Buoyancy effects on structures

ǂa ǂcase study on the controlled lowering of a raised underground garage

Bojan Čas (Author), Jurij Šporin (Author)

Abstract

V zadnjih desetletjih se je povečala višina stavb in število kletnih etaž, zlasti na pomembnejših mestnih lokacijah. Z razvojem mest in infrastrukture, ki je nujna za njihovo delovanje, se gradi tudi obsežna podzemna infrastruktura, vključno s komunalnimi vodi, predori podzemnih železnic itd. Akumulacija vode, nihanje ali visoka raven podtalnice na območju podzemnih konstrukcij lahko zaradi različnih razlogov povzroči, da izvedene konstrukcije, ki tvorijo zaprt prostor, premaknejo navzgor. Inženirji pogosto spregledajo problem prevelikega vzgona, ki nastane, če se ne sprejmejo potrebni varnostni ukrepi. Negativni učinki vzgona na konstrukcije se običajno kažejo kot dvigi, posedki ali rotacije. Stanje konstrukcij, ki jih je poškodoval prekomerni vzgon, je treba temeljito raziskati, da se ugotovi, ali je mogoča njihova sanacija ali pa je treba podzemni objekt popolnoma odstraniti zaradi neizvedljivosti ali stroškovne neučinkovitosti njen e morebitne sanacije. V tem prispevku je predstavljena metodologija za analizo stanja konstrukcij, ki jih je prizadel prekomerni vzgon, z namenom poiskati ustrezno tehnološko rešitev za njihovo sanacijo. Prikazana je tudi študija primera. Ta prikazuje, kako sta neustrezno načrtovanje in napačna izvedba enega samega detajla trinadstropne podzemne garaže povzročila njeno nenadno dvigovanje zaradi vzgona. S temeljitim pregledom lokacije, stanja dvignjene konstrukcije, projektne dokumentacije in osnovni preveritvami stabilnosti proti vzgonu smo razvili sanacijski postopek za uspešno in nadzorovano spuščanje podzemne garaže.

Keywords

civil engineering;underground garage;reinforced concrete;buoyancy;antifloating stability;uplift;cracks;groundwater inflow;controlled lowering;

Data

Language:	English
Year of publishing:	2025
Typology:	1.01 - Original Scientific Article
Organization:	UL NTF - Faculty of Natural Sciences and Engineering
UDC:	69
COBISS:	221926659
ISSN:	2352-0124
Views:	44
Downloads:	37
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary abstract:	In recent decades, the height of buildings and the number of basement floors has increased, especially in valuable urban locations. With the development of cities and the infrastructure essential for their operation, extensive underground construction is being carried out, including utility lines, subway tunnels etc. Water accumulation, fluctuating or high groundwater levels in the area of underground structures, due to various reasons, might cause structures, forming a closed volume, to move upwards. The excessive buoyancy problem, which arises, when necessary, precautions are not taken, is often overlooked by engineers. The negative effects of buoyancy on structures typically manifest as uplifts, settlements, or rotations. The state of structures damaged by excessive buoyancy must be thoroughly investigated to determine whether rehabilitation is possible or if the underground structure needs to be completely removed due to the infeasibility or cost inefficiency of its possible rehabilitation. This paper presents a methodology for addressing the state of structures affected by excessive buoyancy to find a suitable technological rehabilitation solution, supported by a case study. It demonstrates how inadequate design and execution of a single detail of a three-story underground garage resulted in its sudden elevation due to buoyancy. Through a thorough examination of the site, the state of the raised structure, the original project documentation, and basic safety check of anti-floating stability, rehabilitation procedure for the successful and controlled lowering of the underground garage was developed.
Secondary keywords:	gradbeništvo;podzemna garaža;armirani beton;vzgon;stabilnost proti vzgonu;dvig;razpoke;vtekanje podzemnih voda;kontrolirano spuščanje;
Type (COBISS):	Article
Pages:	str. 1-13
Issue:	ǂVol. ǂ71, [article no.] 108121
Chronology:	Jan. 2025
DOI:	10.1016/j.istruc.2024.108121
ID:	25691170