Improvement of Engineering Properties of Peat with Palm Oil Clinker

The aim of this study is to investigate the effects of Palm Oil Clinker (POC) added as a stabilizer forimproving the strength of peat. Cement and POC are added into peat up to 50% of the maximum dry unitweight. Treated peat achieved higher dry unit weight, almost 2.5 times as compared to untreated peat.Unconfined compressive strength (UCS) of treated peat is also investigated for soaked and unsoakedconditions. The results show that curing time improved the unconfined compressive strength of treatedsample and increased by a factor of 20 and 11 for unsoaked and soaked conditions after 28 days ofcuring, respectively. The treated samples added with POC can be related to an increase in unconfinedcompressive strength for long time curing

Static lateral stiffness of wire rope isolators

© 2016, Copyright © Taylor & Francis Group, LLC.This paper presents an analytical model for the static lateral stiffness of Wire Rope Isolators (WRI). The wire rope isolator, which is a passive isolation device, has been widely adopted as a shock and vibration isolation for many types of equipment and lightweight structures. The major advantage of the WRI is its ability to provide isolation in all three planes and in any orientation. The WRI in the lateral roll mode, is required to possess the required lateral stiffness to support and isolate the equipment effectively. The static lateral stiffness of WRI depends mainly on the geometrical characteristics and wire rope properties. The model developed in this paper is validated experimentally using a series of monotonic loading tests. The flexural rigidity of the wire ropes, which is required in the model, was determined from the transverse bending test on several wire rope cables. It was observed that the lateral stiffness is significantly influenced by the wire rope diameter and height of the isolator. The proposed analytical model can be used for the evaluation of lateral stiffness and in the preliminary design of the WRI

Mechanical and durability properties of medium strength self-compacting concrete with high-volume fly ash and blended aggregates

© 2015, Technical University of Budapest. All rights reserved. This research investigates the fresh state properties and hardened state properties of medium strength, self-compacting concrete incorporating a high volume of class F fly ash as a partial replacement to cement and blended fine aggregates while maintaining satisfactory properties of SCC. The properties of self-compaction investigated are: slump flow, J-ring, L-box, V-funnel, sieve stability and Visual Stability Index tests. Those of hardened concrete include compressive strength, splitting tensile strength, complete immersion water absorption, apparent volume of permeable voids, sorptivity, and rapid chloride ion penetration tests. The experiments on fresh state properties investigate the filling ability, the passing ability and the segregation resistance of concrete. The results show that fly ash improves workability and decreases the compressive strength as well as splitting tensile strength. Fly ash based SCC shows better resistance to water absorption, apparent volume of permeable voids, sorptivity, and chloride penetration than the control mix

Practical Soil-Shallow Foundation Model for Nonlinear Structural Analysis

© 2016 Moussa Leblouba et al.Soil-shallow foundation interaction models that are incorporated into most structural analysis programs generally lack accuracy and efficiency or neglect some aspects of foundation behavior. For instance, soil-shallow foundation systems have been observed to show both small and large loops under increasing amplitude load reversals. This paper presents a practical macroelement model for soil-shallow foundation system and its stability under simultaneous horizontal and vertical loads. The model comprises three spring elements: nonlinear horizontal, nonlinear rotational, and linear vertical springs. The proposed macroelement model was verified using experimental test results from large-scale model foundations subjected to small and large cyclic loading cases

Seismic structural demands and inelastic deformation ratios: A theoretical approach

International audienc

Experimental investigation on the hysteresis behavior of the wire rope isolators

© 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. Vibration isolation has been widely applied to filter the external excitation energy and impact forces in building structures and equipment. Wire rope isolator (WRI), a kind of isolator for vibration and shock isolation, shows a better performance in attenuating these forces. WRIs are able to deviate these external forces through their mechanical configuration and high-energy dissipative capabilities. The application of WRI demands knowledge of its behavior and the relation between various geometrical properties and input force. The present work investigates the influence of geometrical parameters, such as wire rope diameter, number of coils, and displacement amplitude on the hysteresis behavior of WRI under quasi-static loading in both vertical and horizontal directions. The hysteresis behavior of different WRIs was evaluated using the calculated parameters from hysteresis force-displacement curves: energy loss ratio (ELR), and effective stiffness. The study indicates that the geometric properties significantly influence the effective stiffness than the energy loss ratio. It is observed that, increased displacement amplitude results in decreased ELR and hence damping capabilities. The study also confirms that the wire rope isolator possesses a good ability in damping through its stiffness and high-energy dissipation capability

Wire rope isolators for vibration isolation of equipment and structures - A review

© Published under licence by IOP Publishing Ltd. Vibrations and shocks are studied using various techniques and analyzed to predict their detrimental effect on the equipment and structures. In cases, where the effects of vibration become unacceptable, it may cause structural damage and affect the operation of the equipment. Hence, adding a discrete system to isolate the vibration from source becomes necessary. The Wire Rope Isolator (WRI) can be used to effectively isolate the system from disturbing vibrations. The WRI is a type of passive isolator that exhibits nonlinear behavior. It consists of stranded wire rope held between two metal retainer bars and the metal wire rope is made up of individual wire strands that are in frictional contact with each other, hence, it is a kind of friction-type isolator. This paper compiles the research work on wire rope isolators. This paper presents the research work under two categories, namely monotonic and cyclic loading behaviors of WRI. The review also discusses the different terminologies associated with vibration isolation system and highlights the comparison between various isolation systems

An analytical study on the static vertical stiffness of wire rope isolators

© 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. The vibrations caused by earthquake ground motions or the operations of heavy machineries can affect the functionality of equipment and cause damages to the hosting structures and surrounding equipment. A Wire rope isolator (WRI), which is a type of passive isolator known to be effective in isolating shocks and vibrations, can be used for vibration isolation of lightweight structures and equipment. The primary advantage of the WRI is that it can provide isolation in all three planes and in any orientation. The load-supporting capability of the WRI is identified from the static stiffness in the loading direction. Static stiffness mainly depends on the geometrical and material properties of the WRI. This study develops an analytical model for the static stiffness in the vertical direction by using Castigliano’s second theorem. The model is validated by using the experimental results obtained from a series of monotonic loading tests. The flexural rigidity of the wire ropes required in the model is obtained from the transverse bending test. Then, the analytical model is used to conduct a parametric analysis on the effects of wire rope diameter, width, height, and number of turns (loops) on vertical stiffness. The wire rope diameter influences stiffness more than the other geometric parameters. The developed model can be accurately used for the evaluation and design of WRIs