Nauki Techniczne

Archives of Civil Engineering

Zawartość

Archives of Civil Engineering | 2014 | No 1

Abstrakt

Steel frame wind bracing systems are usually made of hot rolled profiles connected to frame elements directly or through a gusset plate. The behaviour of angle bracing members is generally complex since controlled by tension or compression, bending and torsion. The common practice is to transform the problem of complex behaviour into the buckling strength of a truss member. This paper deals with an analytical formulation of the force-deformation characteristic of a single angle brace subjected to compression. A strut model takes into consideration the effect of brace end connections and softening effect of its force-deformation characteristic. Two different boundary conditions, typical for engineering practice, are dealt with. Experimental program of testing the behaviour of angle brace in portal sub-frame specimens is described. Results of experimental investigations are presented. They are used for the validation of developed model. Conclusions are formulated with reference to the application of validated brace model in the analysis of braced steel frameworks.

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Autorzy i Afiliacje

A.M. Barszcz

Abstrakt

Starting from consideration that urban intersections are sites with promise for safety and operational improvements, the paper describes the steps taken to develop a crash predictive model for estimating the safety performance of urban unsignalized intersections located in Palermo, Italy. The focus is on unsignalized four-legged one-way intersections widespread in Italian downtowns. The sample considered in the study consist of 92 intersections in Palermo, Italy. For the study were collected crashes occurred in the sites during the years 2006‒2012, geometric design and functional characteristics and traffic flow. Results showed that data were overdispersed and NB1 distributed. In order to account for the correlation within responses Generalized Estimating Equations (GEE) were used under different working correlation matrices.

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Autorzy i Afiliacje

O. Giuffrè
A. Granà
T. Giuffrè
R. Marino
S. Marino

Abstrakt

This study explores the influence of alkali activators on the initiation of polymerization reaction of alumino-silicate minerals present in class-F fly ash material. Different types of fly ash aggregates were produced with silicate rich binders (bentonite and metakaolin) and the effect of alkali activators on the strength gain properties were analyzed. A comprehensive examination on its physical and mechanical properties of the various artificial fly ash aggregates has been carried out systematically. A pelletizer machine was fabricated in this study to produce aggregate pellets from fly ash. The efficiency and strength of pellets was improved by mixing fly ash with different binder materials such as ground granulated blast furnace slag (GGBS), metakaolin and bentonite. Further, the activation of fly ash binders was done using sodium hydroxide for improving its binding properties. Concrete mixes were designed and prepared with the different fly ash based aggregates containing different ingredients. Hardened concrete specimens after sufficient curing was tested for assessing the mechanical properties of different types concrete mixes. Test results indicated that fly ash -GGBS aggregates (30S2‒100) with alkali activator at 10M exhibited highest crushing strength containing of 22.81 MPa. Similarly, the concrete mix with 20% fly ash-GGBS based aggregate reported a highest compressive strength of 31.98 MPa. The fly ash based aggregates containing different binders was found to possess adequate engineering properties which can be suggested for moderate construction works.

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Autorzy i Afiliacje

P. Gomathi
A. Sivakumar

Abstrakt

The paper presents the method of probabilistic optimisation of load bearing capacity and reliability of statically indeterminate bar structures, and of coupling of members in kinematically admissible failure mechanisms (KAFM), which contain minimal critical sets of elements (MCSE). The latter are characterised by the fact that if only a single element is operational, the whole set is operational too. A method of increasing load bearing capacity and reliability of KAFM built from bars dimensioned in accordance with the code is presented. The paper also shows estimation of load bearing capacity and reliability of KAFM of the optimised structures containing elastic-plastic bars with quasi-brittle connections with nodes. The necessity of increasing connection of load bearing capacity and reliability in relation to bar reliability in order to prevent bars from being excluded from MCSE due to connection fracture is estimated.

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Autorzy i Afiliacje

Z. Kowal

Abstrakt

The influence of the CO₂ concentration in a local air zone in naturally ventilated residential houses on the residents’ behaviour was numerically investigated. A numerical two-dimensional CFD model of the indoor zone based on experiments performed by the authors was used. Different resident locations in the fluid domain and different inlet velocities imposed by wind were considered in simulations. The overall thermal comfort and IAQ indices were also calculated. The investigations results show that in contrast to the overall air quality, the local CO₂ was strongly dependent upon the resident location, fresh air inlet velocity and ventilation system type.

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Autorzy i Afiliacje

M. Krzaczek
J. Tejchman

Abstrakt

The transition effect between different track-foundation systems is examined from the point of view of energy that is produced during the passage of load. Analytical solution is given. A model of beam on elastic foundation with damping is used as the base model. It is developed into a model composed of two parts that represent the track-subgrade system with an abrupt change in mechanical parameters: bending stiffness, foundation stiffness, damping, and mass. Several calculations are carried out including examples of comparative calculations with the Finite Difference Model and the Finite Element Model. Transient rail deflections and energy are determined, which may serve to estimate the rate of track-subgrade deterioration.

