Analiza napetostnega in deformacijskega stanja prednapetega "V" nosilca : diplomska naloga

Stanič, Sandi (author), Bratina, Sebastjan (mentor), Čas, Bojan (co-mentor)

V diplomski nalogi analiziramo in projektiramo prednapeti »V« nosilca dolžine 28,08 m ter višine 1,0 m, ki je del strešne konstrukcije armiranobetonske montažne hale. Nosilec je predhodno prednapet z 22 ravnimi kabli, katerih del je na obeh koncih nosilca nevtraliziran. Projektiranje izvajamo skladno z zahtevami iz standarda SIST EN 1992-1-1:2005. V prvem delu naloge preverimo napetostno deformacijsko stanje nosilca v mejnih stanjih uporabnosti ter nosilnosti. V mejnem stanju uporabnosti računsko preverimo napetosti, širino razpok ter povese nosilca, v mejnih stanjih nosilnosti pa varnost proti upogibni in strižni nosilnosti. V izračunih upoštevamo začetne in časovno odvisne izgube prednapetja, vpliv toplotne obdelave betona na izgube ter mehanske karakteristike dejansko vgrajenih materialov. Analizo napetostnega in deformacijskega stanja prečnega prereza izvajamo s pomočjo aplikacije, ki jo izdelamo v programu Microsoft Excel. V drugem delu diplomske naloge predstavimo rezultate obremenilnega preizkusa, ki ga je izvedlo podjetje Pre System S.p.A iz Italije. V okviru preizkusa so se izvajale meritve ter račun povesov nosilca pri karakteristični kombinaciji vplivov. V tretjem delu diplomske naloge s pomočjo računalniškega programa NFIRA izvedemo nelinearno mehansko analizo prednapetega nosilca pri delovanju kratkotrajne statične obtežbe. Ugotovimo dobro medsebojno ujemanje rezultatov različnih analiz prednapetega »V« nosilca.

• Language: Slovenian
• Keywords: gradbeništvo, diplomska naloga, UNI, predhodno prednapeti "V" nosilec, izgube sile prednapetja, napetosti, deformacije, povesi, nosilnost, Evrokodi
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [S. Stanič]
• Year: 2014
• Number of pages: XXIV, 113 str., 1 pril.
• PID: 20.500.12556/RUL-32522
• UDC: 624.072.2(043.2)
• COBISS.SI-ID: 6912609
• Publication date in RUL: 10.07.2015

Secondary language

• Language: English
• Title: Analysis of the stress and strain state of prestressed "V" beam

Abstract

In the thesis, we design and analyze a prestressed concrete "V" beam which is part of the roof structure of a reinforced prefabricated concrete hall. The beam is 28.08 m in length and 1.0 m in height. The beam is prestressed with 22 flat tendons and a part of them are neutralized on both ends. The calculation is made in accordance with the requirements of Standard SIST EN 1992-1-1:2005. In the first part of the thesis, we checked the stress and strain state of the beam for serviceability and ultimate limit state. In calculating its serviceability limit state we checked the stress, the width of cracks and deflection of the beam. In calculating its ultimate limit state we checked shear and the bending resistance of the beam. In our calculations, we took into account the loss of prestressing force, the effect of heat treatment on loss of prestressing force, and the mechanical characteristics of the actual installed materials. The analysis of stress and strain state of the cross-section was made using Microsoft Excel software. In the second part of the thesis, we present the results of the tests carried out by the Italian company Pre System S.p.A.. The test consisted of computer-calculated as well as measured deflection of a load test according to a characteristic combination of loads. In the third part of the thesis, we calculated the beam by using non-linear calculation methods with NFIRA computer software. We found that the results from all three parts of the thesis correspond well.

• Keywords: prestressed "V" beam, loss of prestressing force, stress, strain, deflection, load-bearing capacity, Eurocodes