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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Vibracije izazvane ljudskim delovanjem kod spregnutih međuspratnih konstrukcija tipa drvo-laki beton / Vibrations of composite wood-lightweight concrete floor structures caused by human action

Kozarić Ljiljana 21 September 2016 (has links)
<p>U ovom radu ispitano je dinamičko ponašanje spregnutih međuspratnih&nbsp; konstrukcija tipa drvo-laki&nbsp; beton&nbsp; usled&nbsp; svakodnevnih&nbsp; ljudskih&nbsp; aktivnosti.&nbsp; Pri&nbsp; sanaciji,&nbsp; nadogradnji&nbsp; i seizmičkom ojačanju objekata na postojeće drvene međuspratne konstrukcije najčešće se izlivaju betonske ploče koje se sprežu sa postojećom konstrukcijom. Beton u gornjoj ploči<br />međuspratne konstrukcije povećava njenu krutost i time smanjuje&nbsp; setljivost na dinamičku pobudu.&nbsp; Potreba&nbsp; da&nbsp; se&nbsp; smanji&nbsp; dodatno&nbsp; opterećenje&nbsp; na&nbsp; postojeće&nbsp; temelje&nbsp; konstrukcije, dovodi do sve češće upotrebe lakog betona pri sanaciji i rekonstrukciji objekata. NJegovom primenom povoljni efekti sprezanja ostaju očuvani, a prednosti u vidu smanjenja dodatne težine dolaze do izražaja.<br />Međutim,&nbsp; u&nbsp; dostupnoj&nbsp; literaturi,&nbsp; podataka&nbsp; o&nbsp; dinamičkom&nbsp; ponašanju&nbsp; spregnutih međuspratnih konstrukcija izvedenih sa lakim betonima&nbsp; malih zapreminskih masa nema, pa je cilj ovog rada bio da se ispitaju osnovne dinamičke&nbsp; karakteristike drvenih međuspratnih konstrukcija saniranih lakim betonom raznih zapreminskih težina. Analizirano je&nbsp; dinamičko<br />ponašanje,&nbsp; odnosno&nbsp; sračunate&nbsp; su&nbsp; prve&nbsp; tri&nbsp; sopstvene&nbsp; frekvencije&nbsp; oscilovanja&nbsp; četiri međuspratne&nbsp; spregnute&nbsp; konstrukcije&nbsp; sa&nbsp; identičnim&nbsp; poprečnim&nbsp; presecima&nbsp; i&nbsp; spojnim sredstvima,&nbsp; ali&nbsp; sa&nbsp; različitom&nbsp; klasom&nbsp; zapreminske&nbsp; mase&nbsp; lakog&nbsp; betona&nbsp; u&nbsp; gornjoj&nbsp; betonskoj ploči.&nbsp; Preliminarnim&nbsp; laboratorijskim&nbsp; ispitivanjem&nbsp; relevantnih&nbsp; svojstava&nbsp; četiri&nbsp; vrste&nbsp; lakog<br />betona,&nbsp; monolitnog&nbsp; drveta&nbsp; i&nbsp; spojnih&nbsp; sredstava,&nbsp; koja&nbsp; su&nbsp; se&nbsp; koristila&nbsp; pri&nbsp; sprezanju&nbsp; drveta&nbsp; i lakog betona, dobijeni su potrebni ulazni podaci za numerička istraživanja. Za&nbsp; potrebe&nbsp; analitičkog&nbsp; istraživanja&nbsp; predložena&nbsp; je&nbsp; jednostavna&nbsp; metoda&nbsp; dinamičkog proračuna&nbsp; sopstvenih&nbsp; frekvencija&nbsp; oscilovanja&nbsp; elastično&nbsp; spregnutih&nbsp; konstrukcija.&nbsp; Tačnost rezultata predloženog dinamičkog proračuna potvđena je&nbsp; eksperimentalno, i poređenjem<br />sa rezultatima programskog paketa Ansys.</p> / <p>This&nbsp; work&nbsp; has&nbsp; examines&nbsp; dynamic&nbsp; behavior&nbsp; of&nbsp; composite&nbsp; wood-lightweight&nbsp; concrete&nbsp; floor structures&nbsp; exposed&nbsp; to&nbsp; normal&nbsp; everyday&nbsp; human&nbsp; activities.&nbsp; In&nbsp; a&nbsp; case&nbsp; of&nbsp; restoration, renovation or seismic reinforcement, the most common approach is to pour concrete slabs onto&nbsp; existing&nbsp; wooden&nbsp; floor&nbsp; structures.&nbsp; Concrete&nbsp; in&nbsp; the&nbsp; upper&nbsp; zone&nbsp; of&nbsp; floor&nbsp; structure&nbsp; is increasing its stiffness and thus reducing the dynamic excitation. In the attempt to reduce the&nbsp; weight&nbsp; on&nbsp; the&nbsp; existing&nbsp; foundations,&nbsp; lightweight&nbsp; concrete&nbsp; is&nbsp; used&nbsp; for&nbsp; restoration&nbsp; and renovation. Coupling effect remains undisturbed but added weight is&nbsp;&nbsp; significantly reduced when lightweight concrete is used.<br />However,&nbsp; the&nbsp; available&nbsp; literature&nbsp; does&nbsp; not&nbsp; provide&nbsp; data&nbsp; about&nbsp; dynamic&nbsp; behavior&nbsp; of&nbsp; the composite wood-lightweight concrete floor structures; therefore the goal of this research work&nbsp; is&nbsp; to&nbsp; examine&nbsp; the&nbsp; characteristics&nbsp; of&nbsp; the&nbsp; restored&nbsp; wooden&nbsp; structures&nbsp; coupled&nbsp; with lightweight concrete of the different specific weights. This research work analyzes dynamic behavior&nbsp; that&nbsp; included&nbsp; first&nbsp; three&nbsp; frequencies&nbsp; of&nbsp; four&nbsp; composite&nbsp; floor&nbsp; structures&nbsp; with identical cross&nbsp; sections and&nbsp; connections,&nbsp; but different specific weights&nbsp; of the lightweight concrete&nbsp; in&nbsp; the&nbsp; upper&nbsp; layer&nbsp; of&nbsp; the&nbsp; concrete&nbsp; slab.&nbsp; Preliminary&nbsp; laboratory&nbsp; testing&nbsp; of&nbsp; four different types of the lightweight concrete, wood and connections, yielded necessary data for the further numeric analysis.<br />Simple&nbsp; calculation&nbsp; method&nbsp; for&nbsp; obtaining&nbsp; mode&nbsp; frequencies&nbsp; of&nbsp; the&nbsp; partial&nbsp; composite structures has been proposed, for the purpose of this analytical research. The accuracy of the&nbsp; proposed&nbsp; dynamic&nbsp; model&nbsp; has&nbsp; been&nbsp; confirmed&nbsp; through&nbsp; experimental&nbsp; research&nbsp; and compared up against the results from the Ansys</p>

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