterior clay veneer, and included a first-floor reinforced concrete slab, a second-floor timber framing, and a roof timber structure supported by masonry gables. A timber retrofit was designed and installed inside the second specimen, providing an innovative sustainable, light-weight, reversible, and cost-effective technique, which could be extensively applied to actual buildings. Timber frames were connected to the interior surface of the masonry walls and completed by oriented strands boards nailed to them. The second-floor timber diaphragm was stiffened and strengthened by a layer of oriented-strand boards, nailed to the existing joists and to additional blocking elements through the existing planks. These interventions resulted also in improved wall-to-diaphragm connections with the inner leaf at both floors, while steel ties were added between the cavity-wall leaves. The application of the retrofit system favored a global response of the building with increased lateral capacities of the masonry walls. This paper describes in detail the bare and retrofitted specimens, compares the experimental results obtained through similar incremental dynamic shake-table test protocols up to near-collapse conditions, and identifies damage states and damage limits associated with displacements and deformations.

Effect of guy cable constraint on structural damping of open lattice antenna towers

1980 ◽  
Vol 7 (4) ◽  
pp. 614-620
Author(s):  
J. S. Kennedy ◽  
D. J. Wilson ◽  
P. F. Adams ◽  
M. Perlynn
Keyword(s):  
Natural Frequencies ◽  
Damping Ratio ◽  
Field Tests ◽  
Full Scale ◽  
Structural Damping ◽  
Scale Field ◽  
Modes Of Vibration

This paper presents the results of full-scale field tests on two steel guyed latticed towers. The towers were approximately 83 m in height, were guyed at three levels, and were of bolted angle construction. The observed results consist of the natural frequencies of the first two modes of vibration as well as the damping ratio for the first mode. The observed results are compared with analytical predictions and observations made concerning the contributions of structural and cable action to the damping ratio.

THE RULE OF COMBINING A PRIORI AND EXPERIMENTAL INFORMATION IN THE TASKS OF MANAGING TESTS OF COMPLEX TECHNICAL PRODUCTS ACCORDING TO THE BERNOULLI SCHEME

2020 ◽  
pp. 3-13
Author(s):  
Yu. I. Buryak ◽  
A. A. Skrynnikov
Keyword(s):  
Field Experiments ◽  
A Priori ◽  
Field Tests ◽  
Experimental Information ◽  
Full Scale ◽  
Testing Complex ◽  
Series Of Experiments ◽  
Full Scale Tests ◽  
Technical Products

The article is devoted to the substantiation of the procedure for testing complex technical systems to assess the probability of performing the task, taking into account a priori data obtained from the results of modeling, field tests of components and prototypes, operation of analogues, etc. The conditions for the formation of a combined sample consisting of field experiments and experiments counted on the results of modeling are justified. Data uniformity is checked using the Student's criterion. The minimum volume of full-scale tests is determined by the requirement of equality of the amount of Fischer information about the estimated parameter obtained during full-scale tests and at the expense of a priori data A strategy for conducting field experiments is proposed, in which the required quality of evaluating the probability of completing the task is achieved with the minimum possible number of field experiments. At the first stage, a series of experiments with a volume equal to half of the required sample size is performed. At the second stage, the experiments are conducted sequentially with an assessment after each experiment of the requirements for the amount of information about the evaluated parameter and for the uniformity of data. Experiments are terminated when the specified requirements are met, and then a combined sample is formed, which is used to evaluate the probability of the system performing the task. A model example is considered. The estimation of the gain in the number of experiments performed at different probability values was carried out.

Rockfall Full Scale Field Tests

2013 ◽  
pp. 461-467
Author(s):  
Alberto Clerici ◽  
Ezio Giuriani ◽  
Danilo Cambiaghi ◽  
Antonio Isceri ◽  
Giorgio Vassena ◽  
...  
Keyword(s):  
Field Tests ◽  
Full Scale ◽  
Scale Field

scholarly journals NUMERICAL MODELING AND FULL-SCALE EXPERIMENTS OF GLUED WOODEN STRUCTURES JOINT DESTRUCTION ON CARBON-FIBER DOWEL PINS

2020 ◽  
Vol 16 (2) ◽  
pp. 101-112
Author(s):  
Mikhail Vodiannikov ◽  
Galina Kashevarova ◽  
Danil Starobogatov
Keyword(s):  
Numerical Modeling ◽  
Structural Analysis ◽  
Carbon Fiber ◽  
Structural Parameters ◽  
General Structure ◽  
Failure Process ◽  
Joint Destruction ◽  
Field Tests ◽  
Full Scale ◽  
Glued Laminated Timber

This paper presents the results of numerical modeling and full-scale experiments of the failure process of a glued laminated timber beam with rigid joint in the middle. All the connecting parts are made of carbon fiber. The structural analysis is done with the finite element method (ANSYS software). The nonlinear problem was solved. The contact interaction of the structural elements in the process of deformation and fracture, as well as orthotropy of the wood, the transversely isotropic properties of the plates, and the real diagrams of the deformation of carbon fiber dowel pins were taken into account. The influence of the structural parameters of the joint on the position of the most loaded dowel pin in the joint and the bearing capacity of the general structure are investigated. To verify the structural analysis results, field tests were carried out before destruction by a stepwise increasing load on a personally designed stand. The destruction of the structure occurred according to the forecast of the numerical model as a result of the mutual slip of the glued wood layers and the destruction of the polymer matrix of the glued dowel pins with the beginning of the formation of plastic joints and the formation of cracks in the wood at the junction.

Creative Design-by-Analysis Solutions Applied to High-Temperature Components

1993 ◽  
Vol 115 (3) ◽  
pp. 221-227
Author(s):  
A. K. Dhalla
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Detailed Analysis ◽  
Structural Response ◽  
Cost Effective ◽  
Element Analysis ◽  
Finite Element Software ◽  
Division 1 ◽  
High Temperature Components ◽  
Elevated Temperature Design

Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs.

Study on the Stratum Displacement Changes Caused by the Vertical Shaft Construction in Saturated Ultra Soft Soil

2012 ◽  
Vol 170-173 ◽  
pp. 1005-1012
Author(s):  
Lin You Pan ◽  
Xiao Bing Li ◽  
Chuang Yu ◽  
Fu Xue Sun
Keyword(s):  
Soft Soil ◽  
Field Tests ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Soil Disturbance ◽  
Soil Parameters ◽  
Finite Element Software ◽  
Total Displacement ◽  
Calculation Results ◽  
Engineering Information

In view of Wenzhou saturated super soft soil, This article studied the influence of different soil parameters for the shaft excavation construction and the stratum displacement change law by using Plaxis finite element software, according to the data obtained in field tests. The considered factors included the lateral brace stiffness, the stiffness of the underground diaphragm wall, and the surrounding soil disturbance. The calculation results provided much important engineering information, such as the horizontal displacement nephogram, the vertical displacement nephogram and the total displacement incremental vector diagram of each construction steps, which can be referred for the construction of the similar underground projects in soft soil areas.

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