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Autorzy i Afiliacje

J. Sołkowski

Abstrakt

The main objective of this investigation is to assess the feasibility of strengthening of corroded (damaged) square hollow steel tubular sections subjected to compression and to develop or predict the suitable wrapping scheme of fibre reinforced polymer (FRP) to enhance the structural behaviour of it.For this study, compact mild steel tubes were used with the main variable being FRP characteristics. Carbon fibre reinforced polymer (CFRP) fabrics was used as horizontal strips (lateral ties) with other parameters such as the number of layers and spacing of strips. Among fourteen specimens, six were externally bonded by CFRP strips having a constant width of 50 mm with a spacing of 20 mm and the remaining six were externally bonded by CFRP strips having a constant width of 70 mm with a spacing of 20 mm, two columns were unbonded. Experiments were undertaken until the failure of columns to fully understand the influence of FRP characteristics on the compressive behaviour of the square sections including their failure modes, axial stress-strain behaviour, enhancement in the load carrying capapcity, and effect of distribution of CFRP layers. Finally, the behaviour of externally bonded hollow tubular sections was compared with one another and also with the control specimens. Evaluation of the results will lead to optimum CFRP jacketing/wrapping arrangements for the steel tubes considered here.

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Autorzy i Afiliacje

M.C. Sundarraja
P. Sriram

Zasady etyki publikacyjnej

ETHICS POLICY

”Archives of Civil Engineering” respects and promotes the principles of publishing ethics. Being guided by COPE’s Guidelines ( https://publicationethics.org/resources/guidelines) we ensure that all participants of the publishing process comply with these rules, the journal pays special attention to:

Editor Responsibilities
1. Qualifying individual manuscripts for publication only on the basis of: (a) compliance with the guidelines provided to the authors, (b) substantive value, (c) originality, (d) transparency of presentation
2. Deciding whether the paper fulfills all requirements i.e. formal and scientific and which articles submitted to the journal should be published. In making these decisions, the editor may be guided by the policies of the journal’s editorial board as well as by legal requirements regarding libel, copyright infringement, and plagiarism.
3. Evaluating manuscripts for intellectual content without regard to race, gender, sexual orientation, religious belief, ethnic origin, citizenship, or political philosophy of the author(s).
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Procedura recenzowania

Manuscript Peer-Review Procedure

”Archives of Civil Engineering” makes sure to provide transparent policies for peer-review, and reviewers have an obligation to conduct reviews in an ethical and accountable manner. There is clear communication between the journal and the reviewers which facilitates consistent, fair, and timely review.

-The model of peer-review is double-blind: the reviewers do not know the names of the authors, and the authors do not know who reviewed their manuscript (but if the research is published reviewers can eventually know the names of the authors). A complete list of reviewers is published in a traditional version of the journal: in-print.
-It is the editor who appoints two reviewers; however, if there are discrepancies in the assessment the third reviewer can be appointed.
-After having accepted to review the manuscript (one-week deadline), the reviewers have approximately 6 weeks to finish the process.
-The paper is published in ACE provided that the reviews are positive. All manuscripts receive grades from 1-5, 5 being positive, 1 negative, the authors receive reviews to read and consider the comments.
-Manuscript evaluations are assigned one of five outcomes: accept without changes, accept after changes suggested by the reviewer, rate manuscript once again after major changes and another review, reject, withdraw.
-Manuscripts requiring minor revision (accept after changes suggested by the reviewer) does not require a second review. All manuscripts receiving a "Rate manuscript once again after major changes and another review " evaluation must be subjected to a second review. Rejected manuscripts are given no further consideration. There are cases when the article can be withdrawn, often upon the request of an author, technical reason (e.g. names of authors are placed in the text, lack of references, or inappropriate structure of the text), or plagiarism.
-The revised version of the manuscript should be uploaded to the Editorial System within six weeks. If the author(s) failed to make satisfactory changes, the manuscript is rejected.
-On acceptance, manuscripts are subject to editorial amendment to suit house style.
-Paper publication requires the author's final approval.
- As soon as the publication appears in print and in electronic forms on the Internet there is no possibility to change the content of the article.

Editor’s responsibilities
-The editor decides whether the paper fulfills all requirements i.e. formal and scientific and which articles submitted to the journal should be published.
-In making these decisions, the editor may be guided by the policies of the journal’s editorial board as well as by legal requirements regarding libel, copyright infringement, and plagiarism.
-The editor maintains the integrity of the academic record, precludes business needs from compromising intellectual and ethical standards, and is always willing to publish corrections, clarifications, retractions, and apologies when needed.
-The editor evaluates manuscripts for intellectual content without regard to race, gender, sexual orientation, religious belief, ethnic origin, citizenship, or political philosophy of the author(s).
-The editor does not disclose any information about a manuscript under consideration to anyone other than the author(s), reviewers and potential reviewers, and in some instances the editorial board members, as appropriate.

Reviewers' responsibilities
Any manuscripts received for review are treated as confidential documents. They must not be shown to or discussed with others except if authorized by the editor. Privileged information or ideas obtained through peer review is kept confidential and not used for personal advantage Any invited reviewer who feels unqualified to review the manuscript or knows that its timely review will be impossible should immediately notify the editor so that alternative reviewers can be contacted. Reviewers should identify relevant published work that has not been cited by the authors. Any statement that an observation, derivation, or argument had been previously reported should be accompanied by the relevant citation. A reviewer should also call to the editor's attention any substantial similarity or overlap between the manuscript under consideration and any other published data of which they have personal knowledge. Reviewers should not consider evaluating manuscripts in which they have conflicts of interest resulting from competitive, collaborative, or other relationships or connections with any of the authors, companies, or institutions connected to the submission. Reviews should be conducted objectively. Personal criticism of the author is unacceptable. Referees should express their views clearly with appropriate supporting arguments. All reviews must be carried out on a special form available in the Editorial System.

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